package envoy.config.cluster.v3
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message
circuit_breaker.proto:24:ref:`Circuit breaking<arch_overview_circuit_break>` settings can be specified individually for each defined priority.
Used in: ,
repeated thresholds = 1
If multiple :ref:`Thresholds<envoy_v3_api_msg_config.cluster.v3.CircuitBreakers.Thresholds>` are defined with the same :ref:`RoutingPriority<envoy_v3_api_enum_config.core.v3.RoutingPriority>`, the first one in the list is used. If no Thresholds is defined for a given :ref:`RoutingPriority<envoy_v3_api_enum_config.core.v3.RoutingPriority>`, the default values are used.
repeated per_host_thresholds = 2
Optional per-host limits which apply to each individual host in a cluster. .. note:: currently only the :ref:`max_connections <envoy_v3_api_field_config.cluster.v3.CircuitBreakers.Thresholds.max_connections>` field is supported for per-host limits. If multiple per-host :ref:`Thresholds<envoy_v3_api_msg_config.cluster.v3.CircuitBreakers.Thresholds>` are defined with the same :ref:`RoutingPriority<envoy_v3_api_enum_config.core.v3.RoutingPriority>`, the first one in the list is used. If no per-host Thresholds are defined for a given :ref:`RoutingPriority<envoy_v3_api_enum_config.core.v3.RoutingPriority>`, the cluster will not have per-host limits.
message
circuit_breaker.proto:31A Thresholds defines CircuitBreaker settings for a :ref:`RoutingPriority<envoy_v3_api_enum_config.core.v3.RoutingPriority>`. [#next-free-field: 9]
Used in:
core.v3.RoutingPriority priority = 1
The :ref:`RoutingPriority<envoy_v3_api_enum_config.core.v3.RoutingPriority>` the specified CircuitBreaker settings apply to.
optional max_connections = 2
The maximum number of connections that Envoy will make to the upstream cluster. If not specified, the default is 1024.
optional max_pending_requests = 3
The maximum number of pending requests that Envoy will allow to the upstream cluster. If not specified, the default is 1024. This limit is applied as a connection limit for non-HTTP traffic.
optional max_requests = 4
The maximum number of parallel requests that Envoy will make to the upstream cluster. If not specified, the default is 1024. This limit does not apply to non-HTTP traffic.
optional max_retries = 5
The maximum number of parallel retries that Envoy will allow to the upstream cluster. If not specified, the default is 3.
optional retry_budget = 8
Specifies a limit on concurrent retries in relation to the number of active requests. This parameter is optional. .. note:: If this field is set, the retry budget will override any configured retry circuit breaker.
bool track_remaining = 6
If track_remaining is true, then stats will be published that expose the number of resources remaining until the circuit breakers open. If not specified, the default is false. .. note:: If a retry budget is used in lieu of the max_retries circuit breaker, the remaining retry resources remaining will not be tracked.
optional max_connection_pools = 7
The maximum number of connection pools per cluster that Envoy will concurrently support at once. If not specified, the default is unlimited. Set this for clusters which create a large number of connection pools. See :ref:`Circuit Breaking <arch_overview_circuit_break_cluster_maximum_connection_pools>` for more details.
message
circuit_breaker.proto:35Used in:
optional budget_percent = 1
Specifies the limit on concurrent retries as a percentage of the sum of active requests and active pending requests. For example, if there are 100 active requests and the budget_percent is set to 25, there may be 25 active retries. This parameter is optional. Defaults to 20%.
optional min_retry_concurrency = 2
Specifies the minimum retry concurrency allowed for the retry budget. The limit on the number of active retries may never go below this number. This parameter is optional. Defaults to 3.
message
cluster.proto:49Configuration for a single upstream cluster. [#next-free-field: 59]
Used in:
repeated transport_socket_matches = 43
Configuration to use different transport sockets for different endpoints. The entry of ``envoy.transport_socket_match`` in the :ref:`LbEndpoint.Metadata <envoy_v3_api_field_config.endpoint.v3.LbEndpoint.metadata>` is used to match against the transport sockets as they appear in the list. If a match is not found, the search continues in :ref:`LocalityLbEndpoints.Metadata <envoy_v3_api_field_config.endpoint.v3.LocalityLbEndpoints.metadata>`. The first :ref:`match <envoy_v3_api_msg_config.cluster.v3.Cluster.TransportSocketMatch>` is used. For example, with the following match .. code-block:: yaml transport_socket_matches: - name: "enableMTLS" match: acceptMTLS: true transport_socket: name: envoy.transport_sockets.tls config: { ... } # tls socket configuration - name: "defaultToPlaintext" match: {} transport_socket: name: envoy.transport_sockets.raw_buffer Connections to the endpoints whose metadata value under ``envoy.transport_socket_match`` having "acceptMTLS"/"true" key/value pair use the "enableMTLS" socket configuration. If a :ref:`socket match <envoy_v3_api_msg_config.cluster.v3.Cluster.TransportSocketMatch>` with empty match criteria is provided, that always match any endpoint. For example, the "defaultToPlaintext" socket match in case above. If an endpoint metadata's value under ``envoy.transport_socket_match`` does not match any ``TransportSocketMatch``, the locality metadata is then checked for a match. Barring any matches in the endpoint or locality metadata, the socket configuration fallbacks to use the ``tls_context`` or ``transport_socket`` specified in this cluster. This field allows gradual and flexible transport socket configuration changes. The metadata of endpoints in EDS can indicate transport socket capabilities. For example, an endpoint's metadata can have two key value pairs as "acceptMTLS": "true", "acceptPlaintext": "true". While some other endpoints, only accepting plaintext traffic has "acceptPlaintext": "true" metadata information. Then the xDS server can configure the CDS to a client, Envoy A, to send mutual TLS traffic for endpoints with "acceptMTLS": "true", by adding a corresponding ``TransportSocketMatch`` in this field. Other client Envoys receive CDS without ``transport_socket_match`` set, and still send plain text traffic to the same cluster. This field can be used to specify custom transport socket configurations for health checks by adding matching key/value pairs in a health check's :ref:`transport socket match criteria <envoy_v3_api_field_config.core.v3.HealthCheck.transport_socket_match_criteria>` field. [#comment:TODO(incfly): add a detailed architecture doc on intended usage.]
string name = 1
Supplies the name of the cluster which must be unique across all clusters. The cluster name is used when emitting :ref:`statistics <config_cluster_manager_cluster_stats>` if :ref:`alt_stat_name <envoy_v3_api_field_config.cluster.v3.Cluster.alt_stat_name>` is not provided. Any ``:`` in the cluster name will be converted to ``_`` when emitting statistics.
string alt_stat_name = 28
An optional alternative to the cluster name to be used for observability. This name is used emitting stats for the cluster and access logging the cluster name. This will appear as additional information in configuration dumps of a cluster's current status as :ref:`observability_name <envoy_v3_api_field_admin.v3.ClusterStatus.observability_name>` and as an additional tag "upstream_cluster.name" while tracing. Note: Any ``:`` in the name will be converted to ``_`` when emitting statistics. This should not be confused with :ref:`Router Filter Header <config_http_filters_router_x-envoy-upstream-alt-stat-name>`.
oneof cluster_discovery_type
Cluster.DiscoveryType type = 2
The :ref:`service discovery type <arch_overview_service_discovery_types>` to use for resolving the cluster.
cluster_type = 38
The custom cluster type.
optional eds_cluster_config = 3
Configuration to use for EDS updates for the Cluster.
optional connect_timeout = 4
The timeout for new network connections to hosts in the cluster. If not set, a default value of 5s will be used.
optional per_connection_buffer_limit_bytes = 5
Soft limit on size of the cluster’s connections read and write buffers. If unspecified, an implementation defined default is applied (1MiB).
Cluster.LbPolicy lb_policy = 6
The :ref:`load balancer type <arch_overview_load_balancing_types>` to use when picking a host in the cluster.
optional load_assignment = 33
Setting this is required for specifying members of :ref:`STATIC<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STATIC>`, :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>` or :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>` clusters. This field supersedes the ``hosts`` field in the v2 API. .. attention:: Setting this allows non-EDS cluster types to contain embedded EDS equivalent :ref:`endpoint assignments<envoy_v3_api_msg_config.endpoint.v3.ClusterLoadAssignment>`.
repeated health_checks = 8
Optional :ref:`active health checking <arch_overview_health_checking>` configuration for the cluster. If no configuration is specified no health checking will be done and all cluster members will be considered healthy at all times.
optional max_requests_per_connection = 9
Optional maximum requests for a single upstream connection. This parameter is respected by both the HTTP/1.1 and HTTP/2 connection pool implementations. If not specified, there is no limit. Setting this parameter to 1 will effectively disable keep alive. .. attention:: This field has been deprecated in favor of the :ref:`max_requests_per_connection <envoy_v3_api_field_config.core.v3.HttpProtocolOptions.max_requests_per_connection>` field.
optional circuit_breakers = 10
Optional :ref:`circuit breaking <arch_overview_circuit_break>` for the cluster.
optional upstream_http_protocol_options = 46
HTTP protocol options that are applied only to upstream HTTP connections. These options apply to all HTTP versions. This has been deprecated in favor of :ref:`upstream_http_protocol_options <envoy_v3_api_field_extensions.upstreams.http.v3.HttpProtocolOptions.upstream_http_protocol_options>` in the :ref:`http_protocol_options <envoy_v3_api_msg_extensions.upstreams.http.v3.HttpProtocolOptions>` message. upstream_http_protocol_options can be set via the cluster's :ref:`extension_protocol_options<envoy_v3_api_field_config.cluster.v3.Cluster.typed_extension_protocol_options>`. See :ref:`upstream_http_protocol_options <envoy_v3_api_field_extensions.upstreams.http.v3.HttpProtocolOptions.upstream_http_protocol_options>` for example usage.
optional common_http_protocol_options = 29
Additional options when handling HTTP requests upstream. These options will be applicable to both HTTP1 and HTTP2 requests. This has been deprecated in favor of :ref:`common_http_protocol_options <envoy_v3_api_field_extensions.upstreams.http.v3.HttpProtocolOptions.common_http_protocol_options>` in the :ref:`http_protocol_options <envoy_v3_api_msg_extensions.upstreams.http.v3.HttpProtocolOptions>` message. common_http_protocol_options can be set via the cluster's :ref:`extension_protocol_options<envoy_v3_api_field_config.cluster.v3.Cluster.typed_extension_protocol_options>`. See :ref:`upstream_http_protocol_options <envoy_v3_api_field_extensions.upstreams.http.v3.HttpProtocolOptions.upstream_http_protocol_options>` for example usage.
optional http_protocol_options = 13
Additional options when handling HTTP1 requests. This has been deprecated in favor of http_protocol_options fields in the :ref:`http_protocol_options <envoy_v3_api_msg_extensions.upstreams.http.v3.HttpProtocolOptions>` message. http_protocol_options can be set via the cluster's :ref:`extension_protocol_options<envoy_v3_api_field_config.cluster.v3.Cluster.typed_extension_protocol_options>`. See :ref:`upstream_http_protocol_options <envoy_v3_api_field_extensions.upstreams.http.v3.HttpProtocolOptions.upstream_http_protocol_options>` for example usage.
optional http2_protocol_options = 14
Even if default HTTP2 protocol options are desired, this field must be set so that Envoy will assume that the upstream supports HTTP/2 when making new HTTP connection pool connections. Currently, Envoy only supports prior knowledge for upstream connections. Even if TLS is used with ALPN, ``http2_protocol_options`` must be specified. As an aside this allows HTTP/2 connections to happen over plain text. This has been deprecated in favor of http2_protocol_options fields in the :ref:`http_protocol_options <envoy_v3_api_msg_extensions.upstreams.http.v3.HttpProtocolOptions>` message. http2_protocol_options can be set via the cluster's :ref:`extension_protocol_options<envoy_v3_api_field_config.cluster.v3.Cluster.typed_extension_protocol_options>`. See :ref:`upstream_http_protocol_options <envoy_v3_api_field_extensions.upstreams.http.v3.HttpProtocolOptions.upstream_http_protocol_options>` for example usage.
map<string, > typed_extension_protocol_options = 36
The extension_protocol_options field is used to provide extension-specific protocol options for upstream connections. The key should match the extension filter name, such as "envoy.filters.network.thrift_proxy". See the extension's documentation for details on specific options. [#next-major-version: make this a list of typed extensions.] [#extension-category: envoy.upstream_options]
optional dns_refresh_rate = 16
If the DNS refresh rate is specified and the cluster type is either :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>`, or :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>`, this value is used as the cluster’s DNS refresh rate. The value configured must be at least 1ms. If this setting is not specified, the value defaults to 5000ms. For cluster types other than :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>` and :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>` this setting is ignored. This field is deprecated in favor of using the :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` extension point and configuring it with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`. If :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` is configured with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`, this field will be ignored.
optional dns_jitter = 58
DNS jitter can be optionally specified if the cluster type is either :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>`, or :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>`. DNS jitter causes the cluster to refresh DNS entries later by a random amount of time to avoid a stampede of DNS requests. This value sets the upper bound (exclusive) for the random amount. There will be no jitter if this value is omitted. For cluster types other than :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>` and :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>` this setting is ignored. This field is deprecated in favor of using the :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` extension point and configuring it with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`. If :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` is configured with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`, this field will be ignored.
optional dns_failure_refresh_rate = 44
If the DNS failure refresh rate is specified and the cluster type is either :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>`, or :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>`, this is used as the cluster’s DNS refresh rate when requests are failing. If this setting is not specified, the failure refresh rate defaults to the DNS refresh rate. For cluster types other than :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>` and :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>` this setting is ignored. This field is deprecated in favor of using the :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` extension point and configuring it with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`. If :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` is configured with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`, this field will be ignored.
bool respect_dns_ttl = 39
Optional configuration for setting cluster's DNS refresh rate. If the value is set to true, cluster's DNS refresh rate will be set to resource record's TTL which comes from DNS resolution. This field is deprecated in favor of using the :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` extension point and configuring it with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`. If :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` is configured with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`, this field will be ignored.
Cluster.DnsLookupFamily dns_lookup_family = 17
The DNS IP address resolution policy. If this setting is not specified, the value defaults to :ref:`AUTO<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DnsLookupFamily.AUTO>`. For logical and strict dns cluster, this field is deprecated in favor of using the :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` extension point and configuring it with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`. If :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` is configured with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`, this field will be ignored.
repeated dns_resolvers = 18
If DNS resolvers are specified and the cluster type is either :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>`, or :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>`, this value is used to specify the cluster’s dns resolvers. If this setting is not specified, the value defaults to the default resolver, which uses /etc/resolv.conf for configuration. For cluster types other than :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>` and :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>` this setting is ignored. This field is deprecated in favor of ``dns_resolution_config`` which aggregates all of the DNS resolver configuration in a single message.
bool use_tcp_for_dns_lookups = 45
Always use TCP queries instead of UDP queries for DNS lookups. This field is deprecated in favor of ``dns_resolution_config`` which aggregates all of the DNS resolver configuration in a single message.
optional dns_resolution_config = 53
DNS resolution configuration which includes the underlying dns resolver addresses and options. This field is deprecated in favor of :ref:`typed_dns_resolver_config <envoy_v3_api_field_config.cluster.v3.Cluster.typed_dns_resolver_config>`.
optional typed_dns_resolver_config = 55
DNS resolver type configuration extension. This extension can be used to configure c-ares, apple, or any other DNS resolver types and the related parameters. For example, an object of :ref:`CaresDnsResolverConfig <envoy_v3_api_msg_extensions.network.dns_resolver.cares.v3.CaresDnsResolverConfig>` can be packed into this ``typed_dns_resolver_config``. This configuration replaces the :ref:`dns_resolution_config <envoy_v3_api_field_config.cluster.v3.Cluster.dns_resolution_config>` configuration. During the transition period when both ``dns_resolution_config`` and ``typed_dns_resolver_config`` exists, when ``typed_dns_resolver_config`` is in place, Envoy will use it and ignore ``dns_resolution_config``. When ``typed_dns_resolver_config`` is missing, the default behavior is in place. Also note that this field is deprecated for logical dns and strict dns clusters and will be ignored when :ref:`cluster_type<envoy_v3_api_field_config.cluster.v3.Cluster.cluster_type>` is configured with :ref:`DnsCluster<envoy_v3_api_msg_extensions.clusters.dns.v3.DnsCluster>`. [#extension-category: envoy.network.dns_resolver]
optional wait_for_warm_on_init = 54
Optional configuration for having cluster readiness block on warm-up. Currently, only applicable for :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>`, or :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>`, or :ref:`Redis Cluster<arch_overview_redis>`. If true, cluster readiness blocks on warm-up. If false, the cluster will complete initialization whether or not warm-up has completed. Defaults to true.
optional outlier_detection = 19
If specified, outlier detection will be enabled for this upstream cluster. Each of the configuration values can be overridden via :ref:`runtime values <config_cluster_manager_cluster_runtime_outlier_detection>`.
optional cleanup_interval = 20
The interval for removing stale hosts from a cluster type :ref:`ORIGINAL_DST<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.ORIGINAL_DST>`. Hosts are considered stale if they have not been used as upstream destinations during this interval. New hosts are added to original destination clusters on demand as new connections are redirected to Envoy, causing the number of hosts in the cluster to grow over time. Hosts that are not stale (they are actively used as destinations) are kept in the cluster, which allows connections to them remain open, saving the latency that would otherwise be spent on opening new connections. If this setting is not specified, the value defaults to 5000ms. For cluster types other than :ref:`ORIGINAL_DST<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.ORIGINAL_DST>` this setting is ignored.
optional upstream_bind_config = 21
Optional configuration used to bind newly established upstream connections. This overrides any bind_config specified in the bootstrap proto. If the address and port are empty, no bind will be performed.
optional lb_subset_config = 22
Configuration for load balancing subsetting.
oneof lb_config
Optional configuration for the load balancing algorithm selected by LbPolicy. Currently only :ref:`RING_HASH<envoy_v3_api_enum_value_config.cluster.v3.Cluster.LbPolicy.RING_HASH>`, :ref:`MAGLEV<envoy_v3_api_enum_value_config.cluster.v3.Cluster.LbPolicy.MAGLEV>` and :ref:`LEAST_REQUEST<envoy_v3_api_enum_value_config.cluster.v3.Cluster.LbPolicy.LEAST_REQUEST>` has additional configuration options. Specifying ring_hash_lb_config or maglev_lb_config or least_request_lb_config without setting the corresponding LbPolicy will generate an error at runtime.
ring_hash_lb_config = 23
Optional configuration for the Ring Hash load balancing policy.
maglev_lb_config = 52
Optional configuration for the Maglev load balancing policy.
original_dst_lb_config = 34
Optional configuration for the Original Destination load balancing policy.
least_request_lb_config = 37
Optional configuration for the LeastRequest load balancing policy.
round_robin_lb_config = 56
Optional configuration for the RoundRobin load balancing policy.
optional common_lb_config = 27
Common configuration for all load balancer implementations.
optional transport_socket = 24
Optional custom transport socket implementation to use for upstream connections. To setup TLS, set a transport socket with name ``envoy.transport_sockets.tls`` and :ref:`UpstreamTlsContexts <envoy_v3_api_msg_extensions.transport_sockets.tls.v3.UpstreamTlsContext>` in the ``typed_config``. If no transport socket configuration is specified, new connections will be set up with plaintext.
optional metadata = 25
The Metadata field can be used to provide additional information about the cluster. It can be used for stats, logging, and varying filter behavior. Fields should use reverse DNS notation to denote which entity within Envoy will need the information. For instance, if the metadata is intended for the Router filter, the filter name should be specified as ``envoy.filters.http.router``.
Cluster.ClusterProtocolSelection protocol_selection = 26
Determines how Envoy selects the protocol used to speak to upstream hosts. This has been deprecated in favor of setting explicit protocol selection in the :ref:`http_protocol_options <envoy_v3_api_msg_extensions.upstreams.http.v3.HttpProtocolOptions>` message. http_protocol_options can be set via the cluster's :ref:`extension_protocol_options<envoy_v3_api_field_config.cluster.v3.Cluster.typed_extension_protocol_options>`.
optional upstream_connection_options = 30
Optional options for upstream connections.
bool close_connections_on_host_health_failure = 31
If an upstream host becomes unhealthy (as determined by the configured health checks or outlier detection), immediately close all connections to the failed host. .. note:: This is currently only supported for connections created by tcp_proxy. .. note:: The current implementation of this feature closes all connections immediately when the unhealthy status is detected. If there are a large number of connections open to an upstream host that becomes unhealthy, Envoy may spend a substantial amount of time exclusively closing these connections, and not processing any other traffic.
bool ignore_health_on_host_removal = 32
If set to true, Envoy will ignore the health value of a host when processing its removal from service discovery. This means that if active health checking is used, Envoy will *not* wait for the endpoint to go unhealthy before removing it.
repeated filters = 40
An (optional) network filter chain, listed in the order the filters should be applied. The chain will be applied to all outgoing connections that Envoy makes to the upstream servers of this cluster.
optional load_balancing_policy = 41
If this field is set and is supported by the client, it will supersede the value of :ref:`lb_policy<envoy_v3_api_field_config.cluster.v3.Cluster.lb_policy>`.
optional lrs_server = 42
[#not-implemented-hide:] If present, tells the client where to send load reports via LRS. If not present, the client will fall back to a client-side default, which may be either (a) don't send any load reports or (b) send load reports for all clusters to a single default server (which may be configured in the bootstrap file). Note that if multiple clusters point to the same LRS server, the client may choose to create a separate stream for each cluster or it may choose to coalesce the data for multiple clusters onto a single stream. Either way, the client must make sure to send the data for any given cluster on no more than one stream. [#next-major-version: In the v3 API, we should consider restructuring this somehow, maybe by allowing LRS to go on the ADS stream, or maybe by moving some of the negotiation from the LRS stream here.]
repeated string lrs_report_endpoint_metrics = 57
A list of metric names from :ref:`ORCA load reports <envoy_v3_api_msg_.xds.data.orca.v3.OrcaLoadReport>` to propagate to LRS. If not specified, then ORCA load reports will not be propagated to LRS. For map fields in the ORCA proto, the string will be of the form ``<map_field_name>.<map_key>``. For example, the string ``named_metrics.foo`` will mean to look for the key ``foo`` in the ORCA :ref:`named_metrics <envoy_v3_api_field_.xds.data.orca.v3.OrcaLoadReport.named_metrics>` field. The special map key ``*`` means to report all entries in the map (e.g., ``named_metrics.*`` means to report all entries in the ORCA named_metrics field). Note that this should be used only with trusted backends. The metric names in LRS will follow the same semantics as this field. In other words, if this field contains ``named_metrics.foo``, then the LRS load report will include the data with that same string as the key.
bool track_timeout_budgets = 47
If track_timeout_budgets is true, the :ref:`timeout budget histograms <config_cluster_manager_cluster_stats_timeout_budgets>` will be published for each request. These show what percentage of a request's per try and global timeout was used. A value of 0 would indicate that none of the timeout was used or that the timeout was infinite. A value of 100 would indicate that the request took the entirety of the timeout given to it. .. attention:: This field has been deprecated in favor of ``timeout_budgets``, part of :ref:`track_cluster_stats <envoy_v3_api_field_config.cluster.v3.Cluster.track_cluster_stats>`.
optional upstream_config = 48
Optional customization and configuration of upstream connection pool, and upstream type. Currently this field only applies for HTTP traffic but is designed for eventual use for custom TCP upstreams. For HTTP traffic, Envoy will generally take downstream HTTP and send it upstream as upstream HTTP, using the http connection pool and the codec from ``http2_protocol_options`` For routes where CONNECT termination is configured, Envoy will take downstream CONNECT requests and forward the CONNECT payload upstream over raw TCP using the tcp connection pool. The default pool used is the generic connection pool which creates the HTTP upstream for most HTTP requests, and the TCP upstream if CONNECT termination is configured. If users desire custom connection pool or upstream behavior, for example terminating CONNECT only if a custom filter indicates it is appropriate, the custom factories can be registered and configured here. [#extension-category: envoy.upstreams]
optional track_cluster_stats = 49
Configuration to track optional cluster stats.
optional preconnect_policy = 50
Preconnect configuration for this cluster.
bool connection_pool_per_downstream_connection = 51
If ``connection_pool_per_downstream_connection`` is true, the cluster will use a separate connection pool for every downstream connection
Used in:
USE_CONFIGURED_PROTOCOL = 0
Cluster can only operate on one of the possible upstream protocols (HTTP1.1, HTTP2). If :ref:`http2_protocol_options <envoy_v3_api_field_config.cluster.v3.Cluster.http2_protocol_options>` are present, HTTP2 will be used, otherwise HTTP1.1 will be used.
USE_DOWNSTREAM_PROTOCOL = 1
Use HTTP1.1 or HTTP2, depending on which one is used on the downstream connection.
message
cluster.proto:563Common configuration for all load balancer implementations. [#next-free-field: 9]
Used in:
optional healthy_panic_threshold = 1
Configures the :ref:`healthy panic threshold <arch_overview_load_balancing_panic_threshold>`. If not specified, the default is 50%. To disable panic mode, set to 0%. .. note:: The specified percent will be truncated to the nearest 1%.
oneof locality_config_specifier
zone_aware_lb_config = 2
locality_weighted_lb_config = 3
optional update_merge_window = 4
If set, all health check/weight/metadata updates that happen within this duration will be merged and delivered in one shot when the duration expires. The start of the duration is when the first update happens. This is useful for big clusters, with potentially noisy deploys that might trigger excessive CPU usage due to a constant stream of healthcheck state changes or metadata updates. The first set of updates to be seen apply immediately (e.g.: a new cluster). Please always keep in mind that the use of sandbox technologies may change this behavior. If this is not set, we default to a merge window of 1000ms. To disable it, set the merge window to 0. Note: merging does not apply to cluster membership changes (e.g.: adds/removes); this is because merging those updates isn't currently safe. See https://github.com/envoyproxy/envoy/pull/3941.
bool ignore_new_hosts_until_first_hc = 5
If set to true, Envoy will :ref:`exclude <arch_overview_load_balancing_excluded>` new hosts when computing load balancing weights until they have been health checked for the first time. This will have no effect unless active health checking is also configured.
bool close_connections_on_host_set_change = 6
If set to ``true``, the cluster manager will drain all existing connections to upstream hosts whenever hosts are added or removed from the cluster.
optional consistent_hashing_lb_config = 7
Common Configuration for all consistent hashing load balancers (MaglevLb, RingHashLb, etc.)
optional override_host_status = 8
This controls what hosts are considered valid when using :ref:`host overrides <arch_overview_load_balancing_override_host>`, which is used by some filters to modify the load balancing decision. If this is unset then [UNKNOWN, HEALTHY, DEGRADED] will be applied by default. If this is set with an empty set of statuses then host overrides will be ignored by the load balancing.
message
cluster.proto:601Common Configuration for all consistent hashing load balancers (MaglevLb, RingHashLb, etc.)
Used in:
bool use_hostname_for_hashing = 1
If set to ``true``, the cluster will use hostname instead of the resolved address as the key to consistently hash to an upstream host. Only valid for StrictDNS clusters with hostnames which resolve to a single IP address.
optional hash_balance_factor = 2
Configures percentage of average cluster load to bound per upstream host. For example, with a value of 150 no upstream host will get a load more than 1.5 times the average load of all the hosts in the cluster. If not specified, the load is not bounded for any upstream host. Typical value for this parameter is between 120 and 200. Minimum is 100. Applies to both Ring Hash and Maglev load balancers. This is implemented based on the method described in the paper https://arxiv.org/abs/1608.01350. For the specified ``hash_balance_factor``, requests to any upstream host are capped at ``hash_balance_factor/100`` times the average number of requests across the cluster. When a request arrives for an upstream host that is currently serving at its max capacity, linear probing is used to identify an eligible host. Further, the linear probe is implemented using a random jump in hosts ring/table to identify the eligible host (this technique is as described in the paper https://arxiv.org/abs/1908.08762 - the random jump avoids the cascading overflow effect when choosing the next host in the ring/table). If weights are specified on the hosts, they are respected. This is an O(N) algorithm, unlike other load balancers. Using a lower ``hash_balance_factor`` results in more hosts being probed, so use a higher value if you require better performance.
message
cluster.proto:595Configuration for :ref:`locality weighted load balancing <arch_overview_load_balancing_locality_weighted_lb>`
Used in:
(message has no fields)
message
cluster.proto:569Configuration for :ref:`zone aware routing <arch_overview_load_balancing_zone_aware_routing>`.
Used in:
optional routing_enabled = 1
Configures percentage of requests that will be considered for zone aware routing if zone aware routing is configured. If not specified, the default is 100%. * :ref:`runtime values <config_cluster_manager_cluster_runtime_zone_routing>`. * :ref:`Zone aware routing support <arch_overview_load_balancing_zone_aware_routing>`.
optional min_cluster_size = 2
Configures minimum upstream cluster size required for zone aware routing If upstream cluster size is less than specified, zone aware routing is not performed even if zone aware routing is configured. If not specified, the default is 6. * :ref:`runtime values <config_cluster_manager_cluster_runtime_zone_routing>`. * :ref:`Zone aware routing support <arch_overview_load_balancing_zone_aware_routing>`.
bool fail_traffic_on_panic = 3
If set to true, Envoy will not consider any hosts when the cluster is in :ref:`panic mode<arch_overview_load_balancing_panic_threshold>`. Instead, the cluster will fail all requests as if all hosts are unhealthy. This can help avoid potentially overwhelming a failing service.
message
cluster.proto:184Extended cluster type.
Used in:
string name = 1
The type of the cluster to instantiate. The name must match a supported cluster type.
optional typed_config = 2
Cluster specific configuration which depends on the cluster being instantiated. See the supported cluster for further documentation. [#extension-category: envoy.clusters]
Refer to :ref:`service discovery type <arch_overview_service_discovery_types>` for an explanation on each type.
Used in:
STATIC = 0
Refer to the :ref:`static discovery type<arch_overview_service_discovery_types_static>` for an explanation.
STRICT_DNS = 1
Refer to the :ref:`strict DNS discovery type<arch_overview_service_discovery_types_strict_dns>` for an explanation.
LOGICAL_DNS = 2
Refer to the :ref:`logical DNS discovery type<arch_overview_service_discovery_types_logical_dns>` for an explanation.
EDS = 3
Refer to the :ref:`service discovery type<arch_overview_service_discovery_types_eds>` for an explanation.
ORIGINAL_DST = 4
Refer to the :ref:`original destination discovery type<arch_overview_service_discovery_types_original_destination>` for an explanation.
When V4_ONLY is selected, the DNS resolver will only perform a lookup for addresses in the IPv4 family. If V6_ONLY is selected, the DNS resolver will only perform a lookup for addresses in the IPv6 family. If AUTO is specified, the DNS resolver will first perform a lookup for addresses in the IPv6 family and fallback to a lookup for addresses in the IPv4 family. This is semantically equivalent to a non-existent V6_PREFERRED option. AUTO is a legacy name that is more opaque than necessary and will be deprecated in favor of V6_PREFERRED in a future major version of the API. If V4_PREFERRED is specified, the DNS resolver will first perform a lookup for addresses in the IPv4 family and fallback to a lookup for addresses in the IPv6 family. i.e., the callback target will only get v6 addresses if there were NO v4 addresses to return. If ALL is specified, the DNS resolver will perform a lookup for both IPv4 and IPv6 families, and return all resolved addresses. When this is used, Happy Eyeballs will be enabled for upstream connections. Refer to :ref:`Happy Eyeballs Support <arch_overview_happy_eyeballs>` for more information. For cluster types other than :ref:`STRICT_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.STRICT_DNS>` and :ref:`LOGICAL_DNS<envoy_v3_api_enum_value_config.cluster.v3.Cluster.DiscoveryType.LOGICAL_DNS>`, this setting is ignored. [#next-major-version: deprecate AUTO in favor of a V6_PREFERRED option.]
Used in: ,
AUTO = 0
V4_ONLY = 1
V6_ONLY = 2
V4_PREFERRED = 3
ALL = 4
message
cluster.proto:198Only valid when discovery type is EDS.
Used in:
optional eds_config = 1
Configuration for the source of EDS updates for this Cluster.
string service_name = 2
Optional alternative to cluster name to present to EDS. This does not have the same restrictions as cluster name, i.e. it may be arbitrary length. This may be a xdstp:// URL.
Refer to :ref:`load balancer type <arch_overview_load_balancing_types>` architecture overview section for information on each type.
Used in: ,
ROUND_ROBIN = 0
Refer to the :ref:`round robin load balancing policy<arch_overview_load_balancing_types_round_robin>` for an explanation.
LEAST_REQUEST = 1
Refer to the :ref:`least request load balancing policy<arch_overview_load_balancing_types_least_request>` for an explanation.
RING_HASH = 2
Refer to the :ref:`ring hash load balancing policy<arch_overview_load_balancing_types_ring_hash>` for an explanation.
RANDOM = 3
Refer to the :ref:`random load balancing policy<arch_overview_load_balancing_types_random>` for an explanation.
MAGLEV = 5
Refer to the :ref:`Maglev load balancing policy<arch_overview_load_balancing_types_maglev>` for an explanation.
CLUSTER_PROVIDED = 6
This load balancer type must be specified if the configured cluster provides a cluster specific load balancer. Consult the configured cluster's documentation for whether to set this option or not.
LOAD_BALANCING_POLICY_CONFIG = 7
Use the new :ref:`load_balancing_policy <envoy_v3_api_field_config.cluster.v3.Cluster.load_balancing_policy>` field to determine the LB policy. This has been deprecated in favor of using the :ref:`load_balancing_policy <envoy_v3_api_field_config.cluster.v3.Cluster.load_balancing_policy>` field without setting any value in :ref:`lb_policy<envoy_v3_api_field_config.cluster.v3.Cluster.lb_policy>`.
message
cluster.proto:214Optionally divide the endpoints in this cluster into subsets defined by endpoint metadata and selected by route and weighted cluster metadata. [#next-free-field: 9]
Used in:
LbSubsetConfig.LbSubsetFallbackPolicy fallback_policy = 1
The behavior used when no endpoint subset matches the selected route's metadata. The value defaults to :ref:`NO_FALLBACK<envoy_v3_api_enum_value_config.cluster.v3.Cluster.LbSubsetConfig.LbSubsetFallbackPolicy.NO_FALLBACK>`.
optional default_subset = 2
Specifies the default subset of endpoints used during fallback if fallback_policy is :ref:`DEFAULT_SUBSET<envoy_v3_api_enum_value_config.cluster.v3.Cluster.LbSubsetConfig.LbSubsetFallbackPolicy.DEFAULT_SUBSET>`. Each field in default_subset is compared to the matching LbEndpoint.Metadata under the ``envoy.lb`` namespace. It is valid for no hosts to match, in which case the behavior is the same as a fallback_policy of :ref:`NO_FALLBACK<envoy_v3_api_enum_value_config.cluster.v3.Cluster.LbSubsetConfig.LbSubsetFallbackPolicy.NO_FALLBACK>`.
repeated subset_selectors = 3
For each entry, LbEndpoint.Metadata's ``envoy.lb`` namespace is traversed and a subset is created for each unique combination of key and value. For example: .. code-block:: json { "subset_selectors": [ { "keys": [ "version" ] }, { "keys": [ "stage", "hardware_type" ] } ]} A subset is matched when the metadata from the selected route and weighted cluster contains the same keys and values as the subset's metadata. The same host may appear in multiple subsets.
bool locality_weight_aware = 4
If true, routing to subsets will take into account the localities and locality weights of the endpoints when making the routing decision. There are some potential pitfalls associated with enabling this feature, as the resulting traffic split after applying both a subset match and locality weights might be undesirable. Consider for example a situation in which you have 50/50 split across two localities X/Y which have 100 hosts each without subsetting. If the subset LB results in X having only 1 host selected but Y having 100, then a lot more load is being dumped on the single host in X than originally anticipated in the load balancing assignment delivered via EDS.
bool scale_locality_weight = 5
When used with locality_weight_aware, scales the weight of each locality by the ratio of hosts in the subset vs hosts in the original subset. This aims to even out the load going to an individual locality if said locality is disproportionately affected by the subset predicate.
bool panic_mode_any = 6
If true, when a fallback policy is configured and its corresponding subset fails to find a host this will cause any host to be selected instead. This is useful when using the default subset as the fallback policy, given the default subset might become empty. With this option enabled, if that happens the LB will attempt to select a host from the entire cluster.
bool list_as_any = 7
If true, metadata specified for a metadata key will be matched against the corresponding endpoint metadata if the endpoint metadata matches the value exactly OR it is a list value and any of the elements in the list matches the criteria.
LbSubsetConfig.LbSubsetMetadataFallbackPolicy metadata_fallback_policy = 8
Fallback mechanism that allows to try different route metadata until a host is found. If load balancing process, including all its mechanisms (like :ref:`fallback_policy<envoy_v3_api_field_config.cluster.v3.Cluster.LbSubsetConfig.fallback_policy>`) fails to select a host, this policy decides if and how the process is repeated using another metadata. The value defaults to :ref:`METADATA_NO_FALLBACK<envoy_v3_api_enum_value_config.cluster.v3.Cluster.LbSubsetConfig.LbSubsetMetadataFallbackPolicy.METADATA_NO_FALLBACK>`.
If NO_FALLBACK is selected, a result equivalent to no healthy hosts is reported. If ANY_ENDPOINT is selected, any cluster endpoint may be returned (subject to policy, health checks, etc). If DEFAULT_SUBSET is selected, load balancing is performed over the endpoints matching the values from the default_subset field.
Used in:
NO_FALLBACK = 0
ANY_ENDPOINT = 1
DEFAULT_SUBSET = 2
Used in:
METADATA_NO_FALLBACK = 0
No fallback. Route metadata will be used as-is.
FALLBACK_LIST = 1
A special metadata key ``fallback_list`` will be used to provide variants of metadata to try. Value of ``fallback_list`` key has to be a list. Every list element has to be a struct - it will be merged with route metadata, overriding keys that appear in both places. ``fallback_list`` entries will be used in order until a host is found. ``fallback_list`` key itself is removed from metadata before subset load balancing is performed. Example: for metadata: .. code-block:: yaml version: 1.0 fallback_list: - version: 2.0 hardware: c64 - hardware: c32 - version: 3.0 at first, metadata: .. code-block:: json {"version": "2.0", "hardware": "c64"} will be used for load balancing. If no host is found, metadata: .. code-block:: json {"version": "1.0", "hardware": "c32"} is next to try. If it still results in no host, finally metadata: .. code-block:: json {"version": "3.0"} is used.
message
cluster.proto:276Specifications for subsets.
Used in:
repeated string keys = 1
List of keys to match with the weighted cluster metadata.
bool single_host_per_subset = 4
Selects a mode of operation in which each subset has only one host. This mode uses the same rules for choosing a host, but updating hosts is faster, especially for large numbers of hosts. If a match is found to a host, that host will be used regardless of priority levels. When this mode is enabled, configurations that contain more than one host with the same metadata value for the single key in ``keys`` will use only one of the hosts with the given key; no requests will be routed to the others. The cluster gauge :ref:`lb_subsets_single_host_per_subset_duplicate<config_cluster_manager_cluster_stats_subset_lb>` indicates how many duplicates are present in the current configuration.
LbSubsetSelector.LbSubsetSelectorFallbackPolicy fallback_policy = 2
The behavior used when no endpoint subset matches the selected route's metadata.
repeated string fallback_keys_subset = 3
Subset of :ref:`keys<envoy_v3_api_field_config.cluster.v3.Cluster.LbSubsetConfig.LbSubsetSelector.keys>` used by :ref:`KEYS_SUBSET<envoy_v3_api_enum_value_config.cluster.v3.Cluster.LbSubsetConfig.LbSubsetSelector.LbSubsetSelectorFallbackPolicy.KEYS_SUBSET>` fallback policy. It has to be a non empty list if KEYS_SUBSET fallback policy is selected. For any other fallback policy the parameter is not used and should not be set. Only values also present in :ref:`keys<envoy_v3_api_field_config.cluster.v3.Cluster.LbSubsetConfig.LbSubsetSelector.keys>` are allowed, but ``fallback_keys_subset`` cannot be equal to ``keys``.
Allows to override top level fallback policy per selector.
Used in:
NOT_DEFINED = 0
If NOT_DEFINED top level config fallback policy is used instead.
NO_FALLBACK = 1
If NO_FALLBACK is selected, a result equivalent to no healthy hosts is reported.
ANY_ENDPOINT = 2
If ANY_ENDPOINT is selected, any cluster endpoint may be returned (subject to policy, health checks, etc).
DEFAULT_SUBSET = 3
If DEFAULT_SUBSET is selected, load balancing is performed over the endpoints matching the values from the default_subset field.
KEYS_SUBSET = 4
If KEYS_SUBSET is selected, subset selector matching is performed again with metadata keys reduced to :ref:`fallback_keys_subset<envoy_v3_api_field_config.cluster.v3.Cluster.LbSubsetConfig.LbSubsetSelector.fallback_keys_subset>`. It allows for a fallback to a different, less specific selector if some of the keys of the selector are considered optional.
message
cluster.proto:443Specific configuration for the LeastRequest load balancing policy.
Used in:
optional choice_count = 1
The number of random healthy hosts from which the host with the fewest active requests will be chosen. Defaults to 2 so that we perform two-choice selection if the field is not set.
optional active_request_bias = 2
The following formula is used to calculate the dynamic weights when hosts have different load balancing weights: ``weight = load_balancing_weight / (active_requests + 1)^active_request_bias`` The larger the active request bias is, the more aggressively active requests will lower the effective weight when all host weights are not equal. ``active_request_bias`` must be greater than or equal to 0.0. When ``active_request_bias == 0.0`` the Least Request Load Balancer doesn't consider the number of active requests at the time it picks a host and behaves like the Round Robin Load Balancer. When ``active_request_bias > 0.0`` the Least Request Load Balancer scales the load balancing weight by the number of active requests at the time it does a pick. The value is cached for performance reasons and refreshed whenever one of the Load Balancer's host sets changes, e.g., whenever there is a host membership update or a host load balancing weight change. .. note:: This setting only takes effect if all host weights are not equal.
optional slow_start_config = 3
Configuration for slow start mode. If this configuration is not set, slow start will not be not enabled.
message
cluster.proto:518Specific configuration for the :ref:`Maglev<arch_overview_load_balancing_types_maglev>` load balancing policy.
Used in:
optional table_size = 1
The table size for Maglev hashing. Maglev aims for "minimal disruption" rather than an absolute guarantee. Minimal disruption means that when the set of upstream hosts change, a connection will likely be sent to the same upstream as it was before. Increasing the table size reduces the amount of disruption. The table size must be prime number limited to 5000011. If it is not specified, the default is 65537.
message
cluster.proto:530Specific configuration for the :ref:`Original Destination <arch_overview_load_balancing_types_original_destination>` load balancing policy. [#extension: envoy.clusters.original_dst]
Used in:
bool use_http_header = 1
When true, a HTTP header can be used to override the original dst address. The default header is :ref:`x-envoy-original-dst-host <config_http_conn_man_headers_x-envoy-original-dst-host>`. .. attention:: This header isn't sanitized by default, so enabling this feature allows HTTP clients to route traffic to arbitrary hosts and/or ports, which may have serious security consequences. .. note:: If the header appears multiple times only the first value is used.
string http_header_name = 2
The http header to override destination address if :ref:`use_http_header <envoy_v3_api_field_config.cluster.v3.Cluster.OriginalDstLbConfig.use_http_header>`. is set to true. If the value is empty, :ref:`x-envoy-original-dst-host <config_http_conn_man_headers_x-envoy-original-dst-host>` will be used.
optional upstream_port_override = 3
The port to override for the original dst address. This port will take precedence over filter state and header override ports
optional metadata_key = 4
The dynamic metadata key to override destination address. First the request metadata is considered, then the connection one.
message
cluster.proto:699Used in:
optional per_upstream_preconnect_ratio = 1
Indicates how many streams (rounded up) can be anticipated per-upstream for each incoming stream. This is useful for high-QPS or latency-sensitive services. Preconnecting will only be done if the upstream is healthy and the cluster has traffic. For example if this is 2, for an incoming HTTP/1.1 stream, 2 connections will be established, one for the new incoming stream, and one for a presumed follow-up stream. For HTTP/2, only one connection would be established by default as one connection can serve both the original and presumed follow-up stream. In steady state for non-multiplexed connections a value of 1.5 would mean if there were 100 active streams, there would be 100 connections in use, and 50 connections preconnected. This might be a useful value for something like short lived single-use connections, for example proxying HTTP/1.1 if keep-alive were false and each stream resulted in connection termination. It would likely be overkill for long lived connections, such as TCP proxying SMTP or regular HTTP/1.1 with keep-alive. For long lived traffic, a value of 1.05 would be more reasonable, where for every 100 connections, 5 preconnected connections would be in the queue in case of unexpected disconnects where the connection could not be reused. If this value is not set, or set explicitly to one, Envoy will fetch as many connections as needed to serve streams in flight. This means in steady state if a connection is torn down, a subsequent streams will pay an upstream-rtt latency penalty waiting for a new connection. This is limited somewhat arbitrarily to 3 because preconnecting too aggressively can harm latency more than the preconnecting helps.
optional predictive_preconnect_ratio = 2
Indicates how many streams (rounded up) can be anticipated across a cluster for each stream, useful for low QPS services. This is currently supported for a subset of deterministic non-hash-based load-balancing algorithms (weighted round robin, random). Unlike ``per_upstream_preconnect_ratio`` this preconnects across the upstream instances in a cluster, doing best effort predictions of what upstream would be picked next and pre-establishing a connection. Preconnecting will be limited to one preconnect per configured upstream in the cluster and will only be done if there are healthy upstreams and the cluster has traffic. For example if preconnecting is set to 2 for a round robin HTTP/2 cluster, on the first incoming stream, 2 connections will be preconnected - one to the first upstream for this cluster, one to the second on the assumption there will be a follow-up stream. If this value is not set, or set explicitly to one, Envoy will fetch as many connections as needed to serve streams in flight, so during warm up and in steady state if a connection is closed (and per_upstream_preconnect_ratio is not set), there will be a latency hit for connection establishment. If both this and preconnect_ratio are set, Envoy will make sure both predicted needs are met, basically preconnecting max(predictive-preconnect, per-upstream-preconnect), for each upstream.
message
cluster.proto:681Used in: ,
optional base_interval = 1
Specifies the base interval between refreshes. This parameter is required and must be greater than zero and less than :ref:`max_interval <envoy_v3_api_field_config.cluster.v3.Cluster.RefreshRate.max_interval>`.
optional max_interval = 2
Specifies the maximum interval between refreshes. This parameter is optional, but must be greater than or equal to the :ref:`base_interval <envoy_v3_api_field_config.cluster.v3.Cluster.RefreshRate.base_interval>` if set. The default is 10 times the :ref:`base_interval <envoy_v3_api_field_config.cluster.v3.Cluster.RefreshRate.base_interval>`.
message
cluster.proto:483Specific configuration for the :ref:`RingHash<arch_overview_load_balancing_types_ring_hash>` load balancing policy.
Used in:
optional minimum_ring_size = 1
Minimum hash ring size. The larger the ring is (that is, the more hashes there are for each provided host) the better the request distribution will reflect the desired weights. Defaults to 1024 entries, and limited to 8M entries. See also :ref:`maximum_ring_size<envoy_v3_api_field_config.cluster.v3.Cluster.RingHashLbConfig.maximum_ring_size>`.
RingHashLbConfig.HashFunction hash_function = 3
The hash function used to hash hosts onto the ketama ring. The value defaults to :ref:`XX_HASH<envoy_v3_api_enum_value_config.cluster.v3.Cluster.RingHashLbConfig.HashFunction.XX_HASH>`.
optional maximum_ring_size = 4
Maximum hash ring size. Defaults to 8M entries, and limited to 8M entries, but can be lowered to further constrain resource use. See also :ref:`minimum_ring_size<envoy_v3_api_field_config.cluster.v3.Cluster.RingHashLbConfig.minimum_ring_size>`.
The hash function used to hash hosts onto the ketama ring.
Used in:
XX_HASH = 0
Use `xxHash <https://github.com/Cyan4973/xxHash>`_, this is the default hash function.
MURMUR_HASH_2 = 1
Use `MurmurHash2 <https://sites.google.com/site/murmurhash/>`_, this is compatible with std:hash<string> in GNU libstdc++ 3.4.20 or above. This is typically the case when compiled on Linux and not macOS.
message
cluster.proto:436Specific configuration for the RoundRobin load balancing policy.
Used in:
optional slow_start_config = 1
Configuration for slow start mode. If this configuration is not set, slow start will not be not enabled.
message
cluster.proto:409Configuration for :ref:`slow start mode <arch_overview_load_balancing_slow_start>`.
Used in: ,
optional slow_start_window = 1
Represents the size of slow start window. If set, the newly created host remains in slow start mode starting from its creation time for the duration of slow start window.
optional aggression = 2
This parameter controls the speed of traffic increase over the slow start window. Defaults to 1.0, so that endpoint would get linearly increasing amount of traffic. When increasing the value for this parameter, the speed of traffic ramp-up increases non-linearly. The value of aggression parameter should be greater than 0.0. By tuning the parameter, is possible to achieve polynomial or exponential shape of ramp-up curve. During slow start window, effective weight of an endpoint would be scaled with time factor and aggression: ``new_weight = weight * max(min_weight_percent, time_factor ^ (1 / aggression))``, where ``time_factor=(time_since_start_seconds / slow_start_time_seconds)``. As time progresses, more and more traffic would be sent to endpoint, which is in slow start window. Once host exits slow start, time_factor and aggression no longer affect its weight.
optional min_weight_percent = 3
Configures the minimum percentage of origin weight that avoids too small new weight, which may cause endpoints in slow start mode receive no traffic in slow start window. If not specified, the default is 10%.
message
cluster.proto:164TransportSocketMatch specifies what transport socket config will be used when the match conditions are satisfied.
Used in: ,
string name = 1
The name of the match, used in stats generation.
optional match = 2
Optional metadata match criteria. The connection to the endpoint with metadata matching what is set in this field will use the transport socket configuration specified here. The endpoint's metadata entry in ``envoy.transport_socket_match`` is used to match against the values specified in this field.
optional transport_socket = 3
The configuration of the transport socket. [#extension-category: envoy.transport_sockets.upstream]
message
cluster.proto:43Cluster list collections. Entries are ``Cluster`` resources or references. [#not-implemented-hide:]
optional entries = 1
message
filter.proto:22Used in:
string name = 1
The name of the filter configuration.
optional typed_config = 2
Filter specific configuration which depends on the filter being instantiated. See the supported filters for further documentation. Note that Envoy's :ref:`downstream network filters <config_network_filters>` are not valid upstream network filters. Only one of typed_config or config_discovery can be used.
optional config_discovery = 3
Configuration source specifier for an extension configuration discovery service. In case of a failure and without the default configuration, the listener closes the connections. Only one of typed_config or config_discovery can be used.
message
cluster.proto:1279Extensible load balancing policy configuration. Every LB policy defined via this mechanism will be identified via a unique name using reverse DNS notation. If the policy needs configuration parameters, it must define a message for its own configuration, which will be stored in the config field. The name of the policy will tell clients which type of message they should expect to see in the config field. Note that there are cases where it is useful to be able to independently select LB policies for choosing a locality and for choosing an endpoint within that locality. For example, a given deployment may always use the same policy to choose the locality, but for choosing the endpoint within the locality, some clusters may use weighted-round-robin, while others may use some sort of session-based balancing. This can be accomplished via hierarchical LB policies, where the parent LB policy creates a child LB policy for each locality. For each request, the parent chooses the locality and then delegates to the child policy for that locality to choose the endpoint within the locality. To facilitate this, the config message for the top-level LB policy may include a field of type LoadBalancingPolicy that specifies the child policy.
Used in: , ,
repeated policies = 1
Each client will iterate over the list in order and stop at the first policy that it supports. This provides a mechanism for starting to use new LB policies that are not yet supported by all clients.
message
cluster.proto:1282Used in:
optional typed_extension_config = 4
[#extension-category: envoy.load_balancing_policies]
message
outlier_detection.proto:25See the :ref:`architecture overview <arch_overview_outlier_detection>` for more information on outlier detection. [#next-free-field: 26]
Used in:
optional consecutive_5xx = 1
The number of consecutive server-side error responses (for HTTP traffic, 5xx responses; for TCP traffic, connection failures; for Redis, failure to respond PONG; etc.) before a consecutive 5xx ejection occurs. Defaults to 5.
optional interval = 2
The time interval between ejection analysis sweeps. This can result in both new ejections as well as hosts being returned to service. Defaults to 10000ms or 10s.
optional base_ejection_time = 3
The base time that a host is ejected for. The real time is equal to the base time multiplied by the number of times the host has been ejected and is capped by :ref:`max_ejection_time<envoy_v3_api_field_config.cluster.v3.OutlierDetection.max_ejection_time>`. Defaults to 30000ms or 30s.
optional max_ejection_percent = 4
The maximum % of an upstream cluster that can be ejected due to outlier detection. Defaults to 10% . Will eject at least one host regardless of the value if :ref:`always_eject_one_host<envoy_v3_api_field_config.cluster.v3.OutlierDetection.always_eject_one_host>` is enabled.
optional enforcing_consecutive_5xx = 5
The % chance that a host will be actually ejected when an outlier status is detected through consecutive 5xx. This setting can be used to disable ejection or to ramp it up slowly. Defaults to 100.
optional enforcing_success_rate = 6
The % chance that a host will be actually ejected when an outlier status is detected through success rate statistics. This setting can be used to disable ejection or to ramp it up slowly. Defaults to 100.
optional success_rate_minimum_hosts = 7
The number of hosts in a cluster that must have enough request volume to detect success rate outliers. If the number of hosts is less than this setting, outlier detection via success rate statistics is not performed for any host in the cluster. Defaults to 5.
optional success_rate_request_volume = 8
The minimum number of total requests that must be collected in one interval (as defined by the interval duration above) to include this host in success rate based outlier detection. If the volume is lower than this setting, outlier detection via success rate statistics is not performed for that host. Defaults to 100.
optional success_rate_stdev_factor = 9
This factor is used to determine the ejection threshold for success rate outlier ejection. The ejection threshold is the difference between the mean success rate, and the product of this factor and the standard deviation of the mean success rate: mean - (stdev * success_rate_stdev_factor). This factor is divided by a thousand to get a double. That is, if the desired factor is 1.9, the runtime value should be 1900. Defaults to 1900.
optional consecutive_gateway_failure = 10
The number of consecutive gateway failures (502, 503, 504 status codes) before a consecutive gateway failure ejection occurs. Defaults to 5.
optional enforcing_consecutive_gateway_failure = 11
The % chance that a host will be actually ejected when an outlier status is detected through consecutive gateway failures. This setting can be used to disable ejection or to ramp it up slowly. Defaults to 0.
bool split_external_local_origin_errors = 12
Determines whether to distinguish local origin failures from external errors. If set to true the following configuration parameters are taken into account: :ref:`consecutive_local_origin_failure<envoy_v3_api_field_config.cluster.v3.OutlierDetection.consecutive_local_origin_failure>`, :ref:`enforcing_consecutive_local_origin_failure<envoy_v3_api_field_config.cluster.v3.OutlierDetection.enforcing_consecutive_local_origin_failure>` and :ref:`enforcing_local_origin_success_rate<envoy_v3_api_field_config.cluster.v3.OutlierDetection.enforcing_local_origin_success_rate>`. Defaults to false.
optional consecutive_local_origin_failure = 13
The number of consecutive locally originated failures before ejection occurs. Defaults to 5. Parameter takes effect only when :ref:`split_external_local_origin_errors<envoy_v3_api_field_config.cluster.v3.OutlierDetection.split_external_local_origin_errors>` is set to true.
optional enforcing_consecutive_local_origin_failure = 14
The % chance that a host will be actually ejected when an outlier status is detected through consecutive locally originated failures. This setting can be used to disable ejection or to ramp it up slowly. Defaults to 100. Parameter takes effect only when :ref:`split_external_local_origin_errors<envoy_v3_api_field_config.cluster.v3.OutlierDetection.split_external_local_origin_errors>` is set to true.
optional enforcing_local_origin_success_rate = 15
The % chance that a host will be actually ejected when an outlier status is detected through success rate statistics for locally originated errors. This setting can be used to disable ejection or to ramp it up slowly. Defaults to 100. Parameter takes effect only when :ref:`split_external_local_origin_errors<envoy_v3_api_field_config.cluster.v3.OutlierDetection.split_external_local_origin_errors>` is set to true.
optional failure_percentage_threshold = 16
The failure percentage to use when determining failure percentage-based outlier detection. If the failure percentage of a given host is greater than or equal to this value, it will be ejected. Defaults to 85.
optional enforcing_failure_percentage = 17
The % chance that a host will be actually ejected when an outlier status is detected through failure percentage statistics. This setting can be used to disable ejection or to ramp it up slowly. Defaults to 0. [#next-major-version: setting this without setting failure_percentage_threshold should be invalid in v4.]
optional enforcing_failure_percentage_local_origin = 18
The % chance that a host will be actually ejected when an outlier status is detected through local-origin failure percentage statistics. This setting can be used to disable ejection or to ramp it up slowly. Defaults to 0.
optional failure_percentage_minimum_hosts = 19
The minimum number of hosts in a cluster in order to perform failure percentage-based ejection. If the total number of hosts in the cluster is less than this value, failure percentage-based ejection will not be performed. Defaults to 5.
optional failure_percentage_request_volume = 20
The minimum number of total requests that must be collected in one interval (as defined by the interval duration above) to perform failure percentage-based ejection for this host. If the volume is lower than this setting, failure percentage-based ejection will not be performed for this host. Defaults to 50.
optional max_ejection_time = 21
The maximum time that a host is ejected for. See :ref:`base_ejection_time<envoy_v3_api_field_config.cluster.v3.OutlierDetection.base_ejection_time>` for more information. If not specified, the default value (300000ms or 300s) or :ref:`base_ejection_time<envoy_v3_api_field_config.cluster.v3.OutlierDetection.base_ejection_time>` value is applied, whatever is larger.
optional max_ejection_time_jitter = 22
The maximum amount of jitter to add to the ejection time, in order to prevent a 'thundering herd' effect where all proxies try to reconnect to host at the same time. See :ref:`max_ejection_time_jitter<envoy_v3_api_field_config.cluster.v3.OutlierDetection.base_ejection_time>` Defaults to 0s.
optional successful_active_health_check_uneject_host = 23
If active health checking is enabled and a host is ejected by outlier detection, a successful active health check unejects the host by default and considers it as healthy. Unejection also clears all the outlier detection counters. To change this default behavior set this config to ``false`` where active health checking will not uneject the host. Defaults to true.
repeated monitors = 24
Set of host's passive monitors. [#not-implemented-hide:]
optional always_eject_one_host = 25
If enabled, at least one host is ejected regardless of the value of :ref:`max_ejection_percent<envoy_v3_api_field_config.cluster.v3.OutlierDetection.max_ejection_percent>`. Defaults to false.
message
cluster.proto:1338Used in:
bool timeout_budgets = 1
If timeout_budgets is true, the :ref:`timeout budget histograms <config_cluster_manager_cluster_stats_timeout_budgets>` will be published for each request. These show what percentage of a request's per try and global timeout was used. A value of 0 would indicate that none of the timeout was used or that the timeout was infinite. A value of 100 would indicate that the request took the entirety of the timeout given to it.
bool request_response_sizes = 2
If request_response_sizes is true, then the :ref:`histograms <config_cluster_manager_cluster_stats_request_response_sizes>` tracking header and body sizes of requests and responses will be published. Additionally, number of headers in the requests and responses will be tracked.
bool per_endpoint_stats = 3
If true, some stats will be emitted per-endpoint, similar to the stats in admin ``/clusters`` output. This does not currently output correct stats during a hot-restart. This is not currently implemented by all stat sinks. These stats do not honor filtering or tag extraction rules in :ref:`StatsConfig <envoy_v3_api_msg_config.metrics.v3.StatsConfig>` (but fixed-value tags are supported). Admin endpoint filtering is supported. This may not be used at the same time as :ref:`load_stats_config <envoy_v3_api_field_config.bootstrap.v3.ClusterManager.load_stats_config>`.
message
cluster.proto:1300Used in:
optional tcp_keepalive = 1
If set then set SO_KEEPALIVE on the socket to enable TCP Keepalives.
bool set_local_interface_name_on_upstream_connections = 2
If enabled, associates the interface name of the local address with the upstream connection. This can be used by extensions during processing of requests. The association mechanism is implementation specific. Defaults to false due to performance concerns.
optional happy_eyeballs_config = 3
Configurations for happy eyeballs algorithm. Add configs for first_address_family_version and first_address_family_count when sorting destination ip addresses.
Used in:
DEFAULT = 0
respect the native ranking of destination ip addresses returned from dns resolution
V4 = 1
V6 = 2
message
cluster.proto:1314Used in:
FirstAddressFamilyVersion first_address_family_version = 1
Specify the IP address family to attempt connection first in happy eyeballs algorithm according to RFC8305#section-4.
optional first_address_family_count = 2
Specify the number of addresses of the first_address_family_version being attempted for connection before the other address family.