Service Mesh

Configuration affecting the service mesh as a whole.


AuthenticationPolicy defines authentication policy. It can be set for different scopes (mesh, service …), and the most narrow scope with non-INHERIT value will be used. Mesh policy cannot be INHERIT.


Do not encrypt Envoy to Envoy traffic.


Envoy to Envoy traffic is wrapped into mutual TLS connections.


Use the policy defined by the parent scope. Should not be used for mesh policy.


ConfigSource describes information about a configuration store inside a mesh. A single control plane instance can interact with one or more data sources.


Address of the server implementing the Istio Mesh Configuration protocol (MCP). Can be IP address or a fully qualified DNS name. Use fs:/// to specify a file-based backend with absolute path to the directory.


Use the tls_settings to specify the tls mode to use. If the MCP server uses Istio mutual TLS and shares the root CA with Pilot, specify the TLS mode as ISTIO_MUTUAL.


Locality-weighted load balancing allows administrators to control the distribution of traffic to endpoints based on the localities of where the traffic originates and where it will terminate. These localities are specified using arbitrary labels that designate a hierarchy of localities in {region}/{zone}/{sub-zone} form. For additional detail refer to Locality Weight The following example shows how to setup locality weights mesh-wide.

Given a mesh with workloads and their service deployed to “us-west/zone1/” and “us-west/zone2/”. This example specifies that when traffic accessing a service originates from workloads in “us-west/zone1/”, 80% of the traffic will be sent to endpoints in “us-west/zone1/”, i.e the same zone, and the remaining 20% will go to endpoints in “us-west/zone2/”. This setup is intended to favor routing traffic to endpoints in the same locality. A similar setting is specified for traffic originating in “us-west/zone2/”.

    - from: us-west/zone1/*
        "us-west/zone1/*": 80
        "us-west/zone2/*": 20
    - from: us-west/zone2/*
        "us-west/zone1/*": 20
        "us-west/zone2/*": 80

If the goal of the operator is not to distribute load across zones and regions but rather to restrict the regionality of failover to meet other operational requirements an operator can set a ‘failover’ policy instead of a ‘distribute’ policy.

The following example sets up a locality failover policy for regions. Assume a service resides in zones within us-east, us-west & eu-west this example specifies that when endpoints within us-east become unhealthy traffic should failover to endpoints in any zone or sub-zone within eu-west and similarly us-west should failover to us-east.

   - from: us-east
     to: eu-west
   - from: us-west
     to: us-east

Locality load balancing settings.


Optional: only one of distribute or failover can be set. Explicitly specify loadbalancing weight across different zones and geographical locations. Refer to Locality weighted load balancing If empty, the locality weight is set according to the endpoints number within it.


Optional: only failover or distribute can be set. Explicitly specify the region traffic will land on when endpoints in local region becomes unhealthy. Should be used together with OutlierDetection to detect unhealthy endpoints. Note: if no OutlierDetection specified, this will not take effect.


Describes how traffic originating in the ‘from’ zone or sub-zone is distributed over a set of ‘to’ zones. Syntax for specifying a zone is {region}/{zone}/{sub-zone} and terminal wildcards are allowed on any segment of the specification. Examples: * - matches all localities us-west/* - all zones and sub-zones within the us-west region us-west/zone-1/* - all sub-zones within us-west/zone-1


Originating locality, ‘/’ separated, e.g. ‘region/zone/sub_zone’.

tomap<string, uint32>

Map of upstream localities to traffic distribution weights. The sum of all weights should be == 100. Any locality not assigned a weight will receive no traffic.


Specify the traffic failover policy across regions. Since zone and sub-zone failover is supported by default this only needs to be specified for regions when the operator needs to constrain traffic failover so that the default behavior of failing over to any endpoint globally does not apply. This is useful when failing over traffic across regions would not improve service health or may need to be restricted for other reasons like regulatory controls.


Originating region.


Destination region the traffic will fail over to when endpoints in the ‘from’ region becomes unhealthy.


MeshConfig defines mesh-wide variables shared by all Envoy instances in the Istio service mesh.

NOTE: This configuration type should be used for the low-level global configuration, such as component addresses and port numbers. It should not be used for the features of the mesh that can be scoped by service or by namespace. Some of the fields in the mesh config are going to be deprecated and replaced with several individual configuration types (for example, tracing configuration).


Address of the server that will be used by the proxies for policy check calls. By using different names for mixerCheckServer and mixerReportServer, it is possible to have one set of Mixer servers handle policy check calls while another set of Mixer servers handle telemetry calls.

NOTE: Omitting mixerCheckServer while specifying mixerReportServer is equivalent to setting disablePolicyChecks to true.


Address of the server that will be used by the proxies for policy report calls.


Disable policy checks by the Mixer service. Default is false, i.e. Mixer policy check is enabled by default.


Allow all traffic in cases when the Mixer policy service cannot be reached. Default is false which means the traffic is denied when the client is unable to connect to Mixer.


Enable session affinity for Envoy Mixer reports so that calls from a proxy will always target the same Mixer instance.


Port on which Envoy should listen for incoming connections from other services.


Port on which Envoy should listen for HTTP PROXY requests if set.


Connection timeout used by Envoy. (MUST BE >=1ms)


If set then set SO_KEEPALIVE on the socket to enable TCP Keepalives.


Class of ingress resources to be processed by Istio ingress controller. This corresponds to the value of “” annotation.


Name of theKubernetes service used for the istio ingress controller.


Defines whether to use Istio ingress controller for annotated or all ingress resources.


Flag to control generation of trace spans and request IDs. Requires a trace span collector defined in the proxy configuration.


File address for the proxy access log (e.g. /dev/stdout). Empty value disables access logging.


Format for the proxy access log Empty value results in proxy’s default access log format


Encoding for the proxy access log (text or json). Default value is text.


Default proxy config used by the proxy injection mechanism operating in the mesh (e.g. Kubernetes admission controller) In case of Kubernetes, the proxy config is applied once during the injection process, and remain constant for the duration of the pod. The rest of the mesh config can be changed at runtime and config gets distributed dynamically.


Set the default behavior of the sidecar for handling outbound traffic from the application. If your application uses one or more external services that are not known apriori, setting the policy to ALLOWANY will cause the sidecars to route any unknown traffic originating from the application to its requested destination. Users are strongly encouraged to use ServiceEntries to explicitly declare any external dependencies, instead of using allowany, so that traffic to these services can be monitored.


Enables clide side policy checks.


Unix Domain Socket through which Envoy communicates with NodeAgent SDS to get key/cert for mTLS. Use secret-mount files instead of SDS if set to empty.


ConfigSource describes a source of configuration data for networking rules, and other Istio configuration artifacts. Multiple data sources can be configured for a single control plane.


The trust domain corresponds to the trust root of a system. Refer to SPIFEE-ID Fallback to old identity format(without trust domain) if not set.


Locality based load balancing distribution or failover settings.


Configures DNS refresh rate for Envoy clusters of type STRICT_DNS





Disables Istio ingress controller.


Istio ingress controller will act on ingress resources that do not contain any annotation or whose annotations match the value specified in the ingress_class parameter described earlier. Use this mode if Istio ingress controller will be the default ingress controller for the entireKubernetes cluster.


Istio ingress controller will only act on ingress resources whose annotations match the value specified in the ingress_class parameter described earlier. Use this mode if Istio ingress controller will be a secondary ingress controller (e.g., in addition to a cloud-provided ingress controller).





outbound traffic will be restricted to services defined in the service registry as well as those defined through ServiceEntries


outbound traffic to unknown destinations will be allowed, in case there are no services or ServiceEntries for the destination port


MeshNetworks (config map) provides information about the set of networks inside a mesh and how to route to endpoints in each network. For example

MeshNetworks(file/config map): networks: network1: - endpoints: - fromRegistry: registry1 #must match secret name in Kubernetes - fromCidr: #a VM network for example gateways: - registryServiceName: istio-ingressgateway.istio-system.svc.cluster.local port: 15443 locality: us-east-1a - address: port: 15443 locality: us-east-1a

networksmap<string, Network>

REQUIRED: The set of networks inside this mesh. Each network should have a unique name and information about how to infer the endpoints in the network as well as the gateways associated with the network.


Network provides information about the endpoints in a routable L3 network. A single routable L3 network can have one or more service registries. Note that the network has no relation to the locality of the endpoint. The endpoint locality will be obtained from the service registry.


REQUIRED: The list of endpoints in the network (obtained through the constituent service registries or from CIDR ranges). All endpoints in the network are directly accessible to one another.


REQUIRED: Set of gateways associated with the network.


The gateway associated with this network. Traffic from remote networks will arrive at the specified gateway:port. All incoming traffic must use mTLS.

registryServiceNamestring (oneof)

A fully qualified domain name of the gateway service. Pilot will lookup the service from the service registries in the network and obtain the endpoint IPs of the gateway from the service registry. Note that while the service name is a fully qualified domain name, it need not be resolvable outside the orchestration platform for the registry. e.g., this could be istio-ingressgateway.istio-system.svc.cluster.local.

addressstring (oneof)

IP address or externally resolvable DNS address associated with the gateway.


REQUIRED: The port associated with the gateway.


The locality associated with an explicitly specified gateway (i.e. ip)


NetworkEndpoints describes how the network associated with an endpoint should be inferred. An endpoint will be assigned to a network based on the following rules:

  1. Implicitly: If the registry explicitly provides information about the network to which the endpoint belongs to. In some cases, its possible to indicate the network associated with the endpoint by adding the ISTIO_META_NETWORK environment variable to the sidecar.

  2. Explicitly:

a. By matching the registry name with one of the “fromRegistry” in the mesh config. A “from_registry” can only be assigned to a single network.

b. By matching the IP against one of the CIDR ranges in a mesh config network. The CIDR ranges must not overlap and be assigned to a single network.

(2) will override (1) if both are present.

fromCidrstring (oneof)

A CIDR range for the set of endpoints in this network. The CIDR ranges for endpoints from different networks must not overlap.

fromRegistrystring (oneof)

Add all endpoints from the specified registry into this network. The names of the registries should correspond to the secret name that was used to configure the registry (Kubernetes multicluster) or supplied by MCP server.


ProxyConfig defines variables for individual Envoy instances.


Path to the generated configuration file directory. Proxy agent generates the actual configuration and stores it in this directory.


Path to the proxy binary


Service cluster defines the name for the service_cluster that is shared by all Envoy instances. This setting corresponds to –service-cluster flag in Envoy. In a typical Envoy deployment, the service-cluster flag is used to identify the caller, for source-based routing scenarios.

Since Istio does not assign a local service/service version to each Envoy instance, the name is same for all of them. However, the source/caller’s identity (e.g., IP address) is encoded in the –service-node flag when launching Envoy. When the RDS service receives API calls from Envoy, it uses the value of the service-node flag to compute routes that are relative to the service instances located at that IP address.


The time in seconds that Envoy will drain connections during a hot restart. MUST be >=1s (e.g., 1s/1m/1h)


The time in seconds that Envoy will wait before shutting down the parent process during a hot restart. MUST be >=1s (e.g., 1s/1m/1h). MUST BE greater than drainduration_ parameter.


Address of the discovery service exposing xDS with mTLS connection.


Address of the Zipkin service (e.g. zipkin:9411). DEPRECATED: Use tracing instead.


Connection timeout used by Envoy for supporting services. (MUST BE >=1ms)


IP Address and Port of a statsd UDP listener (e.g.


Address of the Envoy Metrics Service implementation (e.g. metrics-service:15000). See Metric Service for details about Envoy’s Metrics Service API.


Port on which Envoy should listen for administrative commands.


Authentication policy defines the global switch to control authentication for Envoy-to-Envoy communication for istio components Mixer and Pilot.


File path of custom proxy configuration, currently used by proxies in front of Mixer and Pilot.


Maximum length of name field in Envoy’s metrics. The length of the name field is determined by the length of a name field in a service and the set of labels that comprise a particular version of the service. The default value is set to 189 characters. Envoy’s internal metrics take up 67 characters, for a total of 256 character name per metric. Increase the value of this field if you find that the metrics from Envoys are truncated.


The number of worker threads to run. Default value is number of cores on the machine.


Path to the proxy bootstrap template file


The mode used to redirect inbound traffic to Envoy.


Tracing configuration to be used by the proxy.


secret discovery service(SDS) configuration to be used by the proxy.


The mode used to redirect inbound traffic to Envoy. This setting has no effect on outbound traffic: iptables REDIRECT is always used for outbound connections.


The REDIRECT mode uses iptables REDIRECT to NAT and redirect to Envoy. This mode loses source IP addresses during redirection.


The TPROXY mode uses iptables TPROXY to redirect to Envoy. This mode preserves both the source and destination IP addresses and ports, so that they can be used for advanced filtering and manipulation. This mode also configures the sidecar to run with the CAPNETADMIN capability, which is required to use TPROXY.


SDS defines secret discovery service(SDS) configuration to be used by the proxy. For workload, its values are set in sidecar injector(passed as arguments to istio-proxy container). For pilot/mixer, it’s passed as arguments to istio-proxy container in pilot/mixer deployment yaml files directly.


True if SDS is enabled.


Path of k8s service account JWT path.


Tracing defines configuration for the tracing performed by Envoy instances.

zipkinTracing.Zipkin (oneof)

Use a Zipkin tracer.

lightstepTracing.Lightstep (oneof)

Use a LightStep tracer.

datadogTracing.Datadog (oneof)

Use a Datadog tracer.


Datadog defines configuration for a Datadog tracer.


Address of the Datadog Agent.


Defines configuration for a LightStep tracer.


Address of the LightStep Satellite pool.


The LightStep access token.


True if a secure connection should be used when communicating with the pool.


Path to the trusted cacert used to authenticate the pool.


Zipkin defines configuration for a Zipkin tracer.


Address of the Zipkin service (e.g. zipkin:9411).