Proxy Configuration

Linkerd provides a set of annotations that can be used to override the data plane proxy’s configuration. This is useful for overriding the default configurations of auto-injected proxies.

The following is the list of supported annotations:

Annotation	Description
`config.alpha.linkerd.io/proxy-enable-native-sidecar`	Enable KEP-753 native sidecars. This is an experimental feature. It requires Kubernetes >= 1.29. If enabled, .proxy.waitBeforeExitSeconds should not be used.
`config.alpha.linkerd.io/proxy-wait-before-exit-seconds`	The proxy sidecar will stay alive for at least the given period after receiving SIGTERM signal from Kubernetes but no longer than pod’s `terminationGracePeriodSeconds`. Defaults to `0`
`config.linkerd.io/access-log`	Enables HTTP access logging in the proxy. Accepted values are `apache`, to output the access log in the Appache Common Log Format, and `json`, to output the access log in JSON.
`config.linkerd.io/admin-port`	Proxy port to serve metrics on
`config.linkerd.io/close-wait-timeout`	Sets nf_conntrack_tcp_timeout_close_wait. Accepts a duration string, e.g. `1m` or `3600s`
`config.linkerd.io/control-port`	Proxy port to use for control
`config.linkerd.io/debug-image`	Linkerd debug container image name
`config.linkerd.io/debug-image-pull-policy`	Docker image pull policy for debug image
`config.linkerd.io/debug-image-version`	Linkerd debug container image version
`config.linkerd.io/default-inbound-policy`	Proxy’s default inbound policy
`config.linkerd.io/enable-debug-sidecar`	Inject a debug sidecar for data plane debugging
`config.linkerd.io/enable-external-profiles`	Enable service profiles for non-Kubernetes services
`config.linkerd.io/image-pull-policy`	Docker image pull policy
`config.linkerd.io/inbound-port`	Proxy port to use for inbound traffic
`config.linkerd.io/init-image`	Linkerd init container image name
`config.linkerd.io/init-image-version`	Linkerd init container image version
`config.linkerd.io/opaque-ports`	Ports that skip the proxy’s protocol detection mechanism and are proxied opaquely. Comma-separated list of values, where each value can be a port number or a range `a-b`.
`config.linkerd.io/outbound-port`	Proxy port to use for outbound traffic
`config.linkerd.io/pod-inbound-ports`	Comma-separated list of (non-proxy) container ports exposed by the pod spec. Useful when other mutating webhooks inject sidecar containers after the proxy injector has run
`config.linkerd.io/proxy-await`	The application container will not start until the proxy is ready; accepted values are `enabled` and `disabled`
`config.linkerd.io/proxy-cpu-limit`	Maximum amount of CPU units that the proxy sidecar can use
`config.linkerd.io/proxy-cpu-request`	Amount of CPU units that the proxy sidecar requests
`config.linkerd.io/proxy-disable-inbound-protocol-detect-timeout`	When set to true, disables the protocol detection timeout on the inbound side of the proxy by setting it to a very high value
`config.linkerd.io/proxy-disable-outbound-protocol-detect-timeout`	When set to true, disables the protocol detection timeout on the outbound side of the proxy by setting it to a very high value
`config.linkerd.io/proxy-ephemeral-storage-limit`	Used to override the limitEphemeralStorage config
`config.linkerd.io/proxy-ephemeral-storage-request`	Used to override the requestEphemeralStorage config
`config.linkerd.io/proxy-gid`	Run the proxy under this group ID
`config.linkerd.io/proxy-image`	Linkerd proxy container image name
`config.linkerd.io/proxy-inbound-connect-timeout`	Inbound TCP connection timeout in the proxy. Defaults to `100ms`
`config.linkerd.io/proxy-inbound-discovery-cache-unused-timeout`	Maximum time allowed before an unused inbound discovery result is evicted from the cache. Defaults to `90s`
`config.linkerd.io/proxy-log-format`	Log format (plain or json) for the proxy
`config.linkerd.io/proxy-log-level`	Log level for the proxy
`config.linkerd.io/proxy-memory-limit`	Maximum amount of Memory that the proxy sidecar can use
`config.linkerd.io/proxy-memory-request`	Amount of Memory that the proxy sidecar requests
`config.linkerd.io/proxy-outbound-connect-timeout`	Used to configure the outbound TCP connection timeout in the proxy. Defaults to `1000ms`
`config.linkerd.io/proxy-outbound-discovery-cache-unused-timeout`	Maximum time allowed before an unused outbound discovery result is evicted from the cache. Defaults to `5s`
`config.linkerd.io/proxy-uid`	Run the proxy under this user ID
`config.linkerd.io/proxy-version`	Tag to be used for the Linkerd proxy images
`config.linkerd.io/shutdown-grace-period`	Grace period for graceful proxy shutdowns. If this timeout elapses before all open connections have completed, the proxy will terminate forcefully, closing any remaining connections.
`config.linkerd.io/skip-inbound-ports`	Ports that should skip the proxy and send directly to the application. Comma-separated list of values, where each value can be a port number or a range `a-b`.
`config.linkerd.io/skip-outbound-ports`	Outbound ports that should skip the proxy. Comma-separated list of values, where each value can be a port number or a range `a-b`.
`config.linkerd.io/skip-subnets`	Comma-separated list of subnets in valid CIDR format that should be skipped by the proxy
`linkerd.io/inject`	Controls whether or not a pod should be injected; accepted values are `enabled`, `disabled` and `ingress`

For example, to update an auto-injected proxy’s CPU and memory resources, we insert the appropriate annotations into the spec.template.metadata.annotations of the owner’s pod spec, using kubectl edit like this:

spec:
  template:
    metadata:
      annotations:
        config.linkerd.io/proxy-cpu-limit: "1"
        config.linkerd.io/proxy-cpu-request: "0.2"
        config.linkerd.io/proxy-memory-limit: 2Gi
        config.linkerd.io/proxy-memory-request: 128Mi

See here for details on tuning the proxy’s resource usage.

For proxies injected using the linkerd inject command, configuration can be overridden using the command-line flags.

Ingress Mode

Warning

When an ingress is meshed in ingress mode by using linkerd.io/inject: ingress, the ingress must be configured to remove the l5d-dst-override header to avoid creating an open relay to cluster-local and external endpoints.

Proxy ingress mode is a mode of operation designed to help Linkerd integrate with certain ingress controllers. Ingress mode is necessary if the ingress itself cannot be otherwise configured to use the Service port/ip as the destination.

When an individual Linkerd proxy is set to ingress mode, it will route requests based on their :authority, Host, or l5d-dst-override headers instead of their original destination. This will inform Linkerd to override the endpoint selection of the ingress container and to perform its own endpoint selection, enabling features such as per-route metrics and traffic splitting.

The proxy can be made to run in ingress mode by using the linkerd.io/inject: ingress annotation rather than the default linkerd.io/inject: enabled annotation. This can also be done with the --ingress flag in the inject CLI command:

kubectl get deployment <ingress-controller> -n <ingress-namespace> -o yaml | linkerd inject --ingress - | kubectl apply -f -