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-wait-before-exit-seconds The proxy sidecar will stay alive for at least the given period before receiving SIGTERM signal from Kubernetes but no longer than pod’s terminationGracePeriodSeconds. If not provided, it will be defaulted to 0
config.linkerd.io/admin-port Proxy port to serve metrics on
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/disable-identity Disables resources from participating in TLS identity
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/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-image Linkerd proxy container image name
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
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/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.
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

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 used 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 -