Annotations and labels configure service mesh sidecar properties and injection behavior when scheduling Kubernetes clusters. Learn about the annotations and labels that enable Consul’s service mesh and secure upstream communication on k8s in this reference guide.
this annotation is optional. This annotation can be either _labeled_ or _unlabeled_. We recommend the labeled format because it has a more consistent syntax and can be used to reference cluster peers as upstreams.
You cannot reference auto-generated environment variables when the upstream annotation contains a dot. This is because Consul also renders the environment variables to include a dot. For example, Consul renders the variables generated for `static-server.svc:8080` as `STATIC-SERVER.SVC_CONNECT_SERVICE_HOST` and `STATIC_SERVER.SVC_CONNECT_SERVICE_PORT`, which makes the variables unusable.
The labeled annotation format allows you to reference any service as an upstream. You can specify a Consul Enterprise namespace. You can also specify an admin partition in the same datacenter, a cluster peer, or a WAN-federated datacenter.
When namespaces are enabled, you must include the namespace in the annotation before specifying a cluster peer, WAN-federated datacenter, or admin partition in the same datacenter.
The unlabeled annotation format allows you to reference any service not in a cluster peer as an upstream. You can specify a Consul Enterprise namespace. You can also specify an admin partition in the same datacenter or a WAN-federated datacenter. Unlike the labeled annotation, you can also reference a prepared query as an upstream.
- Service name: Place the service name at the beginning of the annotation to specify the upstream service. You also have the option to append the WAN federated datacenter where the service is deployed.
the upstream namespace after the service name. For additional details about configuring the injector, refer to [Consul Enterprise namespaces](#consul-enterprise-namespaces) .
partition. When specifying a partition, you must also specify a namespace. Place the partition name after the namespace. If you specify the name of the datacenter, it must be the local datacenter. Communicating across partitions using this method is only supported within a
datacenter. For cross partition communication across datacenters, [establish a cluster
peering connection](/consul/docs/k8s/connect/cluster-peering/usage/establish-peering) and set the upstream with a labeled annotation format.
- **Multiple upstreams**: Delimit multiple services or upstreams with commas. You can specify any of the unlabeled, labeled, or prepared query formats when using the supported versions for the formats.
The defaults are set in Helm config via the [`connectInject.sidecarProxy.resources`](/consul/docs/k8s/helm#v-connectinject-sidecarproxy-resources) key.
- `consul.hashicorp.com/enable-sidecar-proxy-lifecycle` - Override the default Helm value [`connectInject.sidecarProxy.lifecycle.defaultEnabled`](/consul/docs/k8s/helm#v-connectinject-sidecarproxy-lifecycle-defaultenabled)
- `consul.hashicorp.com/enable-sidecar-proxy-shutdown-drain-listeners` - Override the default Helm value [`connectInject.sidecarProxy.lifecycle.defaultEnableShutdownDrainListeners`](/consul/docs/k8s/helm#v-connectinject-sidecarproxy-lifecycle-defaultenableshutdowndrainlisteners)
- `consul.hashicorp.com/sidecar-proxy-lifecycle-shutdown-grace-period-seconds` - Override the default Helm value [`connectInject.sidecarProxy.lifecycle.defaultShutdownGracePeriodSeconds`](/consul/docs/k8s/helm#v-connectinject-sidecarproxy-lifecycle-defaultshutdowngraceperiodseconds)
- `consul.hashicorp.com/sidecar-proxy-lifecycle-graceful-port` - Override the default Helm value [`connectInject.sidecarProxy.lifecycle.defaultGracefulPort`](/consul/docs/k8s/helm#v-connectinject-sidecarproxy-lifecycle-defaultgracefulport)
- `consul.hashicorp.com/sidecar-proxy-lifecycle-graceful-shutdown-path` - Override the default Helm value [`connectInject.sidecarProxy.lifecycle.defaultGracefulShutdownPath`](/consul/docs/k8s/helm#v-connectinject-sidecarproxy-lifecycle-defaultgracefulshutdownpath)
- `consul.hashicorp.com/enable-metrics` - Override the default Helm value [`connectInject.metrics.defaultEnabled`](/consul/docs/k8s/helm#v-connectinject-metrics-defaultenabled).
- `consul.hashicorp.com/enable-metrics-merging` - Override the default Helm value [`connectInject.metrics.defaultEnableMerging`](/consul/docs/k8s/helm#v-connectinject-metrics-defaultenablemerging).
- `consul.hashicorp.com/merged-metrics-port` - Override the default Helm value [`connectInject.metrics.defaultMergedMetricsPort`](/consul/docs/k8s/helm#v-connectinject-metrics-defaultmergedmetricsport).
- `consul.hashicorp.com/prometheus-scrape-port` - Override the default Helm value [`connectInject.metrics.defaultPrometheusScrapePort`](/consul/docs/k8s/helm#v-connectinject-metrics-defaultprometheusscrapeport).
- `consul.hashicorp.com/prometheus-scrape-path` - Override the default Helm value [`connectInject.metrics.defaultPrometheusScrapePath`](/consul/docs/k8s/helm#v-connectinject-metrics-defaultprometheusscrapepath).
- `consul.hashicorp.com/connect-inject-mount-volume` - Comma separated list of container names to mount the connect-inject volume into. The volume will be mounted at `/consul/connect-inject`. The connect-inject volume contains Consul internals data needed by the other sidecar containers, for example the `consul` binary, and the Pod's Consul ACL token. This data can be valuable for advanced use-cases, such as making requests to the Consul API from within application containers.
- `consul.hashicorp.com/consul-sidecar-user-volume` - JSON objects as specified by the [Volume pod spec](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.24/#volume-v1-core), that define volumes to add to the Envoy sidecar.
- `consul.hashicorp.com/consul-sidecar-user-volume-mount` - JSON objects as specified by the [Volume mount pod spec](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.24/#volumemount-v1-core), that define volumeMounts to add to the Envoy sidecar.
The following Kubernetes resource annotations could be used on a pod to [Service Sync](https://developer.hashicorp.com/consul/docs/k8s/service-sync) behavior:
- `consul.hashicorp.com/service-port`: Configures the port to register to the Consul Catalog for the Kubernetes service. The annotation value may be a name of a port (recommended) or an exact port value. Refer to [service ports](https://developer.hashicorp.com/consul/docs/k8s/service-sync#service-ports) for more information.
- `consul.hashicorp.com/service-tags`: A comma separated list of strings (without whitespace) to use for registering tags to the service registered to Consul. These custom tags automatically include the `k8s` tag which can't be disabled.
- `consul.hashicorp.com/service-meta-KEY`: A map for specifying service metadata for Consul services. The "KEY" below can be set to any key. This allows you to set multiple meta values.
- `consul.hashicorp.com/service-weight:` - Configures ability to support weighted loadbalancing by service annotation for Catalog Sync. The integer provided will be applied as a weight for the `passing` state for the health of the service. Refer to [weights](/consul/docs/services/configuration/services-configuration-reference#weights) in service configuration for more information on how this is leveraged for services in the Consul catalog.