consul/website/source/docs/platform/k8s/helm.html.md

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docs	Helm Chart Reference - Kubernetes	docs-platform-k8s-helm	Reference for the Consul Helm chart.

Helm Chart Reference

Configuration (Values)

The chart is highly customizable using Helm configuration values. Each value has a sane default tuned for an optimal getting started experience with Consul. Before going into production, please review the parameters below and consider if they're appropriate for your deployment.

• global- Holds values that affect multiple components of the chart.

  • enabled (boolean: true) - The master enabled/disabled setting. If true, servers, clients, Consul DNS and the Consul UI will be enabled. Each component can override this default via its component-specific "enabled" config. If false, no components will be installed by default and per-component opt-in is required, such as by setting server.enabled to true.

  • domain (string: "consul") - The domain Consul will answer DNS queries for (see -domain) and the domain services synced from Consul into Kubernetes will have, e.g. service-name.service.consul.

  • image (string: "consul:<latest version>") - The name (and tag) of the Consul Docker image for clients and servers. This can be overridden per component. This should be pinned to a specific version tag, otherwise you may inadvertently upgrade your Consul version.

    Examples:
    
    ```yaml
    # Consul 1.5.0
    image: "consul:1.5.0"
    # Consul Enterprise 1.5.0
    image: "hashicorp/consul-enterprise:1.5.0-ent"
    ```
    

  • imageK8S (string: "hashicorp/consul-k8s:<latest version>") - The name (and tag) of the consul-k8s Docker image that is used for functionality such the catalog sync. This can be overridden per component.

    Note: support for the catalog sync's liveness and readiness probes was added to consul-k8s 0.6.0. If using an older consul-k8s version, you may need to remove these checks to make sync work. If using mesh gateways and bootstrapACLs then must be >= 0.9.0.
    

  • datacenter (string: "dc1") - The name of the datacenter that the agents should register as. This can't be changed once the Consul cluster is up and running since Consul doesn't support an automatic way to change this value currently: https://github.com/hashicorp/consul/issues/1858.

  • enablePodSecurityPolicies (boolean: false) - Controls whether pod security policies are created for the Consul components created by this chart. See https://kubernetes.io/docs/concepts/policy/pod-security-policy/.

  • gossipEncryption - Configures which Kubernetes secret to retrieve Consul's gossip encryption key from (see -encrypt). If secretName or secretKey are not set, gossip encryption will not be enabled. The secret must be in the same namespace that Consul is installed into.

    The secret can be created by running:
    
    ```bash
    $ kubectl create secret generic consul-gossip-encryption-key --from-literal=key=$(consul keygen)
    # To reference, use:
    #   gossipEncryption:
    #     secretName: consul-gossip-encryption-key
    #     secretKey: key
    ```
    
    * <a name="v-global-gossip-encryption-secret-name" href="#v-global-gossip-encryption-secret-name">`secretName`</a> (`string: ""`) - The name of the Kubernetes secret that holds the gossip encryption key. The secret must be in the same namespace that Consul is installed into.
    
    * <a name="v-global-gossip-encryption-secret-key" href="#v-global-gossip-encryption-secret-key">`secretKey`</a> (`string: ""`) - The key within the Kubernetes secret that holds the gossip encryption key.
    

  • bootstrapACLs (boolean: false) - Automatically create and assign ACL tokens within the Consul cluster. This requires servers to be running inside Kubernetes. Additionally requires Consul >= 1.4 and consul-k8s >= 0.8.0.

• server - Values that configure running a Consul server within Kubernetes.

  • enabled (boolean: global.enabled) - If true, the chart will install all the resources necessary for a Consul server cluster. If you're running Consul externally and want agents within Kubernetes to join that cluster, this should probably be false.

  • image (string: global.image) - The name of the Docker image (including any tag) for the containers running Consul server agents.

  • replicas (integer: 3) -The number of server agents to run. This determines the fault tolerance of the cluster. Please see the deployment table for more information.

  • bootstrapExpect (integer: 3) - For new clusters, this is the number of servers to wait for before performing the initial leader election and bootstrap of the cluster. This must be less than or equal to server.replicas. This value is only used when bootstrapping new clusters, it has no effect during ongoing cluster maintenance.

  • storage (string: 10Gi) - This defines the disk size for configuring the servers' StatefulSet storage. For dynamically provisioned storage classes, this is the desired size. For manually defined persistent volumes, this should be set to the disk size of the attached volume.

  • storageClass (string: null) - The StorageClass to use for the servers' StatefulSet storage. It must be able to be dynamically provisioned if you want the storage to be automatically created. For example, to use Local storage classes, the PersistentVolumeClaims would need to be manually created. A null value will use the Kubernetes cluster's default StorageClass. If a default StorageClass does not exist, you will need to create one.

  • connect (boolean: true) - This will enable/disable Connect. Setting this to true will not automatically secure pod communication, this setting will only enable usage of the feature. Consul will automatically initialize a new CA and set of certificates. Additional Connect settings can be configured by setting the server.extraConfig value.

  • resources (string: null) - The resource requests (CPU, memory, etc.) for each of the server agents. This should be a multi-line string mapping directly to a Kubernetes ResourceRequirements object. If this isn't specified, then the pods won't request any specific amount of resources. Setting this is highly recommended.

    ```yaml
    # Resources are defined as a formatted multi-line string:
    resources: |
      requests:
        memory: "10Gi"
      limits:
       memory: "10Gi"
    ```
    

  • updatePartition (integer: 0) - This value is used to carefully control a rolling update of Consul server agents. This value specifies the partition for performing a rolling update. Please read the linked Kubernetes documentation for more information.

  • disruptionBudget - This configures the PodDisruptionBudget for the server cluster.

    • enabled (boolean: true) - This will enable/disable registering a PodDisruptionBudget for the server cluster. If this is enabled, it will only register the budget so long as the server cluster is enabled.

    • maxUnavailable (integer: null) - The maximum number of unavailable pods. By default, this will be automatically computed based on the server.replicas value to be (n/2)-1. If you need to set this to 0, you will need to add a --set 'server.disruptionBudget.maxUnavailable=0' flag to the helm chart installation command because of a limitation in the Helm templating language.

  • extraConfig (string: "{}") - A raw string of extra JSON configuration for Consul servers. This will be saved as-is into a ConfigMap that is read by the Consul server agents. This can be used to add additional configuration that isn't directly exposed by the chart.

    ```yaml
    # ExtraConfig values are formatted as a multi-line string:
    extraConfig: |
      {
        "log_level": "DEBUG"
      }
    ```
    This can also be set using Helm's `--set` flag (consul-helm v0.7.0 and later), using the following syntax:
    
    ```shell
    --set 'server.extraConfig="{"log_level": "DEBUG"}"'
    ```
    

  • extraVolumes (array: []) - A list of extra volumes to mount for server agents. This is useful for bringing in extra data that can be referenced by other configurations at a well known path, such as TLS certificates or Gossip encryption keys. The value of this should be a list of objects. Each object supports the following keys:

    • type (string: required) - Type of the volume, must be one of "configMap" or "secret". Case sensitive.

    • name (string: required) - Name of the configMap or secret to be mounted. This also controls the path that it is mounted to. The volume will be mounted to /consul/userconfig/<name>.

    • load (boolean: false) - If true, then the agent will be configured to automatically load HCL/JSON configuration files from this volume with -config-dir. This defaults to false.

      extraVolumes:
        -  type: "secret"
           name: "consul-certs"
           load: false
      

  • affinity (string) - This value defines the affinity for server pods. It defaults to allowing only a single pod on each node, which minimizes risk of the cluster becoming unusable if a node is lost. If you need to run more pods per node (for example, testing on Minikube), set this value to null.

    ```yaml
    # Recommended default server affinity:
    affinity: |
      podAntiAffinity:
        requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchLabels:
                app: {{ template "consul.name" . }}
                release: "{{ .Release.Name }}"
                component: server
          topologyKey: kubernetes.io/hostname
    ```
    

  • priorityClassName (string) - This value references an existing Kubernetes priorityClassName that can be assigned to server pods.

  • annotations (string) - This value defines additional annotations for server pods. This should be a formatted as a multi-line string.

    ```yaml
    annotations: |
      "sample/annotation1": "foo"
      "sample/annotation2": "bar"
    ```
    

• client - Values that configure running a Consul client on Kubernetes nodes.

  • enabled (boolean: global.enabled) - If true, the chart will install all the resources necessary for a Consul client on every Kubernetes node. This does not require server.enabled, since the agents can be configured to join an external cluster.

  • image (string: global.image) - The name of the Docker image (including any tag) for the containers running Consul client agents.

  • join (array<string>: null) - A list of valid -retry-join values. If this is null (default), then the clients will attempt to automatically join the server cluster running within Kubernetes. This means that with server.enabled set to true, clients will automatically join that cluster. If server.enabled is not true, then a value must be specified so the clients can join a valid cluster.

  • grpc (boolean: true) - If true, agents will enable their GRPC listener on port 8502 and expose it to the host. This will use slightly more resources, but is required for Connect.

  • resources (string: null) - The resource requests (CPU, memory, etc.) for each of the client agents. This should be a multi-line string mapping directly to a Kubernetes ResourceRequirements object. If this isn't specified, then the pods won't request any specific amount of resources.

    ```yaml
    # Resources are defined as a formatted multi-line string:
    resources: |
      requests:
        memory: "10Gi"
      limits:
        memory: "10Gi"
    ```
    

  • extraConfig (string: "{}") - A raw string of extra JSON configuration for Consul clients. This will be saved as-is into a ConfigMap that is read by the Consul agents. This can be used to add additional configuration that isn't directly exposed by the chart.

    ```yaml
    # ExtraConfig values are formatted as a multi-line string:
    extraConfig: |
      {
        "log_level": "DEBUG"
      }
    ```
    This can also be set using Helm's `--set` flag (consul-helm v0.7.0 and later), using the following syntax:
    
    ```shell
    --set 'client.extraConfig="{"log_level": "DEBUG"}"'
    ```
    

  • extraVolumes (array: []) - A list of extra volumes to mount for client agents. This is useful for bringing in extra data that can be referenced by other configurations at a well known path, such as TLS certificates or Gossip encryption keys. The value of this should be a list of objects. Each object supports the following keys:

    • type (string: required) - Type of the volume, must be one of "configMap" or "secret". Case sensitive.

    • name (string: required) - Name of the configMap or secret to be mounted. This also controls the path that it is mounted to. The volume will be mounted to /consul/userconfig/<name>.

    • load (boolean: false) - If true, then the agent will be configured to automatically load HCL/JSON configuration files from this volume with -config-dir. This defaults to false.

      extraVolumes:
        -  type: "secret"
           name: "consul-certs"
           load: false
      

  • priorityClassName (string) - This value references an existing Kubernetes priorityClassName that can be assigned to client pods.

  • annotations (string) - This value defines additional annotations for client pods. This should be a formatted as a multi-line string.

    ```yaml
    annotations: |
      "sample/annotation1": "foo"
      "sample/annotation2": "bar"
    ```
    

• dns - Values that configure Consul DNS service.

  • enabled (boolean: global.enabled) - If true, a consul-dns service will be created that exposes port 53 for TCP and UDP to the running Consul agents (servers and clients). This can then be used to configure kube-dns. The Helm chart does not automatically configure kube-dns.

  • clusterIP (string) - If defined, this value configures the cluster IP of the DNS service.

• syncCatalog - Values that configure the service sync process.

  • enabled (boolean: false) - If true, the chart will install all the resources necessary for the catalog sync process to run.

  • image (string: global.imageK8S) - The name of the Docker image (including any tag) for consul-k8s to run the sync program.

  • default (boolean: true) - If true, all valid services in K8S are synced by default. If false, the service must be annotated properly to sync. In either case an annotation can override the default.

  • toConsul (boolean: true) - If true, will sync Kubernetes services to Consul. This can be disabled to have a one-way sync.

  • toK8S (boolean: true) - If true, will sync Consul services to Kubernetes. This can be disabled to have a one-way sync.

  • k8sPrefix (string: "") - A prefix to prepend to all services registered in Kubernetes from Consul. This defaults to "" where no prefix is prepended; Consul services are synced with the same name to Kubernetes. (Consul -> Kubernetes sync only)

  • consulPrefix (string: "") - A prefix to prepend to all services registered in Consul from Kubernetes. This defaults to "" where no prefix is prepended. Service names within Kubernetes remain unchanged. (Kubernetes -> Consul sync only)

  • k8sTag (string: null) - An optional tag that is applied to all of the Kubernetes services that are synced into Consul. If nothing is set, this defaults to "k8s". (Kubernetes -> Consul sync only)

  • syncClusterIPServices (boolean: true) - If true, will sync Kubernetes ClusterIP services to Consul. This can be disabled to have the sync ignore ClusterIP-type services.

  • nodePortSyncType (string: ExternalFirst) - Configures the type of syncing that happens for NodePort services. The only valid options are: ExternalOnly, InternalOnly, and ExternalFirst. ExternalOnly will only use a node's ExternalIP address for the sync, otherwise the service will not be synced. InternalOnly uses the node's InternalIP address. ExternalFirst will preferentially use the node's ExternalIP address, but if it doesn't exist, it will use the node's InternalIP address instead.

  • aclSyncToken - references a Kubernetes secret that contains an existing Consul ACL token. This will provide the sync process the correct permissions. This is only needed if ACLs are enabled on the Consul cluster.

    • secretName (string: null) - The name of the Kubernetes secret. This defaults to null.

    • secretKey (string: null) - The key for the Kubernetes secret. This defaults to null.

• ui - Values that configure the Consul UI.

  • enabled (boolean: global.enabled) - If true, the UI will be enabled. This will only enable the UI, it doesn't automatically register any service for external access. The UI will only be enabled on server agents. If server.enabled is false, then this setting has no effect. To expose the UI in some way, you must configure ui.service.

  • service - This configures the Service resource registered for the Consul UI.

    • enabled (boolean: true) - This will enable/disable registering a Kubernetes Service for the Consul UI. This value only takes effect if ui.enabled is true and taking effect.

    • type (string: null) - The service type to register. This defaults to null which doesn't set an explicit service type, which typically is defaulted to "ClusterIP" by Kubernetes. The available service types are documented on the Kubernetes website.

• connectInject - Values that configure running the Connect injector.

  • enabled (boolean: false) - If true, the chart will install all the resources necessary for the Connect injector process to run. This will enable the injector but will require pods to opt-in with an annotation by default.

  • image (string: global.imageK8S) - The name of the Docker image (including any tag) for the consul-k8s binary.

  • default (boolean: false) - If true, the injector will inject the Connect sidecar into all pods by default. Otherwise, pods must specify the. injection annotation to opt-in to Connect injection. If this is true, pods can use the same annotation to explicitly opt-out of injection.

  • imageConsul (string: global.image) - The name of the Docker image (including any tag) for Consul. This is used for proxy service registration, Envoy configuration, etc.

  • imageEnvoy (string: "") - The name of the Docker image (including any tag) for the Envoy sidecar. envoy must be on the executable path within this image. This Envoy version must be compatible with the Consul version used by the injector. This defaults to letting the injector choose the Envoy image, which is usually envoyproxy/envoy-alpine.

  • namespaceSelector (string: "") - A selector for restricting injection to only matching namespaces. By default all namespaces except kube-system and kube-public will have injection enabled.

    ```yaml
    namespaceSelector: |
      matchLabels:
        namespace-label: label-value
    ```
    

  • certs - The certs section configures how the webhook TLS certs are configured. These are the TLS certs for the Kube apiserver communicating to the webhook. By default, the injector will generate and manage its own certs, but this requires the ability for the injector to update its own MutatingWebhookConfiguration. In a production environment, custom certs should probably be used. Configure the values below to enable this.

    • secretName (string: null) - secretName is the name of the Kubernetes secret that has the TLS certificate and private key to serve the injector webhook. If this is null, then the injector will default to its automatic management mode.

    • caBundle (string: "") - The PEM-encoded CA public certificate bundle for the TLS certificate served by the injector. This must be specified as a string and can't come from a secret because it must be statically configured on the Kubernetes MutatingAdmissionWebhook resource. This only needs to be specified if secretName is not null.

    • certName (string: "tls.crt") - The name of the certificate file within the secretName secret.

    • keyName (string: "tls.key") - The name of the private key for the certificate file within the secretName secret.

  • aclBindingRuleSelector (string: "serviceaccount.name!=default") - A selector for restricting automatic injection to only matching services based on their associated service account. By default, services using the default Kubernetes service account will not have a proxy injected.

  • centralConfig - Values that configure Consul's central configuration feature (requires Consul v1.5+ and consul-k8s v0.8.1+).

    • enabled (boolean: false) - Turns on the central configuration feature. Pods that have a Connect proxy injected will have their service automatically registered in this central configuration.

    • defaultProtocol (string: null) - If defined, this value will be used as the default protocol type for all services registered with the central configuration. This can be overridden by using the protocol annotation directly on any pod spec.

    • proxyDefaults (string: "{}") - This value is a raw json string that will be applied to all Connect proxy sidecar pods. It can include any valid configuration for the configured proxy.

      # proxyDefaults values are formatted as a multi-line string:
      proxyDefaults: |
        {
          "envoy_dogstatsd_url": "udp://127.0.0.1:9125"
        }  
      

Helm Chart Examples

The below config.yaml results in a single server Consul cluster with a LoadBalancer to allow external access to the UI and API.

# config.yaml
server:
  replicas: 1
  bootstrapExpect: 1

ui:
  service:
    type: LoadBalancer

The below config.yaml results in a three server Consul Enterprise cluster with 100GB of storage and automatic Connect injection.

Note, this would require a secret that contains the enterprise license key.

# config.yaml
global:
  image: "hashicorp/consul-enterprise:1.4.2-ent"

server:
  replicas: 3
  bootstrapExpect: 3
  enterpriseLicense:
    secretName: "consul-license"
    secretKey: "key"
  storage: 100Gi
  connect: true

client:
  grpc: true

connectInject:
  enabled: true
  default: false

Customizing the Helm Chart

Consul within Kubernetes is highly configurable and the Helm chart contains dozens of the most commonly used configuration options. If you need to extend the Helm chart with additional options, we recommend using a third-party tool, such as kustomize or ship. Note that the Helm chart heavily relies on Helm lifecycle hooks, and so features like bootstrapping ACLs or TLS will not work as expected. Additionally, we can make changes to the internal implementation (e.g., renaming template files) that may be backward incompatible with such customizations.