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

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docs	Helm - Kubernetes	docs-platform-k8s-helm	The Consul Helm chart is the recommended way to install and configure Consul on Kubernetes. In addition to running Consul itself, the Helm chart is the primary method for installing and configuring Consul integrations with Kubernetes such as catalog syncing, Connect injection, and more.

Helm Chart

The Consul Helm chart is the recommended way to install and configure Consul on Kubernetes. In addition to running Consul itself, the Helm chart is the primary method for installing and configuring Consul integrations with Kubernetes such as catalog syncing, Connect injection, and more.

This page assumes general knowledge of Helm and how to use it. Using Helm to install Consul will require that Helm is properly installed and configured with your Kubernetes cluster.

-> Important: The Helm chart is new and may still change significantly over time. Please always run Helm with --dry-run before any install or upgrade to verify changes.

Using the Helm Chart

To use the Helm chart, you must download or clone the consul-helm GitHub repository and run Helm against the directory. We plan to transition to using a real Helm repository soon. When running Helm, we highly recommend you always checkout a specific tagged release of the chart to avoid any instabilities from master.

Prior to this, you must have Helm installed and configured both in your Kubernetes cluster and locally on your machine. The steps to do this are out of the scope of this document, please read the Helm documentation for more information.

Example chart usage:

# Clone the chart repo
$ git clone https://github.com/hashicorp/consul-helm.git
$ cd consul-helm

# Checkout a tagged version
$ git checkout v0.1.0

# Run Helm
$ helm install --dry-run ./

~> Warning: By default, the chart will install everything: a Consul server cluster, client agents on all nodes, feature components, etc. This provides a nice out-of-box experience for new users, but may not be appropriate for a production setup. Consider setting the global.enabled value to false and opt-in to the various components.

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 - These values are global values that affect multiple components of the chart.

  • enabled (boolean: true) - The master enabled/disabled configuration. If this is true, most components will be installed by default. If this is false, no components will be installed by default and manually opt-in is required, such as by setting server.enabled to true.

  • domain (string: "consul") - The domain Consul uses for DNS queries. This is used to configure agents both for DNS listening but also to know what domain to join to join the cluster. This should be consistent throughout the chart, but can be overridden per-component as well.

  • image (string: "consul:latest") - The name of the Docker image (including any tag) for the containers running Consul agents. This should be pinned to a specific version when running in production. Otherwise, other changes to the chart may inadvertently upgrade your Consul version.

  • imageK8S (string: "hashicorp/consul-k8s:latest") - The name of the Docker image (including any tag) for the consul-k8s binary. This is used by components such as catalog sync. This should be pinned to a specific version when running in production. Otherwise, other changes to the chart may inadvertently upgrade the version.

  • datacenter (string: "dc1") - The name of the datacenter that the agent cluster should register as. This may not be changed once the cluster is bootstrapped and running, since Consul doesn't yet support an automatic way to change this value.

• server - Values that configure running a Consul server cluster 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.

  # 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 or HCL 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.

  • 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 /config/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.

  • 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.

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

• client - Values that configure running a Consul client agent 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: false) - 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.

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

  • extraConfig (string: "{}") - A raw string of extra JSON or HCL 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.

  • 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 /config/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.

• dns - Values that configure the 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.

• syncCatalog - Values that configure running 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.

  • 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.

  • 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.

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

• 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 envoy/envoy-alpine.

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

  • 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.

Customizing the Helm Chart

Given the wide variety of use cases, it won't be possible to support every configuration option in the Helm chart's values.yaml file without making it difficult to understand and use. For additional flexibility in changing values that aren't listed above, consider using third-party tools such as kustomize and ship.