--- layout: docs page_title: Install with Helm Chart - Kubernetes description: >- Consul can run directly on Kubernetes, both in server or client mode. For pure-Kubernetes workloads, this enables Consul to also exist purely within Kubernetes. For heterogeneous workloads, Consul agents can join a server running inside or outside of Kubernetes. --- # Installing Consul on Kubernetes Consul can run directly on Kubernetes, both in server or client mode. For pure-Kubernetes workloads, this enables Consul to also exist purely within Kubernetes. For heterogeneous workloads, Consul agents can join a server running inside or outside of Kubernetes. You can install Consul on Kubernetes using the following methods: 1. [Helm chart install](#helm-chart-installation) 1. [Consul K8s CLI install ALPHA.](#consul-k8s-cli-installation) Refer to the [architecture](/docs/k8s/installation/install#architecture) section to learn more about the general architecture of Consul on Kubernetes. For a hands-on experience with Consul as a service mesh for Kubernetes, follow the [Getting Started with Consul service mesh](https://learn.hashicorp.com/tutorials/consul/service-mesh-deploy?utm_source=WEBSITE&utm_medium=WEB_IO&utm_offer=ARTICLE_PAGE&utm_content=DOCS) tutorial. ## Helm Chart Installation The recommended way to run Consul on Kubernetes is via the [Helm chart](/docs/k8s/helm). This will install and configure all the necessary components to run Consul. The configuration enables you to run a server cluster, a client cluster, or both. Step-by-step tutorials for how to deploy Consul to Kubernetes, please see our [Deploy to Kubernetes](https://learn.hashicorp.com/collections/consul/kubernetes-deploy) collection. This collection includes configuration caveats for single-node deployments. The Helm chart exposes several useful configurations and automatically sets up complex resources, but it **does not automatically operate Consul.** You must still become familiar with how to monitor, backup, upgrade, etc. the Consul cluster. The Helm chart has no required configuration and will install a Consul cluster with default configurations. We strongly recommend [learning about the configuration options](/docs/k8s/helm#configuration-values) prior to going to production. ~> **Security Warning:** By default, the chart will install an insecure configuration of Consul. This provides a less complicated out-of-box experience for new users, but is not appropriate for a production setup. We strongly recommend using a properly-secured Kubernetes cluster or making sure that you understand and enable the [recommended security features](/docs/internals/security). Currently, some of these features are not supported in the Helm chart and require additional manual configuration. ### Prerequisites The Consul Helm only supports Helm 3. Install the latest version of the Helm CLI here: [Installing Helm](https://helm.sh/docs/intro/install/). ### Installing Consul 1. Add the HashiCorp Helm Repository: ```shell-session $ helm repo add hashicorp https://helm.releases.hashicorp.com "hashicorp" has been added to your repositories ``` 1. Verify that you have access to the consul chart: ```shell-session $ helm search repo hashicorp/consul NAME CHART VERSION APP VERSION DESCRIPTION hashicorp/consul 0.32.0 1.10.0 Official HashiCorp Consul Chart ``` 1. Issue the following command to install Consul with the default configuration using Helm 3: ````shell-session $ helm install consul hashicorp/consul --set global.name=consul NAME: consul ... ``` The Helm chart does everything to set up a recommended Consul-on-Kubernetes deployment. After installation, a Consul cluster will be formed, a leader will be elected, and every node will have a running Consul agent. ### Customizing Your Installation If you want to customize your installation, create a `config.yaml` file to override the default settings. You can learn what settings are available by running `helm inspect values hashicorp/consul` or by reading the [Helm Chart Reference](/docs/k8s/helm). For example, if you want to enable the [Consul Connect](/docs/k8s/connect) feature, use the following config file: ```yaml global: name: consul connectInject: enabled: true controller: enabled: true ```` Once you've created your `config.yaml` file, run `helm install` with the `-f` flag: ```shell-session $ helm install consul hashicorp/consul -f config.yaml NAME: consul ... ``` If you've already installed Consul and want to make changes, you'll need to run `helm upgrade`. See [Upgrading](/docs/k8s/operations/upgrading) for more details. ## Consul K8s CLI Installation You can install Consul on Kubernetes using the Consul K8s CLI tool. The tool is currently availabe as an alpha release and is not recommended for production environments. 1. Download and build the CLI as described in the [Consul K8s CLI reference](/docs/k8s/k8s-cli). 1. Issue the `install` subcommand to install Consul on Kubernetes: ```shell-session consul-k8s install ``` Refer to the [Consul K8s CLI reference](/docs/k8s/k8s-cli) for details about all commands and available options. If you did not set the `-auto-approve` option to `true`, you will be prompted to proceed with the installation if the pre-install checks pass. ```shell-session ==> Pre-Install Checks ✓ No existing installations found ✓ No previous persistent volume claims found ✓ No previous secrets found ==> Consul Installation Summary Installation name: consul Namespace: myns Overrides: connectInject: enabled: true global: name: consul server: bootstrapExpect: 1 replicas: 1 Proceed with installation? (y/n) ``` 1. Enter `y` to proceed. The pre-install checks may fail if existing `PersistentVolumeClaims` (PVC) are detected. Refer to the [uninstall instructions](/docs/k8s/operations/uninstall#uninstall-consul) for information about removing PVCs. ## Viewing the Consul UI The Consul UI is enabled by default when using the Helm chart. For security reasons, it isn't exposed via a `LoadBalancer` Service by default so you must use `kubectl port-forward` to visit the UI. #### TLS Disabled If running with TLS disabled, the Consul UI will be accessible via http on port 8500: ```shell-session $ kubectl port-forward service/consul-server 8500:8500 ... ``` Once the port is forwarded navigate to [http://localhost:8500](http://localhost:8500). #### TLS Enabled If running with TLS enabled, the Consul UI will be accessible via https on port 8501: ```shell-session $ kubectl port-forward service/consul-server 8501:8501 ... ``` Once the port is forwarded navigate to [https://localhost:8501](https://localhost:8501). ~> You'll need to click through an SSL warning from your browser because the Consul certificate authority is self-signed and not in the browser's trust store. #### ACLs Enabled If ACLs are enabled, you will need to input an ACL token into the UI in order to see all resources and make modifications. To retrieve the bootstrap token that has full permissions, run: ```shell-session $ kubectl get secrets/consul-bootstrap-acl-token --template={{.data.token}} | base64 --decode e7924dd1-dc3f-f644-da54-81a73ba0a178% ``` Then paste the token into the UI under the ACLs tab (without the `%`). ~> NOTE: If using multi-cluster federation, your kubectl context must be in the primary datacenter to retrieve the bootstrap token since secondary datacenters use a separate token with less permissions. ### Exposing the UI via a service If you want to expose the UI via a Kubernetes Service, configure the [`ui.service` chart values](/docs/k8s/helm#v-ui-service). This service will allow requests to the Consul servers so it should not be open to the world. ## Accessing the Consul HTTP API The Consul HTTP API should be accessed by communicating to the local agent running on the same node. While technically any listening agent (client or server) can respond to the HTTP API, communicating with the local agent has important caching behavior, and allows you to use the simpler [`/agent` endpoints for services and checks](/api/agent). For Consul installed via the Helm chart, a client agent is installed on each Kubernetes node. This is explained in the [architecture](/docs/k8s/installation/install#client-agents) section. To access the agent, you may use the [downward API](https://kubernetes.io/docs/tasks/inject-data-application/downward-api-volume-expose-pod-information/). An example pod specification is shown below. In addition to pods, anything with a pod template can also access the downward API and can therefore also access Consul: StatefulSets, Deployments, Jobs, etc. ```yaml apiVersion: v1 kind: Pod metadata: name: consul-example spec: containers: - name: example image: 'consul:latest' env: - name: HOST_IP valueFrom: fieldRef: fieldPath: status.hostIP command: - '/bin/sh' - '-ec' - | export CONSUL_HTTP_ADDR="${HOST_IP}:8500" consul kv put hello world restartPolicy: Never ``` An example `Deployment` is also shown below to show how the host IP can be accessed from nested pod specifications: ```yaml apiVersion: apps/v1 kind: Deployment metadata: name: consul-example-deployment spec: replicas: 1 selector: matchLabels: app: consul-example template: metadata: labels: app: consul-example spec: containers: - name: example image: 'consul:latest' env: - name: HOST_IP valueFrom: fieldRef: fieldPath: status.hostIP command: - '/bin/sh' - '-ec' - | export CONSUL_HTTP_ADDR="${HOST_IP}:8500" consul kv put hello world ``` ## Architecture Consul runs on Kubernetes with the same [architecture](/docs/internals/architecture) as other platforms. There are some benefits Kubernetes can provide that eases operating a Consul cluster and we document those below. The standard [production deployment guide](https://learn.hashicorp.com/consul/datacenter-deploy/deployment-guide) is still an important read even if running Consul within Kubernetes. Each section below will outline the different components of running Consul on Kubernetes and an overview of the resources that are used within the Kubernetes cluster. ### Server Agents The server agents are run as a **StatefulSet**, using persistent volume claims to store the server state. This also ensures that the [node ID](/docs/agent/options#_node_id) is persisted so that servers can be rescheduled onto new IP addresses without causing issues. The server agents are configured with [anti-affinity](https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity) rules so that they are placed on different nodes. A readiness probe is configured that marks the pod as ready only when it has established a leader. A **Service** is registered to represent the servers and expose the various ports. The DNS address of this service is used to join the servers to each other without requiring any other access to the Kubernetes cluster. The service is configured to publish non-ready endpoints so that it can be used for joining during bootstrap and upgrades. Additionally, a **PodDisruptionBudget** is configured so the Consul server cluster maintains quorum during voluntary operational events. The maximum unavailable is `(n/2)-1` where `n` is the number of server agents. -> **Note:** Kubernetes and Helm do not delete Persistent Volumes or Persistent Volume Claims when a [StatefulSet is deleted](https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/#stable-storage), so this must done manually when removing servers. ### Client Agents The client agents are run as a **DaemonSet**. This places one agent (within its own pod) on each Kubernetes node. The clients expose the Consul HTTP API via a static port (8500) bound to the host port. This enables all other pods on the node to connect to the node-local agent using the host IP that can be retrieved via the Kubernetes downward API. See [accessing the Consul HTTP API](/docs/k8s/installation/install#accessing-the-consul-http-api) for an example. We do not use a **NodePort** Kubernetes service because requests to node ports get randomly routed to any pod in the service and we need to be able to route directly to the Consul client running on our node. -> **Note:** There is no way to bind to a local-only host port. Therefore, any other node can connect to the agent. This should be considered for security. For a properly production-secured agent with TLS and ACLs, this is safe. We run Consul clients as a **DaemonSet** instead of running a client in each application pod as a sidecar because this would turn a pod into a "node" in Consul and also causes an explosion of resource usage since every pod needs a Consul agent. Service registration should be handled via the catalog syncing feature with Services rather than pods. -> **Note:** Due to a limitation of anti-affinity rules with DaemonSets, a client-mode agent runs alongside server-mode agents in Kubernetes. This duplication wastes some resources, but otherwise functions perfectly fine. ## Next Steps If you are still considering a move to Kubernetes, or to Consul on Kubernetes specifically, our [Migrate to Microservices with Consul Service Mesh on Kubernetes](https://learn.hashicorp.com/collections/consul/microservices?utm_source=WEBSITE&utm_medium=WEB_IO&utm_offer=ARTICLE_PAGE&utm_content=DOCS) collection uses an example application written by a fictional company to illustrate why and how organizations can migrate from monolith to microservices using Consul service mesh on Kubernetes. The case study in this collection should provide information valuable for understanding how to develop services that leverage Consul during any stage of your microservices journey.