consul/website/source/docs/platform/k8s/servers-outside-kubernetes.html.md

layout	page_title	sidebar_current	description
docs	Consul Servers Outside of Kubernetes - Kubernetes	docs-platform-k8s-run-servers-outside	Running Consul servers outside of Kubernetes

Consul Servers Outside of Kubernetes

If you have a Consul cluster already running, you can configure your Consul clients inside Kubernetes to join this existing cluster.

The below config.yaml file shows how to configure the Helm chart to install Consul clients that will join an existing cluster.

The global.enabled value first disables all chart components by default so that each component is opt-in. This allows us to only setup the client agents. We then opt-in to the client agents by setting client.enabled to true.

Next, client.exposeGossipPorts can be set to true or false depending on if you want the clients to be exposed on the Kubernetes node IPs (true) or their pod IPs (false).

Finally, client.join is set to an array of valid -retry-join values. In the example above, a fake cloud auto-join value is specified. This should be set to resolve to the proper addresses of your existing Consul cluster.

# config.yaml
global:
  enabled: false

client:
  enabled: true
  # Set this to true to expose the Consul clients using the Kubernetes node
  # IPs. If false, the pod IPs must be routable from the external servers.
  exposeGossipPorts: true
  join:
    - "provider=my-cloud config=val ..."

-> Networking: Note that for the Kubernetes nodes to join an existing cluster, the nodes (and specifically the agent pods) must be able to connect to all other server and client agents inside and outside of Kubernetes. If this isn't possible, consider running a separate Consul cluster inside Kubernetes and federating it with your cluster outside Kubernetes. You may also consider adopting Consul Enterprise for network segments.