erlang-cluster

Erlang nodes running in a cluster on the nodes in a Kubernetes cluster :)

This project demonstrates the following:

• Running Erlang nodes in a Kubernetes cluster.
• Automatic clustering between the Erlang nodes, using DNS discovery.
• Using TLS for Erlang distribution between the nodes.
• Automatic certificate provisioning using cert-manager.
• Using Erlang/OTP's SSH daemon for the remote console.

Contents

• erlclu: the Erlang node.
• erlclu-cert-init: init container that provisions the certificates.
• erlclu-request-cleanup: cron job that cleans up completed/stale certificate requests.
• k8s: Kubernetes manifests.

Deploying it

1. If you want ArgoCD to track this branch: argocd app set erlang-cluster --revision BRANCH
2. Hack hack hack.
3. Run make at the top-level. This will build and push the container images.
4. Update the image tags in the k8s/ directory. Note that + in the semver is changed to _ in the image tag. If you're working on a branch, you can use the branch name. Use make RELEASE_VSN=0.15.1 (for example) if you don't want the suffix.
5. Either:
   • kubectl apply -k k8s/ (note: -k, not -f; we use kustomize)
   • argocd app sync erlang-cluster
6. If you've made no changes to the deployment, but you want to roll out a new container image:
   • kubectl --namespace erlclu rollout restart deployment erlclu

Or, in 'dev' mode

1. Hack hack hack.
2. make RELEASE_VSN=dev all deploy