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Helm chart

Deploying Comentario in a Kubernetes cluster with Helm

You can easily deploy Comentario into a Kubernetes cluster using a Helm chart.

Kubernetes is a modern, production-grade cloud deployment system developed by Google.

Kubernetes provides numerous tools for reliable, scalable cloud deployments, but its flexibility may well prove overwhelming, especially when it comes to deploying multiple components.

Comentario addresses that complexity by providing a so-called Helm chart, which greatly facilitates server deployment in a cloud environment.

The chart is available in Comentario git repository in the resources/helm/comentario directory.

Prerequisites

  1. Helm package manager 3.x is installed.
  2. We’re using certmanager for dealing with SSL certificates in the cluster: requesting and renewing.
  3. Once you have certmanager up and running, create a new ClusterIssuer for Let’s Encrypt. Or, even better, two issuers: letsencrypt-staging for experimenting with your installation (so that you don’t hit Let’s Encrypt usage limits) and letsencrypt-prod for production usage.

Namespace

All examples below use the same namespace, referred to as $NAMESPACE. If it doesn’t exist yet, create it with:

kubectl create namespace $NAMESPACE

Deploy PostgreSQL

Comentario requires a PostgreSQL server (refer to Requirements for details), which has to be installed separately.

The easiest way to do that in a Kubernetes cluster is by using a Helm chart by Bitnami.

Step 1: Before installing PostgreSQL, it may be a good idea to manually create a storage volume (PVC), because it would give you a full control over its size and lifecycle.

You can create a volume of 1 GiB by using the provided postgres-pvc.yaml:

kubectl create -f resources/k8s/postgres-pvc.yaml --namespace $NAMESPACE

Step 2: install the PostgreSQL server:

helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update
helm install \
    --namespace $NAMESPACE \
    --set "image.repository=postgres" \
    --set "image.tag=16-alpine" \
    --set "primary.persistence.existingClaim=comentario-postgres-pvc" \
    --set "global.postgresql.auth.postgresPassword=SECR3t" \
    --set "global.postgresql.auth.database=comentario" \
    --wait \
    comentario-postgres \
    bitnami/postgresql

After this, a new release called comentario-postgres will be installed, with PostgreSQL version 16-alpine (adjust values as needed), user postgres and password SECR3t.

Deploy Comentario server

  1. Edit the values in resources/k8s/comentario-secrets.yaml as required (see Configuration for details) and copy-paste its contents into comentario-secrets.yaml (indent with 4 spaces)
  2. Create the secret: kubectl create -f resources/k8s/comentario-secrets.yaml --namespace $NAMESPACE
  3. Install Comentario using Helm (adjust the values as you see fit):
helm upgrade --install \
    --namespace $NAMESPACE \                            # The same namespace value as above
    --set "clusterIssuer=letsencrypt-staging" \         # Replace with letsencrypt-prod when you're ready for production
    --set "image.repository=registry.gitlab.com/comentario/comentario" \
    --set "image.tag=<VERSION>" \                       # Use the desired Comentario version here
    --set "comentario.secretName=comentario-secrets" \  # This is the name of the secret from resources/k8s/comentario-secrets.yaml
    --set "comentario.smtpHost=mail.example.com" \      # Name of the SMTP host you're using for emails
    --set "comentario.smtpFromAddress=x@example.com" \  # Email to set in the Reply field
    --set "ingress.host=comment.example.com" \          # Domain where your Comentario instance should be reachable on 
    my-comentario \                                     # Name of your instance (and Helm release)
    resources/helm/comentario

Backing up the database

To get a full database dump from the PostgreSQL database running in the cluster, issue the following command (assuming your PostgreSQL instance is named comentario-postgres):

kubectl exec -t -n $NAMESPACE \
    $(kubectl get -n $NAMESPACE pods -l app.kubernetes.io/instance=comentario-postgres -o name) \
    -- pg_dump -U postgres -d comentario > /path/to/comentario.sql

Restoring the database from backup

To restore the database from a previously downloaded dump file (see above), you can use these commands (also assuming your PostgreSQL instance is named comentario-postgres).

We cannot send it via the pipe directly (I’m not sure why), so we copy it over first and clean up afterwards.

PG_POD=$(kubectl get -n $NAMESPACE pods -l app.kubernetes.io/instance=comentario-postgres -o 'jsonpath={.items..metadata.name}')
kubectl cp -n $NAMESPACE /path/to/comentario.sql $PG_POD:/tmp/c.sql
kubectl exec -t -n $NAMESPACE $PG_POD -- psql -U postgres -d comentario -f /tmp/c.sql
kubectl exec -t -n $NAMESPACE $PG_POD -- rm /tmp/c.sql