Deploying Mattermost on Kubernetes with Helm

Mattermost is an open‑source messaging platform designed for development teams, offering private‑cloud deployment, extensive DevOps tool integrations, and a full DevOps lifecycle support including planning, coding, building, testing, releasing, deploying, and monitoring.

Helm Repository Setup

# helm repo add mattermost https://helm.mattermost.com
# helm repo list
NAME        URL
stable      http://mirror.azure.cn/kubernetes/charts/
gitlab      https://charts.gitlab.io
mattermost  https://helm.mattermost.com

Chart Search and Version Selection

# helm search repo -l mattermost/mattermost-team-edition
NAME                                 CHART VERSION  APP VERSION  DESCRIPTION
mattermost/mattermost-team-edition   3.10.0         5.13.2       Mattermost Team Edition server.
... (other versions omitted for brevity) ...

Download Source for Customization

# helm fetch mattermost/mattermost-team-edition --version=3.10.0

Create Namespace

# kubectl create ns mattermost

Create PersistentVolumes for Data and Plugins

apiVersion: v1
kind: PersistentVolume
metadata:
  name: mattermost-data
  namespace: mattermost
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/data/devops/mattermost/data"
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mattermost-plugins
  namespace: mattermost
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/data/devops/mattermost/plugins"

Apply the PV definitions:

# kubectl create -f pv.yaml
persistentvolume/mattermost-data created
persistentvolume/mattermost-plugins created

Create PostgreSQL Database and User

# CREATE DATABASE mattermost;
# CREATE USER mmuser WITH PASSWORD 'mmuser-password';
# GRANT ALL PRIVILEGES ON DATABASE mattermost TO mmuser;

Customize values.yaml for Persistence and Ingress

persistence:
  data:
    enabled: true
    size: 10Gi
    storageClass: manual
    accessMode: ReadWriteOnce
  plugins:
    enabled: true
    size: 1Gi
    storageClass: manual
    accessMode: ReadWriteOnce
ingress:
  enabled: true
  path: "/"
  annotations:
    kubernetes.io/ingress.class: nginx
  hosts:
    - mm.idevops.site
  tls: []

External Database Configuration (PostgreSQL example)

externalDB:
  enabled: true
  externalDriverType: "postgres"
  externalConnectionString: "postgres://mmuser:[email protected]:5432/mattermost?sslmode=disable&connect_timeout=10"

Verify connectivity:

# psql -h 192.168.1.200 -p 5432 -d mattermost -U mmuser

Deploy the Chart

# helm install mattermost-server --namespace mattermost ./mattermost-team-edition

If deployment fails due to a read‑only configuration file, create a PersistentVolume and PersistentVolumeClaim for /mattermost/config and mount it in the deployment template:

# mkdir -p /data/devops/mattermost/config
# (PV and PVC YAML omitted for brevity)
# Update templates/deployment.yaml to mount the PVC at /mattermost/config

After fixing the configuration, reinstall the chart:

# helm delete mattermost-server --namespace mattermost
# kubectl delete -f ./mattermost-team-edition/config-pvc.yaml
# kubectl delete -f ./mattermost-team-edition/pv.yaml
# kubectl create -f ./mattermost-team-edition/config-pvc.yaml
# kubectl create -f ./mattermost-team-edition/pv.yaml
# helm install mattermost-server --namespace mattermost ./mattermost-team-edition

Access the service at http://mm.idevops.site , create an admin user (admin:Devops.com123), set up a team, and configure language preferences as needed.

Common FAQ: error "no pg_hba.conf entry for host ..." – resolve by adding appropriate host entries to pg_hba.conf and setting listen_addresses = '*' in postgres.conf .