Deploy MySQL on Kubernetes: Step‑by‑Step Guide with Helm, PVs, and Monitoring

Overview

MySQL is a relational database management system originally developed by MySQL AB and now owned by Oracle. It is one of the most popular RDBMS for web applications. Deploying MySQL on Kubernetes offers resource isolation, dynamic scaling, environment consistency, and easier operations.

Resource isolation

Dynamic scaling

Environment consistency

Operational convenience

Official documentation: https://docs.oracle.com/en-us/iaas/mysql-database/doc/getting-started.html

Deploying a Primary‑Replica MySQL Cluster

1) Add Helm repository

helm repo add bitnami https://charts.bitnami.com/bitnami
helm pull bitnami/mysql
tar -xf mysql-9.3.3.tgz

2) Modify configuration

Edit mysql/values.yaml to set image registry, repository, tag, architecture, persistence, storageClass, nodePort, and other parameters.

... 
image:
  registry: myharbor.com
  repository: bigdata/mysql
  tag: 8.0.30-debian-11-r15

architecture: replication

primary:
  persistence:
    enabled: true
    size: 10Gi
    storageClass: "mysql-local-storage"
    local:
    - name: mysql-0
      host: "local-168-182-110"
      path: "/opt/bigdata/servers/mysql/data/data1"
  service:
    type: NodePort
    nodePorts:
      mysql: "30306"

secondary:
  replicaCount: 2
  persistence:
    enabled: true
    size: 10Gi
    storageClass: "mysql-local-storage"
    local:
    - name: mysql-1
      host: "local-168-182-111"
      path: "/opt/bigdata/servers/mysql/data/data1"
    - name: mysql-2
      host: "local-168-182-112"
      path: "/opt/bigdata/servers/mysql/data/data1"
  service:
    type: NodePort
    nodePorts:
      mysql: "30307"

metrics:
  enabled: true
  image:
    registry: myharbor.com
    repository: bigdata/mysqld-exporter
    tag: 0.14.0-debian-11-r33

3) Add PersistentVolume definitions

{{- range .Values.primary.persistence.local }}
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: {{ .name }}
  labels:
    name: {{ .name }}
spec:
  storageClassName: {{ $.Values.primary.persistence.storageClass }}
  capacity:
    storage: {{ $.Values.primary.persistence.size }}
  accessModes:
    - ReadWriteOnce
  local:
    path: {{ .path }}
  nodeAffinity:
    required:
      nodeSelectorTerms:
        - matchExpressions:
            - key: kubernetes.io/hostname
              operator: In
              values:
                - {{ .host }}
---
{{- end }}
{{- range .Values.secondary.persistence.local }}
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: {{ .name }}
  labels:
    name: {{ .name }}
spec:
  storageClassName: {{ $.Values.secondary.persistence.storageClass }}
  capacity:
    storage: {{ $.Values.secondary.persistence.size }}
  accessModes:
    - ReadWriteOnce
  local:
    path: {{ .path }}
  nodeAffinity:
    required:
      nodeSelectorTerms:
        - matchExpressions:
            - key: kubernetes.io/hostname
              operator: In
              values:
                - {{ .host }}
---
{{- end }}

4) Create StorageClass

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: {{ .Values.primary.persistence.storageClass }}
provisioner: kubernetes.io/no-provisioner

5) Install the chart

# Create persistent directories
mkdir -p /opt/bigdata/servers/mysql/data/data1

# Pull and push MySQL image to private registry
docker pull docker.io/bitnami/mysql:8.0.30-debian-11-r15
docker tag docker.io/bitnami/mysql:8.0.30-debian-11-r15 myharbor.com/bigdata/mysql:8.0.30-debian-11-r15
docker push myharbor.com/bigdata/mysql:8.0.30-debian-11-r15

# Pull and push mysqld‑exporter image
docker pull docker.io/bitnami/mysqld-exporter:0.14.0-debian-11-r33
docker tag docker.io/bitnami/mysqld-exporter:0.14.0-debian-11-r33 myharbor.com/bigdata/mysqld-exporter:0.14.0-debian-11-r33
docker push myharbor.com/bigdata/mysqld-exporter:0.14.0-debian-11-r33

# Install Helm chart
helm install mysql ./mysql -n mysql --create-namespace

Check deployment status with kubectl get pods -w -n mysql and retrieve the root password:

MYSQL_ROOT_PASSWORD=$(kubectl get secret -n mysql mysql -o jsonpath="{.data.mysql-root-password}" | base64 -d)

NAME: mysql
LAST DEPLOYED: Mon Sep 19 23:57:18 2022
NAMESPACE: mysql
STATUS: deployed
REVISION: 1
CHART: mysql 9.3.3
APP VERSION: 8.0.30

6) Test and verify

Primary service (read/write) is reachable at mysql-primary.mysql.svc.cluster.local:3306; secondary service (read‑only) at mysql-secondary.mysql.svc.cluster.local:3306. Use a client pod to run MySQL commands against each endpoint.

7) Prometheus monitoring

Deploy the mysqld‑exporter sidecar, forward port 9104, and query metrics (e.g.,

kubectl port-forward -n mysql svc/mysql-metrics 9104:9104 &

then curl http://127.0.0.1:9104/metrics). Grafana can visualize the metrics; retrieve the admin password with:

kubectl get secret -n grafana grafana -o jsonpath="{.data.admin-password}" | base64 --decode

8) Uninstall

helm uninstall mysql -n mysql
kubectl delete pod -n mysql $(kubectl get pod -n mysql | awk 'NR>1{print $1}') --force
kubectl patch ns mysql -p '{"metadata":{"finalizers":null}}'
kubectl delete ns mysql --force

Conclusion

The guide implements a primary‑replica MySQL cluster on Kubernetes but does not cover high‑availability solutions; those are left for future exploration.