Create ConfigMap

Introduction

ConfigMap allow you to decouple configuration artifacts and secrets from image content to keep containerized applications portable. Using ConfigMap, you can independently control the MySQL configuration.

Create the mysql Namespace

We will create a new Namespace called mysql that will host all the components.

kubectl create namespace mysql

Create ConfigMap

Run the following commands to create the ConfigMap.

cd ${HOME}/environment/ebs_statefulset

cat << EoF > ${HOME}/environment/ebs_statefulset/mysql-configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-config
  namespace: mysql
  labels:
    app: mysql
data:
  master.cnf: |
    # Apply this config only on the leader.
    [mysqld]
    log-bin
  slave.cnf: |
    # Apply this config only on followers.
    [mysqld]
    super-read-only
EoF

The ConfigMap stores master.cnf, slave.cnf and passes them when initializing leader and follower pods defined in StatefulSet:

  • master.cnf is for the MySQL leader pod which has binary log option (log-bin) to provide a record of the data changes to be sent to follower servers.
  • slave.cnf is for follower pods which have super-read-only option.

Create “mysql-config” ConfigMap.

kubectl create -f ${HOME}/environment/ebs_statefulset/mysql-configmap.yaml