CODEWITHSUNDEEP
kubernetes
EoinHanan
EoinHanan

Reputation: 77

How to initialise MySQL data in a replicated stateful

I have created a persistent MySQL database on a Kubernetes Cluster following this tutorial. I am trying to create the tables on initialization but cant get it to work.

I tried two different approaches.

First creating a new Config map:

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-initdb-config
data:
  initdb.sql: |
    #SQL GOES HERE

And I added it to the volumes here with the stateful service (the commented out lines are what I added):

      volumes:
        - name: conf
          emptyDir: {}
        - name: config-map
          configMap:
            name: mysql
#        - name: mysql-initdb
#          configMap:
#            name: mysql-initdb-config

I also tried add the SQL data into the current config map in use:

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql
  namespace: thesis
  labels:
    app: mysql
data:
  primary.cnf: |
    [mysqld]
    log-bin
  replica.cnf: |
    [mysqld]
    super-read-only
  initdb.sql: |
#   SQL goes here

Once again referencing it in the stateful set:

      volumes:
        - name: conf
          emptyDir: {}
        - name: config-map
          configMap:
            name: mysql
#        - name: mysql-initdb
#          configMap:
#            name: mysql;

Am I taking the complete wrong approach or is there just a small mistake?

Upvotes: 0

Views: 1024

Answers (1)

Alif Biswas
Alif Biswas

Reputation: 408

When a mysql container is started for the first time, it will execute files with extensions .sh, .sql and sql.sz that are found in /docker-entrypoint-initdb.d after creating a new database. So we have to mount the initialization script on that specific directory.

First create a new configmap/secret that will be used as volume source.

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-initdb-config
data:
  initdb.sql: |
    #SQL GOES HERE

Then create a volume that will be mounted in /docker-entrypoint-initdb.d directory.

  volumes:
    - name: init-script
      configMap:
        name: mysql-initdb-config

Now mount this volume on the specific directory.

  volumeMounts:
    - name: init-script
      mountPath: /docker-entrypoint-initdb.d

Further read: How to use MySQL image

Upvotes: 1

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