[FIXED] How to mount configuration files into a Kubernetes Pod?

Issue

I have a postgres instance that I generally spin up using a docker-compose.yml file. It mounts some configuration files like this:

    volumes:
      - postgres-volume:/var/lib/postgresql/data
      - ./postgresql.conf:/etc/postgresql.conf
      - ./logs:/logs
      - ./pg_hba.conf:/etc/pg_hba.conf

These files are located in the same folder as the docker-compose.yml file is.

My question is: how do I make a Pod that contains this container also mount these configuration files? I read something about PVC in Kubernetes but I'm having a hard time connecting the dots and going from the docker-compose way of thinking to the Kubernetes way of thinking.

Any help is greatly appreciated.

Solution

Easiest approach would be to store the files in a ConfigMap and mount those as volumes in the container.

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-config
data:
  my.properties: |
    url=example.com
    username=username
    password=password
  index.html: |
    Hello world

[...]
  containers:
    - name: my-container
      image: some-registry/some-image
      volumeMounts:
      - name: config-volume
        mountPath: /etc/config/my.properties
        subPath: my.properties
      - name: config-volume
        mountPath: /some/different/path/index.html
        subPath: index.html
  volumes:
    - name: config-volume
      configMap:
        name: my-config
[...]

By that the my.properties file is mounted into /etc/config and index.html into /some/different/path of the my-container file system.

You can also generate the configmap from the file by kubectl create configmap my-config --from-file /path/to/my.properties --from-file /path/to/index.html

See docs for more info on that.

Answered By - Chris

Answer Checked By - Marie Seifert (PHPFixing Admin)