Kubernetes kind: Job

Örnek

Elimizde şöyle bash script içeren bir ConfigMap olsun

apiVersion: v1
kind: ConfigMap
metadata:
  name: slim-shady-configmap
data:
  slim-shady.sh: |
    #!/bin/bash

    echo "Hi!"
    echo "My name is"
    echo "What?"
    echo "My name is"
    echo "Who?"
    echo "My name is"
    echo "Chika-chika"
    echo "Slim Shady"

Job şöyle olsun

apiVersion: batch/v1
kind: Job
metadata:
  name: chicka-chicka-slim-shady
spec:
  template:
    spec:
      containers:
        - name: shady
          image: centos
          command: ["/script/slim-shady.sh"]
          volumeMounts:
            - name: script
              mountPath: "/script"
      volumes:
        - name: script
          configMap:
            name: slim-shady-configmap
            defaultMode: 0500
      restartPolicy: Never

Açıklaması şöyle

In the above Job manifest you can see that we create a new volume for the configmap. We then take that volume and mount it under the shady container at “/script” and then execute the script file slim-shady.sh which is the name of the file in our configmap.

Two things I would like to point out here:

A) Inside the volume, we must specify a defaultMode of atleast 0500 (read+execute to the user). This defines the file permissions inside the container when the pod is run. If we do not set this, we get permission denied errors. This is because as a default the configmap will be mounted with 0644 and you will end up with an error like below.

 Warning  Failed     7s    kubelet            Error: failed to create containerd task: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: exec: "/script/slim-shady.sh": permission denied: unknown

B) Here we were also able to use an existing and well known container image instead of creating our own. This takes less effort for us because we did not have to build a new image with new code etc… but instead only needed to deploy the configmap and a Job.

Örnek - Python

Şöyle yaparız

apiVersion: batch/v1
kind: Job
metadata:
  name: promote-model-a
spec:
  template:
    spec:
      containers:
        - name: promote
          image: wbassler/mlflow-utils:0.0.1
          command:
            - python
          args:
            - /mlflow/promote.py
          env: 
            - name: MODEL_NAME
              value: model-a
          volumeMounts:
            - name: promote
              mountPath: "/mlflow"
      volumes:
        - name: promote
          configMap:
            name: promote-model
            defaultMode: 0500
      restartPolicy: Never