Kubernetes ConfigMap expets 'string' in valid YAML

April 7, 2024

I’m trying to set up a Cron Job in Kubernetes using a ConfigMap, and mount a shell script to a volume. I have valid YAML, but line 9 throws an error that it’s expecting a string:

apiVersion: v1
kind: ConfigMap
metadata:
  name: elasticdump-configmap
  namespace: default
data:
  job.schedule: "*/5 * * * *"
  spec:
    restartPolicy: OnFailure
    containers:
    - name: elasticdump
      image: elasticdump/elasticsearch-dump
      imagePullPolicy: IfNotPresent
      command: ["/bin/sh", "-c", "elasticdump.sh"]
    volumeMounts:
      - mountPath: /opt/data
        name: blob01
    resources:
      requests:
        memory: 1Gi
      limits:
        memory: 5Gi
  volumes:
     - name: blob01
       persistentVolumeClaim:
        claimName: pvc-blob
       configMap:
        name: elasticdump-configmap
        items:
          - key: elasticdump.sh
            path: elasticdump.sh

I know I’m doing something wrong in the structure of the YAML, but I’m very new to Kubernetes, so would appreciate even a hint of what to do.

>Solution :

As it states in docs:

A ConfigMap is an API object that lets you store configuration for
other objects to use.

So, it’s not possible to define a CronJob such way. Please, look at special k8s Object called CronJob

apiVersion: batch/v1
kind: CronJob
metadata:
  name: elasticdump-configmap
  namespace: default
spec:
  schedule: "*/5 * * * *"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
          - name: elasticdump
            image: elasticdump/elasticsearch-dump
            imagePullPolicy: IfNotPresent
            command: ["/bin/sh", "-c", "elasticdump.sh"]
            volumeMounts:
            - mountPath: /opt/data
              name: blob01
            resources:
              requests:
                memory: 1Gi
              limits:
                memory: 5Gi
          volumes:
          - name: blob01
            persistentVolumeClaim:
              claimName: pvc-blob
          - name: elasticdump-configmap
            configMap:
              name: elasticdump-configmap
              items:
              - key: elasticdump.sh
                path: elasticdump.sh
          restartPolicy: OnFailure