How to pass kubernetes namespaces dynamically to k8s cronjob-CodePudding

I have a cronjob that cleans some job since my kubernetes is on older version so cannot use ttlafterfinished. How can I fetch the namespaces that have this job deployed and pass the namespaces name dynamically instead of repeating the same command several times?

This is my cronjob:

kind: CronJob
metadata:
  name: jobs-cleanup
spec:
  schedule: "*/30 * * * *"
  successfulJobsHistoryLimit: 1
  failedJobsHistoryLimit: 1
  jobTemplate:
    spec:
      template:
        spec:
          serviceAccountName: cleanup-operator
          containers:
          - name: jobs-cleanup
            image: google.io/test/job:1.0
            args:
            - -c
            - |
              for i in $(seq 9);do 
              kubectl get jobs --sort-by=.metadata.creationTimestamp -n dev$i | grep "job-init" | cut -d' ' -f1 | tac | tail -n  2 | xargs -I % kubectl delete jobs % -n dev$i;done
              kubectl get jobs --sort-by=.metadata.creationTimestamp -n stg1 | grep "fusionauth-job" | cut -d' ' -f1 | tac | tail -n  2 | xargs -I % kubectl delete jobs % -n stg1
              kubectl get jobs --sort-by=.metadata.creationTimestamp -n pt1 | grep "fusionauth-job" | cut -d' ' -f1 | tac | tail -n  2 | xargs -I % kubectl delete jobs % -n pt1
              kubectl get jobs --sort-by=.metadata.creationTimestamp -n sit1 | grep "fusionauth-job" | cut -d' ' -f1 | tac | tail -n  2 | xargs -I % kubectl delete jobs % -n sit1
            command:
            - /bin/sh
          restartPolicy: Never
          imagePullSecrets:
            - name: secret

CodePudding user response：

You can use the Downward API and propagate the namespace to an env var. This env var can then be used in your job/pod.

kind: CronJob
metadata:
  name: jobs-cleanup
spec:
  schedule: "*/30 * * * *"
  successfulJobsHistoryLimit: 1
  failedJobsHistoryLimit: 1
  jobTemplate:
    spec:
      template:
        spec:
          serviceAccountName: cleanup-operator
          containers:
          - name: jobs-cleanup
            image: google.io/test/job:1.0
            env:
            - name: MY_POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
            args:
            - -c
            - |
              for i in $(seq 9);do 
              kubectl get jobs --sort-by=.metadata.creationTimestamp -n dev$i | grep "job-init" | cut -d' ' -f1 | tac | tail -n  2 | xargs -I % kubectl delete jobs % -n dev$i;done
              kubectl get jobs --sort-by=.metadata.creationTimestamp -n stg1 | grep "fusionauth-job" | cut -d' ' -f1 | tac | tail -n  2 | xargs -I % kubectl delete jobs % -n stg1
              kubectl get jobs --sort-by=.metadata.creationTimestamp -n pt1 | grep "fusionauth-job" | cut -d' ' -f1 | tac | tail -n  2 | xargs -I % kubectl delete jobs % -n pt1
              kubectl get jobs --sort-by=.metadata.creationTimestamp -n sit1 | grep "fusionauth-job" | cut -d' ' -f1 | tac | tail -n  2 | xargs -I % kubectl delete jobs % -n sit1
            command:
            - /bin/sh
          restartPolicy: Never
          imagePullSecrets:
            - name: secret

If your cleanup job is running in another namespace, you can also use the --all-namespaces (shorthand -A) param so get all resources/jobs from all namespaces and play a bit around with custom columns and awk: So in your case:

kubectl get po -o custom-columns=NAME:.metadata.name,NAMESPACE:.metadata.namespace -A | grep "fusionauth-job" | awk '{print "kubectl delete job "$1" -n "$2}' | sh

CodePudding user response：

A more flexible alternative to what you're doing now would be to store the list of job names you want to delete in a list/array. Then, you can iterate through the list of job names and execute the command.

Below is a simpler (IMO) version of your command that uses the -o=jsonpath support instead in kubectl to specify a search criteria.

# The list of jobs you want to delete from any/all namespaces.
jobs_list="job-init fusionauth-job"

for job_name in ${jobs_list}; do
    kubectl get jobs -A --sort-by=.metadata.creationTimestamp \
        -o=jsonpath="{range .items[?(@.metadata.name == '${job_name}')]}{.metadata.namespace} {.metadata.name}{'\n'}{end}" \
          | while read namespace job;do kubectl delete job ${job} -n ${namespace};done;
done