Using a PV in an OpenShift 3 cron job - cron

Question

I have been able to successfully create a cron job for my OpenShift 3 project. The project is a lift and shift from an existing Linux web server. Part of the existing application requires several cron tasks to run. The one I am looking at the moment is a daily update to the applications database. As part of the execution of the cron job I want to write to a log file. There is already a PV/PVC defined for the main application and I was intending to use that hold the logs for my cron job but it seems the cron job is not being provided access to the PV.
I am using the following inProgress.yml for the definition of the cron job
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: in-progress
spec:
schedule: "*/5 * * * *"
concurrencyPolicy: "Replace"
startingDeadlineSeconds: 200
suspend: false
successfulJobsHistoryLimit: 3
failedJobsHistoryLimit: 1
jobTemplate:
spec:
template:
metadata:
labels:
parent: "cronjobInProgress"
spec:
containers:
- name: in-progress
image: <image name>
command: ["php", "inProgress.php"]
restartPolicy: OnFailure
volumeMounts:
- mountPath: /data-pv
name: log-vol
volumes:
- name: log-vol
persistentVolumeClaim:
claimName: data-pv
I am using the following command to create the cron job
oc create -f inProgress.yml
PHP Warning: fopen(/data-pv/logs/2022-04-27-app.log): failed to open
stream: No such file or directory in
/opt/app-root/src/errorHandler.php on line 75 WARNING: [2] mkdir():
Permission denied, line 80 in file
/opt/app-root/src/errorLogger.php WARNING: [2]
fopen(/data-pv/logs/2022-04-27-inprogress.log): failed to open stream:
No such file or directory, line 60 in file
/opt/app-root/src/errorLogger.php
Looking at the yml for pod that is executed, there is no mention of data-pv - it appears as though secret volumeMount, which has been added by OpenShift, is removing any further volumeMounts.
apiVersion: v1 kind: Pod metadata: annotations:
openshift.io/scc: restricted creationTimestamp: '2022-04-27T13:25:04Z' generateName: in-progress-1651065900- ...
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: default-token-n9jsw
readOnly: true ... volumes:
- name: default-token-n9jsw
secret:
defaultMode: 420
secretName: default-token-n9jsw
How can I access the PV from within the cron job?

Answer 1

Your manifest is incorrect. The volumes block needs to be part of the spec.jobTemplate.spec.template.spec, that is, it needs to be indented at the same level as spec.jobTemplate.spec.template.spec.containers. In its current position it is invisible to OpenShift. See e.g. this pod example.
Similarly, volumeMounts and restartPolicy are arguments to the container block, and need to be indented accordingly.
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: in-progress
spec:
schedule: '*/5 * * * *'
concurrencyPolicy: Replace
startingDeadlineSeconds: 200
suspend: false
successfulJobsHistoryLimit: 3
failedJobsHistoryLimit: 1
jobTemplate:
spec:
template:
metadata:
labels:
parent: cronjobInProgress
spec:
containers:
- name: in-progress
image: <image name>
command:
- php
- inProgress.php
restartPolicy: OnFailure
volumeMounts:
- mountPath: /data-pv
name: log-vol
volumes:
- name: log-vol
persistentVolumeClaim:
claimName: data-pv

Answer 2

Thanks for the informative response larsks.
OpenShift displayed the following when I copied your manifest suggestions
$ oc create -f InProgress.yml The CronJob "in-progress" is invalid:
spec.jobTemplate.spec.template.spec.restartPolicy: Unsupported value:
"Always": supported values: "OnFailure", " Never"
As your answer was very helpful I was able to resolve this problem by moving restartPolicy: OnFailure so the final manifest is below.
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: in-progress
spec:
schedule: "*/5 * * * *"
concurrencyPolicy: "Replace"
startingDeadlineSeconds: 200
suspend: false
successfulJobsHistoryLimit: 3
failedJobsHistoryLimit: 1
jobTemplate:
spec:
template:
metadata:
labels:
parent: "cronjobInProgress"
spec:
restartPolicy: OnFailure
containers:
- name: in-progress
image: <image name>
command: ["php", "updateToInProgress.php"]
volumeMounts:
- mountPath: /data-pv
name: log-vol
volumes:
- name: log-vol
persistentVolumeClaim:
claimName: data-pv