chore: runAsNonRoot and fix empty CRD fields

[sbernauer]

Description

Part of stackabletech/issues#876

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker

[xeniape]

I had one test fail with

    logger.go:42: 10:34:42 | smoke_hadoop-3.5.0_zookeeper-3.9.4_zookeeper-latest-3.9.5_number-of-datanodes-1_datanode-pvcs-2hdd-1ssd_listener-class-external-unstable_openshift-false/50-create-file | 2026-08-10 08:34:42,904 DEBUG: Starting new HTTP connection (1): hdfs-namenode-default-0.hdfs-namenode-default.kuttl-test-cute-monster.svc.cluster.local:9870
    logger.go:42: 10:34:42 | smoke_hadoop-3.5.0_zookeeper-3.9.4_zookeeper-latest-3.9.5_number-of-datanodes-1_datanode-pvcs-2hdd-1ssd_listener-class-external-unstable_openshift-false/50-create-file | 2026-08-10 08:34:42,953 DEBUG: http://hdfs-namenode-default-0.hdfs-namenode-default.kuttl-test-cute-monster.svc.cluster.local:9870 "PUT /webhdfs/v1/testdata.txt?user.name=stackable&op=CREATE HTTP/1.1" 403 177
    logger.go:42: 10:34:42 | smoke_hadoop-3.5.0_zookeeper-3.9.4_zookeeper-latest-3.9.5_number-of-datanodes-1_datanode-pvcs-2hdd-1ssd_listener-class-external-unstable_openshift-false/50-create-file | command terminated with exit code 1
    case.go:396: failed in step 50-create-file
    case.go:398: command "kubectl exec -n $NAMESPACE test-runner-0 -- python /tmp/webhdfs.py ..." failed, exit status 1

But if that just locally for me again and it passed for you and Nick, feel free to ignore.

[sbernauer]

The mentioned test passed for me :)
--- PASS: kuttl/harness/smoke_hadoop-3.5.0_zookeeper-3.9.4_zookeeper-latest-3.9.5_number-of-datanodes-1_datanode-pvcs-2hdd-1ssd_listener-class-external-unstable_openshift-false (206.64s)