I confirm this behavior on 4.10 nightlies on RHCOS nodes. This is weird as by looking at MCO code for writing files does consider user name. This looks like a bug to me.

@Sergio did you notice this behavior in 4.10 or earlier version as well?

Marking not a blocker due to this being not a regression

Verified using IPI on AWS version:

$ oc get clusterversion
NAME      VERSION                              AVAILABLE   PROGRESSING   SINCE   STATUS
version   4.13.0-0.nightly-2023-02-09-032930   True        False         97m     Cluster version is 4.13.0-0.nightly-2023-02-09-032930


Steps:

1. Create a MC deploying several files with different users:

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: test-machine-config-users
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:text/plain;charset=utf-8;base64,dGVzdA==
          verification: {}
        mode: 420 #0644
        path: /etc/core-name-test-file.test
        user:
          name: core
      - contents:
          source: data:text/plain;charset=utf-8;base64,dGVzdA==
          verification: {}
        mode: 416 #0640
        path: /etc/core-id-test-file.test
        user:
          id: 1000
      - contents:
          source: data:text/plain;charset=utf-8;base64,dGVzdA==
          verification: {}
        mode: 384 #0600
        path: /etc/root-id-test-file.test
        user:
          id: 0


2. Wait for MCP to be updated

3. Check that the values are the right ones

]$ oc debug node/ip-10-0-141-152.us-east-2.compute.internal -- chroot /host ls -larth /etc |grep "test-file"
Starting pod/ip-10-0-141-152us-east-2computeinternal-debug ...
To use host binaries, run `chroot /host`

Removing debug pod ...
-rw-r--r--.  1 core        root         4 Feb  9 10:21 core-name-test-file.test
-rw-r-----.  1 core        root         4 Feb  9 10:21 core-id-test-file.test
-rw-------.  1 root        root         4 Feb  9 10:21 root-id-test-file.test

[fedora@preserve-sregidor-work openshift-tests-private]$ oc debug node/ip-10-0-141-152.us-east-2.compute.internal -- chroot /host cat /etc/core-name-test-file.test /etc/core-id-test-file.test /etc/root-id-test-file.test
Starting pod/ip-10-0-141-152us-east-2computeinternal-debug ...
To use host binaries, run `chroot /host`
testtesttest
Removing debug pod ...


4. Create a MC with a wrong user

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: test-machine-config-wrong
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:text/plain;charset=utf-8;base64,dGVzdA==
          verification: {}
        filesystem: root
        mode: 420
        path: /etc/nouser-test-file.test
        user:
          name: coret

5. MCP is degraded reporting this error:

  - lastTransitionTime: "2023-02-09T10:07:18Z"
    message: 'Node ip-10-0-141-152.us-east-2.compute.internal is reporting: "failed
      to retrieve file ownership for file \"/etc/nouser-test-file.test\": failed to
      retrieve UserID for username: coret"'
    reason: 1 nodes are reporting degraded status on sync
    status: "True"
    type: NodeDegraded

6. Remove the wrong MC, fix the node and create new MC with a non-existent user id:

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: test-machine-config-wrong-id
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:text/plain;charset=utf-8;base64,dGVzdA==
          verification: {}
        filesystem: root
        mode: 420  #0644
        path: /etc/nouser-test-file.test
        user:
          id: 12343

7. Wait for MCP to be updated

8. A file was created with this ID

-rw-r--r--.  1       12343 root         4 Feb  9 11:00 nouser-id-test-file.test


We move the status to VERFIED.

There is an error  in the "test-machine-config-wrong-id" MC in my previous comment. Obviously the path that I used was " path: /etc/nouser-test-id-file.test" and not "path: /etc/nouser-test-file.test".

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Important: OpenShift Container Platform 4.13.0 security update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2023:1326