You’re troubleshooting file permissions. Remove your init container and try out the following. If you could provide this output it might also be useful in helping you.
Get a shell into the container.
kubectl exec -it POD_NAME -- sh
Confirm your uid and gid.
/ $ id
uid=1001 gid=1001 groups=1001
Test writing to the directory.
/ $ echo test > /opt/var/logs/docker/test.txt
/ $ cat /opt/var/logs/docker/test.txt
test
Walk the directory and confirm permissions along the directory.
/ $ ls -lah /opt /opt/var /opt/var/logs /opt/var/logs/docker/
/opt:
total 12K
drwxr-xr-x 1 root root 4.0K Jun 30 14:06 .
drwxr-xr-x 1 root root 4.0K Jun 30 14:06 ..
drwxr-xr-x 3 root root 4.0K Jun 30 14:06 var
/opt/var:
total 12K
drwxr-xr-x 3 root root 4.0K Jun 30 14:06 .
drwxr-xr-x 1 root root 4.0K Jun 30 14:06 ..
drwxr-xr-x 3 root root 4.0K Jun 30 14:06 logs
/opt/var/logs:
total 12K
drwxr-xr-x 3 root root 4.0K Jun 30 14:06 .
drwxr-xr-x 3 root root 4.0K Jun 30 14:06 ..
drwxrwsr-x 3 root 1001 4.0K Jun 30 14:07 docker
/opt/var/logs/docker/:
total 28K
drwxrwsr-x 3 root 1001 4.0K Jun 30 14:07 .
drwxr-xr-x 3 root root 4.0K Jun 30 14:06 ..
drwxrws--- 2 root 1001 16.0K Jun 30 13:58 lost+found
-rw-r--r-- 1 1001 1001 5 Jun 30 14:14 test.txt