ext2fs immutable attribute on Plesk files can interrupt upgrade

Symptoms

Plesk upgrade or update procedure fails with errors like the following:

CONFIG_TEXT: cpio: open failed - Permission denied

Plesk files attributes are the following:

# lsattr -R /usr/local/psa/ 2>/dev/null |awk '{split($1, a, ""); if (a[5] ~ /i/) {print;}}'
----i--------e- /usr/local/psa/immutable-file
----i--------e- /usr/local/psa/admin/immutable-dir

Cause

Operating system package manager and/or Plesk autoinstaller cannot update directories/files because of an immutable attribute for Plesk directories/files.

Resolution

Connect to the server via SSH and remove the immutable attribute from Plesk directories/files:

# chattr -iR /usr/local/psa/