How to Solve Plesk Upgrade Failed to Restart Problem

ERROR: Plesk Unit File Error.

Step 01: Login plesk control panel to check if the ERROR display or not.

If the ERROR display, follow the below steps.

Step 02: Connect the server via SSH.

Step 03: Create a directory.

# mkdir /root/example

Step 04: Move session files from /run/systemd/system.

# mv /run/systemd/system/session-*.scope* /root/example/

Step 05: Restart services from the error message

           # service sw-engine restart

N.B.: If the issue has not been resolved with the above solution, please follow the below mentioned process from your system.

Step 01: Connect the Server.

Step 02: Run the below command.

# systemctl | grep abandoned | wc -l (To check abandoned  files)

# time /bin/systemctl list-unit-files (To check the list of unit files)

# wget https://plesk.zendesk.com/hc/article_attachments/360044074594/cleanup_systemd_sessions.zip ( To download the script file )

Step 03: Extract the zip file using the below command.

# unzip cleanup_systemd_sessions.zip

Step 04: Now, schedule a cron task which will run every one hour interval.

            Create a cron task that will execute this script every hour, Open the crontab editor:

# crontab -e

Add the below line in the file.

0 * * * * /root/cleanup_systemd_sessions.sh

REFERENCES:

https://support.plesk.com/hc/en-us/articles/115000166825-Plesk-upgrade-fails-Failed-to-list-unit-files-Connection-timed-out

https://support.plesk.com/hc/en-us/articles/115004603434-Plesk-fails-to-restart-services-control-script-doesn-t-exist-or-isn-t-executable