How to Find and Kill All Zombie Processes
On Unix operating servers, a zombie process or defunct process is a process that has completed execution but still has an entry in the process table, allowing the process that started it to read its exit status.
It almost always means that the parent is still around. If the parent exited, the child would be orphaned and re-parented to init, which would immediately perform the wait(). In other words, they should go away once the parent process is done.
A zombie process doesn’t react to signals.
1. How can I get the Zombie from process list…?
Its very simple. You can find out Zombie process with the following way:
# ps aux |grep "defunct" user1 3366 0.0 0.0 0 0 ? Z 07:34 0:00 [chromium-browse] user1 3435 0.0 0.0 0 0 ? Z 07:44 0:19 [chromium-browse] user1 3722 0.0 0.0 0 0 ? Z 08:21 0:00 [pidgin] defunct user1 4287 0.1 0.0 0 0 ? Z 09:26 0:38 [chromium-browse] user1 5378 0.1 0.0 0 0 ? Z 11:24 0:15 [chromium-browse] defunct
# ps aux |grep Z USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND user1 3366 0.0 0.0 0 0 ? Z 07:34 0:00 [chromium-browse] user1 3435 0.0 0.0 0 0 ? Z 07:44 0:19 [chromium-browse] user1 3722 0.0 0.0 0 0 ? Z 08:21 0:00 [pidgin] user1 4287 0.1 0.0 0 0 ? Z 09:26 0:38 [chromium-browse] user1 5378 0.1 0.0 0 0 ? Z 11:24 0:15 [chromium-browse]
2. How many Zombie process running on your server?
# ps aux | awk {'print $8'}|grep -c Z
5
# ps aux | awk '{ print $8 " " $2 }' | grep -wc Z
5
# ps aux | awk {'print $8'}|grep Z|wc -l
5
3. List the PID of Zombie ?
# ps aux | awk '{ print $8 " " $2 }' | grep -w Z
Z 3366
Z 3435
Z 3722
Z 4287
Z 5378
In order to kill these processes, you need to find the parent process first.
# pstree -paul
This will show the pid of the of the parent of the zombie process. Now you need to kill the parent process.
[root@webhostingchennai]# kill -9
Hope this article helps you. Please share you valuable comments to improve us.
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