Linux – Kill process that hogs all CPU

killlinuxPHPresources

So ImageMagick has the "convert" command which I use for my (Linux) web platform to deal with image resizing and such.

Sometimes this command gets "stuck", meaning it starts eating machine resources until the entire machine is unavailable. Logging in to the machine can take minutes when this happens.

SO, I'm looking for one of two solutions:

  1. Upon using this command – is there a way to determine just how much max resources it may use?

  2. Can I run a cron script that identifies these "stuck" processes and kill them? I.e. filter on CPU time, or CPU usage and kill when over a specific threshold.

I would probably prefer solution number 2, since solution number 1 could still yield several such processes that each is limited, and stuck, and together they would still eat up my resources.

I can't identify when and why this is happening, the system is slugish and stuck until I "killall convert", then all is well. This command is run thousands of times each hour so unless I would log each and every usage in some way, I can't say which one got stuck, unfortunately.

So, basically, a shell script that identifies, kills and logs when convert gets stuck.

Any ideas?

Best Answer

Upon using this command - is there a way to determine just how much max resources it may use?

Just before invoking the convert command you can set a resource limit on the max CPU time the process can use, convert then will get killed automatically after exceeding the limit.

This will work depending upon how you invoke the command initially. The exec may be unnecessary.

#!/bin/sh
ulimit -St 60
exec /usr/bin/convert $*
## if exec not present this gets executed after.
ulimit -St unlimited
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