[201803][monit] Restart rsyslog service if rsyslogd consumes > 800 MB memory#2963
[201803][monit] Restart rsyslog service if rsyslogd consumes > 800 MB memory#2963lguohan merged 1 commit intosonic-net:201803from jleveque:rsyslog_mem_limit_201803
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| if memory usage > 50% for 5 times within 10 cycles then alert | ||
| if cpu usage (user) > 90% for 5 times within 10 cycles then alert | ||
| if cpu usage (system) > 90% for 5 times within 10 cycles then alert | ||
| check process rsyslog with pidfile /var/run/rsyslogd.pid |
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/var/run/rsyslogd.pid [](start = 35, length = 21)
How about the rsyslog processes inside docker? Do they matter?
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We have not seen the rsyslogd memory leak occur on a rsyslogd process inside any Docker container. The assumption is that those rsyslogd processes have a very light load, whereas the rsyslogd process in the host image also acts as the rsyslog server for all of those processes, so it handles a much higher load of messages.
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rsyslog within container is better managed within the container, for example use superlance with supervisord or use container option to limit the whole memory consumption for the container.
| check process rsyslog with pidfile /var/run/rsyslogd.pid | ||
| start program = "/bin/systemctl start rsyslog.service" | ||
| stop program = "/bin/systemctl stop rsyslog.service" | ||
| if totalmem > 800 MB for 5 times within 10 cycles then restart |
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restart [](start = 57, length = 7)
Do we need to keep a restart counter somewhere?
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good question, what is the log message for such restart. we can search the syslog for such cases.
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Each cycle that monit detects the memory has exceeded the threshold it will log the following:
ERR monit[607]: 'rsyslog' total mem amount of 1.6 GB matches resource limit [total mem amount>800.0 MB]
And if it meets the criteria (5 of these within 10 cycles), it will log the following when it attempts to restart the service:
INFO monit[607]: 'rsyslog' trying to restart
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Get this change in 201811 branch until we have a better memory resource monitor/mitigation in place. |
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Configure monit to monitor the resident memory consumption of rsyslogd. If memory usage is > 800 MB for 5 out of 10 checks (2-minute cycle interval, so 10 out of 20 minutes), restart the rsyslog service, because rsyslogd is most likely leaking memory.