Cobra Forum

Question: Website in Plesk fails to load with error 503: Memory cgroup out of memory: Kill process


Applicable to:

• Plesk for Linux

Symptoms

• The following error appears when attempting to load a file in a site:

Server Error
503
Service Temporarily Unavailable

• Site shows error 504 intermittently
• CloudLinux operating system is used or the extension Plesk Cgroups Manager is installed
• PHP-FPM pool exits after some time with the following warning found at PHP-FPM log file (/var/log/plesk-php8x-fpm/error.log):

WARNING: [pool example.com] child 2920572 exited on signal 9 (SIGKILL) after 2611.194074 seconds from start

• PHP-FPM pool memory errors as below examples are found at /var/log/messages:

129 kernel: Killed process 675388 (php-fpm) in VE "0" total-vm:1767832kB, anon-rss:114724kB, file-rss:11132kB, shmem-rss:12268kB
129 kernel: OOM killer in rage 0: 0 tasks killed
host kernel: [6441970.759935] 2996362 (php-fpm) invoked oom-killer in ub 10061 generation 504 gfp 0x200d2
host kernel: LVE: [8884] _lve_enter: Can't alloc ve #10151 lvp #0, rc -22
kernel: oom_reaper: reaped process 1234 (php-fpm)
host mysqld: 2020-01-11T16:03:58.979977Z 16499264 [Note] Aborted connection 16499264 to db: 'example_db' user: 'jdoe' host: 'localhost' (Got an error reading communication packets)

Cause

PHP-FPM process is killed by Cgroups due to reached memory limits.


Resolution

Increase Cgroup memory limits:

                                    For Plesk Cgroups Manager extension

1.Log into Plesk

2.To increase limits for all subscriptions under a service plan, navigate to Service Plan > Default Domain > RAM, CPU, DISK I/O.

For a single subscription, navigate to Subscriptions > example.com > Customize > RAM, CPU, DISK I/O

3.Below secion RAM, increase value of Limit or enable checkbox Unlimited
Click Apply
Additional information can be found in (Plesk for Linux) Cgroups Manager documentation.