Knowledge Base

Error on Plesk for Linux: Fork failed – Cannot allocate memory

Symptoms

Many actions on a Plesk server cannot be performed with the following error:

Cannot allocate memory
Sites or random Plesk pages are not accessible with:

502 Bad Gateway

503 Service Unavailable
The following error appears in the system log:
- On RHEL-based OSes the following error appears in /var/log/messages:
  
  Out of memory in UB 69762: OOM killed process 22008 (php-cgi) score 0 vm:429108kB, rss:107332kB, swap:0kB
  Out of memory in UB 69762: OOM killed process 22028 (php-cgi) score 0 vm:429968kB, rss:108648kB, swap:0kB
- Debian/Ubuntu based OSes the following error appears in /var/log/syslog:
  
  Nov 12 06:44:42 systemd[1]: mariadb.service: A process of this unit has been killed by the OOM killer.
Unable to open Tools & Settings > IP Address Banning (Fail2Ban):

Error: The IP Address Banning (Fail2Ban) service failed: f2bmng failed: Traceback (most recent call last): File "/usr/local/psa/admin/sbin/f2bmng",
line 5, in <module> import f2bmng File "/usr/local/psa/lib/modules/python/f2bmng/f2bmng.py",
line 6, in <module> import json File "/usr/lib/python2.6/json/init.py",
line 108, in <module> from .decoder import JSONDecoder ImportError: No module named decoder
The following error can appear during migration:

Migration tools tried to perform operation in 3 attempts.
----------------------------------------------------------------------------
Attempt #1 failed with the following error:
Rsync failed to copy files from the source server 'source' (203.0.113.2) to target Plesk server: Command execution failed on the local server with non-zero exit code.
...
exit code: 23
stdout:
stderr: rsync: recv_generator: failed to stat "/var/www/vhosts/example.com/httpdocs/cache/cachefs/2/2b7e2f329409023b850af3509758defe": Cannot allocate memory (12)
The next error appears from time to time in an attempt to open the Plesk > Tools & Settings > Mail Server Settings > Mail Queue page:

external error:
mailqueuemng failed: Unable to prepare reading queue.
Message mailqueuemng failed: Unable to prepare reading queue.
File Agent.php
Line 228
Type PleskUtilException