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

Plesk for Linux kb: technical ABT: Group A

Applicable to:

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

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

CONFIG_TEXT: 502 Bad Gateway

CONFIG_TEXT: 503 Service Unavailable
Cannot access Plesk or edit PHP settings:

PLESK_ERROR: Error: The license key is invalid. To use Plesk, you must obtain and install a new, valid license key. The license key is for use only with Plesk within the following virtual environments: Virtuozzo, VMware, Microsoft Hyper-V, Xen, KVM, Virtuozzo Server, LXC, Docker.
The following error appears in the system log:
- RHEL based OSes the following error appears in /var/log/messages:
  
  CONFIG_TEXT: 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:
  
  CONFIG_TEXT: Nov 12 06:44:42 systemd[1]: mariadb.service: A process of this unit has been killed by the OOM killer.

Container limits have been reached:

# awk '$NF > 0' /proc/user_beancounters
Version: 2.5
uid resource held maxheld barrier limit failcnt
privvmpages 1954900 5089134 3500000 4000000 **93324
**physpages 901769 1048750 1048576 1048576 24576
kmemsize 138969088 210599936 209715200 209715200 **1139056640
**
The following error is shown when attempting to open Plesk web interface or update a license key:

PLESK_ERROR: Error: The license key is invalid. In order to use Plesk, you need to obtain and install a new valid license key.
The license key is intended only for use with Plesk operating inside the following virtual environments: Virtuozzo containers, VMWare, Microsoft Hyper-V, Xen, KVM, Virtuozzo Server, LXC, Docker.
The following errors can be found in /usr/local/psa/admin/logs/panel.log file:

CONFIG_TEXT: ERR [1] Exception: PHP Warning: proc_open(): fork failed - Cannot allocate memory
ERR [1] PleskUtilException: /usr/local/psa/admin/bin/filwrpr '93' failed with message: Unable to execute the utility.

The following errors can be found in /var/log/sw-cp-server/error_log :

CONFIG_TEXT: (mod_fastcgi.c.2746) FastCGI-stderr: PHP Warning: proc_open() [<a href='function.proc-open'>function.proc-open</a>]: fork failed - Cannot allocate memory; File: /opt/psa/admin/plib/common_func.php3, Line: 1318
MemoryError: out of memory
The following error can appear during backup creation:

# /usr/local/psa/admin/sbin/pmm-ras --get-dump-info --dump-file-specification=backup_info_1606282257.xml --with-feedback --session-path=/opt/psa/PMM/sessions/2016-06-28-225702.380 --verbose
error : Memory allocation failed : buffer error: text too long
error : Memory allocation failed : growing buffer
I/O error : write error
Error: boost::too_many_args: format-string referred to less arguments than were passed
The following error can appear in /usr/local/psa/admin/logs/panel.log file when a FTP backup upload fails:

CONFIG_TEXT: ERR [panel] Get dump 'backup_example.com_1905151450.tar'
Error:
@ESCAPE_VALUE_BEGIN@Runtime error: Unable to upload the backup to the FTP storage: Repository error: Unable to add files to an archive: /usr/lib/plesk-9.0/sw-tar: -: Cannot write: Cannot allocate memory /usr/lib/plesk-9.0/sw-tar: Error is not recoverable: exiting now @ESCAPE_VALUE_END@
Error: server "server"
@ESCAPE_VALUE_BEGIN@Cannot encrypt dump file (this is not fatal error!): SQLSTATE[HY000] [2002] Connection refused @ESCAPE_VALUE_END@

Plesk update via CLI fails with error:
CONFIG_TEXT: Error in PREUN scriptlet in rpm package psa-libpam-plesk-18.0-2.centos.7+p18.0.29.3+t200825.2156.x86_64 error: Couldn't fork %preun(psa-libpam-plesk-18.0-2.centos.7+p18.0.29.3+t200825.2156.x86_64):
Cannot allocate memory Error: The Yum utility failed to install the required packages.
Attention! Your software might be inoperable.

Server is running out of physical RAM, some limits are exceeded on the server

Increase amount of RAM or SWAP values on the server.

Note: This is a task that should be performed by the System Administrator

Note: In the case of a virtual environment (VPS or Virtual Machine), contact your service provider in order to increase server limits.