System updates fail to be installed due to insufficient free RAM: Cannot allocate memory

Symptoms

• System update via Plesk fails with:

  PLESK_ERROR: Update information is not available for package(s)

• When updating system packages manually via a command-line interface, the operation fails with the 'Cannot allocate memory' error:

  # yum update
  freetype-devel-2.4.11-15.el7.x86_64: [Errno 5] [Errno 12] Cannot allocate memory
  psmisc-22.20-15.el7.x86_64: [Errno 5] [Errno 12] Cannot allocate memory
  samba-4.6.2-10.el7_4.x86_64: [Errno 5] [Errno 12] Cannot allocate memory
  libfontenc-1.1.3-3.el7.x86_64: [Errno 5] [Errno 12] Cannot allocate memory
  libselinux-devel-2.5-11.el7.x86_64: [Errno 5] [Errno 12] Cannot allocate memory
  binutils-2.25.1-32.base.el7_4.1.x86_64: [Errno 5] [Errno 12] Cannot allocate memory
  glibc-headers-2.17-196.el7.x86_64: [Errno 5] [Errno 12] Cannot allocate memory

• There is less than 100MB free RAM on the server:

  # free -h
         total   used   free    shared   buff/cache   available
  Mem:    1.0G   499M    23M      263M         501M       378M
  Swap:   256M   170M    85M

Cause

Insufficient RAM on the server.

Resolution

Allocate additional RAM to the server.

Additional Information

• Plesk Documentation: Hardware Requirements for Plesk Onyx