Several system services fails at boot and there is no ssh access nor network available.

Issue

• System services failing upon restart in AWS. The server is very slow and sluggish. After a reboot, sometimes it doesn't allow to login and even if it does, it takes a long time for login prompt to appear. It's failing to start the login service (systemd-logind.service). The NetworkManager service is failing to start. It complains about a failed dependency and journalctl doesn't give clear info. Unable to get into the single user mode for further troubleshooting.

• Below failed services can be seen on boot log:

  [FAILED] Failed to start Login Service.
  ..
  [FAILED] Failed to start Network Manager.
  See 'systemctl status NetworkManager.service' for details
  [DEPEND] Dependency failed for Network Manager Wait online.
  ..
  ..
  [FAILED] Failed to start Login Service.
  

• While logging in through the console we observe this message:

  server login: <user>
  Password:
  Unable to get valid context for <user>