InformationService container may be present after upgrade to Parallels Virtual Automation 4.6 in stopped state on Windows-based Parallels Containers servers.
It is preserved for upgrade rollback purposes. If rollback is not planned, it is safe to remove service container using vzctl destroy 1 command.
On Parallels Containers for Linux there may exist fake service container (ID 1) with 1-4 processes running, which provides Offline Management functionality.
If there is service container with more than 4 processes running after upgrade from 4.0, then it is necessary to destroy it manually and reinstall PVA Agent.