KVM/libvirt/Review libvirt error messages in journald

journalctl -r | grep libvirt | grep error

Errors:

Cannot allocate memory
No space left on device
Failed to get shared "write" lock
Operation failed: Storage source conflict with pool
internal error:
- qemu unexpectedly closed the monitor
- End of file from qemu monitor
- connection closed due to keepalive timeout
- process exited while connecting to monitor
End of file while reading data: Input/output error
Failed to acquire pid file
argument unsupported
Operation not supported