Ubuntu 12.04 uses virsh to create lxc container. Problems and Solutions

I was frustrated by ubuntu. Previously, it was very smooth to create Linux container through libvirt on Ubuntu 12.04 server manually installed by ISO without any problems. Recently, we have deployed the Ubuntu OS Deployment Tool Maas, which is also a Ubuntu 12.04 server, but a series of problems have occurred!

What are the differences between the OS deployed by Maas and those manually installed? These things disappoint developers!

Libvirt version: 0.9.8-2ubuntu17. 4
Ubuntu kernel version: Linux compute-63-30 3.2.0-35-generic # 55-ubuntu SMP wed Dec 5 17:42:16 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

Question 1: Warning: lxccapsinit: 77: failed to get host power management capabilities
This error is caused by the absence of a power management package, which can be ignored or solved by installing a power management package.
Sudo apt-get-y install pm-utils

Problem 2: Error: lxccontainermountdevfs: 519: failed to mount/dev/PTS in container: no such file or directory
This problem is caused by symbol link, that is, when the rootfs path of the container specified in the container configuration file is in the directory of a symbolic link, this issue will be reported, which can be solved without symbolic links.

These problems did not occur on the Ubuntu 12.04 server I manually installed. This is so depressing!