I like solaris zones and I am using SmartOS on my home servers. A few days ago I need to install virtual servers. KVM uses so much resources, hence I do not want to use them. I searched usages of Docker and LXC containers. A lot of people do not like lightweight virtualization. The famous video is Hitler uses Docker.
However, I do not agree some parts of that video. You can easily harden your servers, which is hated by developers - do not run whatever their way. Hardening is the infinite war between sysadmins and developers. I do not like docker because of personal reasons. However it is very powerful. If there is a well-written docker file, iSCSI or GlusterFS (who needs NFS), you can run your docker where ever you wanna, without wondering data or physical server fault. But these conditions needs good developers too. Good developers train themselves, not copying youtube videos or tutorials. Hence I do not find any good developers to run docker. If I can run SmartOS, I choose it, however I need to use Linux. Developers hate big changes, they may force developers to rewrite their codes as good way - give up spaghetti codes. It is very annoying because developers want to be agile, to protect themselves from the due date nightmares.
So, I need to install CentOS as host OS, and I chose to run LXC Ubuntu containers - ubuntu cloud. I may be use Open Stack, however it needs several hosts to control. We only have four servers and we need all resources on them. I write several bash scripts to create LXC containers. I need to use hard disk very efficiently. I do not have ZFS, oh my good SmartOS, I used Thin Provisioned LVM. It is not good as ZFS, however I love it very much. The tool fstrim is wonderful when using thin provisioned lvm.
The Ubuntu lightweight virtual machines uses 60MiB and it is wonderful. I can use all my memory for applications. LXC can attach threads to any cpu or limits usage of given CPUs, limits memory. It is very like to Solaris Zones, however the main problem is from htop, my wonderful tool for monitoring, I see all memory, cpu and programs of host machine and other containers. Hence it is very ugly. Also developers hate it very much. Please fix it my dear LXC team.