I'm a long term Debian user and have used the linux-vserver kernels extensively in the past; however the Debian project is removing its support for it and I really prefer the kernel packages.
I use linux-vserver less for security but for separating "machines" used for development, different entvironements, software, applications, etc. I kind of like the chroot-on-steroid approach, i.e. it doesn't give me the impression it's bloated.
There's one feature which sets it apart from other implementations, at least as far as my knowledge goes, in that I can mount directories from the host into the guest. With linux-vserver I do this:
$ # on host $ ls -ld /data/ drwxrwsr-x 86 root samba 4096 2012-01-02 10:57 /data/ $ # showing config of a guest $ cat /etc/vservers/filer01/fstab none /proc proc defaults 0 0 none /tmp tmpfs size=1024m,mode=1777 0 0 none /dev/pts devpts gid=5,mode=620 0 0 /data /data auto rbind 0 0
The last list is the important one; it effectively blends my host directory into the guests. Carefully settings permission in host/guest makes this work flawlessly. I can avoid any kind of overhead (in setup and usage) with samba/nfs this way.
In this scenario I even use a guest to provide SMB service and do not run it directly on the host; yet still I can access the host's files transparently. Even within multiple guests.
I found the Debian Wiki Page about System Virtualization to learn about the provided alternatives, however there are so many. Is there a recommendation for my requirements?
I also love the way I can use the vserver tools to simply "build" a new guest which just uses debootstrap to install any flavor I like (Etch, Lenny, Squeeze, etc.). Other distro support is nice but not required.
It would also be nice to know how to migration actual guests to the new technology. I.e. powering down all guests, upgrading the hosts kernel and migration each guest to the new virtualization technology.
Is there any recommendation what to do?