Openvz support

[ncharles]

Detect OpenVZ/Virtuozzo and Parallels Cloud Server, and define the following hard classes:

• virt_host_openvz: for the openVZ host
• virt_host_vz_vzps: for openVZ host, if the /bin/vzps tool is available
• virt_guest_openvz: for the openVZ guest

On the host:

# cf-promises/cf-promises -v | grep openvz
virt_host_openvz

Inside an OpenVZ container:

# cf-promises/cf-promises -v |  grep openvz
virt_guest_openvz

On the OpenVZ host, the ps command list the processes on both host and containers, making the processes promise type unusable.
The tool /bin/vzps let you select the host or container you want to have the processes from; so this PR add detection for this tool on the host, and define the class virt_host_vz_vzps, and uses vzps instead of of ps

This is contains part of the code and naming discussion in #582, and also part of the patch proposed by Liviu Damian http://pastebin.com/ipTeh1Mk / https://groups.google.com/forum/#!topic/help-cfengine/h098EgAusoA

This Pull request is targeted on 3.4 because it corresponds to my need, but I'd be happy to create a new pull request as well for Master

[jooooooon]

This looks good, from my point of view, I'm pleased to see this long standing issue addressed :)

A few comments:

• Is there a reason the hard class virt_host_vz_vzps isn't virt_host_openvz_vzps? That would fit better with the other class names. Or does this apply to other virtualization systems too?
• CFEngine only accept pull requests on master (except bug fixes only applicable to specific versions). You should rebase this and retarget the pull request.

[jooooooon]

By the way, for future reference, this is Rudder bug #3909, see http://www.rudder-project.org/redmine/issues/3909.

[ncharles]

For virt_host_vz_vzps, i choosed this name in favour of vith_host_openvz_vzps as it seems to be installed by default on non-open vz based system (like virtuozzo).
I don't know if it exists on others system as well.

[cduclos]

Can one of the admins verify this patch?

[kacf]

For virt_host_vz_vzps, i choosed this name in favour of vith_host_openvz_vzps as it seems to be installed by default on non-open vz based system (like virtuozzo).

I'm a little confused. Is openvz a subset of vz? Or are they two distinct technologies?

[kacf]

Never mind, continue discussion in #956 instead.

Closing because this PR is directed to an old release branch.