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==== Rebooting and restarting Virtual Machines. ====

From: Michael C Voorhis <mvoorhis@cs.wpi.edu>
  To: "John Leveillee" <jleveillee@cs.wpi.edu>
  Cc: "'Michael C Voorhis'" <mvoorhis@cs.wpi.edu>
  Subject: vmware reboot?
  Date: Fri, 9 Sep 2011 08:52:47 -0400

John Leveillee writes:
> Mike, Can you please provide me the vmware procedure for rebooting
> machines?  Thanks, John

CS-VM2 is our virtual machine server,  It is running 13 VMs right
now.  VMWare is a program for running virtual machines but is *not*
the system we use on cs-vm2; we use something called KVM there, it is
a free system associated with Linux.  Some virtual machines use
vmware, but not all of them.

Anyway--we need to make sure you can ssh/PuTTY into cs-vm2.cs.wpi.edu,
and we need to make sure you can run SUDO there.  Last time I checked
you were able to run sudo there, and it does look like you logged in
there on the 6th.  Check anyway. :)

Note that when you login to cs-vm2, You'll see a login-message saying
that the system wants a reboot.  Ignore that--we'll reboot it sometime
after I come back.  Even if you decide to reboot it, it should come
back up no problem anyway.

So.. try logging in there and run:

sudo virsh list --all

That command will show all the virtual machines that are running on
the server (and those that are installed there but not active).

Now, if you want to shutdown one of these machines, the most sensible
way would be to login to the vm itself (Sequoia, for example) via SSH
and run

sudo shutdown -h now "Reason for shutdown"

or

sudo shutdown -r now "Reason for rebooting"

Note the -h means "shutdown and halt" and -r means "shutdown and
reboot."  Asking the OS to shut itself down is always the better,
cleaner solution.

But if the VM is hung or locked up and not responding (or you don't
have an account there--some of these VMs are project boxes where even
I don't have an account!), then you can't actually log into it and do
the shutdown.  So you need to back up a level and do what we're
talking about here--the VM equivalant of pulling the plug on a machine
you can't reach any other way.  The command from cs-vm2 to pull the
plug on a VM would be

sudo virsh destroy [vm-name]

This will cause the VM to immediately shut off.  You would follow this
up with

sudo virsh start [vm-name]

which would cause the VM to boot after being shutoff.  Most VMs will
reboot in a pretty short period of time, perhaps a minute for machines
like Sequoia, but the smaller VMs, like the print server, the samba
server or the webserver should be back up in under a minute.
Sometimes you can reboot them without anyone noticing the downtime,
which is great.

If you would like to test the shutdown/reboot procedure, you can give
it a try with the "mag-iqp" or "cskrb0" machines, which are only very
occasionally used.

See you soon,

--MCV

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