Exercising live migration

One of the scenarios that we had running at TechEd NZ was a continuous live migration between two hosts which I had set up using Virtual Machine Manager & the Powershell components.  Someone asked for it internally, and I thought I’d post it here in case anyone else would find it useful.

This is useful if you want to do any long running tests of live migration, and record the number of migrations you have done.

To set up, create C:\temp\counter.txt and edit it so that it has a single line which has the content 0.  It uses this text file to record the number of migrations (it also stores in memory but uses the file in case you have to restart the script for any reason).  Edit the script to replace the following fields:

vmmhost.yourdomain.com –> FQDN of your VMM Server

HyperVHost1.yourdomain.com –> FQDN of Hyper-V host 1

HyperVHost2.yourdomain.com –> FQDN of Hyper-V host 2

VMName –> Name of the VM you are going to migrate.

There is also a random delay introduced at the end of the script so the migration is not predictable.

get-vmmserver -computername "vmmhost.yourdomain.com"
$vm = get-vm | where { $_.Name -eq "VMName"}
$host1 = get-vmhost | where {$_.Name -eq "HyperVHost1.yourdomain.com"}
$host2 = get-vmhost | where {$_.Name -eq "HyperVHost2.yourdomain.com"}

Do
{

if ($vm.VMhost -eq "HyperVHost1.yourdomain.com")
{$desthost=$host2}
else
{$desthost=$host1}

move-vm -vm $vm -vmhost $desthost -jobvariable movejob
if ($movejob.Errorinfo.DetailedCode -eq 0)
{
$rawmigrations = get-content -Path C:\temp\counter.txt -TotalCount 1
$migrations = [int32] $rawmigrations
$migrations++
$migrations
set-content -Path C:\temp\counter.txt -value $migrations
}
$wait=get-random -minimum 60 -maximum 240
start-sleep -seconds $wait

}
while ($true)

To enhance this you could also randomise the guest that is being migrated, and if you have more than a two node cluster you could randomise the destination host.  If I get bored over the next few weeks I’ll update it so that it does these things.