Migrating Physical systems to HyperV

This guidance note is based upon experience of migrating the tomtools service to HyperV. 'tomtools.cern.ch (aka lxbra1905) is an 8 core machine with 16G of ram and two 160G disks that were not arranged in a raid1 set. (hence the requirement for migration - there was a fault on sda)

The initial plan was to bring up a new fresh minimal SLC machine on Hyper-V and install the applications on to the host. Due to (unknown) issues with tomcat, this was not possible - the jira service was starting and showing as listening. but there was no content being rendered. This was done on 'jira01', initially created as a 8G/4 core machine (the largest possible in the self-service interface). Due to constraints with hypervisor availability this was reduced later in the VMM Management console.

The actual migration was eventually done by creating fresh SLC 5x x96_64 machine (jira02) in Hyper-V and performing an rsync from lxbra1905 to this host. Configuration changes were then done to reflect the new hardware layout (disk type / partitioning, network, hostname)

Points to note

• when you rsync, you will lose the ability to kerberos-SSH in to the new host as kerberos information will be invalid until reset.
  • copy an ssh key into /root/.ssh/authorized_keys on the target (and make sure its not overwritten by the source machine)
  • start up a new ssh session to the target and leave it open as you'll need to run some reconfiguration after the rsync finishes.
• remove /etc/mtab from targer once the sync completes -- unless the partitioning matches the original system
• update /etc/fstab to match the target filesystem
• check HOSTNAME in /etc/sysconfig/networking
• if you're using synthetic Ethernet (recommended) on target it will be seth* -- remove /etc/sysconfig/network-scripts/ifcfg-eth*
• make sure you have the mshvic and kmod-mshvic packages installed AND in the initrd.
• rebuild krb5.keytab
• check for any legacy hard-coded references to the old hostname -- (only if you're moving name) such as apache configuration

-- AndrewElwell - 03-May-2011