Linux VMs on Hyper-V – be sure to install and run hyperv-daemons!

A short post, just to say that if you are running Linux VMs on Hyper-V hypervisors you really should install and run the hyperv daemons.

On RHEL7-based distros this leads to :

yum install hyperv-daemons
systemctl enable hypervvssd
systemctl enable hypervkvpd

Ubuntu users should install the packages specified on this Microsoft TechNet page (I’ve not tested this myself, as I don’t yet have any Ubuntu VMs on Hyper-V).

Once you’ve done this a whole host of important features will work, including:

  • Live migration of VMs
  • IP injection (?)
  • Dynamic memory sizing
  • etc..

This will avoid any surprise reboots when hypervisor nodes are taken down for maintenance (which is what happened to me before I installed these..).
Obviously the complete failure of a hypervisor will still cause VM downtime,

I leave it as an exercise to the reader to use configuration management to add these to all their Hyper-V VMs automatically 🙂

Further reading : Best Practices for running Linux on Hyper-V