====== Ganeti ======

Ganeti is a cluster virtual server management software tool built on top of existing virtualization technologies such as Xen or KVM and other open source software.
===== Some Links =====

[[http://jfut.integ.jp/linux/ganeti/|Ganeti Repo]]

[[http://docs.ganeti.org/|Ganeti Docs]]

===== Installation =====
On the [[http://jfut.integ.jp/linux/ganeti/|Ganeti Repo]] side you find a pretty good tutorial. Here is just a litte summary for RHEL/CentOS 7 and useing KVM. 

===== Troubleshooting =====
You will have some strange problems, This should help you out. 

==== Can not open backing device ====
You almost tried [[http://docs.ganeti.org/ganeti/2.15/html/admin.html#restoring-redundancy-for-drbd-based-instances|Restoring redundancy for DRBD-based instances]] and had no success. Take a look if you have some active LV's from your DRBD and deactivate it. 
<code>
# lvscan
...
  ACTIVE            '/dev/vg_yourVM/lv_disk' [10.00 GiB] inherit
...
# gnt-cluster command vgchange -an vg_yourVM
</code>
Now you should be able to start your VM. 


==== State change failed: (-12) Device is held open by someone ====
Somehow the DRBD-disks from the VM are visible on the host and you have to remove them. Check if there is a DRBD-disk mounted and unmount it. 
<code>
grep -i drbd /proc/mounts
</code>
After that, take a look at the device mapper itself. 
<code>
dmsetup ls
dmsetup remove drbd0-0
</code>
Remove all DRBD-disks that are listed by dmsetup.