Ganet extstorage provider for local zfs volumes

http://docs.ganeti.org/ganeti/master/html/man-ganeti-extstorage-interface.html

INSTALLATION

On node which has zfs storage pool

  cd /usr/share/ganeti/extstorage/
  git clone https://github.com/ffzg/ganeti-extstorage-zfs zfs
  cd zfs
  vi defaults.sh

You need to specify zfs filesystem under which block devices will be created.

Now ssh into ganeti master node and do following:

1. enable new disk template

  gnt-cluster modify --enabled-disk-templates plain,drbd,ext \
	--ipolicy-disk-templates plain,drbd,ext

2. create log directory

  mkdir /var/log/ganeti/extstorage

3. try instance creation with something similar to

  gnt-instance add -t ext --disk=0:size=10G,provider=zfs \
	--net 0:mode=bridged,link=br1001 \
	--net 1:mode=bridged,link=br0060 \
	--net 2:mode=bridged,link=br0080 \
	--no-name-check --no-ip-check \
	-o debootstrap+default \
	-B maxmem=1G -n arh-hw zfs

4. install helper scripts for daily block snapshots

  ln -sf /usr/share/ganeti/extstorage/zfs/bin/daily-block-snapshot /etc/cron.daily/

5. install lvm wrapper scripts to report zfs volumes as lv

  find /usr/share/ganeti/extstorage/zfs/sbin/ -type f | xargs -i ln -v -s -f {} /sbin/

This scripts enable gnt-node commands to work:

root@vmh02:/home/dpavlin# gnt-node list arh-hw
Node               DTotal DFree MTotal MNode MFree Pinst Sinst
arh-hw.gnt.ffzg.hr  87.8G 87.2G   7.8G  252M  5.6G     1     0

root@vmh02:/home/dpavlin# gnt-node list-storage arh-hw
Node               Type   Name     Size  Used   Free Allocatable
arh-hw.gnt.ffzg.hr lvm-vg arh-hw 190.0G 62.7G 127.3G Y
arh-hw.gnt.ffzg.hr lvm-vg ffzgvg  87.8G  610M  87.2G Y


HELPER SCRIPTS

Helper scripts in bin directory list volumes, show size or snapshots.


arh-hw:/usr/share/ganeti/extstorage/zfs# ./bin/list 
NAME                                                           USED  AVAIL  REFER  MOUNTPOINT
tmp500g/block                                                  612M  87.2G    30K  /tmp500g/block
tmp500g/block/af1a90e8-0566-4cbf-bc8c-99fc82b67ce3.ext.disk0   612M  87.2G   610M  -


arh-hw:/usr/share/ganeti/extstorage/zfs# ./bin/size 
NAME                                                          PROPERTY  VALUE    SOURCE
tmp500g/block/af1a90e8-0566-4cbf-bc8c-99fc82b67ce3.ext.disk0  volsize   11G      local


arh-hw:/usr/share/ganeti/extstorage/zfs# ./bin/snapshots 
NAME                                                                      USED  AVAIL  REFER  MOUNTPOINT
tmp500g/block@etckeeper                                                      0      -    30K  -
tmp500g/block/af1a90e8-0566-4cbf-bc8c-99fc82b67ce3.ext.disk0@2014-06-24  2.64M      -   610M  -

KNOWN BUGS

- in current ganeti, gnt-backup export doesn't work because extstorage
  snapshoot hook is not available
- gnt-instance move works from somewhere to zfs, but not from zfs to somewhere