The 'shared-filer' ExtStorage provider

[Constantinos Venetsanopoulos]

Hello team,

I'm attaching an ExtStorage provider called "shared-filer" which can be used
with the ExtStorage interface. It's purpose is to provide a way to test the
ExtStorage interface, without having to write custom scripts for a specific
NAS. It can also act as a template for those wanting to write their own
custom scripts to fit their needs/hardware.

This provider will create all instance's disks as files under a shared
directory,
the same way the `sharedfile' template operates. However, it will do it
using
the `ext' template.


An ExtStorage provider is a set of scripts that you install under a
directory,
the same way you would do with a Ganeti OS Definition. So, to install this
provider all you have to do is:

1. Create the 'extstorage' dir, according to where you have installed
Ganeti.
This is the same place where you have your 'os' directory for OS
Definitions.

# mkdir /usr/share/ganeti/extstorage

2. Untar the provider inside that directory, which will result in having
all the
scripts under /usr/share/ganeti/extstorage/shared-filer/ :

/usr/share/ganeti/extstorage/shared-filer/{create,attach,detach,remove,verify}

3. Run the corresponding command to see everything was setup correctly:

# gnt-storage diagnose

4. Make sure you setup the $SHARED_DIR variable in all scripts to point
to the
shared directory in which all file-disks will be created.
(this is by default set to /srv/ganeti/shared-file-storage)

5. Also, make sure you have created the corresponding logging directory:

# mkdir /var/log/ganeti/extstorage


You are now ready to use the new ExtStorage provider. You can do that by
running:

# gnt-instance add .... -t ext --disk 0:size=2G,provider=shared-filer
testVM1

For more info see the man pages for `ganeti-extstorage-interface' and
`gnt-storage' plus the shared-storage design doc.


Kind Regards,
Constantinos