On 03/25/2015 03:16 AM, Deepak Shetty wrote: > > > On Wed, Mar 25, 2015 at 11:29 AM, Deepak Shetty <dpkshe...@gmail.com > <mailto:dpkshe...@gmail.com>> wrote: > > > > On Wed, Mar 25, 2015 at 12:58 AM, Ian Wienand <iwien...@redhat.com > <mailto:iwien...@redhat.com>> wrote: > > On 03/24/2015 03:17 PM, Deepak Shetty wrote: > > For eg: Look at [1] > > [1] > https://github.com/stackforge/devstack-plugin-glusterfs/blob/master/devstack/settings > > > I would like ability to change these while I use the enable_plugin > > apporach to setup devstack w/ GlusterFS per my local glusterfs setup > > So I think the plugin should do > > > CINDER_ENABLED_BACKENDS=${CINDER_ENABLED_BACKENDS:-glusterfs:glusterfs,lvm:lvm1} > > i.e. provide a default only if the variable is unset. > > > Bah! That was easy, i should have figured that myself :) > Thanks for catching that > > > > This seems like one of those "traps for new players" and is one > concern I have with devstack plugins -- that authors keep having to > find out lessons learned independently. I have added a note on this > to the documentation in [1]. > > -i > > [1] https://review.openstack.org/#/c/167375/ > > > Great, i +1'ed it. > > Also i posted patch to fix settings file @ > https://review.openstack.org/167494 > > > Ian, > Looks like usign bash default in settings file of plugin is not > working, in my patch it didn't use glusterfs driver, it used LVM (default) > I think whats happening here is that by the time settings file is > sourced, CINDER_ENABLED_BACKENDS is already set to lvm by lib/cinder > so settings file's default value is never taken > > IIUC there are 3 scenarios (taking CINDER_ENABLED_BACKENDS as example var) : > > 1) localrc doesn't have CINDER_ENABLED_BACKENDS and enable_plugin > - Here we want the lib/cinder's default value to be taken > - this should work fine > > 2) localrc doesn't have CINDER_ENABLED_BACKENDS but has enable_plugin > glusterfs > - Here we want the plugin's default values to be taken, but its not > as lib/cinder already initialized CINDER_ENABLED_BACKENDS to use lvm backend > - Thus broken > > 3) localrc has both CINDER_ENABLED_BACKENDS and enable_plugin glusterfs > specified > - Here we want CINDER_ENABLED_BACKENDS present in my localrc to be > chosen > - This will work as by the time settings file is sourced > CINDER_ENABLED_BACKENDS is already initialised to my value in localrc > > So #2 scenario would need some changes in stack.sh handling of plugin code ?
Right, so this code runs late enough that you don't get to change the
defaults. I think that's ok.
I would instead do the following:
1) CINDER_ENABLED_BACKENDS+=,glusterfs:glusterfs
or
2) CINDER_ENABLED_BACKENDS=glusterfs:glusterfs
in the plugin.
Clearly, if you've enabled the plugin, you want glusterfs. I think that
in most cases you probably only want glusterfs as your backend, so
option #2 seems sensible.
-Sean
--
Sean Dague
http://dague.net
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