Re: [Rdo-list] introspection and raid configuration

On 05/27/2015 09:38 AM, Imre Farkas wrote: > On 05/26/2015 05:43 PM, Dmitry Tantsur wrote: >> On 05/26/2015 04:42 PM, Imre Farkas wrote: >>> Hi all, >>> >>> I would like to gather some feedback on the current worfklow regarding >>> the subject. RAID configuration on DRAC machines works as follows (it >>> assumes there's no RAID volume on the machine): >>> 1. user defines the deployment profile and the target raid >>> configuration >>> for each profile >>> 2. ironic-discoverd introspects the node to gather facts >>> 3. ach-match picks a deployment profile based on the gathered facts >>> 4. instack triggers the raid configuration based on the selected >>> profile >>> >>> A bug[1] has been discovered regarding step 2: ironic-discoverd fails >>> because it tries to figure out the size of the local disk but it can't >>> find any as no volume exists on the RAID controller yet. This is a >>> chicken-and-egg problem because ironic-discoverd doesn't work if the >>> RAID volume(s) has not been configured but the RAID configuration can't >>> be triggered if ironic-discoverd hasn't gathered the facts about the >>> node. >>> >>> Few possible workarounds: >>> #1: make saving the local disk size optional in the standard plugin in >>> ironic-discoverd. The downside is that the standard plugin is supposed >>> to enroll nodes in ironic with all attributes necessary for scheduling. >>> This assumption might fail with this solution. >> >> -1 will never get upstream for the reasons you stated >> >>> >>> #2: run discovery multiple times with different set of plugins. The run >>> before RAID configuration would exclude the standard plugin while the >>> run afterwards could potentially exclude others. The parameters passed >>> by the user to ironic-discoverd for each run need to be properly >>> documented. It would slow down the installation because each run >>> requires a reboot which takes a lot of time on bare metal. >> >> Possible, but better (IMO) idea below. >> >>> >>> #3: name your suggestion! >> >> #3. modify your existing root_device_hint plugin to insert a fake >> local_gb value (with issuing a warning), and then put it to the >> beginning of the plugin pipeline. WDYT? >> > > I would avoid that for the very same reason as we rejected option #1: it > would do things quite differently than it is expected. However, building > on top of this idea, we could introduce a fake_local_gb plugin and > enable it as default in instack. Thoughts? ETOOMANYPLUGINS :D I would say it's fine for root_device_hint plugin. It's not enabled by default upstream, and it's a normal flow involving it.

> > Imre > > >>> >>> Any thoughts/preference on the above described workarounds? >>> >>> Thanks, >>> Imre >>> >>> >>> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1222124 >> >