Re: [Rdo-list] introspection and raid configuration

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?

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