Ken Gaillot <[email protected]> wrote: > On 07/20/2016 11:47 AM, Adam Spiers wrote: > > Ken Gaillot <[email protected]> wrote: > >> Hello all, > >> > >> I've been meaning to address the implementation of "reload" in Pacemaker > >> for a while now, and I think the next release will be a good time, as it > >> seems to be coming up more frequently. > > > > [snipped] > > > > I don't want to comment directly on any of the excellent points which > > have been raised in this thread, but it seems like a good time to make > > a plea for easier reload / restart of individual instances of cloned > > services, one node at a time. Currently, if nodes are all managed by > > a configuration management system (such as Chef in our case), when the > > system wants to perform a configuration run on that node (e.g. when > > updating a service's configuration file from a template), it is > > necessary to place the entire node in maintenance mode before > > reloading or restarting that service on that node. It works OK, but > > can result in ugly effects such as the node getting stuck in > > maintenance mode if the chef-client run failed, without any easy way > > to track down the original cause. > > > > I went through several design iterations before settling on this > > approach, and they are detailed in a lengthy comment here, which may > > help you better understand the challenges we encountered: > > > > > > https://github.com/crowbar/crowbar-ha/blob/master/chef/cookbooks/crowbar-pacemaker/providers/service.rb#L61 > > Wow, that is a lot of hard-earned wisdom. :-)
Yep 8-/ > I don't think the problem is restarting individual clone instances. You > can already restart an individual clone instance, by unmanaging the > resource and disabling any monitors on it, then using crm_resource > --force-* on the desired node. > > The problem (for your use case) is that is-managed is cluster-wide for > the given resource. Exactly. > I suspect coming up with a per-node > interface/implementation for is-managed would be difficult. > > If we implement --force-reload, there won't be a problem with reloads, > since unmanaging shouldn't be necessary. OK, sounds good :) > FYI, maintenance mode is supported for Pacemaker Remote nodes as of 1.1.13. Yep, we're relying on it already! _______________________________________________ Users mailing list: [email protected] http://clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
