Hi all, please see below original email below from Dmitry. I've modified the subject to bring larger audience to the issue.
I'd like to split the issue into two parts: 1. Maintenance mode for OpenStack controllers in HA mode (HA-ed Keystone, Glance, etc.) 2. Maintenance mode for OpenStack computes/storage nodes (no HA) For first category, we might not need to have maintenance mode at all. For example, if we apply patching/upgrade one by one node to 3-node HA cluster, 2 nodes will serve requests normally. Is that possible for our HA solutions in Fuel, TripleO, other frameworks? For second category, can not we simply do "nova-manage service disable...", so scheduler will simply stop scheduling new workloads on particular host which we want to do maintenance on? On Thu, Aug 28, 2014 at 6:44 PM, Dmitry Pyzhov <dpyz...@mirantis.com> wrote: > All, > > I'm not sure if it deserves to be mentioned in our documentation, this > seems to be a common practice. If an administrator wants to patch his > environment, he should be prepared for a temporary downtime of OpenStack > services. And he should plan to perform patching in advance: choose a time > with minimal load and warn users about possible interruptions of service > availability. > > Our current implementation of patching does not protect from downtime > during the patching procedure. HA deployments seems to be more or less > stable. But it looks like it is possible to schedule an action on a compute > node and get an error because of service restart. Deployments with one > controller... well, you won’t be able to use your cluster until the > patching is finished. There is no way to get rid of downtime here. > > As I understand, we can get rid of possible issues with computes in HA. > But it will require migration of instances and stopping of nova-compute > service before patching. And it will make the overall patching procedure > much longer. Do we want to investigate this process? > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > -- Mike Scherbakov #mihgen
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