On Wed, Apr 17, 2013 at 02:07:20PM +0530, Abhinandan Prateek wrote: > On 17/04/13 12:33 PM, "Prasanna Santhanam" <t...@apache.org> wrote: > > >On Tue, Apr 16, 2013 at 07:33:28PM +0530, Abhinandan Prateek wrote: > >> > >> I have some queries regarding Database Creator: > >> > >> Can this feature be tested on 4.1 ? > >> > >> Could someone also provide more details on the following: > >> > >> 1. Outline the exact steps that are involved in rolling upgrade > >>procedure? > >> 2. Can you confirm if rolling upgrades are specific to only upgrade > >> procedure involving multiple management servers in a cluster? > >> 3. Would rolling upgrades mean that there will be zero downtime for > >> customers when upgrading? Are we also dealing with NOT having to > >>restart all > >> system Vms ? Currently restarting system Vms is part of our upgrade > >> procedure. > >> > >Rohit has written most of the design goals and implementation in the > >wiki: > >https://cwiki.apache.org/confluence/display/CLOUDSTACK/Database+Creator > > > >The term 'rolling upgrade' might be loaded here. I don't see anything > >in the spec/code that guarantees that no downtime is reqd. It only > >alters the way upgrades are done - sticking to a base schema at 4.0 > >and doing incremental upgrades from there. > > Also what exactly does no downtime means ? Is it just that the one of the > MS in the cluster will be running providing minimal services during > upgrade Or that there will be no disruption of services.
I don't think the dbcreator right now guarantees consistency of the db when one MS is down and the other functional. So I don't see one MS in the cluster functional because the other was brought down while you are tinkering the db in the background. Besides, only the portal is down. Tenant VMs are unaffected and will be functional in all this. SystemVMs are separate from this and shouldn't be mixed with the db issue I think. IMO, it's better to invest in a solution proven for the purpose of db change management, rolling upgrades as you refer to it than building our own. Something like liquibase, dbMaintain. That will enable easier upgrade testing without the presence of a running management server as well. Thoughts? -- Prasanna.,
