Thanks for the comments David. See inline. -Koushik
On 22-Nov-2013, at 7:31 PM, David Nalley <da...@gnsa.us> wrote: > Hi Koushik: > > In general I like the idea. A couple of comments: > > The upgrade section has a manual step for enabling HA manually per > instance. Why a manual step? Why is CloudStack not checking the > desired state (e.g. if HA is enabled in the instance service group) > with the actual state (what is reflected on the hypervisor) and > changing it when appropriate. > > We are already going to need to reconcile the state (things like host > the instance is running on will change for instance) with reality > already - so it seems like making this an automatic step wouldn't be > much extra effort and would scale far easier. [Koushik] Are you suggesting that as part of the upgrade process, all impacted VMs should be automatically updated? If so, yes it can be done. For now I am keeping it manual, in future the process can be automated. > > Are there plans on deprecating the custom HA solution, or will it be > supported forever? If the plan is to deprecate, lets go ahead and > start planning that/announcing/etc and not let it fall into disrepair. [Koushik] That's the plan going forward. For the next release both options will be there. Maybe post that the custom HA solution can be removed for XS 6.2 and above. > > --David > > On Fri, Nov 22, 2013 at 7:27 AM, Koushik Das <koushik....@citrix.com> wrote: >> Initial draft of the FS >> https://cwiki.apache.org/confluence/display/CLOUDSTACK/User+VM+HA+using+native+XS+HA+capabilities >> >> -Koushik >> >> On 21-Nov-2013, at 9:59 AM, Koushik Das <koushik....@citrix.com> wrote: >> >>> Cloudstack relies on custom HA logic for user VMs running on Xenserver. The >>> reason for doing it like this may be due the fact that native HA >>> capabilities in XS was not mature enough during the initial days. Also in >>> the custom HA logic, Cloudstack has to correctly determine the state of a >>> VM from the hypervisor before it can take any action. In case there are any >>> issues in determining the state, HA mechanism can get impacted. Since the >>> hypervisor best knows the state of the VM it is a better approach to rely >>> on native HA capabilities. >>> >>> The idea is to rely on native HA capabilities for user VMs from XS 6.2 >>> onwards. HA for system VMs would still be based on application logic. For >>> sake of backward compatibility the earlier option will be there as well and >>> there will be a choice to use any one option. >>> >>> The additional requirement for this is to pre-configure native HA on a >>> Xenserver cluster before deploying any user VMs as documented here [1]. >>> >>> I have created a ticket in Jira [2]. I will post the FS for this shortly. >>> >>> Thanks, >>> Koushik >>> >>> [1] >>> http://support.citrix.com/servlet/KbServlet/download/34969-102-704897/reference.pdf >>> (refer section 3.8) >>> [2] https://issues.apache.org/jira/browse/CLOUDSTACK-5203 >>> >>> >>
