> -----Original Message----- > From: Hari Kannan [mailto:[email protected]] > Sent: 28 February 2013 10:36 > To: [email protected]; [email protected] > Subject: RE: HA question > > Hi Kelcey, > > At the risk of stating the obvious, I just wish to re-iterate my earlier > point - with > CloudStack, HA is for VM, not for host. That is different than VMware's HA in > someways - in VMware, if a cluster is HA, when any host crashes, all VMs on > that > host will be restarted on a different host. With cloudstack, only VMs that > are HA > enabled will be restarted.
Yes, wanted to add more here... VMware provides granular options at level of VM to override the cluster lelvel setting. That means even if a host in a HA enabled cluster, crashes, only those VMs that are marked for HA would be taken care. Apart from that it is also possible to override other HA parameters like priority etc. Regards, Sateesh > > At least, that is the way I understand this.. > > I also wonder what happens in CloudStack if a host crashes (assume there were > no VMs on it) - would CloudStack detect this host is down and reduce the > available capacity? > > Hari > > -----Original Message----- > From: Kelcey Damage (BT) [mailto:[email protected]] On Behalf > Of [email protected] > Sent: Wednesday, February 27, 2013 8:51 PM > To: [email protected] > Cc: Hari Kannan > Subject: RE: HA question > > So it's safe to conclude that HA while enabled on the host(As in the module), > must be available cluster wide(uniform cluster). This is how VMware and others > operate. > > Thanks all. > > -Kelcey > > > >-----Original Message----- > >From: Sateesh Chodapuneedi [mailto:[email protected]] > >Sent: Wednesday, February 27, 2013 8:46 PM > >To: [email protected] > >Cc: Hari Kannan > >Subject: RE: HA question > > > >For VMware, CloudStack uses native HA provided by VMware. > >VMware provides HA at the level of cluster. > > > >Regards, > >Sateesh > > > >> -----Original Message----- > >> From: Nitin Mehta [mailto:[email protected]] > >> Sent: 28 February 2013 10:13 > >> To: [email protected] > >> Cc: Hari Kannan > >> Subject: Re: HA question > >> > >> CS has its own HA logic and doesn't use the native HA of the HV and > >> so the question for enabling the HA for hosts doesn't arise. This is > >> true > for XS. > >> For Vmware and KVM, I will let the guru's speak :) > >> > >> On 28/02/13 9:55 AM, "[email protected]" <[email protected]> > >wrote: > >> > >> >Thanks that¹s awesome, but not quite the answer I was looking for. > >> > > >> >To better phrase my question, if the cluster is the basic unit of > >> >availability, when hosts are enabled for HA, must all hosts in the > >> >cluster be enabled? Or can the cluster exist with a non-uniform > >> >structure, having only some hosts enabled for HA? > >> > > >> >You partially answered it with the special reserve HA hosts, but I'm > >> >looking more in terms of general use. > >> > > >> >Thanks > >> > > >> >-kelcey > >> > > >> > > >> >>-----Original Message----- > >> >>From: Hari Kannan [mailto:[email protected]] > >> >>Sent: Wednesday, February 27, 2013 8:21 PM > >> >>To: [email protected] > >> >>Subject: RE: HA question > >> >> > >> >>Hi Kelsey, > >> >> > >> >>HA is at 2 levels VMs can be marked HA. In addition, you can mark > >> >>some hosts as reserved for ³Dedicated² HA hosts. Quoting from the > >> >>manual, the dedicated HA option is set through a special host tag > >> >>when the host is created. > >> >>To allow the administrator to dedicate hosts to only HA-enabled > >> >>VMs, set the global configuration variable ha.tag to the desired > >> >>tag (for example, "ha_host"), and restart the Management Server. > >> >>Enter the value in the Host Tags field when adding the host(s) that > >> >>you want to dedicate to HA-enabled VMs. > >> >> > >> >>Hari > >> >> > >> >>From: Kelcey Damage (BT) [mailto:[email protected]] > >> >>Sent: Wednesday, February 27, 2013 8:00 PM > >> >>To: CloudStack dev list > >> >>Subject: RE: HA question > >> >> > >> >>Hi, > >> >> > >> >>I can¹t remember, do we enable HA on a per host basis, or on a per > >> >>cluster basis? > >> >> > >> >>Thanks. > >> >> > >> >>[cid:[email protected]]Kelcey Damage Infrastructure > >> >>Systems Architect > >> > >>>www.backbonetechnology.com<http://www.backbonetechnology.com/> > >> >>------------------------------------------------------------------- > >> >>- > >> >>----- > >> > >>>[email protected]<mailto:[email protected] > >m > >> >>> > >> >> > >> >>address: 55 East 7th Ave, Vancouver, BC, V5T 1M4 > >> >>tel: +1 604 713 8560 ext:114 > >> >>fax: +1 604 605 0964 > >> >>skype: kelcey.damage > >> >> > >> > > >> > >
