[ovirt-users] oVirt non-self-hosted HA

TomK tomkcpr at mdevsys.com
Sun Apr 15 01:26:48 UTC 2018


On 4/5/2018 8:59 AM, Tom wrote:
> 
> 
> Sent from my iPhone
> 
> On Apr 5, 2018, at 5:29 AM, Yaniv Kaul <ykaul at redhat.com 
> <mailto:ykaul at redhat.com>> wrote:
> 
>>
>>
>> On Thu, Apr 5, 2018 at 9:08 AM, TomK <tomkcpr at mdevsys.com 
>> <mailto:tomkcpr at mdevsys.com>> wrote:
>>
>>     On 4/4/2018 3:11 AM, Yaniv Kaul wrote:
>>
>>
>>
>>         On Wed, Apr 4, 2018 at 12:39 AM, Tom <tk at mdevsys.com
>>         <mailto:tk at mdevsys.com> <mailto:tk at mdevsys.com
>>         <mailto:tk at mdevsys.com>>> wrote:
>>
>>
>>
>>             Sent from my iPhone
>>
>>             On Apr 3, 2018, at 9:32 AM, Yaniv Kaul <ykaul at redhat.com
>>         <mailto:ykaul at redhat.com>
>>             <mailto:ykaul at redhat.com <mailto:ykaul at redhat.com>>> wrote:
>>
>>
>>
>>                 On Tue, Apr 3, 2018 at 3:12 PM, TomK
>>             <tomkcpr at mdevsys.com <mailto:tomkcpr at mdevsys.com>
>>                 <mailto:tomkcpr at mdevsys.com
>>             <mailto:tomkcpr at mdevsys.com>>> wrote:
>>
>>                     Hey Guy's,
>>
>>                     If I'm looking to setup the oVirt engine in an HA
>>                     configuration off the physical servers hosting my
>>             VM's (non
>>                     self hosted), what are my options here?
>>
>>                     I want to setup two to four active oVirt engine
>>             instances
>>                     elsewhere and handle the HA via something like
>>             haproxy /
>>                     keepalived to keep the entire experience seamless
>>             to the user.
>>
>>
>>                 You will need to set up the oVirt engine service as
>>             well as the PG
>>                 database (and ovirt-engine-dwhd service and any other
>>             service we
>>                 run next to the engine) as highly available module.
>>                 In pacemaker[1], for example.
>>                 You'll need to ensure configuration is also sync'ed
>>             between nodes,
>>                 etc.
>>                 Y.
>>
>>
>>             So already have one ovirt engine setup separately on a vm that
>>             manages two remote physical hosts.  So familiar with the
>>         single host
>>             approach which I would simply replicate.  At least that’s
>>         the idea
>>             anyway.  Could you please expand a bit on the highly available
>>             module and  syncing the config between hosts?
>>
>>
>>         That's a different strategy, which is also legit - you treat
>>         this VM as a highly available resource. Now you do not need to
>>         sync the config - just the VM disk and config.
>>
>>
>>     I think there's a postgres component too and if oVirt engine keeps
>>     all it's date on the postgres tables, then synchronizing this
>>     piece might be all I need?  I'm not sure how the separate oVirt
>>     engines sitting on various separate physical hosts keep their
>>     settings in sync about the rest of the physicals in an oVirt
>>     environment. (Assume we may have 100 oVirt physicals for example.)
>>
>>
>> There's more than just the database, although it contains 99% of what 
>> you need. See the content of the result of 'engine-backup' command.
>> I think you might be somewhat confusing between the number of oVirt 
>> hypervisors (we support hundreds) and the Engine - the management, 
>> which is single - and with hosted-engine, it's a single, but highly 
>> available virtual machine - that can run on one of several (I suggest 
>> 3-8) of those hypervisors.
>> Y.
> 
> Yah, still very new to much of this.  Thank you again.
> 
> I’ll take that away and do some reading.
> 
> Cheers,
> Tom
> 

"that can run on one of several (I suggest 3-8) of those hypervisors."
To clarify.  So if I have 3-8 copies of the oVirt Engine in a 
self-hosted config, only one can run at any one time?  Is this correct?

Cheers,
Tom

>>
>>
>>         Perhaps something like
>>         https://www.unixarena.com/2015/12/rhel-7-pacemaker-configuring-ha-kvm-guest.html
>>         <https://www.unixarena.com/2015/12/rhel-7-pacemaker-configuring-ha-kvm-guest.html>
>>         .
>>
>>         But if you are already doing that, I'm not sure why you'd
>>         prefer this over hosted-engine setup.
>>
>>
>>     I'm comparing both options.  I really don't want to ask too many
>>     specific until I have the chance to read into the details of both.
>>
>>         Y.
>>
>>
>>     Cheers,
>>     Tom
>>
>>
>>
>>             Cheers,
>>             Tom
>>
>>
>>                 [1] https://clusterlabs.org/quickstart-redhat.html
>>             <https://clusterlabs.org/quickstart-redhat.html>
>>                 <https://clusterlabs.org/quickstart-redhat.html
>>             <https://clusterlabs.org/quickstart-redhat.html>>
>>
>>
>>                     From what I've seen in oVirt, that seems to be
>>             possible
>>                     without the two oVirt engines even knowing each
>>             other's
>>                     existence but is it something anyone has ever
>>             done?  Any
>>                     recommendations in this case?
>>
>>                     Having settings replicated would be a bonus but I
>>             would be
>>                     comfortable if they weren't and I handle that myself.
>>
>>                     --         Cheers,
>>                     Tom K.
>>                    
>>             -------------------------------------------------------------------------------------
>>
>>                     Living on earth is expensive, but it includes a
>>             free trip
>>                     around the sun.
>>
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>>
>>
>>
>>
>>     -- 
>>     Cheers,
>>     Tom K.
>>     -------------------------------------------------------------------------------------
>>
>>     Living on earth is expensive, but it includes a free trip around
>>     the sun.
>>
>>


-- 
Cheers,
Tom K.
-------------------------------------------------------------------------------------

Living on earth is expensive, but it includes a free trip around the sun.



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