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From Rohit Yadav <rohit.ya...@citrix.com>
Subject Re: Domr and Network
Date Wed, 22 Aug 2012 19:48:57 GMT
I had some discussion on this issue, pasting the email and my comments are inline:

On 23-Aug-2012, at 12:46 AM, Alena Prokharchyk <Alena.Prokharchyk@citrix.com> wrote:
> 
> Rohit,
> 
> Your suggestion makes sense, just trying to add more detailed description
> for the flow.
> 
> Cleanup=true flow in restartNetwork:
> ==============================================
> 1) cleanup network rules
> 2) shutdown all network elements (destroy in router case)
> 3) re-implement all the elements (restart/re-create)
> 4) reapply all the rules
> 
> When cleanup=false, first 2 steps are eliminated.
> 
> We should continue disallowing having cleanup=false for Shared networks.

Why? This may be useful when someone is upgrading CS. For example, they have a shared network
and the upgrade brings in new systemvm template.
The Admin may be required to recreate VRs and SystemVMs with the new systemvm template, in
such a case recreating VRs for shared network would make sense.
To have that, we give admin option to cleanup and restart network. And it would be upto the
Admin if they choose to cleanup and recreate their shared network?

> What I think we can do is, when implement the element on step 3), for
> Shared networks (btw, you can have those in Advance zone as well) do this:
> 
> * Basic zone - get all the PODs having user vms Starting/Running user vms.
> If the virtual router missing in this setup, re-create it. Do if for every
> Pod having vms and missing the VR.

Yes, this way CS will not waste resource on creating VRs for Pods with no hosts in basic zone.

> * Advance zone - check if there are user vms running in the network (not
> pod this time), and re-create the VR in the network if needed.

+1.


Regards,
Rohit

> 
> Let me know what you think, and please feel free to copy/paste the
> discussion to the apache mailing thread + corresponding bug. And we'll
> proceed there.

Thanks: http://bugs.cloudstack.org/browse/CS-16104

> 
> -Alena.
> 
> 
>> 
>> Note: CS should check if there are any hosts in all Pods and deploy VR in
>> only those which have any host as it's pod based.
>> 
>> a. Cleanup selected: cleanup=true
>> - Running VRs: Stops and deletes them, recreates and starts new VRs.
>> - Stopped VRs: Deletes them, recreates and starts new VRs.
>> - Deleted VRs: Recreates and starts new VRs.
>> 
>> b. Cleanup not selected: cleanup=false
>> - Running VRs: Checks/prepares, proceeds.
>> - Stopped VRs: Checks/prepares, starts them.
>> - Deleted VRs: Checks/prepares, starts new VRs.
>> 
>> If this proposed logic makes sense, in a customer setup in basic zone the
>> Admin has option to use cleanup (unchecked in UI/API) to false and
>> restart, which only recreates deleted VRs and starts stopped VRs.
>> This will be in-sync with how restart works for advance zone/network and
>> how cleanup is used in that use case.
>> 
>> I'm not sure, if this will cause future problems, but this gives Admin
>> more control over CS?
>> 
>> Regards,
>> Rohit
> 
> 




On 22-Aug-2012, at 4:59 PM, Rohit Yadav <rohit.yadav@citrix.com> wrote:

> Hi,
> 
> The restart network behaviour is different for advance and basic network. I've opened
this improvement ticket:
> http://bugs.cloudstack.org/browse/CS-16104
> 
> In its description, I've mentioned the present behaviour and proposed an improvement
for its behaviour on basic network.
> The main agenda is to allow a way for the Admin to recreate (deleted) VRs. A way around
is to create a new instance, but it's not elegant.
> 
> Please have a look at that and suggest/comment if that makes sense? Thanks.
> 
> Regards,
> Rohit
> 
> 
> On 21-Aug-2012, at 10:27 PM, Chiradeep Vittal <Chiradeep.Vittal@citrix.com> wrote:
> 
>> 
>> 
>> On 8/20/12 10:26 PM, "Rohit Yadav" <rohit.yadav@citrix.com> wrote:
>> 
>>> Hi,
>>> 
>>> On 21-Aug-2012, at 2:52 AM, Chiradeep Vittal
>>> <Chiradeep.Vittal@citrix.com> wrote:
>>>> On 8/20/12 2:34 AM, "Rohit Yadav" <rohit.yadav@citrix.com> wrote:
>>>> 
>>>>> Hi,
>>>>> 
>>>>> A domr is checked for its existence and if it does not exist it is
>>>>> created whenever an instance is launched. If I stop or stop and delete
>>>>> the domr, HA won't recreate domr. Is it intentional or a bug?
>>>> 
>>>> Are you doing this from the API?
>>> 
>>> No, trying to do this from the web app/client.
>> 
>> The web app uses the API, so that is equivalent.
>> 
>>> 
>>> 
>>>> If you are then, presumably you as the
>>>> admin know what you are doing and do not want the VR to automagically
>>>> recreate?
>>> 
>>> I agree, but don't we want to provide HA when domr VM crashes? How about
>>> we introduce a force stop (by admin) Boolean to know if this was
>>> intentional?
>> 
>> HA does happen if the hypervisor reports that the VR has gone away when
>> CloudStack thinks that it should be running.
>> 
>>> 
>>> At least after deletion, when the Admin user restarts the network they
>>> should be recreated?
>>> 
>>>>> Further, when I restart the network after either stopping the domr or
>>>>> stopping and deleting domr, restarting fails. From the surface the
>>>>> problem is null is passed instead of the correct Pod, but I'm not sure.
>>>> 
>>>> Looks like a bug to me
>>> 
>>> +1 Filed that here: http://bugs.cloudstack.org/browse/CS-16104
>>> 
>>> Regards,
>>> Rohit
>> 
> 


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