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From Hang Qi <hangq.1...@gmail.com>
Subject Re: Is there any way to force controller to re-elect leader
Date Mon, 07 Dec 2015 23:56:33 GMT
Hi Kishore,

Thanks very much for your detailed instructions, I tried it on my test
cluster, it works!

Thanks
Hang Qi

On Wed, Dec 2, 2015 at 12:54 PM, kishore g <g.kishore@gmail.com> wrote:

> Here are the steps. Please try them on a dummy cluster
>
> Lets call the existing cluster - ServingCluster. First we create a new
> cluster called SuperCluster
>
> helix-admin.sh createCluster SuperCluster
>
> Now add controller nodes C1, C2, C3 as participants to SuperCluster
>
> helix-admin.sh addInstance SuperCluster C1
> helix-admin.sh addInstance SuperCluster C2
> helix-admin.sh addInstance SuperCluster C3
>
> Add a resource named after original cluster, ServingCluster. This resource
> can be set up in any mode.
>
> AUTO ---> one of C1, C2, C3 will start managing ServingCluster
> SEMI_AUTO - leader is selected based on the preference list. If you want
> C2 to be the leader, set it to C2, C3, C1. If C2 crashes, C3 will take over
> automatically.
> CUSTOM- > you get complete control here, if you want to C2  to control the
> ServingCluster, set the IS as follows. Note: there is not automatic
> re-election of leader in this case.
>
> C1:STANDBY,
> C2:LEADER,
> C3:STANDBY
>
> Stop all controllers. Restart them in distributed mode, and this time the
> cluster name you provide to start will be SuperCluster.
>
> Hope this helps.
>
> Once you test your changes, you can go back to standalone mode by simply
> restarting the controllers again in standalone mode and provide the
> ServingCluster as the clustername.
>
> Hope this helps.
>
> Try this out on a dummy cluster.
>
> thanks,
> Kishore G
>
>
> On Wed, Dec 2, 2015 at 12:07 PM, Hang Qi <hangq.1985@gmail.com> wrote:
>
>> Hi Kishore,
>>
>> Thanks very much for your response.
>>
>> We are using Standalone mode.
>>
>> Do you have any instructions how to convert controllers from standalone
>> to distributed mode, I can not find it in
>> http://helix.apache.org/0.6.5-docs/tutorial_controller.html
>>
>> Thanks
>> Hang Qi
>>
>> On Wed, Dec 2, 2015 at 11:55 AM, kishore g <g.kishore@gmail.com> wrote:
>>
>>> What is the mode in which controller is deployed?
>>>
>>> Standalone or Distributed.
>>>
>>> Standalone is the mode where we run 3 controllers independently and one
>>> of them becomes the leader and starts managing.
>>>
>>> In Distributed, the controllers are participant of another super cluster
>>> and cluster to manage will become a resource in the super cluster. This
>>> mode is useful when there are too many clusters and we dont need to bring
>>> up controllers for each cluster.
>>>
>>> What you want can be achieved easily with distributed mode. You can
>>> enable/disable controllers since they come participants of super cluster.
>>>
>>> I cant think of a straight forward way to achieve that in standalone
>>> mode.
>>>
>>> Another option is to convert controllers from standalone to distributed.
>>> This can be done without causing any interruption to running servers.
>>>
>>>
>>> On Wed, Dec 2, 2015 at 11:16 AM, Hang Qi <hangq.1985@gmail.com> wrote:
>>>
>>>> Hi All,
>>>>
>>>> Is there any way to force controller to re-elect leader, or one step
>>>> further, is there any way we can force particular controller to be the
>>>> leader?
>>>>
>>>> The reason I am asking is that we are using customized rebalancer, and
>>>> we need to update all the controllers to let the controller to use the new
>>>> code, it is not very bucket testing friendly.
>>>>
>>>> Thanks
>>>> Hang Qi
>>>>
>>>>
>>>
>>
>>
>> --
>> Qi hang
>>
>
>


-- 
Qi hang

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