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Posted to user@cassandra.apache.org by Jonathan Colby <jo...@gmail.com> on 2011/03/17 14:09:13 UTC

Replacing a dead seed

Hi - 

If a seed crashes (i.e., suddenly unavailable due to HW problem),   what is the best way to replace the seed in the cluster?

I've read that you should not bootstrap a seed.  Therefore I came up with this procedure, but it seems pretty complicated.  any better ideas?
 
1. update the seed list on all nodes, taking out the dead node  and restart the nodes in the  cluster so the new seed list is updated
2. then bootstrap the new (replacement ) node as a normal node  (not yet as a seed)
3. when bootstrapping is done, make the new node a seed.
4. update the seed list again adding back the replacement seed (and rolling restart the cluster as in step 1)


That seems to me like a whole lot of work.  Surely there is a better way?

Jon

Re: Replacing a dead seed

Posted by Jonathan Colby <jo...@gmail.com>.
Of course!  why didn't i think of that?  Thanks!!
On Mar 17, 2011, at 3:11 PM, Edward Capriolo wrote:

> On Thu, Mar 17, 2011 at 9:09 AM, Jonathan Colby
> <jo...@gmail.com> wrote:
>> Hi -
>> 
>> If a seed crashes (i.e., suddenly unavailable due to HW problem),   what is the best way to replace the seed in the cluster?
>> 
>> I've read that you should not bootstrap a seed.  Therefore I came up with this procedure, but it seems pretty complicated.  any better ideas?
>> 
>> 1. update the seed list on all nodes, taking out the dead node  and restart the nodes in the  cluster so the new seed list is updated
>> 2. then bootstrap the new (replacement ) node as a normal node  (not yet as a seed)
>> 3. when bootstrapping is done, make the new node a seed.
>> 4. update the seed list again adding back the replacement seed (and rolling restart the cluster as in step 1)
>> 
>> 
>> That seems to me like a whole lot of work.  Surely there is a better way?
>> 
>> Jon
> 
> It is true that Seeds do not auto bootstrap. But in this case it does
> not matter if the other nodes believe this node is a seed. It only
> matters what the joining node is configured to believe.
> 
> On the joining node do not include it's hostname/IP in the seed list
> and it should auto-bootstrap normally.


Re: Replacing a dead seed

Posted by Edward Capriolo <ed...@gmail.com>.
On Thu, Mar 17, 2011 at 9:09 AM, Jonathan Colby
<jo...@gmail.com> wrote:
> Hi -
>
> If a seed crashes (i.e., suddenly unavailable due to HW problem),   what is the best way to replace the seed in the cluster?
>
> I've read that you should not bootstrap a seed.  Therefore I came up with this procedure, but it seems pretty complicated.  any better ideas?
>
> 1. update the seed list on all nodes, taking out the dead node  and restart the nodes in the  cluster so the new seed list is updated
> 2. then bootstrap the new (replacement ) node as a normal node  (not yet as a seed)
> 3. when bootstrapping is done, make the new node a seed.
> 4. update the seed list again adding back the replacement seed (and rolling restart the cluster as in step 1)
>
>
> That seems to me like a whole lot of work.  Surely there is a better way?
>
> Jon

It is true that Seeds do not auto bootstrap. But in this case it does
not matter if the other nodes believe this node is a seed. It only
matters what the joining node is configured to believe.

On the joining node do not include it's hostname/IP in the seed list
and it should auto-bootstrap normally.