How to replace cluster name without any impact?

[Check Peck <co...@gmail.com>]

We have around 36 node Cassandra cluster and we have three Datacenters.
Each datacenter have 12 node.

We already have data flowing in Cassandra now and we cannot wipe out all
our data now.

Considering this - what is the right way to rename the cluster name without
any or minimal impact?

Re: How to replace cluster name without any impact?

[Robert Coli <rc...@eventbrite.com>]

On Wed, Apr 9, 2014 at 10:50 PM, Mark Reddy <ma...@boxever.com> wrote:
>
> Please be aware that you will have two partial clusters until you complete
> your rolling restart. Also considering that the cluster name is only a
> cosmetic value my opinion would be to leave it, as the risk far outweighs
> the benefits of changing it.
>

+1, though you should of course avoid having other clusters (dev version)
with the same name, which is the case cluster name exists to protect you
from.

@OP : did you get the bogus default cluster name by installing a debian
package which auto-started? If so, your input as an operator who had a
negative consequence from this behavior is welcome at :

https://issues.apache.org/jira/browse/CASSANDRA-2356

=Rob

Re: How to replace cluster name without any impact?

[Mark Reddy <ma...@boxever.com>]

What version are you running? As of 1.2.x you can do the following:

1. Start the cqlsh connected locally to the node.
2. Run:
update system.local set cluster_name='$CLUSTER_NAME' where key='local';
3. Run nodetool flush on the node.
4. Update the cassandra.yaml file on the node, changing the cluster_name to
the same as you set in step 2.
5. Restart the node.


Please be aware that you will have two partial clusters until you complete
your rolling restart. Also considering that the cluster name is only a
cosmetic value my opinion would be to leave it, as the risk far outweighs
the benefits of changing it.


Mark


On Thu, Apr 10, 2014 at 2:49 AM, Check Peck <co...@gmail.com> wrote:

> We have around 36 node Cassandra cluster and we have three Datacenters.
> Each datacenter have 12 node.
>
> We already have data flowing in Cassandra now and we cannot wipe out all
> our data now.
>
> Considering this - what is the right way to rename the cluster name
> without any or minimal impact?
>