Re: Topology settings before/after decommission node

[Anthony Grasso]

Hi Robert,

Your action plan looks good.

You can think of the *cassandra-topology.properties* file as a map for the
cluster. The map between the nodes must be consistent because each node
uses it to determine where it is meant to be located logically.

It is good hygiene to maintain the *cassandra-topology.properties* so it
contains only the IPs (broadcast addresses) currently used in the cluster.
Technically, you cloud leave the entry for the decommissioned node in
there. The problem is later on if that IP address is used by a node it will
be placed back in DC1 and this could be the wrong logical placement for it.
So I would advise removing the address if the node is inactive.

For step 3, there is no need to restart all the nodes. However if you do
want them to reload the configuration you will need to perform a rolling
restart on the cluster (i.e. restart one node at a time).

Regards,
Anthony

On Thu, 11 Apr 2019 at 03:38, rastrent 
wrote:

> Hi there,
>
> I am running a cassandra cluster (v3.0.9) with 2 DCs (4/3 nodes
> respectively) using endpoint_snitch: PropertyFileSnitch and I would like to
> decommission one node in DC1 but I wonder about what kind of actions I need
> to take related with the the topology settings.
> My cassandra-topology.properties has the those simple settings below:
>
> x.x.x.x=DC1:RAC1
> x.x.x.x=DC1:RAC1
> x.x.x.x=DC1:RAC1
> x.x.x.x=DC1:RAC1
> x.x.x.x=DC2:RAC1
> x.x.x.x=DC2:RAC1
> x.x.x.x=DC2:RAC1
>
> default=DC1:r1
>
> My action plan is to:
>
> 1)Decomission a node in DC1
> 2) After node leaves cluster,  edit cassandra-topology.properties in every
> node in the cluster
> 3) Question: No I need to restart all nodes in cluster? (one each time of
> course)
>
> Bonus question: Do I need to change the cassandra-topology.properties
> before move/remove nodes?
>
> Cheers,
>
> Robert,
>
>
> Sent with ProtonMail  Secure Email.
>
>

Topology settings before/after decommission node

[rastrent]

Hi there,

I am running a cassandra cluster (v3.0.9) with 2 DCs (4/3 nodes respectively) 
using endpoint_snitch: PropertyFileSnitch and I would like to decommission one 
node in DC1 but I wonder about what kind of actions I need to take related with 
the the topology settings.
My cassandra-topology.properties has the those simple settings below:

x.x.x.x=DC1:RAC1
x.x.x.x=DC1:RAC1
x.x.x.x=DC1:RAC1
x.x.x.x=DC1:RAC1
x.x.x.x=DC2:RAC1
x.x.x.x=DC2:RAC1
x.x.x.x=DC2:RAC1

default=DC1:r1

My action plan is to:

1)Decomission a node in DC1
2) After node leaves cluster,  edit cassandra-topology.properties in every node 
in the cluster
3) Question: No I need to restart all nodes in cluster? (one each time of 
course)

Bonus question: Do I need to change the cassandra-topology.properties before 
move/remove nodes?

Cheers,

Robert,

Sent with [ProtonMail](https://protonmail.com) Secure Email.