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From Ben Bromhead <...@instaclustr.com>
Subject Re: Cassandra 2.1.13: Using JOIN_RING=False
Date Thu, 11 May 2017 17:32:27 GMT
A rough guess on the best way to do this with cql, without looking too
deeply into it:

You would likely have to implement a custom load balancing policy within
the driver that only uses coordinator nodes and/or modify
refreshNodeListAndTokenMap() behaviour in ControlConnection.java (there
should also be an equivalent class in the python driver).

On Thu, 11 May 2017 at 08:19 Dikang Gu <dikang85@gmail.com> wrote:

> 1. The coordinator still store system data and hints, but they should not
> store any user data since they are not part of ring.
> 2. We are using coordinator for thrift client. For cql based drivers, they
> needs to talk to nodes in the ring, so I think coordinator mode won't work
> for them.
>
> -Dikang
>
> On Tue, May 9, 2017 at 2:01 PM, Anubhav Kale <
> Anubhav.Kale@microsoft.com.invalid> wrote:
>
>> Hello,
>>
>>
>>
>> With some inspiration from the Cassandra Summit talk from last year, we
>> are trying to setup a cluster with coordinator-only nodes. We setup
>> join_ring=false in env.sh, disabled auth in YAML and the nodes are able to
>> start just fine. However, we’re running into a few problems
>>
>>
>>
>> 1] The nodes marked with join_ring=false continue to store data. Why ?
>>
>> 2] We tried Python driver’s whitelistedpolicy. But we notice message like
>> below, so we are not able to send queries to all nodes marked as
>> coordinators. We also changed the Scala driver to support whitelisting, but
>> see the same thing. What are we missing ?
>>
>> 3] Is there any way to concretely tell that only coordinator nodes are
>> getting requests from clients ? We don’t have OpsCenter.
>>
>>
>>
>> Thanks !
>>
>>
>>
>> 2017-05-09 20:45:25,060 [DEBUG] cassandra.cluster: [control connection]
>> Removing host not found in peers metadata: <Host: 10.80.10.128>
>>
>> 2017-05-09 20:45:25,060 [INFO] cassandra.cluster: Cassandra host
>> 10.80.10.128 removed
>>
>> 2017-05-09 20:45:25,060 [DEBUG] cassandra.cluster: Removing host
>> 10.80.10.128
>>
>> 2017-05-09 20:45:25,060 [DEBUG] cassandra.cluster: [control connection]
>> Removing host not found in peers metadata: <Host: 10.80.10.127>
>>
>> 2017-05-09 20:45:25,060 [INFO] cassandra.cluster: Cassandra host
>> 10.80.10.127 removed
>>
>> 2017-05-09 20:45:25,060 [DEBUG] cassandra.cluster: Removing host
>> 10.80.10.127
>>
>> 2017-05-09 20:45:25,060 [DEBUG] cassandra.cluster: [control connection]
>> Removing host not found in peers metadata: <Host: 10.80.10.129>
>>
>> 2017-05-09 20:45:25,060 [INFO] cassandra.cluster: Cassandra host
>> 10.80.10.129 removed
>>
>> 2017-05-09 20:45:25,060 [DEBUG] cassandra.cluster: Removing host
>> 10.80.10.129
>>
>> 2017-05-09 20:45:25,060 [DEBUG] cassandra.cluster: [control connection]
>> Finished fetching ring info
>>
>> 2017-05-09 20:45:25,060 [DEBUG] cassandra.cluster: [control connection]
>> Rebuilding token map due to topology changes
>>
>> 2017-05-09 20:45:25,081 [DEBUG] cassandra.metadata: user functions table
>> not found
>>
>> 2017-05-09 20:45:25,081 [DEBUG] cassandra.metadata: user aggregates table
>> not found
>>
>> 2017-05-09 20:45:25,098 [DEBUG] cassandra.cluster: Control connection
>> created
>>
>> 2017-05-09 20:45:25,099 [DEBUG] cassandra.pool: Initializing connection
>> for host 10.80.10.125
>>
>> 2017-05-09 20:45:25,099 [DEBUG] cassandra.pool: Initializing connection
>> for host 10.80.10.126
>>
>>
>>
>
>
>
> --
> Dikang
>
> --
Ben Bromhead
CTO | Instaclustr <https://www.instaclustr.com/>
+1 650 284 9692
Managed Cassandra / Spark on AWS, Azure and Softlayer

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