[jira] [Updated] (CASSANDRA-9603) Expose private listen_address in system.local

["Carl Yeksigian (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CASSANDRA-9603?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Carl Yeksigian updated CASSANDRA-9603:
--------------------------------------
    Component/s: Distributed Metadata

> Expose private listen_address in system.local
> ---------------------------------------------
>
>                 Key: CASSANDRA-9603
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9603
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Distributed Metadata
>            Reporter: Piotr Kołaczkowski
>            Assignee: Carl Yeksigian
>             Fix For: 2.0.17, 2.1.8, 2.2.0 rc2
>
>
> We had some hopes CASSANDRA-9436 would add it, yet it added rpc_address instead of both rpc_address *and* listen_address. We really need listen_address here, because we need to get information on the private IP C* binds to. Knowing this we could better match Spark nodes to C* nodes and process data locally in environments where rpc_address != listen_address like EC2. 
> See, Spark does not know rpc addresses nor it has a concept of broadcast address. It only knows the hostname / IP its workers bind to. In case of cloud environments, these are private IPs. Now if we give Spark a set of C* nodes identified by rpc_addresses, Spark doesn't recognize them as belonging to the same cluster. It treats them as "remote" nodes and has no idea where to send tasks optimally. 
> Current situation (example):
> Spark worker nodes: [10.0.0.1, 10.0.0.2, 10.0.0.3]
> C* nodes: [10.0.0.1 / node1.blah.ec2.com, 10.0.0.2 / node2.blah.ec2.com, 10.0.0.3 / node3.blah.ec2.com]
> What the application knows about the cluster: [node1.blah.ec2.com, node2.blah.ec2.com, node3.blah.ec2.com]
> What the application sends to Spark for execution:
>  Task1 - please execute on node1.blah.ec2.com
>  Task2 - please execute on node2.blah.ec2.com
>  Task3 - please execute on node3.blah.ec2.com
> How Spark understands it: "I have no idea what node1.blah.ec2.com is, let's assign Task1 it to a *random* node" :(
> Expected:
> Spark worker nodes: [10.0.0.1, 10.0.0.2, 10.0.0.3]
> C* nodes: [10.0.0.1 / node1.blah.ec2.com, 10.0.0.2 / node2.blah.ec2.com, 10.0.0.3 / node3.blah.ec2.com]
> What the application knows about the cluster: [10.0.0.1 / node1.blah.ec2.com, 10.0.0.2 / node2.blah.ec2.com, 10.0.0.3 / node3.blah.ec2.com]
> What the application sends to Spark for execution:
>  Task1 - please execute on node1.blah.ec2.com or 10.0.0.1
>  Task2 - please execute on node2.blah.ec2.com or 10.0.0.2
>  Task3 - please execute on node3.blah.ec2.com or 10.0.0.3
> How Spark understands it: "10.0.0.1? - I have a worker on that node, lets put Task 1 there"



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