Redis cluster support for Redis Modules

[Sam Fang]

Hi,

With Redis cluster and for example redis-cli as the client:

1) Does "MODULE LOAD" command install a Redis module on all cluster nodes?

2) When issuing a custom command defined by modules with key argument, is the key hashed to find out the target node? Or the module command is broadcasted to all nodes?

Thanks a lot,

Sam

[Itamar Haber]

Hello Sam,

1. No, you have to issue it on each node (and, better yet, via the conf file)

2. Yes, custom module commands need to let Redis know which arguments are keys during command creation. Just like any other command, accessing a node with an operation on a key that doesn't belong to the node's hashslots will result in a redirect.

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Itamar Haber Technicalist Evangely Phone: +972.54.567.9692

[new sewe]

Hi Itamar,

What's if the custom command doesn't have a key? Say, it's a MODULE.HELP SUBCOMMAND command, which prints the help info of a subcommand.

I did some experiments, and it seems that I can specify the command flag string as "readonly getkeys-api" when creating the command.  So that when I issue the command, Redis Cluster will serve the request with the connecting node, and won't redirect the client to other node.

I'm not sure if this is correct solution for custom command that doesn't have a key. Can you confirm it? Thanks!

Regards

在 2019年6月11日星期二 UTC+8上午3:17:36，Itamar Haber写道：

Hello Sam,

1. No, you have to issue it on each node (and, better yet, via the conf file)

2. Yes, custom module commands need to let Redis know which arguments are keys during command creation. Just like any other command, accessing a node with an operation on a key that doesn't belong to the node's hashslots will result in a redirect.

On Mon, Jun 10, 2019 at 11:30 AM Sam Fang <rappor...@gmail.com> wrote:

Hi,

With Redis cluster and for example redis-cli as the client:

1) Does "MODULE LOAD" command install a Redis module on all cluster nodes?

2) When issuing a custom command defined by modules with key argument, is the key hashed to find out the target node? Or the module command is broadcasted to all nodes?

Thanks a lot,

Sam

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For more options, visit https://groups.google.com/d/optout.

[Itamar Haber]

Commands that don't expect keys as arguments can be run on any shard.

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