Is it possible to interact with a garnet cluster through the redis-py client.

[1henrypage]

I've tried using this, and it works with a regular REDIS cluster, however, it doesn't seem to work with garnet.

[Vijay-Nirmal]

@1henrypage Can you provide details on the error you got when using Garnet?

[1henrypage]

@Vijay-Nirmal

I am using this docker compose to spin up the 3 instances required for the cluster

services:

  garnet-1:
    image: 'ghcr.io/microsoft/garnet'
    command: "--cluster"
    ulimits:
      memlock: -1

  garnet-2:
    image: 'ghcr.io/microsoft/garnet'
    command: "--cluster"
    ulimits:
      memlock: -1

  garnet-3:
      image: 'ghcr.io/microsoft/garnet'
      command: "--cluster"
      ulimits:
        memlock: -1

They are alive and healthy

CONTAINER ID   IMAGE                       COMMAND                  CREATED         STATUS                      PORTS      NAMES
9353835e484f   ghcr.io/microsoft/garnet    "/app/GarnetServer -…"   4 minutes ago   Up 4 minutes                6379/tcp   garnet-garnet-1-1
0425d2ebfa03   ghcr.io/microsoft/garnet    "/app/GarnetServer -…"   4 minutes ago   Up 4 minutes                6379/tcp   garnet-garnet-2-1
73b9f5816bc9   ghcr.io/microsoft/garnet    "/app/GarnetServer -…"   4 minutes ago   Up 4 minutes                6379/tcp   garnet-garnet-3-1

root@henrylinux:/home/henry/garnet# docker compose up --build

[+] Running 3/3
✔ Container garnet-garnet-2-1    Created    0.1s
✔ Container garnet-garnet-3-1    Created    0.1s
✔ Container garnet-garnet-1-1    Created    0.1s

Attaching to garnet-1-1, garnet-2-1, garnet-3-1

garnet-2-1  | 
garnet-2-1  |     /\_/\
garnet-2-1  |    ( o.o )    Garnet 1.0.57 64 bit; Cluster mode
garnet-2-1  |    >  ^  <    Listening on: 0.0.0.0:6379
garnet-2-1  |               https://aka.ms/GetGarnet
garnet-2-1  | 

garnet-1-1  | 
garnet-1-1  |     /\_/\
garnet-1-1  |    ( o.o )    Garnet 1.0.57 64 bit; Cluster mode
garnet-1-1  |    >  ^  <    Listening on: 0.0.0.0:6379
garnet-1-1  |               https://aka.ms/GetGarnet
garnet-1-1  | 

garnet-3-1  | 
garnet-3-1  |     /\_/\
garnet-3-1  |    ( o.o )    Garnet 1.0.57 64 bit; Cluster mode
garnet-3-1  |    >  ^  <    Listening on: 0.0.0.0:6379
garnet-3-1  |               https://aka.ms/GetGarnet
garnet-3-1  | 

garnet-2-1  | * Ready to accept connections
garnet-1-1  | * Ready to accept connections
garnet-3-1  | * Ready to accept connections

Furthermore, I follow the instructions detailed here to create a Garnet cluster

root@henrylinux:/home/henry# docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' garnet-garnet-1-1
172.26.0.3
root@henrylinux:/home/henry# docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' garnet-garnet-2-1
172.26.0.2
root@henrylinux:/home/henry# docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' garnet-garnet-3-1
172.26.0.4
root@henrylinux:/home/henry# redis-cli --cluster create 172.26.0.3:6379 172.26.0.2:6379 172.26.0.4:6379 --cluster-yes
>>> Performing hash slots allocation on 3 nodes...
Master[0] -> Slots 0 - 5460
Master[1] -> Slots 5461 - 10922
Master[2] -> Slots 10923 - 16383

M: b57ca5872805d90aa50e1b406b58128a346de3df 172.26.0.3:6379
   slots:[0-5460] (5461 slots) master
M: d8b56d0416e34cb818f073cd80f82552001fa0 172.26.0.2:6379
   slots:[5461-10922] (5462 slots) master
M: f7925c0e5954582c7717b3a3d555509180daf69e 172.26.0.4:6379
   slots:[10923-16383] (5461 slots) master

>>> Nodes configuration updated
>>> Assign a different config epoch to each node
>>> Sending CLUSTER MEET messages to join the cluster
Waiting for the cluster to join
...

>>> Performing Cluster Check (using node 172.26.0.3:6379)
M: b57ca5872805d90aa50e1b406b58128a346de3df 172.26.0.3:6379
   slots:[0-5460] (5461 slots) master
M: d8b56d0416e34cb818f073cd80f82552001fa0 172.26.0.2:6379
   slots:[5461-10922] (5462 slots) master
M: f7925c0e5954582c7717b3a3d555509180daf69e 172.26.0.4:6379
   slots:[10923-16383] (5461 slots) master

[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.

root@henrylinux:/home/henry#

Now when I try to use redis-py to connect normally (not in cluster mode), it works perfectly (albeit, no support for clustering). But when I use the cluster client, it seems to give me an error.

Python 3.13.2 | packaged by Anaconda, Inc. | (main, Feb  6 2025, 18:56:02) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from redis.cluster import RedisCluster as Redis
>>> rc = Redis(host='172.26.0.3', port=6379)
Traceback (most recent call last):
  File "<python-input-1>", line 1, in <module>
    rc = Redis(host='172.26.0.3', port=6379)
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/cluster.py", line 657, in __init__
    self.commands_parser = CommandsParser(self)
                           ~~~~~~~~~~~~~~^^^^^^
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/_parsers/commands.py", line 67, in __init__
    self.initialize(redis_connection)
    ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/_parsers/commands.py", line 70, in initialize
    commands = r.command()
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/commands/core.py", line 788, in command
    return self.execute_command("COMMAND", **kwargs)
           ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/cluster.py", line 1060, in execute_command
    return self._internal_execute_command(*args, **kwargs)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/cluster.py", line 1130, in _internal_execute_command
    raise e
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/cluster.py", line 1116, in _internal_execute_command
    res[node.name] = self._execute_command(node, *args, **kwargs)
                     ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/cluster.py", line 1228, in _execute_command
    raise e
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/cluster.py", line 1165, in _execute_command
    response = redis_node.parse_response(connection, command, **kwargs)
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/client.py", line 597, in parse_response
    return self.response_callbacks[command_name](response, **options)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/home/henry/anaconda3/envs/wdm/lib/python3.13/site-packages/redis/_parsers/helpers.py", line 545, in parse_command
    cmd_name = str_if_bytes(command[0])
                            ~~~~~~~^^^
TypeError: 'NoneType' object is not subscriptable
>>>