Read and write tests redis-py-cluster modes in trunked mode Redis

And MySQL master-slave replication, the slave node may share part of the read pressure is not the same, or even increase the slave slave or slave to share the read pressure, the Redis cluster from the node, the default is not sharing a read request from the node only as a master node backup is only responsible for failover.
If the master node is read pressure, the pressure can be shared by way of increasing the number of cluster nodes.

The case when the respective nodes read the following simple test Redis cluster, the node cluster as follows the relationship between the three primary cluster nodes, the nodes corresponding to the three

10W writing of "string type" of test data to the cluster

<div ">

#!/usr/bin/env 3
import time
from time import ctime,sleep
from rediscluster import StrictRedisCluster

startup_nodes = [
    {"host":"127.0.0.1", "port":9000},
    {"host":"127.0.0.1", "port":9001},
    {"host":"127.0.0.1", "port":9002},
    {"host":"127.0.0.1", "port":9003},
    {"host":"127.0.0.1", "port":9004},
    {"host":"127.0.0.1", "port":9005}
]
redis_conn= StrictRedisCluster(startup_nodes=startup_nodes, decode_responses=True)

for i in range(0, 100000):
    try:
        redis_conn.set('name'+str(i),str(i)
    except:
        print("connect to redis cluster error")
        #time.sleep(2)

10W个key值基本上均匀地落在三个节点上

连续读数据测试，同时观察某一个主从节点的负载

<div ">

#!/usr/bin/env python3
import time
from time import ctime,sleep
from rediscluster import StrictRedisCluster

startup_nodes = [
    {"host":"127.0.0.1", "port":9000},
    {"host":"127.0.0.1", "port":9001},
    {"host":"127.0.0.1", "port":9002},
    {"host":"127.0.0.1", "port":9003},
    {"host":"127.0.0.1", "port":9004},
    {"host":"127.0.0.1", "port":9005}
]
redis_conn= StrictRedisCluster(startup_nodes=startup_nodes, decode_responses=True)

for i in range(0, 100000):
    try:
        redis_conn.get('name'+str(i))
    except:
        print("connect to redis cluster error")
        time.sleep(2)

这里以9000和9003集群中的一对主从节点为例，当查询发起时，同时观察这两个节点的负载，
可以发现主节点9000负责处理定位到当前节点的请求，与此同时，而对应的从节点9003则没有处理请求信息。

Redis集群中，默认情况下，查询是根据key值的slot信息找到其对应的主节点，然后进行查询，而不会在从节点上发起查询

使用readonly命令打开客户端连接只读状态，则从节点可以接受读请求（当然在slave节点上读，因为复制延迟造成的问题另说）

根据https://redis-py-cluster.readthedocs.io/en/master/readonly-mode.html中的说明，
You can overcome this limitation [for scaling read with READONLY mode](http://redis.io/topics/cluster-spec#scaling-reads-using-slave-nodes).
redis-py-cluster also implements this mode. You can access slave by passing readonly_mode=True to StrictRedisCluster (or RedisCluster) constructor.

通过以readonly_mode=True的方式连接至集群，重复一下测试，发现从节点依然没有处理读请求

<div ">

#!/usr/bin/env python3
import time
from time import ctime,sleep
from rediscluster import StrictRedisCluster

startup_nodes = [
    {"host":"127.0.0.1", "port":9000},
    {"host":"127.0.0.1", "port":9001},
    {"host":"127.0.0.1", "port":9002},
    {"host":"127.0.0.1", "port":9003},
    {"host":"127.0.0.1", "port":9004},
    {"host":"127.0.0.1", "port":9005}
]
redis_conn= StrictRedisCluster(startup_nodes=startup_nodes, decode_responses=True, readonly_mode=True)

for i in range(0, 100000):
    try:
        print(redis_conn.get('name'+str(i)))
    except:
        print("connect to redis cluster error")
        time.sleep(2000)

Redis版本为 5.0.4

不知道为什么slave节点没有请求读处理，观察Redis请求处理的stat状态，依旧重定向到了master节点，不知道是否与单机多实例有关
如果每个实例独立部署在一台机器上，readonly_mode=True的访问模式，slave节点就可以处理读请求？

ps:测试环境是在腾讯云服务器EC2上安装的Redis，如果要在本地访问，需要bind的IP为内网的IP，然后本地用公网IP访问，而不是直接bind公网IP，为此折腾了一阵子。