Redis-5.0.5集群配置
阅读原文时间:2021年04月22日阅读:3

版本:redis-5.0.5

参考:http://redis.io/topics/cluster-tutorial

集群部署交互式命令行工具:https://github.com/eyjian/redis-tools/tree/master/deploy

集群运维命令行工具:https://github.com/eyjian/redis-tools/tree/master

批量操作工具:https://github.com/eyjian/libmooon/releases

目录

目录 1

1. 前言 2

2. 名词解释 2

3. 部署计划 2

4. 修改系统参数 3

4.1. 修改最大可打开文件数 3

4.2. TCP监听队列大小 4

4.3. OOM相关:vm.overcommit_memory 4

4.4. /sys/kernel/mm/transparent_hugepage/enabled 4

5. 目录结构 4

6. 编译安装 5

7. 配置redis 6

8. 启动redis实例 10

9. 创建和启动redis集群 10

9.1. 创建redis cluster 11

9.2. ps aux|grep redis 12

10. redis cluster client 13

10.1. 命令行工具redis-cli 13

10.2. 从slaves读数据 13

10.3. jedis(java cluster client) 13

10.4. r3c(C++ cluster client) 14

11. 新增节点 14

11.1. 添加一个新主(master)节点 14

11.2. 添加一个新从(slave)节点 16

12. 删除节点 16

13. master机器硬件故障 17

14. 检查节点状态 17

15. 变更主从关系 17

16. slots相关命令 18

17. 迁移slosts 18

18. 人工主备切换 20

19. 查看集群信息 21

20. 禁止指定命令 21

21. 数据迁移 21

22. 各版本配置文件 22

23. 大压力下Redis参数调整要点 22

24. 问题排查 24

  1. 前言

2019年5月15日REdis发布了最新版本5.0.5,在5.0.4基础上修复了部分BUG。本文档基于以前写的《Redis-3.0.5集群配置》和《Redis-4.0.11集群配置》。

redis-3.0.0开始支持集群,redis-4.0.0开始支持module,redis-5.0.0开始支持类似于kafka那样的消息队列。

本文参考官方文档而成:http://redis.io/topics/cluster-tutorial,不适用redis-5.0.0以下版本,原因是从redis-5.0.0版本开始,redis-trib.rb的功能被redis-cli替代了。

redis-5.0.0以下版本的安装和部署,可参考:https://blog.csdn.net/Aquester/article/details/50150163

redis运维工具和部署工具:https://github.com/eyjian/redis-tools

  1. 名词解释

名词

解释

ASAP

As Soon As Possible,尽可能

RESP

Redis Serialization Protocol,redis的序列化协议

replica

从5.0开始,原slave改叫replica,相关的配置参数也做了同样改名

  1. 部署计划

redis要求至少三主三从共6个节点才能组成redis集群,测试环境可一台物理上启动6个redis节点,但生产环境至少要准备3台物理机。

服务端口

IP地址

配置文件名

6381

192.168.0.251

redis-6381.conf

6382

192.168.0.251

redis-6382.conf

6383

192.168.0.251

redis-6383.conf

6384

192.168.0.251

redis-6384.conf

6385

192.168.0.251

redis-6385.conf

6386

192.168.0.251

redis-6386.conf

疑问:如果是3台物理机,会不会主和从节点分布在同一个物理机上?

  1. 修改系统参数
    1. 修改最大可打开文件数

修改文件/etc/security/limits.conf,加入以下两行:

* soft nofile 102400

* hard nofile 102400

# End of file

其中102400为一个进程最大可以打开的文件个数,当与RedisServer的连接数多时,需要设定为合适的值。

有些环境修改后,root用户需要重启机器才生效,而普通用户重新登录后即生效。如果是crontab,则需要重启crontab,如:service crond restart,有些平台可能是service cron restart(类似重启系统日志服务:service rsyslog restart或systemctl restart rsyslog)。

有些环境下列设置即可让root重新登录即生效,而不用重启机器:

root soft nofile 102400

root hard nofile 102400

# End of file

但是要小心,有些环境上面这样做,可能导致无法ssh登录,所以在修改时最好打开两个窗口,万一登录不了还可自救。

如何确认更改对一个进程生效?按下列方法(其中$PID为被查的进程ID):

$ cat /proc/$PID/limits

系统关于/etc/security/limits.conf文件的说明:

#This file sets the resource limits for the users logged in via PAM.

#It does not affect resource limits of the system services.

PAM:全称“Pluggable Authentication Modules”,中文名“插入式认证模块”。/etc/security/limits.conf实际为pam_limits.so(位置:/lib/security/pam_limits.so)的配置文件,只针对单个会话。要使用limits.conf生效,必须保证pam_limits.so被加入到了启动文件中。

注释说明只对通过PAM登录的用户生效,与PAM相关的文件(均位于/etc/pam.d目录下):

/etc/pam.d/login

/etc/pam.d/sshd

/etc/pam.d/crond

如果需要设置Linux用户的密码策略,可以修改文件/etc/login.defs,但这个只对新增的用户有效,如果要影响已有用户,可使用命令chage。

  1. 1. TCP监听队列大小

即TCP listen的backlog大小,“/proc/sys/net/core/somaxconn”的默认值一般较小如128,需要修改大一点,比如改成32767。立即生效还可以使用命令:sysctl -w net.core.somaxconn=32767。

要想永久生效,需要在文件/etc/sysctl.conf中增加一行:net.core.somaxconn = 32767,然后执行命令“sysctl -p”以生效。

Redis配置项tcp-backlog的值不能超过somaxconn的大小。

  1. 1. OOM相关:vm.overcommit_memory

“/proc/sys/vm/overcommit_memory”默认值为0,表示不允许申请超过CommitLimmit大小的内存。可以设置为1关闭Overcommit,设置方法请参照net.core.somaxconn完成。

  1. 1. /sys/kernel/mm/transparent_hugepage/enabled

默认值为“[always] madvise never”,建议设置为never,以开启内核的“Transparent Huge Pages (THP)”特性,设置后redis进程需要重启。为了永久生效,请将“echo never > /sys/kernel/mm/transparent_hugepage/enabled”加入到文件/etc/rc.local中。

什么是Transparent Huge Pages?为提升性能,通过大内存页来替代传统的4K页,使用得管理虚拟地址数变少,加快从虚拟地址到物理地址的映射,以及摒弃内存页面的换入换出以提高内存的整体性能。内核Kernel将程序缓存内存中,每页内存以2M为单位。相应的系统进程为khugepaged。

在Linux中,有两种方式使用Huge Pages,一种是2.6内核引入的HugeTLBFS,另一种是2.6.36内核引入的THP。HugeTLBFS主要用于数据库,THP广泛应用于应用程序。

一般可以在rc.local或/etc/default/grub中对Huge Pages进行设置。

  1. 目录结构

redis.conf为从https://raw.githubusercontent.com/antirez/redis/5.0/redis.conf下载的配置文件,带端口号的配置文件基于redis.conf修改。实际只需要完成公共的redis.conf和一个端口号的,如redis-6381.conf,其它端口号的配置文件基于一个修改后的端口号配置文件即可。

本文将redis安装在/data/redis,建议将bin目录加入到环境变量PATH中,以简化后续的使用。

如果拿到的是redis源代码,在make成功后,推荐按下列目录结构部署各程序文件:

/data/redis

|-- bin

|   |-- redis-benchmark

|   |-- redis-check-aof

|   |-- redis-check-rdb

|   |-- mkreleasehdr.sh

|   |-- redis-cli

|   |-- redis-sentinel -> redis-server

|   `-- redis-server

|-- conf

|   |-- redis-6381.conf

|   |-- redis-6382.conf

|   |-- redis-6383.conf

|   |-- redis-6384.conf

|   |-- redis-6385.conf

|   |-- redis-6386.conf

|   `-- redis.conf

`-- log

3 directories, 14 files

注意,redis-check-dump和redis-check-rdb是同一个程序,在redis-3.0.0之前叫redis-check-dump,之后更名为redis-check-rdb。

  1. 编译安装

打开redis的Makefile文件,可以看到如下内容:

PREFIX?=/usr/local

INSTALL_BIN=$(PREFIX)/bin

INSTALL=install

Makefile中的“?=”表示,如果该变量之前没有定义过,则赋值为/usr/local,否则什么也不做。

如果不设置环境变量PREFIX或不修改Makefile中的值,则默认安装到/usr/local/bin目录下。建议不要使用默认配置,而是指定安装目录,如/data/redis-5.0.5:

$ make

$ make install PREFIX=/data/redis-5.0.5

$ ln -s /data/redis-5.0.5 /data/redis

$ mkdir /data/redis/conf

$ mkdir /data/redis/log

$ mkdir /data/redis/data

  1. 配置redis

推荐配置分成两部分:一是公共配置,另一个与端口相关的配置。公共配置文件名可命令为redis.conf,而端口相关的配置文件名可命令为redis-PORT.conf或redis_PORT.conf。假设端口为6379,则端口相关的配置文件名为redis-6379.conf。redis-PORT.conf通过include的方式包含redis.conf,如:include /data/redis/conf/redis.conf。

https://raw.githubusercontent.com/antirez/redis/5.0/redis.conf下载配置文件(也可直接复制源代码包中的redis.conf,然后在它的基础上进行修改),在这个基础上,进行如下表所示的修改(配置文件名redis-PORT.conf中的PORT替换为实际使用的端口号,如6381等)。

高效完成多个端口配置的一个方法是先完成一个指定端口的配置文件,然后替换端口方式生成另一个端口的配置文件。如通过端口6381的配置文件redis-6381.conf生成端口号6382的配置文件redis-6382.conf,只需要这样:sed 's/6381/6382/g' redis-6381.conf > redis-6382.conf。

下表配置项,加粗部分是必须和建议修改的,其它可根据实际需求修改:

配置项

加粗部分必须或建议修改

配置文件

说明

include

redis.conf

指定端口的配置文件

redis-PORT.conf

(该文件定义所有与端口相关的配置项,PORT需要替换为具体的端口,如6381)

引用公共的配置文件,建议为全路径值

port

PORT

客户端连接端口,并且总有一个刚好大于10000的端口,这个大的端口用于主从复制和集群内部通讯。

cluster-config-file

nodes-PORT.conf

默认放在dir指定的目录,注意不能包含目录,纯文件名,redis-server进程自动维护,不能手工修改

pidfile

/var/run/redis-PORT.pid

只有当daemonize值为yes时,才有意义;并且这个要求对目录/var/run有写权限,否则可以考虑设置为/tmp/redis-PORT.pid,或者放在bin或log目录下,如:/data/redis/log/redis-PORT.pid。只有当配置项daemonize的值为yes时,才会产生这个文件。

dir

/data/redis/data/PORT

dbfilename

dump-PORT.rdb

纯文件名,位于dir指定的目录下,不能包含目录,否则报错“appendfilename can't be a path, just a filename”。

如果开启了AOF,REdis进程启动时并不会读取RDB文件,所以配置上可以考虑关闭RDB,这样可以提升REdis稳定性。

appendfilename

"appendonly-PORT.aof"

纯文件名,位于dir指定的目录下,不能包含目录,否则报错“appendfilename can't be a path, just a filename

logfile

/data/redis/log/redis-PORT.log

日志文件,包含目录和文件名,注意redis不会自动滚动日志文件

cluster-enabled

yes

redis.conf

(公共配置文件,定义所有与端口无关的配置项)

yes表示以集群方式运行,为no表示以非集群方式运行

loglevel

verbose

日志级别,建议为notice,另外注意redis是不会滚动日志文件的,每次写日志都是先打开日志文件再写日志再关闭方式

maxclients

10000

最大连接数

timeout

0

客户端多长(秒)时间没发包过来关闭它,0表示永不关闭

cluster-node-timeout

15000

集群中的节点最大不可用时长,在这个时长内,不会被判定为fail。对于master节点,当不可用时长超过此值时,slave在延迟至少0.5秒后会发起选举进行failover成为master。Redis集群的很多其它值与cluster-node-timeout有关。

cluster-slave-validity-factor

(5.0开始请使用cluster-replica-validity-factor)

0

如果设置为0,则slave总是尝试成为master,无论slave和master间的链接断开时间的长短。如果是一个大于0的值,则最大可断开时长为:(cluster-slave-validity-factor * cluster-node-timeout)。例如:当cluster-node-timeout值为5,cluster-slave-validity-factor值为10时,slave和master间的连接断开50秒内,slave不会尝试成为master。

repl-timeout

10

这个参数一定不能小于repl-ping-replica-period,可以考虑为repl-ping-replica-period的3倍或更大。定义多长时间内均PING不通时,判定心跳超时。对于redis集群,达到这个值并不会发生主从切换,主从何时切换由参数cluster-node-timeout控制,只有master状态为fail后,它的slaves才能发起选举。

repl-ping-slave-period

(5.0开始请使用repl-ping-replica-period)

1

定义slave多久(秒)ping一次master,如果超过repl-timeout指定的时长都没有收到响应,则认为master挂了

slave-read-only

(5.0开始请用replica-read-only)

yes

slave是否只读

slave-serve-stale-data

(5.0开始请使用replica-serve-stale-data)

yes

当slave与master断开连接,slave是否继续提供服务

slave-priority

(5.0开始请使用replica-priority)

100

slave权重值,当master挂掉,只有权重最大的slave接替master

aof-use-rdb-preamble

4.0新增配置项,用于控制是否启用RDB-AOF混用,值为no表示关闭

appendonly

yes

当同时写AOF或RDB,则redis启动时只会加载AOF,AOF包含了全量数据。如果当队列使用,入队压力又很大,建议设置为no

appendfsync

no

可取值everysec,其中no表示由系统自动,当写压力很大时,建议设置为no,否则容易造成整个集群不可用

daemonize

yes

相关配置项pidfile

protected-mode

no

3.2.0新增的配置项,默认值为yes,限制从其它机器登录Redis server,而只能从127.0.0.1登录。

tcp-backlog

32767

取值不能超过系统的/proc/sys/net/core/somaxconn

auto-aof-rewrite-percentage

100

设置自动rewite AOF文件(手工rewrite只需要调用命令BGREWRITEAOF)

auto-aof-rewrite-min-size

64mb

触发rewrite的AOF文件大小,只有大于此大小时才会触发rewrite

no-appendfsync-on-rewrite

yes

子进程在做rewrite时,主进程不调用fsync(由内核默认调度)

stop-writes-on-bgsave-error

yes

如果因为磁盘故障等导致保存rdb失败,停止写操作,可设置为NO。

cluster-require-full-coverage

no

为no表示有slots不可服务时其它slots仍然继续服务,建议值为no,以提供最高的可用性

maxmemory

26843545600

设置最大的内存,单位为字节

maxmemory-policy

volatile-lru

设置达到最大内存时的淘汰策略

client-output-buffer-limit

设置master端的客户端缓存,三种:normal、slave和pubsub

cluster-migration-barrier

1

最少slave数,用来保证集群中不会有裸奔的master。当某个master节点的slave节点挂掉裸奔后,会从其他富余的master节点分配一个slave节点过来,确保每个master节点都有至少一个slave节点,不至于因为master节点挂掉而没有相应slave节点替换为master节点导致集群崩溃不可用。

repl-backlog-size

1mb

当slave失联时的,环形复制缓区大小,值越大可容忍更长的slave失联时长

repl-backlog-ttl

slave失联的时长达到该值时,释放backlog缓冲区

save

save 900 1

save 300 10

save 60 10000

刷新快照(RDB)到磁盘的策略,根据实际调整值,“save 900 1”表示900秒后至少有1个key被修改才触发save操作,其它类推。

注意执行flushall命令也会产生RDB文件,不过是空文件。

如果不想生成RDB文件,可以将save全注释掉。

  1. 启动redis实例

在启动之前,需要创建好配置中的各目录。然后启动好所有的redis实例,如以本文中定义的6个节点为例(带个目录是个良好和规范的习惯):

/data/redis/bin/redis-server /data/redis/conf/redis-6381.conf

/data/redis/bin/redis-server /data/redis/conf/redis-6382.conf

/data/redis/bin/redis-server /data/redis/conf/redis-6383.conf

/data/redis/bin/redis-server /data/redis/conf/redis-6384.conf

/data/redis/bin/redis-server /data/redis/conf/redis-6385.conf

/data/redis/bin/redis-server /data/redis/conf/redis-6386.conf

可以写一个启动脚本start-redis-cluster.sh:

#!/bin/sh

REDIS_HOME=/data/redis

$REDIS_HOME/bin/redis-server $REDIS_HOME/conf/redis-6379.conf

$REDIS_HOME/bin/redis-server $REDIS_HOME/conf/redis-6380.conf

一般需要加上进程监控,可直接使用process_monitor.sh,监控示例(放在crontab中,下载网址:https://github.com/eyjian/libmooon/blob/master/shell/process_monitor.sh):

REDIS_HOME=/data/redis

* * * * * /usr/local/bin/process_monitor.sh "$REDIS_HOME/bin/redis-server 6381" "$REDIS_HOME/bin/redis-server $REDIS_HOME/conf/redis_6381.conf"

* * * * * log=$REDIS_HOME/log/redis_6381.log;if test `ls -l $log|cut -d' ' -f5` -gt 104857600; then mv $log $log.old; fi

注意:redis的日志文件不会自动滚动,redis-server每次在写日志时,均会以追加方式调用fopen写日志,而不处理滚动。也可借助linux自带的logrotate来滚动redis日志,命令logrotate一般位于目录/usr/sbin下。

  1. 创建和启动redis集群

如果只是想快速创建和启动redis集群,而不关心过程,可使用redis官方提供的脚本create-cluster,两步完成:

create-cluster start

create-cluster create

第二步“create-cluster create”是一个交互式过程,当提示时,请输入“yes”再回车继续,第一个节点的端口号为30001,一共会启动六个redis节点。

create-cluster在哪儿?它位于redis源代码的utils/create-cluster目录下,是一个bash脚本文件。停止集群:create-cluster stop

但如果是为学习和运营,建议按下列步骤操作,以加深对redis集群的理解,提升掌控能力:

  1. 1. 创建redis cluster

创建redis集群命令(三主三从,每个主一个从,注意redis-5.0.0版本开始才支持“--cluster”,之前的版本会报错“Unrecognized option or bad number of args for: '--cluster'”):

redis-cli --cluster create 192.168.0.251:6381 192.168.0.251:6382 192.168.0.251:6383 192.168.0.251:6384 192.168.0.251:6385 192.168.0.251:6386 --cluster-replicas 1

如果配置项cluster-enabled的值不为yes,则执行时会报错“[ERR] Node 192.168.0.251:6381 is not configured as a cluster node.”。这个时候需要先将cluster-enabled的值改为yes,然后重启redis-server进程,之后才可以重新执行redis-cli创建集群。

  • redis-cli的参数说明:
  1. create

表示创建一个redis集群。

  1. --cluster-replicas 1

表示为集群中的每一个主节点指定一个从节点,即一比一的复制。\

运行过程中,会有个提示,输入yes回车即可。从屏幕输出,可以很容易地看出哪些是主(master)节点,哪些是从(slave)节点:

$ ./redis-cli --cluster create 192.168.0.251:6381 192.168.0.251:6382 192.168.0.251:6383 192.168.0.251:6384 192.168.0.251:6385 192.168.0.251:6386 --cluster-replicas 1

>>> Performing hash slots allocation on 6 nodes…

Master[0] -> Slots 0 - 5460

Master[1] -> Slots 5461 - 10922

Master[2] -> Slots 10923 - 16383

Adding replica 192.168.0.251:6384 to 192.168.0.251:6381

Adding replica 192.168.0.251:6385 to 192.168.0.251:6382

Adding replica 192.168.0.251:6386 to 192.168.0.251:6383

>>> Trying to optimize slaves allocation for anti-affinity

[WARNING] Some slaves are in the same host as their master

M: f805e652ff8abe151393430cb3bcbf514b8a7399 192.168.0.251:6381

   slots:[0-5460] (5461 slots) master

M: bfad383775421b1090eaa7e0b2dcfb3b38455079 192.168.0.251:6382

   slots:[5461-10922] (5462 slots) master

M: 44eb43e50c101c5f44f48295c42dda878b6cb3e9 192.168.0.251:6383

   slots:[10923-16383] (5461 slots) master

S: 29fcce29837d3e5266b6178a15aecfa938ff241a 192.168.0.251:6384

   replicates bfad383775421b1090eaa7e0b2dcfb3b38455079

S: 0ae8b5400d566907a3d8b425d983ac3b7cbd8412 192.168.0.251:6385

   replicates 44eb43e50c101c5f44f48295c42dda878b6cb3e9

S: c67dc9e02e25f2e6321df8ac2eb4d99789917783 192.168.0.251:6386

   replicates f805e652ff8abe151393430cb3bcbf514b8a7399

Can I set the above configuration? (type 'yes' to accept): yes

>>> 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 192.168.0.251:6381)

M: f805e652ff8abe151393430cb3bcbf514b8a7399 192.168.0.251:6381

   slots:[0-5460] (5461 slots) master

   1 additional replica(s)

S: c67dc9e02e25f2e6321df8ac2eb4d99789917783 192.168.0.251:6386

   slots: (0 slots) slave

   replicates f805e652ff8abe151393430cb3bcbf514b8a7399

S: 29fcce29837d3e5266b6178a15aecfa938ff241a 192.168.0.251:6384

   slots: (0 slots) slave

   replicates bfad383775421b1090eaa7e0b2dcfb3b38455079

M: bfad383775421b1090eaa7e0b2dcfb3b38455079 192.168.0.251:6382

   slots:[5461-10922] (5462 slots) master

   1 additional replica(s)

S: 0ae8b5400d566907a3d8b425d983ac3b7cbd8412 192.168.0.251:6385

   slots: (0 slots) slave

   replicates 44eb43e50c101c5f44f48295c42dda878b6cb3e9

M: 44eb43e50c101c5f44f48295c42dda878b6cb3e9 192.168.0.251:6383

   slots:[10923-16383] (5461 slots) master

   1 additional replica(s)

[OK] All nodes agree about slots configuration.

>>> Check for open slots…

>>> Check slots coverage…

[OK] All 16384 slots covered.

  1. 1. ps aux|grep redis

查看redis进程是否已切换为集群状态(cluster):

[test@test-168-251 ~]$ ps aux|grep redis-server

redis   3824  0.7  5.9 6742404 3885144 ?    Ssl   2018 1639:13 /data/redis/bin/redis-server *:6381 [cluster]

redis   3825  0.5  3.9 6709636 2618536 ?    Ssl   2018 1235:43 /data/redis/bin/redis-server *:6382 [cluster]

redis   3826  0.5  3.9 6709636 2618536 ?    Ssl   2018 1235:43 /data/redis/bin/redis-server *:6383 [cluster]

redis   3827  0.5  3.9 6709636 2618536 ?    Ssl   2018 1235:43 /data/redis/bin/redis-server *:6384 [cluster]

redis   3828  0.5  3.9 6709636 2618536 ?    Ssl   2018 1235:43 /data/redis/bin/redis-server *:6385 [cluster]

redis   3829  0.5  3.9 6709636 2618536 ?    Ssl   2018 1235:43 /data/redis/bin/redis-server *:6386 [cluster]

停止redis实例,直接使用kill命令即可,如:kill 3825,重启和单机版相同。

  1. redis cluster client
    1. 命令行工具redis-cli

官方提供的命令行客户端工具,在单机版redis基础上指定参数“-c”即可。以下是在192.168.0.251上执行redis-cli的记录:

$ ./redis-cli -c -p 6379

127.0.0.1:6379> set foo bar

-> Redirected to slot [12182] located at 192.168.0.251:6379

OK

192.168.0.251:6379> set hello world

-> Redirected to slot [866] located at 192.168.0.251:6379

OK

192.168.0.251:6379> get foo

-> Redirected to slot [12182] located at 192.168.0.251:6379

"bar"

192.168.0.251:6379> get hello

-> Redirected to slot [866] located at 192.168.0.251:6379

"world"

查看集群中的节点:

192.168.0.251:6379> cluster nodes

  1. 1. 从slaves读数据

默认不能从slaves读取数据,但建立连接后,执行一次命令READONLY ,即可从slaves读取数据。如果想再次恢复不能从slaves读取数据,可以执行下命令READWRITE。

  1. 1. jedis(java cluster client)

官网:https://github.com/xetorthio/jedis,编程示例:

Set<HostAndPort> jedisClusterNodes = new HashSet();

//Jedis Cluster will attempt to discover cluster nodes automatically

jedisClusterNodes.add(new HostAndPort("127.0.0.1", 7379));

JedisCluster jc = new JedisCluster(jedisClusterNodes);

jc.set("foo", "bar");

String value = jc.get("foo");

  1. 1. r3c(C++ cluster client)

官网:https://github.com/eyjian/r3c

  1. 新增节点
    1. 添加一个新主(master)节点

假设要添加新的节点“192.168.0.251:6390”,先以单机版配置和启动好6387,然后执行命令(“192.168.0.251:6381”为集群中任一可用的节点):

redis-cli --cluster add-node 192.168.0.251:6390 192.168.0.251:6381

如果执行顺利,看到的输出如下:

$ ./redis-cli --cluster add-node 192.168.0.251:6390 192.168.0.251:6381

>>> Adding node 192.168.0.251:6390 to cluster 192.168.0.251:6381

>>> Performing Cluster Check (using node 192.168.0.251:6381)

M: f805e652ff8abe151393430cb3bcbf514b8a7399 192.168.0.251:6381

   slots:[0-5460] (5461 slots) master

   1 additional replica(s)

S: c67dc9e02e25f2e6321df8ac2eb4d99789917783 192.168.0.251:6386

   slots: (0 slots) slave

   replicates f805e652ff8abe151393430cb3bcbf514b8a7399

S: 29fcce29837d3e5266b6178a15aecfa938ff241a 192.168.0.251:6384

   slots: (0 slots) slave

   replicates bfad383775421b1090eaa7e0b2dcfb3b38455079

M: bfad383775421b1090eaa7e0b2dcfb3b38455079 192.168.0.251:6382

   slots:[5461-10922] (5462 slots) master

   1 additional replica(s)

S: 0ae8b5400d566907a3d8b425d983ac3b7cbd8412 192.168.0.251:6385

   slots: (0 slots) slave

   replicates 44eb43e50c101c5f44f48295c42dda878b6cb3e9

M: 44eb43e50c101c5f44f48295c42dda878b6cb3e9 192.168.0.251:6383

   slots:[10923-16383] (5461 slots) master

   1 additional replica(s)

[OK] All nodes agree about slots configuration.

>>> Check for open slots…

>>> Check slots coverage…

[OK] All 16384 slots covered.

>>> Send CLUSTER MEET to node 192.168.0.251:6390 to make it join the cluster.

[OK] New node added correctly.

在执行“add-node”之前的集群:

$ redis-cli -c -p 6381 cluster nodes|grep master

bfad383775421b1090eaa7e0b2dcfb3b38455079 192.168.0.251:6382@16382 master - 0 1540549992591 2 connected 5461-10922

f805e652ff8abe151393430cb3bcbf514b8a7399 192.168.0.251:6381@16381 myself,master - 0 1540549993000 1 connected 0-5460

44eb43e50c101c5f44f48295c42dda878b6cb3e9 192.168.0.251:6383@16383 master - 0 1540549994593 3 connected 10923-16383

$ redis-cli -c -p 6381 cluster nodes|grep slave

c67dc9e02e25f2e6321df8ac2eb4d99789917783 192.168.0.251:6386@146386 slave f805e652ff8abe151393430cb3bcbf514b8a7399 0 1540549996595 6 connected

29fcce29837d3e5266b6178a15aecfa938ff241a 192.168.0.251:6384@16384 slave bfad383775421b1090eaa7e0b2dcfb3b38455079 0 1540549995595 4 connected

0ae8b5400d566907a3d8b425d983ac3b7cbd8412 192.168.0.251:6385@16385 slave 44eb43e50c101c5f44f48295c42dda878b6cb3e9 0 1540549996000 5 connected

执行“add-node”之后的集群(可以看到新增的master节点192.168.0.251:6390没有负责任何slots):

$ redis-cli -c -p 6381 cluster nodes|grep master

082c079149a9915612d21cca8e08c831a4edeade 192.168.0.251:6390@16390 master - 0 1540550992379 0 connected

bfad383775421b1090eaa7e0b2dcfb3b38455079 192.168.0.251:6382@16382 master - 0 1540550991000 2 connected 5461-10922

f805e652ff8abe151393430cb3bcbf514b8a7399 192.168.0.251:6381@16381 myself,master - 0 1540550990000 1 connected 0-5460

44eb43e50c101c5f44f48295c42dda878b6cb3e9 192.168.0.251:6383@16383 master - 0 1540550991377 3 connected 10923-16383

$ redis-cli -c -p 6381 cluster nodes|grep slave

c67dc9e02e25f2e6321df8ac2eb4d99789917783 192.168.0.251:6386@16386 slave f805e652ff8abe151393430cb3bcbf514b8a7399 0 1540550996000 6 connected

29fcce29837d3e5266b6178a15aecfa938ff241a 192.168.0.251:6384@16384 slave bfad383775421b1090eaa7e0b2dcfb3b38455079 0 1540550994383 4 connected

0ae8b5400d566907a3d8b425d983ac3b7cbd8412 192.168.0.251:6385@16385 slave 44eb43e50c101c5f44f48295c42dda878b6cb3e9 0 1540550998388 5 connected

如果报错“[ERR] Node 192.168.0.251:4077 is not configured as a cluster node.”,是因为新节点的配置项“cluster-enabled”的值不为“yes”。这时需要将“cluster-enabled”的值改为“yes”,并重启该节点,然后再重新执行“add-node”操作。

也可能遇到错误“[ERR] Sorry, can't connect to node 127.0.0.1:6390”,引起这个问题的原因是从Redis 3.2.0版本开始引入了“保护模式(protected mode),防止redis-cli远程访问”,仅限redis-cli绑定到127.0.0.1才可以连接Redis server。

为了完成添加新主节点,可以暂时性的关闭保护模式,使用redis-cli,不指定-h参数(但可以指定-p参数,或者-h参数值为127.0.0.1)进入操作界面:CONFIG SET protected-mode no

注意:6390是新增的节点,而6381是已存在的节点(可为master或slave)。如果需要将6390变成某master(假如为3c3a0c74aae0b56170ccb03a76b60cfe7dc1912e)的slave节点,只需要在6390上执行redis命令(前提:这个master没有负责任何slots,亦即需为一个空master):

redis-cli -h 192.168.0.251 -p 6390 cluster replicate 3c3a0c74aae0b56170ccb03a76b60cfe7dc1912e

新加入的master节点上没有任何数据(slots,运行redis命令cluster nodes可以看到这个情况)。当一个slave想成为master时,由于这个新的master节点不管理任何slots,它不参与选举。可以使用redis-cli的reshard为这个新master节点分配slots,如:

redis-cli --cluster reshard 192.168.0.251:6390

  1. 1. 添加一个新从(slave)节点

以添加“192.168.0.251:6390”为例:

redis-cli --cluster add-node 192.168.0.251:6390 192.168.0.251:6381 --cluster-slave

“192.168.0.251:6390”为新添加的从节点,“192.168.0.251:6381”可为集群中已有的任意节点,这种方法随机为6390指定一个master,如果想明确指定master,假设目标master的ID为“3c3a0c74aae0b56170ccb03a76b60cfe7dc1912e”,则:

redis-cli --cluster add-node 127.0.0.1:7006 127.0.0.1:7000 --cluster-slave --cluster-master-id 3c3a0c74aae0b56170ccb03a76b60cfe7dc1912e

  1. 删除节点

从集群中删除一个节点命令格式:

redis-cli --cluster del-node 127.0.0.1:7000 `<node-id>`

“127.0.0.1:7000”为集群中任意一个非待删除节点,“node-id”为待删除节点的ID。如果待删除的是master节点,则在删除之前需要将该master负责的slots先全部迁到其它master。

$ ./redis-cli --cluster del-node 192.168.0.251:6381 082c079149a9915612d21cca8e08c831a4edeade

>>> Removing node 082c079149a9915612d21cca8e08c831a4edeade from cluster 192.168.0.251:6381

>>> Sending CLUSTER FORGET messages to the cluster…

>>> SHUTDOWN the node.

如果删除后,其它节点还看得到这个被删除的节点,则可通过FORGET命令解决,需要在所有还看得到的其它节点上执行:

CLUSTER FORGET `<node-id>`

FORGET做两件事:

  1. 从节点表剔除节点;

  2. 在60秒的时间内,阻止相同ID的节点加进来。

  3. master机器硬件故障

这种情况下,master机器可能无法启动,导致其上的master无法连接,master将一直处于“master,fail”状态,如果是slave则处于“slave,fail”状态。

如果是master,则会它的slave变成了master,因此只需要添加一个新的从节点作为原slave(已变成master)的slave节点。完成后,通过CLUSTER FORGET将故障的master或slave从集群中剔除即可。

!!!请注意,需要在所有node上执行一次“CLUSTER FORGET”,否则可能遇到被剔除node的总是处于handshake状态。

  1. 检查节点状态

以检查节点“192.168.0.251:6381”的状态为例:

redis-cli --cluster check 192.168.0.251:6381

如发现如下这样的错误:

[WARNING] Node 192.168.0.251:6381 has slots in migrating state (5461).

[WARNING] The following slots are open: 5461

可以使用redis命令取消slots迁移(5461为slot的ID):

cluster setslot 5461 stable

需要注意,须登录到192.168.0.251:6381上执行redis的setslot子命令。

  1. 变更主从关系

在目标slave上执行,命令格式:

cluster replicate

假设将“192.168.0.251:6381”的master改为“3c3a0c74aae0b56170ccb03a76b60cfe7dc1912e”:

redis-cli -h 192.168.0.251 -p 6381 cluster replicate 3c3a0c74aae0b56170ccb03a76b60cfe7dc1912e

使用命令cluster replicate,参数为master节点ID,注意不是IP和端口,在被迁移的slave上执行该命令。

  1. slots相关命令

CLUSTER ADDSLOTS slot1 [slot2] … [slotN]

CLUSTER DELSLOTS slot1 [slot2] … [slotN]

CLUSTER KEYSLOT key # 查看指定key的slot值

CLUSTER SETSLOT slot IMPORTING node # 在目标节点上执行,将slot设置为importing状态

CLUSTER SETSLOT slot MIGRATING node # 在源节点执行,将slot设置为migrating状态

CLUSTER SETSLOT slot STABLE # 清除slot的importing / migrating状态

CLUSTER SETSLOT slot NODE # 将slot和node关系绑定,清除importing / migrating状态

  1. 迁移slosts

官方参考:https://redis.io/commands/cluster-setslot。示例:将值为8的slot从源节点A迁移到目标节点B。

  1. 在目标节点B上执行,从节点A导入slot到节点B:

CLUSTER SETSLOT 8 IMPORTING src-A-node-id

对于迁移的slot,正常访问返回MOVED;但如果在正常访问之前先执行ASKING,则能正常处理该slot。

  1. 在源节点A上执行,将节点A上的slot迁移到节点B

CLUSTER SETSLOT 8 MIGRATING dst-B-node-id

命令“SETSLOT slot MIGRATING”将slot标记为正在迁移(MIGRATING)状态。如果访问的key在源节点上存在,则正常访问;如果访问的key在源节点上不存在,则返回ASK重定向到目标节点。

如果是操作多个keys,则情况有些复杂。如果全不存在或者全存在,则和操作单key相同。但如果是部分存在,部分不存在,则返回错误“TRYAGAIN”。

注意,上列步骤1和2的执行顺序不能颠倒,目的是让目标节点先准备好接受ASK重定向命令(The order of step 1 and 2 is important. We want the destination node to be ready to accept ASK redirections when the source node is configured to redirect.)。

  1. 迁移数据/数据迁移

如果是一个空集群,则这一步可以跳过省去,因为此时还没有任何需要迁移的数据。前面的步骤1和步骤2只影响新的keys,并不会自动迁移已有的keys。

已有的keys需用命令MIGRATE迁移,借助命令“CLUSTER GETKEYSINSLOT”可知道slot有哪些keys。

在源节点上执行获得需要迁移的keys(参数“count”指标一次返回多少个keys):

CLUSTER GETKEYSINSLOT slot count

源节点上执行命令MIGRATE迁移keys:

MIGRATE dest-host dest-port key|"" destination-db timeout [COPY] [REPLACE] [AUTH password] [KEYS key [key …]]

命令“MIGRATE”的参数dest-host和dest-port为目标节点的IP和端口号,参数“REPLACE”表示覆盖目标节点相同的keys,而“COPY”不会删除源节点上的keys。

迁移单个key格式:

MIGRATE dest-host dest-port key destination-db timeout [COPY] [REPLACE] [AUTH password]

或者:

MIGRATE dest-host dest-port "" destination-db timeout [COPY] [REPLACE] [AUTH password] KEYS key

迁移多个keys格式:

MIGRATE dest-host dest-port "" destination-db timeout [COPY] [REPLACE] [AUTH password] [KEYS key [key …]]

AUTH用于指定访问密码,从Redis-6.0开始,新增支持AUTH2。参数timeout用于指定超时时长,单位毫秒。

如果是一个集群对另一个集群,必须保证保证目标节点是key对应的节点。对于集群间迁移,如果多keys需保证对应的slots都在目标节点上,否则报错“CROSSSLOT Keys in request don't hash to the same slot”。

如果版本号不同,则还会遇到错误“ERR Target instance replied with error: ERR DUMP payload version or checksum are wrong”。

如果不执行这一步,则将无法访问已有的keys,会生成这部分数据丢失(访问源节点报错“MOVED 11465 1.9.12.8:1380”,访问目标节点返回nil),但是不影响新的keys。

  1. 完成迁移

上述操作只是将slot标记为迁移状态,完成迁移还需要执行(在源node和目标node上执行),将slot指派给dst-node-id指定的节点:

CLUSTER SETSLOT NODE 

执行“NODE”会产生新的配置,实际上可在所有master节点上执行“NODE”,这样避免了新的配置在集群中传播,加快了配置的更新,官方说明可参见“Cluster live reconfiguration”一节。

重复执行“NODE”,会报错“ERR I'm already the owner of hash slot 1703”。

“NODE”命令中的dst-node-id为目标节点的Node ID,取消迁移和导入使用“CLUSTER SETSLOT STABLE”。

手动完成上列4步操作繁琐且容易出错,如有需要可直接使用现在的迁移工具https://github.com/eyjian/redis-tools/blob/master/move_redis_slot.sh

  1. 人工主备切换

在需要的slaves节点上执行命令:

CLUSTER FAILOVER

人工发起failover,其它master会收到“Failover auth granted to 4291f18b5e9729e832ed15ceb6324ce5dfc2ffbe for epoch 31”,每次epoch值增一。

23038:M 06 Sep 20:31:24.815 # Failover auth granted to 4291f18b5e9729e832ed15ceb6324ce5dfc2ffbe for epoch 31

当出现下面两条日志时,表示failover完成:

23038:M 06 Sep 20:32:44.019 * FAIL message received from ea28f68438e5bb79c26a9cb2135241f11d7a50ba about 5e6ffacb2c5d5761e39aba5270fbf48f296cb5ee

23038:M 06 Sep 20:32:58.487 * Clear FAIL state for node 5e6ffacb2c5d5761e39aba5270fbf48f296cb5ee: slave is reachable again.

成为新master的slave日志:

Manual failover user request accepted.

Received replication offset for paused master manual failover: 347540

All master replication stream processed, manual failover can start.

Start of election delayed for 0 milliseconds (rank #0, offset 347540).

Starting a failover election for epoch 7545.

Failover election won: I'm the new master.

原master收到failover后的日志:

35475:M 06 Sep 20:35:43.396 - DB 0: 16870482 keys (7931571 volatile) in 50331648 slots HT.

35475:M 06 Sep 20:35:43.396 - 1954 clients connected (1 slaves), 5756515544 bytes in use

35475:M 06 Sep 20:35:48.083 # Manual failover requested by slave 58a40dbe01e1563773724803854406df04c62724.

35475:M 06 Sep 20:35:48.261 # Failover auth granted to 58a40dbe01e1563773724803854406df04c62724 for epoch 32

35475:M 06 Sep 20:35:48.261 - Client closed connection

10.51.147.216:7388为failover前的slave,

10.51.147.216:7388的ID为58a40dbe01e1563773724803854406df04c62724

35475:M 06 Sep 20:35:48.261 # Connection with slave 10.51.147.216:7388 lost.

35475:M 06 Sep 20:35:48.278 # Configuration change detected. Reconfiguring myself as a replica of 58a40dbe01e1563773724803854406df04c62724

35475:S 06 Sep 20:35:48.280 - Client closed connection

35475:S 06 Sep 20:35:48.408 - DB 0: 16870296 keys (7931385 volatile) in 50331648 slots HT.

35475:S 06 Sep 20:35:48.408 - 1953 clients connected (0 slaves), 5722753736 bytes in use

35475:S 06 Sep 20:35:48.408 * Connecting to MASTER 10.51.147.216:7388

35475:S 06 Sep 20:35:48.408 * MASTER <-> SLAVE sync started

35475:S 06 Sep 20:35:48.408 * Non blocking connect for SYNC fired the event.

35475:S 06 Sep 20:35:48.408 * Master replied to PING, replication can continue…

35475:S 06 Sep 20:35:48.408 * Partial resynchronization not possible (no cached master)

35475:S 06 Sep 20:35:48.459 * Full resync from master: 36beb63d32b3809039518bf4f3e4e10de227f3ee:16454238619

35475:S 06 Sep 20:35:48.493 - Client closed connection

35475:S 06 Sep 20:35:48.880 - Client closed connection

  1. 查看集群信息

对应的redis命令为:cluster info,示例:

127.0.0.1:6381> cluster info

cluster_state:ok 所有slots正常则显示为OK,否则为error

cluster_slots_assigned:16384 多少slots被分配了,即多少被master管理了,16384为全部slots

cluster_slots_ok:16384 有多少slots是正常的

cluster_slots_pfail:0 有多少slots可能处于异常状态,处于这个状态并不表示有问题,仍能继续提供服务

cluster_slots_fail:0 有多少slots处于异常状态,需要修复才能服务

cluster_known_nodes:10 集群中的节点数

cluster_size:3 集群中master个数

cluster_current_epoch:11 本地的当前时间变量,用于故障切换时生成独一无二的增量版本号

cluster_my_epoch:0

cluster_stats_messages_sent:4049 通过集群消息总线发送的消息总数

cluster_stats_messages_received:4051 通过过集通过群消息总线收到的消息总数

  1. 禁止指定命令

KEYS命令很耗时,FLUSHDB和FLUSHALL命令可能导致误删除数据,所以线上环境最好禁止使用,可以在Redis配置文件增加如下配置:

rename-command KEYS ""

rename-command FLUSHDB ""

rename-command FLUSHALL ""

  1. 数据迁移

可使用命令“redis-cli --cluster import”将数据从一个redis集群迁到另一个redis集群。

  1. 各版本配置文件

https://raw.githubusercontent.com/antirez/redis/5.0.5/redis.conf

https://raw.githubusercontent.com/antirez/redis/4.0.11/redis.conf

https://raw.githubusercontent.com/antirez/redis/4.0.9/redis.conf

https://raw.githubusercontent.com/antirez/redis/4.0.5/redis.conf

https://raw.githubusercontent.com/antirez/redis/4.0.3/redis.conf

https://raw.githubusercontent.com/antirez/redis/4.0.1/redis.conf

https://raw.githubusercontent.com/antirez/redis/4.0/redis.conf

https://raw.githubusercontent.com/antirez/redis/3.2.9/redis.conf

https://raw.githubusercontent.com/antirez/redis/3.0/redis.conf

  1. 大压力下Redis参数调整要点

参数

建议最小值

说明

repl-ping-slave-period

10

每10秒ping一次

repl-timeout

60

60秒超时,也就是ping十次

cluster-node-timeout

15000

repl-backlog-size

1GB

Master对slave的队列大小

appendfsync

no

让系统自动刷

save

大压力下,调大参数值,以减少写RDB带来的压力:

"900 20 300 200 60 200000"

appendonly

对于队列,建议单独建立集群,并且设置该值为no

为何大压力下要这样调整?

最重要的原因之一Redis的主从复制,两者复制共享同一线程,虽然是异步复制的,但因为是单线程,所以也十分有限。如果主从间的网络延迟不是在0.05左右,比如达到0.6,甚至1.2等,那么情况是非常糟糕的,因此同一Redis集群一定要部署在同一机房内。

这些参数的具体值,要视具体的压力而定,而且和消息的大小相关,比如一条200~500KB的流水数据可能比较大,主从复制的压力也会相应增大,而10字节左右的消息,则压力要小一些。大压力环境中开启appendfsync是十分不可取的,容易导致整个集群不可用,在不可用之前的典型表现是QPS毛刺明显。

这么做的目的是让Redis集群尽可能的避免master正常时触发主从切换,特别是容纳的数据量很大时,和大压力结合在一起,集群会雪崩。

当Redis日志中,出现大量如下信息,即可能意味着相关的参数需要调整了:

22135:M 06 Sep 14:17:05.388 * FAIL message received from 1d07e208db56cfd7395950ca66e03589278b8e12 about e438a338e9d9834a6745c12931950da87e360ca2

22135:M 06 Sep 14:17:07.551 * FAIL message received from ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467 about d6eb06e9d118c120d3961a659972a1d0191a8652

22135:M 06 Sep 14:17:08.438 # Failover auth granted to f7d6b2c72fa3b801e7dcfe0219e73383d143dd0f for epoch 285 (We can vote for this slave

有投票资格的node:

  1. 为master
  2. 至少有一个slot
  3. 投票node的epoch不能小于node自己当前的epoch(reqEpoch < curEpoch)
  4. node没有投票过该epoch(already voted for epoch)
  5. 投票node不能为master(it is a master node)
  6. 投票node必须有一个master(I don't know its master)
  7. 投票node的master处于fail状态(its master is up)

22135:M 06 Sep 14:17:19.844 # Failover auth denied to 534b93af6ba45a7033dbf38c8f47cd688514125a: already voted for epoch 285

如果一个node又联系上了,则它当是一个slave,或者无slots的master时,直接清除FAIL标志;但如果是一个master,则当“(now - node->fail_time) > (server.cluster_node_timeout * CLUSTER_FAIL_UNDO_TIME_MULT)”时,也清除FAIL标志,定义在cluster.h中(cluster.h:#define CLUSTER_FAIL_UNDO_TIME_MULT 2 /* Undo fail if master is back. */

22135:M 06 Sep 14:17:29.243 * Clear FAIL state for node d6eb06e9d118c120d3961a659972a1d0191a8652: master without slots is reachable again.

如果消息类型为fail。

22135:M 06 Sep 14:17:31.995 * FAIL message received from f7d6b2c72fa3b801e7dcfe0219e73383d143dd0f about 1ba437fa1683a8caafd38ff977e5fbabdaf84fd6

22135:M 06 Sep 14:17:32.496 * FAIL message received from 1d07e208db56cfd7395950ca66e03589278b8e12 about d7942cfe636b25219c6d56aa72828fcfde2ee261

22135:M 06 Sep 14:17:32.968 # Failover auth granted to 938d9ae2de278938beda1d39185608b02d3b31ec for epoch 286

22135:M 06 Sep 14:17:33.177 # Failover auth granted to d9dadf3342006e2c92def3071ca0a76390be62b0 for epoch 287

22135:M 06 Sep 14:17:36.336 * Clear FAIL state for node 1ba437fa1683a8caafd38ff977e5fbabdaf84fd6: master without slots is reachable again.

22135:M 06 Sep 14:17:36.855 * Clear FAIL state for node d7942cfe636b25219c6d56aa72828fcfde2ee261: master without slots is reachable again.

22135:M 06 Sep 14:17:38.419 * Clear FAIL state for node e438a338e9d9834a6745c12931950da87e360ca2: is reachable again and nobody is serving its slots after some time.

22135:M 06 Sep 14:17:54.954 * FAIL message received from ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467 about 7990d146cece7dc83eaf08b3e12cbebb2223f5f8

22135:M 06 Sep 14:17:56.697 * FAIL message received from 1d07e208db56cfd7395950ca66e03589278b8e12 about fbe774cdbd2acd24f9f5ea90d61c607bdf800eb5

22135:M 06 Sep 14:17:57.705 # Failover auth granted to e1c202d89ffe1c61b682e28071627635974c84a7 for epoch 288

22135:M 06 Sep 14:17:57.890 * Clear FAIL state for node 7990d146cece7dc83eaf08b3e12cbebb2223f5f8: slave is reachable again.

22135:M 06 Sep 14:17:57.892 * Clear FAIL state for node fbe774cdbd2acd24f9f5ea90d61c607bdf800eb5: master without slots is reachable again.

  1. 问题排查

  2. 如果最后一条日志为“16367:M 08 Jun 14:48:15.560 # Server started, Redis version 3.2.0”,节点状态始终终于fail状态,则可能是aof文件损坏了,这时可以使用工具edis-check-aof --fix进行修改,如:

../../bin/redis-check-aof --fix appendonly-6380.aof

0x        a1492b9b: Expected prefix '

AOF analyzed: size=2705928192, ok_up_to=2705927067, diff=1125

This will shrink the AOF from 2705928192 bytes, with 1125 bytes, to 2705927067 bytes

Continue? [y/N]: y

  1. in `call': ERR Slot 16011 is already busy (Redis::CommandError)

将所有节点上的配置项cluster-config-file指定的文件删除,然后重新启;或者在所有节点上执行下FLUSHALL命令。

另外,如果使用主机名而不是IP,也可能遇到这个错误,如:“redis-cli create --replicas 1 redis1:6379 redis2:6379 redis3:6379 redis4:6379 redis5:6379 redis6:6379”,可能也会得到错误“ERR Slot 16011 is already busy (Redis::CommandError)”。

  1. for lack of backlog (Slave request was: 51875158284)

默认值:

# redis-cli config get repl-timeout

A) "repl-timeout"

B) "10"

# redis-cli config get client-output-buffer-limit

A) "client-output-buffer-limit"

B) "normal 0 0 0 slave 268435456 67108864 60 pubsub 33554432 8388608 60"

增大:

redis-cli config set "client-output-buffer-limit" "normal 0 0 0 slave 2684354560 671088640 60 pubsub 33554432 8388608 60"

  1. 复制中断场景

  2. master的slave缓冲区达到限制的硬或软限制大小,与参数client-output-buffer-limit相关;

  3. 复制时间超过repl-timeout指定的值,与参数repl-timeout相关。

slave反复循环从master复制,如果调整以上参数仍然解决不了,可以尝试删除slave上的aof和rdb文件,然后再重启进程复制,这个时候可能能正常完成复制。

  1. 日志文件出现:Asynchronous AOF fsync is taking too long (disk is busy?). Writing the AOF buffer without waiting for fsync to complete, this may slow down Redis.

考虑优化以下配置项:

no-appendfsync-on-rewrite值设为yes

repl-backlog-size和client-output-buffer-limit调大一点

  1. 日志文件出现:MISCONF Redis is configured to save RDB snapshots, but is currently not able to persist on disk. Commands that may modify the data set are disabled. Please check Redis logs for details about the error.

考虑设置stop-writes-on-bgsave-error值为“no”。

  1. Failover auth granted to

当日志大量反反复复出现下列内容时,很可能表示master和slave间同步和通讯不顺畅,导致无效的failover和状态变更,这个时候需要调大相关参数值,容忍更长的延迟,因此也特别注意集群内所有节点间的网络延迟要尽可能的小,最好达到0.02ms左右的水平,调大参数的代价是主备切换变迟钝。

Slave日志:

31019:S 06 Sep 11:07:24.169 * Connecting to MASTER 10.5.14.8:6379

31019:S 06 Sep 11:07:24.169 * MASTER <-> SLAVE sync started

31019:S 06 Sep 11:07:24.169 # Start of election delayed for 854 milliseconds (rank #0, offset 5127277817).

31019:S 06 Sep 11:07:24.169 * Non blocking connect for SYNC fired the event.

31019:S 06 Sep 11:07:25.069 # Starting a failover election for epoch 266.

31019:S 06 Sep 11:07:29.190 * Clear FAIL state for node ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467: is reachable again and nobody is serving its slots after some time.

31019:S 06 Sep 11:07:29.191 * Master replied to PING, replication can continue…

31019:S 06 Sep 11:07:29.191 * Clear FAIL state for node f7d6b2c72fa3b801e7dcfe0219e73383d143dd0f: is reachable again and nobody is serving its slots after some time.

31019:S 06 Sep 11:07:29.192 * Trying a partial resynchronization (request ea2261c827fbc54135a95f707046581a55dff133:5127277818).

31019:S 06 Sep 11:07:29.192 * Successful partial resynchronization with master.

31019:S 06 Sep 11:07:29.192 * MASTER <-> SLAVE sync: Master accepted a Partial Resynchronization.

31019:S 06 Sep 11:07:29.811 * Clear FAIL state for node e438a338e9d9834a6745c12931950da87e360ca2: is reachable again and nobody is serving its slots after some time.

31019:S 06 Sep 11:07:37.680 * FAIL message received from 5b41f7860cc800e65932e92d1d97c6c188138e56 about 3114cec541c5bcd36d712cd6c9f4c5055510e386

31019:S 06 Sep 11:07:43.710 * Clear FAIL state for node 3114cec541c5bcd36d712cd6c9f4c5055510e386: slave is reachable again.

31019:S 06 Sep 11:07:48.119 * FAIL message received from 7d61af127c17d9c19dbf9af0ac8f7307f1c96c4b about e1c202d89ffe1c61b682e28071627635974c84a7

31019:S 06 Sep 11:07:49.410 * FAIL message received from 5b41f7860cc800e65932e92d1d97c6c188138e56 about d9dadf3342006e2c92def3071ca0a76390be62b0

31019:S 06 Sep 11:07:53.352 * Clear FAIL state for node d9dadf3342006e2c92def3071ca0a76390be62b0: slave is reachable again.

31019:S 06 Sep 11:07:57.147 * Clear FAIL state for node e1c202d89ffe1c61b682e28071627635974c84a7: slave is reachable again.

31019:S 06 Sep 11:08:36.516 * FAIL message received from ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467 about 938d9ae2de278938beda1d39185608b02d3b31ec

31019:S 06 Sep 11:08:41.900 * Clear FAIL state for node 938d9ae2de278938beda1d39185608b02d3b31ec: slave is reachable again.

31019:S 06 Sep 11:08:46.380 * FAIL message received from d7942cfe636b25219c6d56aa72828fcfde2ee261 about fbe774cdbd2acd24f9f5ea90d61c607bdf800eb5

31019:S 06 Sep 11:08:46.531 * Marking node 7990d146cece7dc83eaf08b3e12cbebb2223f5f8 as failing (quorum reached).

31019:S 06 Sep 11:09:01.882 * Clear FAIL state for node 7990d146cece7dc83eaf08b3e12cbebb2223f5f8: master without slots is reachable again.

31019:S 06 Sep 11:09:01.883 * Clear FAIL state for node fbe774cdbd2acd24f9f5ea90d61c607bdf800eb5: master without slots is reachable again.

31019:S 06 Sep 11:09:06.538 * FAIL message received from e438a338e9d9834a6745c12931950da87e360ca2 about d7942cfe636b25219c6d56aa72828fcfde2ee261

31019:S 06 Sep 11:09:06.538 * FAIL message received from e438a338e9d9834a6745c12931950da87e360ca2 about 1ba437fa1683a8caafd38ff977e5fbabdaf84fd6

31019:S 06 Sep 11:09:12.555 * Clear FAIL state for node 1ba437fa1683a8caafd38ff977e5fbabdaf84fd6: is reachable again and nobody is serving its slots after some time.

31019:S 06 Sep 11:09:12.555 * Clear FAIL state for node d7942cfe636b25219c6d56aa72828fcfde2ee261: master without slots is reachable again.

31019:S 06 Sep 11:09:15.565 * Marking node 534b93af6ba45a7033dbf38c8f47cd688514125a as failing (quorum reached).

31019:S 06 Sep 11:09:16.599 * FAIL message received from 0a92bd7472c9af3e52f9185eac1bd1bbf36146e6 about e1c202d89ffe1c61b682e28071627635974c84a7

31019:S 06 Sep 11:09:22.262 * Clear FAIL state for node 534b93af6ba45a7033dbf38c8f47cd688514125a: slave is reachable again.

31019:S 06 Sep 11:09:27.906 * Clear FAIL state for node e1c202d89ffe1c61b682e28071627635974c84a7: is reachable again and nobody is serving its slots after some time.

31019:S 06 Sep 11:09:50.744 * FAIL message received from ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467 about e1c202d89ffe1c61b682e28071627635974c84a7

31019:S 06 Sep 11:09:55.141 * FAIL message received from 5b41f7860cc800e65932e92d1d97c6c188138e56 about d9dadf3342006e2c92def3071ca0a76390be62b0

31019:S 06 Sep 11:09:55.362 * FAIL message received from 7d61af127c17d9c19dbf9af0ac8f7307f1c96c4b about 938d9ae2de278938beda1d39185608b02d3b31ec

31019:S 06 Sep 11:09:55.557 * FAIL message received from ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467 about 1d07e208db56cfd7395950ca66e03589278b8e12

31019:S 06 Sep 11:09:55.578 * FAIL message received from ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467 about 144347d5a51acf047887fe81f22e8f7705c911ec

31019:S 06 Sep 11:09:56.521 * Marking node 534b93af6ba45a7033dbf38c8f47cd688514125a as failing (quorum reached).

31019:S 06 Sep 11:09:57.996 * Clear FAIL state for node 1d07e208db56cfd7395950ca66e03589278b8e12: slave is reachable again.

31019:S 06 Sep 11:09:58.329 * FAIL message received from 5b41f7860cc800e65932e92d1d97c6c188138e56 about 0a92bd7472c9af3e52f9185eac1bd1bbf36146e6

31019:S 06 Sep 11:10:09.239 * Clear FAIL state for node 144347d5a51acf047887fe81f22e8f7705c911ec: slave is reachable again.

31019:S 06 Sep 11:10:09.812 * Clear FAIL state for node d9dadf3342006e2c92def3071ca0a76390be62b0: is reachable again and nobody is serving its slots after some time.

31019:S 06 Sep 11:10:13.549 * Clear FAIL state for node 534b93af6ba45a7033dbf38c8f47cd688514125a: slave is reachable again.

31019:S 06 Sep 11:10:13.590 * FAIL message received from 716f2e2dd9792eaf4ee486794c9797fa6e1c9650 about 1ba437fa1683a8caafd38ff977e5fbabdaf84fd6

31019:S 06 Sep 11:10:13.591 * FAIL message received from f7d6b2c72fa3b801e7dcfe0219e73383d143dd0f about d7942cfe636b25219c6d56aa72828fcfde2ee261

31019:S 06 Sep 11:10:14.316 * Clear FAIL state for node e1c202d89ffe1c61b682e28071627635974c84a7: is reachable again and nobody is serving its slots after some time.

31019:S 06 Sep 11:10:15.108 * Clear FAIL state for node d7942cfe636b25219c6d56aa72828fcfde2ee261: slave is reachable again.

31019:S 06 Sep 11:10:17.588 * Clear FAIL state for node 938d9ae2de278938beda1d39185608b02d3b31ec: slave is reachable again.

31019:S 06 Sep 11:10:32.622 * Clear FAIL state for node 0a92bd7472c9af3e52f9185eac1bd1bbf36146e6: slave is reachable again.

31019:S 06 Sep 11:10:32.623 * FAIL message received from 5b41f7860cc800e65932e92d1d97c6c188138e56 about 3114cec541c5bcd36d712cd6c9f4c5055510e386

31019:S 06 Sep 11:10:32.623 * Clear FAIL state for node 3114cec541c5bcd36d712cd6c9f4c5055510e386: slave is reachable again.

Master日志:

31014:M 06 Sep 14:08:54.083 * Background saving terminated with success

31014:M 06 Sep 14:09:55.093 * 10000 changes in 60 seconds. Saving…

31014:M 06 Sep 14:09:55.185 * Background saving started by pid 41395

31014:M 06 Sep 14:11:00.269 # Disconnecting timedout slave: 10.15.40.9:6018

31014:M 06 Sep 14:11:00.269 # Connection with slave 10.15.40.9:6018 lost.

41395:C 06 Sep 14:11:01.141 * DB saved on disk

41395:C 06 Sep 14:11:01.259 * RDB: 5 MB of memory used by copy-on-write

31014:M 06 Sep 14:11:01.472 * Background saving terminated with success

31014:M 06 Sep 14:11:11.525 * FAIL message received from 1d07e208db56cfd7395950ca66e03589278b8e12 about 534b93af6ba45a7033dbf38c8f47cd688514125a

31014:M 06 Sep 14:11:23.039 * FAIL message received from 1ba437fa1683a8caafd38ff977e5fbabdaf84fd6 about d78845370c98b3ce4cfc02e8d3e233a9a1d84a83

31014:M 06 Sep 14:11:23.541 * Clear FAIL state for node 534b93af6ba45a7033dbf38c8f47cd688514125a: slave is reachable again.

31014:M 06 Sep 14:11:23.813 * Slave 10.15.40.9:6018 asks for synchronization

31014:M 06 Sep 14:11:23.813 * Partial resynchronization request from 10.15.40.9:6018 accepted. Sending 46668 bytes of backlog starting from offset 5502672944.

31014:M 06 Sep 14:11:23.888 # Failover auth granted to 7d61af127c17d9c19dbf9af0ac8f7307f1c96c4b for epoch 283

31014:M 06 Sep 14:11:32.464 * FAIL message received from d6eb06e9d118c120d3961a659972a1d0191a8652 about 3114cec541c5bcd36d712cd6c9f4c5055510e386

31014:M 06 Sep 14:11:47.616 * Clear FAIL state for node d78845370c98b3ce4cfc02e8d3e233a9a1d84a83: master without slots is reachable again.

31014:M 06 Sep 14:11:55.515 * FAIL message received from d6eb06e9d118c120d3961a659972a1d0191a8652 about ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467

31014:M 06 Sep 14:11:57.135 # Failover auth granted to ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467 for epoch 284

31014:M 06 Sep 14:12:01.766 * Clear FAIL state for node ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467: slave is reachable again.

31014:M 06 Sep 14:12:08.753 * Clear FAIL state for node 3114cec541c5bcd36d712cd6c9f4c5055510e386: master without slots is reachable again.

31014:M 06 Sep 14:16:02.070 * 10 changes in 300 seconds. Saving…

31014:M 06 Sep 14:16:02.163 * Background saving started by pid 13832

31014:M 06 Sep 14:17:18.443 * FAIL message received from ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467 about d6eb06e9d118c120d3961a659972a1d0191a8652

31014:M 06 Sep 14:17:18.443 # Failover auth granted to f7d6b2c72fa3b801e7dcfe0219e73383d143dd0f for epoch 285

31014:M 06 Sep 14:17:29.272 # Connection with slave client id #40662 lost.

31014:M 06 Sep 14:17:29.273 # Failover auth denied to 534b93af6ba45a7033dbf38c8f47cd688514125a: already voted for epoch 285

31014:M 06 Sep 14:17:29.278 * Slave 10.15.40.9:6018 asks for synchronization

31014:M 06 Sep 14:17:29.278 * Partial resynchronization request from 10.15.40.9:6018 accepted. Sending 117106 bytes of backlog starting from offset 5502756264.

13832:C 06 Sep 14:17:29.850 * DB saved on disk

13832:C 06 Sep 14:17:29.970 * RDB: 7 MB of memory used by copy-on-write

31014:M 06 Sep 14:17:38.449 * FAIL message received from f7d6b2c72fa3b801e7dcfe0219e73383d143dd0f about 1ba437fa1683a8caafd38ff977e5fbabdaf84fd6

31014:M 06 Sep 14:17:38.449 * FAIL message received from 1d07e208db56cfd7395950ca66e03589278b8e12 about d7942cfe636b25219c6d56aa72828fcfde2ee261

31014:M 06 Sep 14:17:38.449 # Failover auth denied to 938d9ae2de278938beda1d39185608b02d3b31ec: reqEpoch (286) < curEpoch(287)

31014:M 06 Sep 14:17:38.449 # Failover auth granted to d9dadf3342006e2c92def3071ca0a76390be62b0 for epoch 287

31014:M 06 Sep 14:17:38.449 * Background saving terminated with success

31014:M 06 Sep 14:17:38.450 * Clear FAIL state for node d7942cfe636b25219c6d56aa72828fcfde2ee261: master without slots is reachable again.

31014:M 06 Sep 14:17:38.450 * Clear FAIL state for node 1ba437fa1683a8caafd38ff977e5fbabdaf84fd6: master without slots is reachable again.

31014:M 06 Sep 14:17:38.452 * Clear FAIL state for node d6eb06e9d118c120d3961a659972a1d0191a8652: slave is reachable again.

31014:M 06 Sep 14:17:54.985 * FAIL message received from ae8f6e7e0ab16b04414c8f3d08b58c0aa268b467 about 7990d146cece7dc83eaf08b3e12cbebb2223f5f8

31014:M 06 Sep 14:17:56.729 * FAIL message received from 1d07e208db56cfd7395950ca66e03589278b8e12 about fbe774cdbd2acd24f9f5ea90d61c607bdf800eb5

31014:M 06 Sep 14:17:57.737 # Failover auth granted to e1c202d89ffe1c61b682e28071627635974c84a7 for epoch 288

31014:M 06 Sep 14:17:57.922 * Clear FAIL state for node fbe774cdbd2acd24f9f5ea90d61c607bdf800eb5: master without slots is reachable again.

31014:M 06 Sep 14:17:57.923 * Clear FAIL state for node 7990d146cece7dc83eaf08b3e12cbebb2223f5f8: slave is reachable again.

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