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Based on how to build redis master-slave cluster in docker environment, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

1 preface

The author introduces how to build a Redis master-slave replication cluster based on docker, how to make the redis master-slave cluster run well on the docker container, and how to switch between the redis master and slave in case of failure under the container.

2 Redis master-slave replication characteristics

L uses asynchronous replication.

L supports one master and multiple slaves. A master can have more than one slave.

L Slave can accept connections from other slaves. In addition to being able to connect multiple slaves to the same master, slaves can also connect to other slaves in a similar cascading manner.

L Redis replication is non-blocking on the master side. This means that master can continue to process requests (from the client) when slave is performing the first synchronization.

L Redis replication can be used for capacity expansion, such as using multiple slaves for read-only queries, or just for data redundancy.

L Redis replication may also be used to prevent master from writing the entire dataset to the hard disk. This technique requires configuring master's redis.conf file and then connecting to a slave, which must be configured to save from time to time, or AOF enabled.

3 advantages of Redis containerization

1. Save the installation and configuration of redis master / slave

2. The redis container can be started in seconds

3. It can quickly expand redis slave nodes.

4. It can quickly switch between redis master and slave.

5. Strong transferability.

4 Redis master-slave replication architecture

5 Redis Master-Slave Cluster Building 5.1 redis Node Information

Here, one master and two slaves are used to test.

Serial number

Node name

IP address

Use

one

Redis-master

192.168.56.108

Redis master node, node data can be written and read

two

Redis-slave01

192.168.56.109

Redis slave node 1, node data is readable and unwritable

three

Redis-slave02

192.168.56.110

Redis slave node 2, node data is readable and unwritable

5.2 Redis basic image encapsulation

1. Redis image dockerfile script

FROM jaymarco/centos:7.3

MAINTAINER jaymarco

ENV VERSION=3.2.5

ENV DOWN_URL= http://download.redis.io/releases/redis-${VERSION}.tar.gz\

TEMP_DIR=/tmp/redis\

DATA_DIR=/data/redis

RUN mkdir-p ${TEMP_DIR} ${DATA_DIR} &

Yum install-y gcc gcc-c++ make cmake tar & &\

Groupadd redis & & useradd-g redis-d ${DATA_DIR}-s / sbin/nologin redis & &\

Curl-Lk ${DOWN_URL} | tar xz-C ${TEMP_DIR}-strip-components=1 & &\

Cd ${TEMP_DIR} & &\

Make-C ${TEMP_DIR}-j $(awk'/ processor/ {ionization +} END {print I}'/ proc/cpuinfo) & &\

Make-C ${TEMP_DIR} install & &\

Rm-rf ${TEMP_DIR} & &\

/ bin/cp / usr/share/zoneinfo/Asia/Shanghai / etc/localtime & &\

Echo 'Asia/Shanghai' > / etc/timezone

COPY entrypoint.sh / entrypoint.sh

RUN chmod + x / entrypoint.sh

VOLUME ${DATA_DIR}

WORKDIR ${DATA_DIR}

EXPOSE 6379/tcp

ENTRYPOINT ["/ entrypoint.sh"]

2. Redis initialization startup script

The operating system parameters are optimized when building dockerfile.

#! / bin/bash

If! Which redis-server > / dev/null 2 > & 1; then

Source / etc/profile.d/redis.sh

Fi

Set-e

Sysctl-w net.core.somaxconn=1024 > / dev/null 2 > & 1

Sysctl-w vm.overcommit_memory=1 > / dev/null 2 > & 1

Echo never > / sys/kernel/mm/transparent_hugepage/enabled

Echo never > / sys/kernel/mm/transparent_hugepage/defrag

# first arg is `- f` or`-some- option`

# or first arg is `something.conf`

If ["${1clients -}"! = "$1"] | | ["${1%.conf}"! = "$1"]; then

Set-redis-server "$@"

Fi

# allow the container to be started with `--user`

If ["$1" = 'redis-server'-a "$(id-u)" =' 0']; then

Chown-R redis.

# exec gosu redis "$0"$@"

Fi

If ["$1" = 'redis-server']; then

DoProtectedMode=1

ConfigFile=

If [- f "$2"]; then

ConfigFile= "$2"

If grep-Q'^ protected-mode' "$configFile"; then

DoProtectedMode=

Fi

Fi

If ["$doProtectedMode"]; then

Shift # "redis-server"

If ["$configFile"]; then

Shift

Fi

Set-protected-mode no "$@"

If ["$configFile"]; then

Set-- "$configFile"$@"

Fi

Set-redis-server "$@"

Fi

Fi

Exec "$@"

3. Build a basic image of redis

Encapsulate the redis image in the same directory of the dockerfile file, and finally generate an image file of jaymarco/redis:3.2.5. You can refer to the following command to build a redis image:

Docker build-t jaymarco/redis: 3.2.5.

4. Import redis image to other nodes

When the docker image of Redis has been encapsulated on one of the nodes, you need to synchronize the docker image of redisr to the other two redis host nodes.

1. Check the redis image and get the image ID: 04fd033441e2.

2. Use the docker save command to save the redis image to the host disk as a file.

3. Copy the redis325.tar file remotely to the other two redis nodes.

Scp redis325.tar 192.168.56.109:/home

Scp redis325.tar 192.168.56.110:/home

4. Import redis325.tar into docker using the docker load command.

Through the above operations, the encapsulation of redis image has been completed, and the mirror has been synchronized to other nodes, indicating that redis docker image exists on all three nodes of redis.

5.3 Redis master-slave cluster configuration

The key to the Redis master-slave cluster is the redis.conf configuration file between the master and slave, which makes the parameter setting and performance optimization configuration of the master-slave. Previously, we have installed the redis software in a mirror image on the three nodes. Next, we set up the redis master-slave cluster environment through configuration. At the same time, we start the redis container and use the host network mode to run the redis container on three virtual hosts.

5.3.1 master Primary Node (192.168.56.108)

Next, configure the redis-master master node.

1. Redis configuration file

Bind 0.0.0.0

Protected-mode yes

Port 6379

Tcp-backlog 511

Timeout 0

Tcp-keepalive 300

Daemonize no

Supervised no

Pidfile / var/run/redis_6379.pid

Loglevel notice

Logfile ""

Databases 8

Save 900 1

Save 300 10

Save 60 10000

Stop-writes-on-bgsave-error yes

Rdbcompression yes

Rdbchecksum yes

Dbfilename dump.rdb

Dir / data/redis

Slave-serve-stale-data yes

Slave-read-only yes

Repl-diskless-sync no

Repl-diskless-sync-delay 5

Repl-disable-tcp-nodelay no

Slave-priority 100

Appendonly no

Appendfilename "appendonly.aof"

Appendfsync everysec

No-appendfsync-on-rewrite no

Auto-aof-rewrite-percentage 100

Auto-aof-rewrite-min-size 64mb

Aof-load-truncated yes

Lua-time-limit 5000

Slowlog-log-slower-than 10000

Slowlog-max-len 128

Latency-monitor-threshold 0

Notify-keyspace-events ""

Hash-max-ziplist-entries 512

Hash-max-ziplist-value 64

List-max-ziplist-size-2

List-compress-depth 0

Set-max-intset-entries 512

Zset-max-ziplist-entries 128

Zset-max-ziplist-value 64

Hll-sparse-max-bytes 3000

Activerehashing yes

Client-output-buffer-limit normal 0 0 0

Client-output-buffer-limit slave 256mb 64mb 60

Client-output-buffer-limit pubsub 32mb 8mb 60

Hz 10

Aof-rewrite-incremental-fsync yes

Masterauth JayRedisHaZi

Requirepass JayRedisHaZi

2. Start the master redis container

Docker run-d\

-- privileged-- name redis-master\

-- network host\

-v / etc/redis.conf:/etc/redis.conf\

-v / etc/localtime:/etc/localtime\

Jaymarco/redis:3.2.5

See below: the redis container of the primary node starts successfully

5.3.2 Slave slave node 1 (192.168.56.109)

Next, configure the redis-slave01 slave node.

1. Redis configuration file

Bind 0.0.0.0

Protected-mode yes

Port 6379

Tcp-backlog 511

Timeout 0

Tcp-keepalive 300

Daemonize no

Supervised no

Pidfile / var/run/redis_6379.pid

Loglevel notice

Logfile ""

Databases 8

Save 900 1

Save 300 10

Save 60 10000

Stop-writes-on-bgsave-error yes

Rdbcompression yes

Rdbchecksum yes

Dbfilename dump.rdb

Dir / data/redis

Slave-serve-stale-data yes

Slave-read-only yes

Repl-diskless-sync no

Repl-diskless-sync-delay 5

Repl-disable-tcp-nodelay no

Slave-priority 100

Appendonly no

Appendfilename "appendonly.aof"

Appendfsync everysec

No-appendfsync-on-rewrite no

Auto-aof-rewrite-percentage 100

Auto-aof-rewrite-min-size 64mb

Aof-load-truncated yes

Lua-time-limit 5000

Slowlog-log-slower-than 10000

Slowlog-max-len 128

Latency-monitor-threshold 0

Notify-keyspace-events ""

Hash-max-ziplist-entries 512

Hash-max-ziplist-value 64

List-max-ziplist-size-2

List-compress-depth 0

Set-max-intset-entries 512

Zset-max-ziplist-entries 128

Zset-max-ziplist-value 64

Hll-sparse-max-bytes 3000

Activerehashing yes

Client-output-buffer-limit normal 0 0 0

Client-output-buffer-limit slave 256mb 64mb 60

Client-output-buffer-limit pubsub 32mb 8mb 60

Hz 10

Aof-rewrite-incremental-fsync yes

Slaveof 192.168.56.108 6379

Masterauth JayRedisHaZi

Requirepass JayRedisHaZi

2 start the master redis container

Docker run-d\

-- privileged-- name redis-slave01\

-- network host\

-v / etc/redis.conf:/etc/redis.conf\

-v / etc/localtime:/etc/localtime\

Jaymarco/redis:3.2.5

See below: the redis container of the primary node starts successfully

5.3.3 Slave Slave Node 2 (192.168.56.110)

Next, configure the redis-slave02 slave node.

1. Redis configuration file

Bind 0.0.0.0

Protected-mode yes

Port 6379

Tcp-backlog 511

Timeout 0

Tcp-keepalive 300

Daemonize no

Supervised no

Pidfile / var/run/redis_6379.pid

Loglevel notice

Logfile ""

Databases 8

Save 900 1

Save 300 10

Save 60 10000

Stop-writes-on-bgsave-error yes

Rdbcompression yes

Rdbchecksum yes

Dbfilename dump.rdb

Dir / data/redis

Slave-serve-stale-data yes

Slave-read-only yes

Repl-diskless-sync no

Repl-diskless-sync-delay 5

Repl-disable-tcp-nodelay no

Slave-priority 100

Appendonly no

Appendfilename "appendonly.aof"

Appendfsync everysec

No-appendfsync-on-rewrite no

Auto-aof-rewrite-percentage 100

Auto-aof-rewrite-min-size 64mb

Aof-load-truncated yes

Lua-time-limit 5000

Slowlog-log-slower-than 10000

Slowlog-max-len 128

Latency-monitor-threshold 0

Notify-keyspace-events ""

Hash-max-ziplist-entries 512

Hash-max-ziplist-value 64

List-max-ziplist-size-2

List-compress-depth 0

Set-max-intset-entries 512

Zset-max-ziplist-entries 128

Zset-max-ziplist-value 64

Hll-sparse-max-bytes 3000

Activerehashing yes

Client-output-buffer-limit normal 0 0 0

Client-output-buffer-limit slave 256mb 64mb 60

Client-output-buffer-limit pubsub 32mb 8mb 60

Hz 10

Aof-rewrite-incremental-fsync yes

Slaveof 192.168.56.108 6379

Masterauth JayRedisHaZi

Requirepass JayRedisHaZi

2 start the master redis container

Docker run-d\

-- privileged-- name redis-slave02\

-- network host\

-v / etc/redis.conf:/etc/redis.conf\

-v / etc/localtime:/etc/localtime\

Jaymarco/redis:3.2.5

See below: the redis container of the primary node starts successfully

5.4 Redis Master-Slave check

Check the master-slave synchronization status of master and slave with the following command

1. Redis-master status log

Docker exec-it redis-master redis-cli-h 192.168.56.108-a JayRedisHaZi info replication

# Replication

Role:master

Connected_slaves:2

Slave0:ip=192.168.56.110,port=6379,state=online,offset=99,lag=0

Slave1:ip=192.168.56.109,port=6379,state=online,offset=99,lag=1

Master_repl_offset:113

Repl_backlog_active:1

Repl_backlog_size:1048576

Repl_backlog_first_byte_offset:2

Repl_backlog_histlen:112

2. Redis-slave01 status log

Docker exec-it redis-slave01 redis-cli-h 192.168.56.109-a JayRedisHaZi info replication

# Replication

Role:slave

Master_host:192.168.56.108

Master_port:6379

Master_link_status:up

Master_last_io_seconds_ago:8

Master_sync_in_progress:0

Slave_repl_offset:253

Slave_priority:100

Slave_read_only:1

Connected_slaves:0

Master_repl_offset:0

Repl_backlog_active:0

Repl_backlog_size:1048576

Repl_backlog_first_byte_offset:0

Repl_backlog_histlen:0

3. Redis-slave02 status log

Docker exec-it redis-slave02 redis-cli-h 192.168.56.110-a JayRedisHaZi info replication

# Replication

Role:slave

Master_host:192.168.56.108

Master_port:6379

Master_link_status:up

Master_last_io_seconds_ago:9

Master_sync_in_progress:0

Slave_repl_offset:281

Slave_priority:100

Slave_read_only:1

Connected_slaves:0

Master_repl_offset:0

Repl_backlog_active:0

Repl_backlog_size:1048576

Repl_backlog_first_byte_offset:0

Repl_backlog_histlen:0

6 Redis master-slave synchronization test 6.1 verifies master-slave data synchronization

1. The redis master master node inserts two values

2. Redis slave01 can view the data normally from node 1.

3. Redis slave01 can view the data normally from node 1.

6.2 verify that slave nodes are read-only and cannot write

Two slave of redis failed to validate write data from the node, indicating read-only mode.

7 Redis Master-Slave switch

Next, we do such a master-slave switching simulation test, stop the redis service of the redis master master node (192.168.56.108), and switch the redis slave from node 1 (192.168.56.109) to the redis master master node. Also switch the original master master node to slave slave node, and then verify the master-slave node.

7.1 Master-Slave switch

The following are the steps for master-slave switching and slave switching:

1. Simulated primary node outage (192.168.56.108 operation)

Docker stop redis-master

2. Switch slave Node 1 to master Master Node (192.168.56.109 operation)

Docker exec-it redis-slave01 redis-cli-h 192.168.56.109-a JayRedisHaZi CONFIG SET slave-read-only no

Docker exec-it redis-slave01 redis-cli-h 192.168.56.109-a JayRedisHaZi SLAVEOF NO ONE

3. Add slave Node 2 to the new master node (192.168.56.110 operation)

Docker exec-it redis-slave02 redis-cli-h 192.168.56.110-a JayRedisHaZi SLAVEOF 192.168.56.109 6379

4. Switch the original master master node to slave slave node (192.168.56.108 operation)

Docker exec-it redis redis-cli-h 192.168.56.108-a JayRedisHaZi CONFIG SET slave-read-only no

Docker exec-it redis redis-cli-h 192.168.56.108-a JayRedisHaZi SLAVEOF NO ONE

7.2 Master-Slave switch check

From the following status data, we can see that the redis container on host 192.168.56.109 has changed from the original slave node to master node, while the redis container on 192.168.56.108 on the host has changed from the original master to slave. The master-slave switch has occurred, and finally the switch is successful.

1. Host 192.168.56.109

[root@dcos-redis01 redis] # docker exec-it redis-slave01 redis-cli-h 192.168.56.109-a JayRedisHaZi info replication

# Replication

Role:master

Connected_slaves:2

Slave0:ip=192.168.56.110,port=6379,state=online,offset=1601,lag=1

Slave1:ip=192.168.56.108,port=6379,state=online,offset=1601,lag=1

Master_repl_offset:1601

Repl_backlog_active:1

Repl_backlog_size:1048576

Repl_backlog_first_byte_offset:2

Repl_backlog_histlen:1600

2. Host 192.168.56.108

[root@docker-build-env etc] # docker exec-it redis-master redis-cli-h 192.168.56.108-a JayRedisHaZi info replication

# Replication

Role:slave

Master_host:192.168.56.109

Master_port:6379

Master_link_status:up

Master_last_io_seconds_ago:0

Master_sync_in_progress:0

Slave_repl_offset:1713

Slave_priority:100

Slave_read_only:1

Connected_slaves:0

Master_repl_offset:0

Repl_backlog_active:0

Repl_backlog_size:1048576

Repl_backlog_first_byte_offset:0

Repl_backlog_histlen:0

3. Host 192.168.56.110

[root@dcos-redis02 redis] # docker exec-it redis-slave02 redis-cli-h 192.168.56.110-a JayRedisHaZi info replication

# Replication

Role:slave

Master_host:192.168.56.109

Master_port:6379

Master_link_status:up

Master_last_io_seconds_ago:6

Master_sync_in_progress:0

Slave_repl_offset:1755

Slave_priority:100

Slave_read_only:1

Connected_slaves:0

Master_repl_offset:0

Repl_backlog_active:0

Repl_backlog_size:1048576

Repl_backlog_first_byte_offset:0

Repl_backlog_histlen:0

7.3 verify master-slave data synchronization

1. Check that the two slave nodes 192.168.56.108 and 192.168.56.110 are in read-only mode.

2. Master node 192.168.56.109 writes data and synchronizes to two slave nodes normally.

This is the answer to the question about how to build a redis master-slave cluster based on docker. I hope the above content can be of some help to you. If you still have a lot of doubts to be solved, you can follow the industry information channel for more related knowledge.

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