# Redis

### 环境

Ubuntu 18.04



### 安装redis

```shell
apt-get install redis-server
```

### 修改密码

```shell
vi /etc/redis/redis.conf
# requirepass 你的密码
```

### 限制外网访问

```shell
vi /etc/redis/redis.conf
# bind 127.0.0.1 ::1
```

### 卸载

```shell
apt-get purge --auto-remove redis-server
```

### 修改dump.rdb文件存储路径

```properties
# 修改 /etc/redis/redis.conf
dir /data/bin/redis/data
# 修改 /etc/systemd/system/redis.service，添加以下文本
ReadWriteDirectories=-/data/bin/redis/data

```

###### 注：之前只修改了 `/etc/redis/redis.conf` 下的配置，而没有修改 `/etc/systemd/system/redis.service` ，所以一直报如下错误

```properties
2397:M 17 Sep 17:06:13.910 # Failed opening the RDB file dump.rdb (in server root dir /data/bin/redis/data) for saving: Read-only file system
```

# redis集群

1. ### 源码安装，版本redis-4.0.14

   ```shell
   wget http://download.redis.io/releases/redis-4.0.14.tar.gz
   tar xzf redis-4.0.14.tar.gz
   cd redis-4.0.14
   make
   ```

2. ### 服务启动

   ```shell
   cd redis-4.0.14
   # 启动服务端
   src/redis-server
   # 启动客户端
   src/redis-cli
   # 优雅关闭服务
   src/redis-cli shutdown save
   ```

3. ### 集群部署

   ```shell
   # 节点服务启动
   /data/bin/redis/redis/src/redis-server /data/bin/redis/cluster/conf/9901/redis.conf
   /data/bin/redis/redis/src/redis-server /data/bin/redis/cluster/conf/9902/redis.conf
   /data/bin/redis/redis/src/redis-server /data/bin/redis/cluster/conf/9903/redis.conf
   /data/bin/redis/redis/src/redis-server /data/bin/redis/cluster/conf/9904/redis.conf
   /data/bin/redis/redis/src/redis-server /data/bin/redis/cluster/conf/9905/redis.conf
   /data/bin/redis/redis/src/redis-server /data/bin/redis/cluster/conf/9906/redis.conf
   # 集群启动
   /data/bin/redis/redis/src/redis-trib.rb create --replicas 1 172.16.0.32:9901 172.16.0.32:9902 172.16.0.32:9903 172.16.0.32:9904 172.16.0.32:9905 172.16.0.32:9906
   # 连接client
   /data/bin/redis/redis/src/redis-cli -c -h 172.16.0.32 -p 9901 -a wisdomCity@redis2019
   # 优雅关闭节点服务
   /data/bin/redis/redis/src/redis-cli -c -h 172.16.0.32 -p 9901 -a wisdomCity@redis2019 shutdown
   /data/bin/redis/redis/src/redis-cli -c -h 172.16.0.32 -p 9902 -a wisdomCity@redis2019 shutdown
   /data/bin/redis/redis/src/redis-cli -c -h 172.16.0.32 -p 9903 -a wisdomCity@redis2019 shutdown
   /data/bin/redis/redis/src/redis-cli -c -h 172.16.0.32 -p 9904 -a wisdomCity@redis2019 shutdown
   /data/bin/redis/redis/src/redis-cli -c -h 172.16.0.32 -p 9905 -a wisdomCity@redis2019 shutdown
   /data/bin/redis/redis/src/redis-cli -c -h 172.16.0.32 -p 9906 -a wisdomCity@redis2019 shutdown
   # 查看redis节点信息
   ps -ef | grep redis
   # 带密码集群，修改以下文件，不知道路径的话可以执行查找命令 find / -name 'client.rb'
   # 修改 password 对应的值
   vi /var/lib/gems/2.5.0/gems/redis-4.1.3/lib/redis/client.rb
   
   
   ```

   

4. ### 集群进入fail状态的必要条件

   1. 某个主节点和所有从节点全部挂掉，我们集群就进入faill状态
   2. 如果集群超过半数以上master挂掉，无论是否有slave，集群进入fail状态
   3. 如果集群任意master挂掉,且当前master没有slave，集群进入fail状态

5. 异常处理

   ```
   # 登陆
   /data/bin/redis/redis/src/redis-cli -c -p 9902
   # set时候出现以下错误
   (error) CLUSTERDOWN The cluster is down
   # 检查命令
   /data/bin/redis/redis/src/redis-trib.rb check 127.0.0.1:9902
   # 发现一下错误
   [ERR] Not all 16384 slots are covered by nodes.
   # 执行一下修复命令（实战没用）
   /data/bin/redis/redis/src/redis-trib.rb fix 127.0.0.1:9902
   ```