etcd 分布式集群搭建和使用

逃离我推掉我的手 2022-12-13 12:45 230阅读 0赞

### 目录 ###

*  1.多节点服务集群搭建
 *   *  启动节点1
     *  启动节点2
     *  启动节点3
 *  2.使用
 *   *  查看节点信息
     *  集群状态
     *  键值对 读写
     *  分布式锁
 *  3.参考

上篇文章[etcd 入门][etcd] 中已经介绍了etcd基本功能，单节点服务的安装和使用。

本文将介绍etcd 分布式多节点的安装、配置和使用。

由于资源限制，本文以单机多节点服务为例进行阐述。

在实际应用场景中，为了高可用和容灾，是需要多机器安装的。

# 1.多节点服务集群搭建 #

操作系统使用的 centos 6.8。

默认情况下，端口2379用于提供HTTP API服务，端口2380用于节点间通信。

在单机情况下，多节点服务需要使用不同端口。

三节点集群信息如下：

## 启动节点1 ##

定义启动脚本start\_etcd1.sh

TOKEN=token-01
    CLUSTER_STATE=new
    NAME_1=etcd-01
    NAME_2=etcd-02
    NAME_3=etcd-03
    HOST_1=127.0.0.1
    HOST_2=127.0.0.1
    HOST_3=127.0.0.1
    PORT_API_1=2379
    PORT_PEER_1=2380
    PORT_API_2=2479
    PORT_PEER_2=2480
    PORT_API_3=2579
    PORT_PEER_3=2580
    
    CLUSTER=${NAME_1}=http://${HOST_1}:${PORT_PEER_1},${NAME_2}=http://${HOST_2}:${PORT_PEER_2},${NAME_3}=http://${HOST_3}:${PORT_PEER_3}
    
    # For every machine
    THIS_NAME=${NAME_1}
    THIS_IP=${HOST_1}
    THIS_PORT_API=${PORT_API_1}
    THIS_PORT_PEER=${PORT_PEER_1}
    
    ./etcd --data-dir=data.${THIS_NAME} --name ${THIS_NAME} \
    	--initial-advertise-peer-urls http://${THIS_IP}:${THIS_PORT_PEER} --listen-peer-urls http://${THIS_IP}:${THIS_PORT_PEER} \
    	--advertise-client-urls http://${THIS_IP}:${THIS_PORT_API} --listen-client-urls http://${THIS_IP}:${THIS_PORT_API} \
    	--initial-cluster ${CLUSTER} \
    	--initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}

启动

bash start_etcd2.sh

## 启动节点2 ##

定义启动脚本start\_etcd2.sh,  
只需将启动脚本start\_etcd1.sh中的配置项修改：

THIS_NAME=${NAME_2}
    THIS_IP=${HOST_2}
    THIS_PORT_API=${PORT_API_2}
    THIS_PORT_PEER=${PORT_PEER_2}

启动

bash start_etcd2.sh

## 启动节点3 ##

定义启动脚本start\_etcd3.sh，  
只需将启动脚本start\_etcd1.sh中的配置项修改：

THIS_NAME=${NAME_3}
    THIS_IP=${HOST_3}
    THIS_PORT_API=${PORT_API_3}
    THIS_PORT_PEER=${PORT_PEER_3}

启动

bash start_etcd3.sh

# 2.使用 #

## 查看节点信息 ##

export ETCDCTL_API=3
    HOST_1=127.0.0.1
    HOST_2=127.0.0.1
    HOST_3=127.0.0.1
    PORT_API_1=2379
    PORT_API_2=2479
    PORT_API_3=2579
    
    
    ENDPOINTS=$HOST_1:${PORT_API_1},$HOST_2:${PORT_API_2},$HOST_3:${PORT_API_3}
    
    ./etcdctl --endpoints=$ENDPOINTS member list

$ ./etcdctl --endpoints=$ENDPOINTS member list
    264ae6bc59e99892, started, etcd-01, http://127.0.0.1:2380, http://127.0.0.1:2379, false
    dbafe5ad6b652eda, started, etcd-02, http://127.0.0.1:2480, http://127.0.0.1:2479, false
    f570ae41f524bdcb, started, etcd-03, http://127.0.0.1:2580, http://127.0.0.1:2579, false

或者

## 集群状态 ##

$ ./etcdctl --endpoints=$ENDPOINTS endpoint status
    127.0.0.1:2379, 264ae6bc59e99892, 3.4.13, 20 kB, false, false, 8, 10, 10, 
    127.0.0.1:2479, dbafe5ad6b652eda, 3.4.13, 33 kB, true, false, 8, 10, 10, 
    127.0.0.1:2579, f570ae41f524bdcb, 3.4.13, 20 kB, false, false, 8, 10, 10, 
    
    $ ./etcdctl --endpoints=$ENDPOINTS --write-out=table  endpoint status
    +----------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
    |    ENDPOINT    |        ID        | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS |
    +----------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
    | 127.0.0.1:2379 | 264ae6bc59e99892 |  3.4.13 |   20 kB |     false |      false |         8 |         10 |                 10 |        |
    | 127.0.0.1:2479 | dbafe5ad6b652eda |  3.4.13 |   33 kB |      true |      false |         8 |         10 |                 10 |        |
    | 127.0.0.1:2579 | f570ae41f524bdcb |  3.4.13 |   20 kB |     false |      false |         8 |         10 |                 10 |        |
    +----------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+

可以看到，127.0.0.1:2479 这个节点是leader。

查看节点健康状况

$ ./etcdctl --endpoints=$ENDPOINTS endpoint health
    127.0.0.1:2379 is healthy: successfully committed proposal: took = 5.843376ms
    127.0.0.1:2479 is healthy: successfully committed proposal: took = 4.92724ms
    127.0.0.1:2579 is healthy: successfully committed proposal: took = 7.661623ms
    
    $ ./etcdctl --endpoints=$ENDPOINTS --write-out=table  endpoint health
    +----------------+--------+------------+-------+
    |    ENDPOINT    | HEALTH |    TOOK    | ERROR |
    +----------------+--------+------------+-------+
    | 127.0.0.1:2379 |   true | 8.470348ms |       |
    | 127.0.0.1:2479 |   true | 4.540441ms |       |
    | 127.0.0.1:2579 |   true | 8.666543ms |       |
    +----------------+--------+------------+-------+

## 键值对 读写 ##

$ ./etcdctl --endpoints=$ENDPOINTS put foo "Hello World"
    OK
    $ ./etcdctl --endpoints=$ENDPOINTS get foo
    foo
    Hello World

## 分布式锁 ##

在终端1中获取锁

$  ./etcdctl --endpoints=$ENDPOINTS lock mutex1
    mutex1/3dcb7516bf48a904

在终端2中获取同一把锁，会被卡住

$  ./etcdctl --endpoints=$ENDPOINTS lock mutex1

此时，停止终端1的操作，释放锁，终端2才可以获取到锁:

$ ./etcdctl --endpoints=$ENDPOINTS lock mutex1
    mutex1/3dcb7516bf48a907

# 3.参考 #

[github etcd 官方文档][github etcd]

[etcd]: https://blog.csdn.net/lanyang123456/article/details/109005629
[github etcd]: https://github.com/etcd-io/etcd