etcd如何使用？

2023-10-21 18:02:16

在每一个etcd节点指定集群成员

TOKEN=token-01

CLUSTER_STATE=new

NAME_1=master

NAME_2=node1

NAME_3=node2

HOST_1=9.30.215.42

HOST_2=9.30.250.239

HOST_3=9.30.188.77

CLUSTER=${NAME_1}=http://${HOST_1}:2380,${NAME_2}=http://${HOST_2}:2380,${NAME_3}=http://${HOST_3}:2380

机器1上执行



# For machine 1

THIS_NAME=${NAME_1}

THIS_IP=${HOST_1}

etcd --data-dir=data.etcd --name ${THIS_NAME} \

--initial-advertise-peer-urls http://${THIS_IP}:2380 --listen-peer-urls http://${THIS_IP}:2380 \

--advertise-client-urls http://${THIS_IP}:2379 --listen-client-urls http://${THIS_IP}:2379 \

--initial-cluster ${CLUSTER} \

--initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}

机器2上执行：



# For machine 2

THIS_NAME=${NAME_2}

THIS_IP=${HOST_2}

etcd --data-dir=data.etcd --name ${THIS_NAME} \

--initial-advertise-peer-urls http://${THIS_IP}:2380 --listen-peer-urls http://${THIS_IP}:2380 \

--advertise-client-urls http://${THIS_IP}:2379 --listen-client-urls http://${THIS_IP}:2379 \

--initial-cluster ${CLUSTER} \

--initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}

机器3上执行



# For machine 3

THIS_NAME=${NAME_3}

THIS_IP=${HOST_3}

etcd --data-dir=data.etcd --name ${THIS_NAME} \

--initial-advertise-peer-urls http://${THIS_IP}:2380 --listen-peer-urls http://${THIS_IP}:2380 \

--advertise-client-urls http://${THIS_IP}:2379 --listen-client-urls http://${THIS_IP}:2379 \

--initial-cluster ${CLUSTER} \

--initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}

使用etcdctl连接etcd



export ETCDCTL_API=3

HOST_1=9.30.215.42

HOST_2=9.30.250.239

HOST_3=9.30.188.77

ENDPOINTS=$HOST_1:2379,$HOST_2:2379,$HOST_3:2379


etcdctl --endpoints=$ENDPOINTS member list

从etcd集群中插入和获取值

etcdctl --endpoints=$ENDPOINTS put foo "Hello World!"

etcdctl --endpoints=$ENDPOINTS get foo

etcdctl --endpoints=$ENDPOINTS --write-out="json" get foo

通过前缀获取相应的Keys

etcdctl --endpoints=$ENDPOINTS put demoZh value1

etcdctl --endpoints=$ENDPOINTS put demoYu value2

etcdctl --endpoints=$ENDPOINTS put demoLong value3


etcdctl --endpoints=$ENDPOINTS get demo --prefix

删除key

etcdctl --endpoints=$ENDPOINTS put key myvalue

etcdctl --endpoints=$ENDPOINTS del key


etcdctl --endpoints=$ENDPOINTS put k1 value1

etcdctl --endpoints=$ENDPOINTS put k2 value2

etcdctl --endpoints=$ENDPOINTS del k --prefix

如何在一笔交易中进行多次写入

etcdctl --endpoints=$ENDPOINTS put user1 bad

etcdctl --endpoints=$ENDPOINTS txn --interactive


compares:

value("user1") = "bad"


success requests (get, put, delete):

del user1


failure requests (get, put, delete):

put user1 good

如何监视keys

一个terminal运行：

etcdctl --endpoints=$ENDPOINTS watch stock --prefix

再打开一个terminal运行：



etcdctl --endpoints=$ENDPOINTS put stock1 10

etcdctl --endpoints=$ENDPOINTS put stock2 20

如果出现以下错误：



Error: etcdclient: no available endpoints

需要在当前terminal执行：



export ETCDCTL_API=3

HOST_1=9.30.215.42

HOST_2=9.30.250.239

HOST_3=9.30.188.77

ENDPOINTS=$HOST_1:2379,$HOST_2:2379,$HOST_3:2379


etcdctl --endpoints=$ENDPOINTS member list

创建lease

Lease service 提供租约的支持。Lease 是一种检测客户端存活状况的机制。群集授予具有生存时间的租约。如果 etcd 群集在给定的 TTL 时间内未收到 keepAlive，则租约到期。

为了将租约绑定到键值存储中，每个 key 最多可以附加一个租约。当租约到期或被撤销时，该租约所附的所有 key 都将被删除。每个过期的密钥都会在事件历史记录中生成一个删除事件。



[root@Master ~]# etcdctl --endpoints=$ENDPOINTS lease grant 300

lease 520f7d9295bac906 granted with TTL(300s)



etcdctl --endpoints=$ENDPOINTS put sample value --lease=520f7d9295bac906

etcdctl --endpoints=$ENDPOINTS get sample

etcdctl --endpoints=$ENDPOINTS lease keep-alive 520f7d9295bac906

创建分布式锁

其中一个terminal1输入：

etcdctl --endpoints=$ENDPOINTS lock mutex1

在另一个terminal2输入：

etcdctl --endpoints=$ENDPOINTS lock mutex1

此时可以看到该锁mutex1被另外一个程序占用，stop掉terminal1，则termminal2创建成功

如何在etcd集群中进行leader选举



etcdctl --endpoints=$ENDPOINTS elect one p1


# another client with the same name blocks

etcdctl --endpoints=$ENDPOINTS elect one p2

检查集群状态

etcdctl --write-out=table --endpoints=$ENDPOINTS endpoint status

etcdctl --endpoints=$ENDPOINTS endpoint health

如何保存数据库

获取 etcd 数据库快照

snapshot 保存 etcd 数据库的时间点快照

快照只能从一个 etcd 节点请求，因此 --endpoints 标志应该只包含一个端点。

ENDPOINTS=$HOST_1:2379

etcdctl --endpoints=$ENDPOINTS snapshot save my.db

etcdctl --write-out=table --endpoints=$ENDPOINTS snapshot status my.db

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