etcd 官方示例

作者: 鼠工 | 来源:发表于2019-07-31 10:49 被阅读0次

原文地址：https://etcd.io/docs/v3.3.12/demo/

启动集群(Set up a cluster)

在每个etcd节点上，指定集群成员:

TOKEN=token-01
CLUSTER_STATE=new
NAME_1=machine-1
NAME_2=machine-2
NAME_3=machine-3
HOST_1=10.240.0.17
HOST_2=10.240.0.18
HOST_3=10.240.0.19
CLUSTER=${NAME_1}=http://${HOST_1}:2380,${NAME_2}=http://${HOST_2}:2380,${NAME_3}=http://${HOST_3}:2380

在每个etcd节点上进行如下操作:

# 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}

# 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}

# 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}

或使用我们的公共发现服务:

curl https://discovery.etcd.io/new?size=3
https://discovery.etcd.io/a81b5818e67a6ea83e9d4daea5ecbc92

# grab this token
TOKEN=token-01
CLUSTER_STATE=new
NAME_1=machine-1
NAME_2=machine-2
NAME_3=machine-3
HOST_1=10.240.0.17
HOST_2=10.240.0.18
HOST_3=10.240.0.19
DISCOVERY=https://discovery.etcd.io/a81b5818e67a6ea83e9d4daea5ecbc92

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 \
    --discovery ${DISCOVERY} \
    --initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}

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 \
    --discovery ${DISCOVERY} \
    --initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}

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 \
    --discovery ${DISCOVERY} \
    --initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}

现在etcd准备好了！使用etcdctl连接到etcd：

export ETCDCTL_API=3
HOST_1=10.240.0.17
HOST_2=10.240.0.18
HOST_3=10.240.0.19
ENDPOINTS=$HOST_1:2379,$HOST_2:2379,$HOST_3:2379

etcdctl --endpoints=$ENDPOINTS member list

访问etcd(Access etcd)

put 写操作:

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

get 读操作:

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

前缀查找(Get by prefix)

etcdctl --endpoints=$ENDPOINTS put web1 value1
etcdctl --endpoints=$ENDPOINTS put web2 value2
etcdctl --endpoints=$ENDPOINTS put web3 value3

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

删除操作(Delete)

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

事务(Transactional write)

etcd中事务是原子执行的，只支持if … then … else …这种表达，类似三元表达式:

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

监听(Watch)

watch to get notified of future changes:

etcdctl --endpoints=$ENDPOINTS watch stock1
etcdctl --endpoints=$ENDPOINTS put stock1 1000

etcdctl --endpoints=$ENDPOINTS watch stock --prefix
etcdctl --endpoints=$ENDPOINTS put stock1 10
etcdctl --endpoints=$ENDPOINTS put stock2 20

租约(Lease)

lease to write with TTL:

etcdctl --endpoints=$ENDPOINTS lease grant 300
# lease 2be7547fbc6a5afa granted with TTL(300s)

etcdctl --endpoints=$ENDPOINTS put sample value --lease=2be7547fbc6a5afa
etcdctl --endpoints=$ENDPOINTS get sample

etcdctl --endpoints=$ENDPOINTS lease keep-alive 2be7547fbc6a5afa
etcdctl --endpoints=$ENDPOINTS lease revoke 2be7547fbc6a5afa
# or after 300 seconds
etcdctl --endpoints=$ENDPOINTS get sample

分布式锁(Distributed locks)

lock for distributed lock:

etcdctl --endpoints=$ENDPOINTS lock mutex1

# another client with the same name blocks
etcdctl --endpoints=$ENDPOINTS lock mutex1

选举(Elections)

elect for leader election:

etcdctl --endpoints=$ENDPOINTS elect one p1

# another client with the same name blocks
etcdctl --endpoints=$ENDPOINTS elect one p2

集群状态监控(Cluster status)

健康状态检查

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

+------------------+------------------+---------+---------+-----------+-----------+------------+
|     ENDPOINT     |        ID        | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
+------------------+------------------+---------+---------+-----------+-----------+------------+
| 10.240.0.17:2379 | 4917a7ab173fabe7 | 3.0.0   | 45 kB   | true      |         4 |      16726 |
| 10.240.0.18:2379 | 59796ba9cd1bcd72 | 3.0.0   | 45 kB   | false     |         4 |      16726 |
| 10.240.0.19:2379 | 94df724b66343e6c | 3.0.0   | 45 kB   | false     |         4 |      16726 |
+------------------+------------------+---------+---------+-----------+-----------+------------+

etcdctl --endpoints=$ENDPOINTS endpoint health

10.240.0.17:2379 is healthy: successfully committed proposal: took = 3.345431ms
10.240.0.19:2379 is healthy: successfully committed proposal: took = 3.767967ms
10.240.0.18:2379 is healthy: successfully committed proposal: took = 4.025451ms

快照(Snapshot)

snapshot 用于保存etcd数据库的快照:

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

Snapshot saved at my.db

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

+---------+----------+------------+------------+
|  HASH   | REVISION | TOTAL KEYS | TOTAL SIZE |
+---------+----------+------------+------------+
| c55e8b8 |        9 |         13 | 25 kB      |
+---------+----------+------------+------------+

(迁移)Migrate

migrate 用于将v2迁移到v3:

# write key in etcd version 2 store
export ETCDCTL_API=2
etcdctl --endpoints=http://$ENDPOINT set foo bar

# read key in etcd v2
etcdctl --endpoints=$ENDPOINTS --output="json" get foo

# stop etcd node to migrate, one by one

# migrate v2 data
export ETCDCTL_API=3
etcdctl --endpoints=$ENDPOINT migrate --data-dir="default.etcd" --wal-dir="default.etcd/member/wal"

# restart etcd node after migrate, one by one

# confirm that the key got migrated
etcdctl --endpoints=$ENDPOINTS get /foo

集群成员管理(Member)

member 用于添加，删除，更新成员:

# For each machine
TOKEN=my-etcd-token-1
CLUSTER_STATE=new
NAME_1=etcd-node-1
NAME_2=etcd-node-2
NAME_3=etcd-node-3
HOST_1=10.240.0.13
HOST_2=10.240.0.14
HOST_3=10.240.0.15
CLUSTER=${NAME_1}=http://${HOST_1}:2380,${NAME_2}=http://${HOST_2}:2380,${NAME_3}=http://${HOST_3}:2380

# For node 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}

# For node 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}

# For node 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}

然后使用命令 member remove 和 member add替换成员:

# get member ID
export ETCDCTL_API=3
HOST_1=10.240.0.13
HOST_2=10.240.0.14
HOST_3=10.240.0.15
etcdctl --endpoints=${HOST_1}:2379,${HOST_2}:2379,${HOST_3}:2379 member list

# remove the member
MEMBER_ID=278c654c9a6dfd3b
etcdctl --endpoints=${HOST_1}:2379,${HOST_2}:2379,${HOST_3}:2379 \
    member remove ${MEMBER_ID}

# add a new member (node 4)
export ETCDCTL_API=3
NAME_1=etcd-node-1
NAME_2=etcd-node-2
NAME_4=etcd-node-4
HOST_1=10.240.0.13
HOST_2=10.240.0.14
HOST_4=10.240.0.16 # new member
etcdctl --endpoints=${HOST_1}:2379,${HOST_2}:2379 \
    member add ${NAME_4} \
    --peer-urls=http://${HOST_4}:2380

接下来启动新成员，使用--initial-cluster-state标志:

# [WARNING] If the new member starts from the same disk space,
# make sure to remove the data directory of the old member
# [警告] 如果新成员和旧成员使用同一个磁盘空间，需要先清除旧成员的历史数据
#
# restart with 'existing' flag
TOKEN=my-etcd-token-1
CLUSTER_STATE=existing
NAME_1=etcd-node-1
NAME_2=etcd-node-2
NAME_4=etcd-node-4
HOST_1=10.240.0.13
HOST_2=10.240.0.14
HOST_4=10.240.0.16 # new member
CLUSTER=${NAME_1}=http://${HOST_1}:2380,${NAME_2}=http://${HOST_2}:2380,${NAME_4}=http://${HOST_4}:2380

THIS_NAME=${NAME_4}
THIS_IP=${HOST_4}
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}

权限(Auth)

auth,user,role for authentication:

export ETCDCTL_API=3
ENDPOINTS=localhost:2379

etcdctl --endpoints=${ENDPOINTS} role add root
etcdctl --endpoints=${ENDPOINTS} role grant-permission root readwrite foo
etcdctl --endpoints=${ENDPOINTS} role get root

etcdctl --endpoints=${ENDPOINTS} user add root
etcdctl --endpoints=${ENDPOINTS} user grant-role root root
etcdctl --endpoints=${ENDPOINTS} user get root

etcdctl --endpoints=${ENDPOINTS} auth enable
# now all client requests go through auth

etcdctl --endpoints=${ENDPOINTS} --user=root:123 put foo bar
etcdctl --endpoints=${ENDPOINTS} get foo
etcdctl --endpoints=${ENDPOINTS} --user=root:123 get foo
etcdctl --endpoints=${ENDPOINTS} --user=root:123 get foo1

etcd 官方示例

启动集群(Set up a cluster)

访问etcd(Access etcd)

前缀查找(Get by prefix)

删除操作(Delete)

事务(Transactional write)

监听(Watch)

租约(Lease)

分布式锁(Distributed locks)

选举(Elections)

集群状态监控(Cluster status)

快照(Snapshot)

(迁移)Migrate

集群成员管理(Member)

权限(Auth)

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