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部署、配置和维护 etcd 集群的操作指南

1 - 如何搭建演示集群

etcd 集群部署指南
01_etcd_clustering_2016050601

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

在每台机器上运行以下命令：

# 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}

或使用我们的公开发现服务：

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 已准备就绪！使用 etcdctl 连接 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

2 - 如何在 etcd 集群中进行领导者选举

通过 etcdctl 客户端开展领导者选举的步骤

先决条件

  • 确保已安装 etcd 和 etcdctl 。
  • 检查 etcd 集群是否处于活跃状态。

进行领导者选举

etcdctl 命令用于在 etcd 集群中执行选举操作。该命令确保同一时间仅有一个客户端可成为领导者。

etcdctl --endpoints=$ENDPOINTS elect <election-name> [proposal]

etcdctl --endpoints=$ENDPOINTS elect election-name p1

选项

  • --endpoints : $ENDPOINTS

每个 etcd 集群成员的地址。

  • election-name 字符串

用于选举的字符串标识符。所有竞争领导权的参与者必须使用相同的选举名称。

  • leader-name 字符串

新领导者的提案值。

示例 

./etcdctl elect my-election proposal1
my-election/694d99fafea88404
proposal1

another election:
./etcdctl elect new-election proposal1
new-election/694d99fafea8840f
proposal1

3 - 如何检查集群状态

etcd 集群状态检查指南

先决条件

检查整体状态

使用 endpoint status 检查 --endpoints 标志中指定的每个端点的总体状态：

etcdctl endpoint status (--endpoints=$ENDPOINTS|--cluster)

选项 

--cluster[=false]: use all endpoints from the cluster member list

检查健康状况

使用 endpoint health 检查 --endpoints 标志中指定的每个端点的健康状态：

etcdctl endpoint health (--endpoints=$ENDPOINTS|--cluster)

选项 

--cluster[=false]: use all endpoints from the cluster member list

检查键值哈希

使用 endpoint hashkv 检查 --endpoints 标志中指定的每个端点的 KV 历史哈希值：

etcdctl endpoint hashkv (--endpoints=$ENDPOINTS|--cluster) [rev=$REV]

选项 

--cluster[=false]: use all endpoints from the cluster member list
--rev=0: maximum revision to hash (default: latest revision)

继承自父命令的选项 

--endpoints="127.0.0.1:2379": gRPC endpoints
-w, --write-out="simple": set the output format (fields, json, protobuf, simple, table)

示例 

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

+------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
|    ENDPOINT      |        ID        | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS |
+------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
| 10.240.0.17:2379 | 4917a7ab173fabe7 |  3.5.0  |   45 kB |      true |      false |         4 |      16726 |              16726 |        |
| 10.240.0.18:2379 | 59796ba9cd1bcd72 |  3.5.0  |   45 kB |     false |      false |         4 |      16726 |              16726 |        |
| 10.240.0.19:2379 | 94df724b66343e6c |  3.5.0  |   45 kB |     false |      false |         4 |      16726 |              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
etcdctl --cluster endpoint hashkv  --write-out=table

+------------------+------------+---------------+
|     ENDPOINT     |    HASH    | HASH REVISION |
+------------------+------------+---------------+
| 10.240.0.17:2379 | 3892279174 |             3 |
| 10.240.0.18:2379 | 3892279174 |             3 |
| 10.240.0.19:2379 | 3892279174 |             3 |
+------------------+------------+---------------+

4 - 如何保存数据库

etcd 数据库快照的使用指南

先决条件

快照数据库

snapshot 用于保存 etcd 数据库的指定时间点快照：

etcdctl --endpoints=$ENDPOINT snapshot save DB_NAME

全局选项

etcdctl 

--endpoints=[127.0.0.1:2379], gRPC endpoints

快照只能从一个 etcd 节点请求，因此 --endpoints 标志中应仅包含一个端点。

etcd 工具 

-w, --write-out string   set the output format (fields, json, protobuf, simple, table) (default "simple")

示例

11_etcdctl_snapshot_2016051001
ENDPOINTS=$HOST_1:2379
etcdctl --endpoints=$ENDPOINTS snapshot save my.db

Snapshot saved at my.db
etcdutl --write-out=table snapshot status my.db

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

5 - 如何添加和删除成员

etcd 集群成员管理指南

member 用于添加、删除或更新成员关系：

13_etcdctl_member_2016062301
# 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 member remove 和 member add 命令替换成员：

# 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，使用 --initial-cluster-state existing 标志启动新成员：

# [WARNING] If the new member starts from the same disk space,
# make sure to remove the data directory of the old member
#
# 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}