etcd安装和简单使用

etcd作为一个高可用强一致性的服务发现存储仓库，在Kubernetes等开源项目中用的很多，这里简单记录下安装和常用命令以及api

安装

安装包可以从 https://github.com/etcd-io/etcd/releases 选择对应的版本和架构，下载后解压即可，里面有安装包和相关文档，安装和使用其实都可以看这些文档。

为了方便管理弄成了服务，加了一个etcd.service文件

[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target

[Service]
Type=notify
WorkingDirectory=/var/lib/etcd/
EnvironmentFile=-/etc/etcd/etcd.conf
User=etcd

# set GOMAXPROCS to number of processors
ExecStart=/bin/bash -c "GOMAXPROCS=$(nproc) /usr/bin/etcd --name=\"${ETCD_NAME}\" --data-dir=\"${ETCD_DATA_DIR}\" --listen-client-urls=\"${ETCD_LISTEN_CLIENT_URLS}\" --listen-peer-urls=\"${ETCD_LISTEN_PEER_URLS}\" --advertise-client-urls=\"${ETCD_ADVERTISE_CLIENT_URLS}\" --initial-advertise-peer-urls=\"${ETCD_INITIAL_ADVERTISE_PEER_URLS}\" --initial-cluster=\"${ETCD_INITIAL_CLUSTER}\" --initial-cluster-state=\"${ETCD_INITIAL_CLUSTER_STATE}\""
Restart=on-failure
LimitNOFILE=

[Install]
WantedBy=multi-user.target

etcd.conf配置文件类似下面这样，每个节点只要修改name和ip就可以，其他的不用动，ETCD_INITIAL_CLUSTER_TOKEN同一各集群值一样，不同集群不能重复。

## 配置文件每个节点只要修改name和ip地址即可
#[Member]
ETCD_NAME=node1
ETCD_DATA_DIR=/var/lib/etcd/data
ETCD_LISTEN_PEER_URLS=http://0.0.0.0:2380
ETCD_LISTEN_CLIENT_URLS=http://0.0.0.0:2379

#[cluster]
ETCD_INITIAL_ADVERTISE_PEER_URLS=http://192.168.19.136:2380
ETCD_ADVERTISE_CLIENT_URLS=http://192.168.19.136:2379
ETCD_INITIAL_CLUSTER=node1=http://192.168.19.136:2380,node2=http://192.168.19.137:2380,node3=http://192.168.19.138:2380
ETCD_INITIAL_CLUSTER_STATE=new
#创建集群的 token，这个值每个集群保持唯一
ETCD_INITIAL_CLUSTER_TOKEN=etcd-1

安装方式都差不多，放个例子，都差不多，配置文件那部分自己根据实际情况处理就行了。

## 创建用户和用户组
groupadd etcd;
useradd -c "Etcd user" -g etcd -s /sbin/nologin -r etcd;
service firewalld stop;

## 创建安装文件夹
mkdir -p /usr/bin/etcd3.3.13/;
mkdir -p /etc/etcd/;
mkdir -p /var/lib/etcd/data;

## 将文件etcd.service、etcd、etcdctl、etcd.conf上传到/usr/bin/etcd3.3.13/
chmod +x /usr/bin/etcd3.3.13/*;

mv /usr/bin/etcd3.3.13/etcd.service /usr/lib/systemd/system/;
mv /usr/bin/etcd3.3.13/etcd /usr/bin/;
mv /usr/bin/etcd3.3.13/etcdctl /usr/bin/;

## 每个节点配置文件ip地址不一样
mv /usr/bin/etcd3.3.13/etcd1.conf /etc/etcd/etcd.conf;
mv /usr/bin/etcd3.3.13/etcd2.conf /etc/etcd/etcd.conf;
mv /usr/bin/etcd3.3.13/etcd3.conf /etc/etcd/etcd.conf;

echo 'export ETCDCTL_API=3' >> /etc/profile
source /etc/profile

chown etcd:etcd -R /var/lib/etcd/data /etc/etcd*;
systemctl enable etcd.service;
systemctl start etcd.service;

后台命令

etcd命令可以通过etcdctl来执行，具体命令可以查看官方文档，或者 etcdctl -h 来查看。

[root@nmgecqud-etcd-pufthgqf ~]# etcdctl -h
NAME:
    etcdctl - A simple command line client for etcd3.

USAGE:
    etcdctl

VERSION:
    3.3.

API VERSION:
    3.3

COMMANDS:
    get            Gets the key or a range of keys
    put            Puts the given key into the store
    del            Removes the specified key or range of keys [key, range_end)
    txn            Txn processes all the requests in one transaction
    compaction        Compacts the event history in etcd
    alarm disarm        Disarms all alarms
    alarm list        Lists all alarms
    defrag            Defragments the storage of the etcd members with given endpoints
    endpoint health        Checks the healthiness of endpoints specified in `--endpoints` flag
    endpoint status        Prints out the status of endpoints specified in `--endpoints` flag
    endpoint hashkv        Prints the KV history hash for each endpoint in --endpoints
    move-leader        Transfers leadership to another etcd cluster member.
    watch            Watches events stream on keys or prefixes
    version            Prints the version of etcdctl
    lease grant        Creates leases
    lease revoke        Revokes leases
    lease timetolive    Get lease information
    lease list        List all active leases
    lease keep-alive    Keeps leases alive (renew)
    member add        Adds a member into the cluster
    member remove        Removes a member from the cluster
    member update        Updates a member in the cluster
    member list        Lists all members in the cluster
    snapshot save        Stores an etcd node backend snapshot to a given file
    snapshot restore    Restores an etcd member snapshot to an etcd directory
    snapshot status        Gets backend snapshot status of a given file
    make-mirror        Makes a mirror at the destination etcd cluster
    migrate            Migrates keys in a v2 store to a mvcc store
    lock            Acquires a named lock
    elect            Observes and participates in leader election
    auth enable        Enables authentication
    auth disable        Disables authentication
    user add        Adds a new user
    user delete        Deletes a user
    user get        Gets detailed information of a user
    user list        Lists all users
    user passwd        Changes password of user
    user grant-role        Grants a role to a user
    user revoke-role    Revokes a role from a user
    role add        Adds a new role
    role delete        Deletes a role
    role get        Gets detailed information of a role
    role list        Lists all roles
    role grant-permission    Grants a key to a role
    role revoke-permission    Revokes a key from a role
    check perf        Check the performance of the etcd cluster
    help            Help about any command

OPTIONS:
      --cacert=""                verify certificates of TLS-enabled secure servers using this CA bundle
      --cert=""                    identify secure client using this TLS certificate file
      --command-timeout=5s            timeout for short running command (excluding dial timeout)
      --debug[=false]                enable client-side debug logging
      --dial-timeout=2s                dial timeout for client connections
  -d, --discovery-srv=""            domain name to query for SRV records describing cluster endpoints
      --endpoints=[127.0.0.1:]        gRPC endpoints
      --hex[=false]                print byte strings as hex encoded strings
      --insecure-discovery[=true]        accept insecure SRV records describing cluster endpoints
      --insecure-skip-tls-verify[=false]    skip server certificate verification
      --insecure-transport[=true]        disable transport security for client connections
      --keepalive-time=2s            keepalive time for client connections
      --keepalive-timeout=6s            keepalive timeout for client connections
      --key=""                    identify secure client using this TLS key file
      --user=""                    username[:password] for authentication (prompt if password is not supplied)
  -w, --write-out="simple"            set the output format (fields, json, protobuf, simple, table)

上面讲全部命令列出来了，下面简单列几个测试集群是否可用的命令

查看版本

[root@nmgecqud-etcd-pufthgqf ~]# etcdctl version
etcdctl version: 3.3.
API version: 3.3

查看集群状态和节点

[root@nmgecqud-etcd-pufthgqf ~]# etcdctl member list
1804fe6aa6e0806f, started, nmgecqud-etcd-iqqn6mxj, http://10.110.30.213:2380, http://10.110.30.213:2379
5dfebcf67955db33, started, nmgecqud-etcd-u1qyxszm, http://10.110.30.210:2380, http://10.110.30.210:2379
745835aca4e59e07, started, nmgecqud-etcd-pufthgqf, http://10.110.30.212:2380, http://10.110.30.212:2379

插入一条数据

[root@nmgecqud-etcd-pufthgqf ~]# etcdctl put foo bar
  OK

根据key查询数据

[root@nmgecqud-etcd-pufthgqf ~]# etcdctl get foo
  foo
  bar

删除一条数据

[root@nmgecqud-etcd-pufthgqf ~]# etcdctl del foo1
  1

查询全部的key

[root@wwjaen60-etcd-sefgxiui opt]# etcdctl --prefix --keys-only=true get ""
/test/zyh

/zyh/fooa

foo

fooa

也支持通过restAPI来操作，可以测试从集群外访问是否正常，例如下面几个

查看版本get：http://10.110.30.183:2379/version
插入一个键值对put: http://10.110.30.183:2379/v2/keys/foo?value=bar
查询一个键get: http://10.110.30.179:2379/v2/keys/foo
查看集群的状态get：http://10.110.30.183:2379/v2/stats/store

查看全部键值get：http://10.110.30.183:2379/v2/keys