ETCD 单机安装

由于测试的需要，有时需要搭建一个单机版的etcd 环境，为了方便以后搭建查看，现在对单机部署进行记录。

一、部署单机etcd

下载指定版本的etcd
下载地址

ftp://ftp.pbone.net/mirror/archive.fedoraproject.org/fedora/linux/updates/22/x86_64/e/etcd-2.2.5-1.fc22.x86_64.rpm

先判断是否已经安装了etcd，已经安装的话就需要先删除掉，注意权限问题

[vagrant@localhost wae]$ yum list installed | grep etcd
etcd.x86_64                      2.2.-.el7                  installed
[vagrant@localhost wae]$ yum remove etcd.x86_64
Loaded plugins: fastestmirror
You need to be root to perform this command.
[vagrant@localhost wae]$ sudo  yum remove etcd.x86_64
Loaded plugins: fastestmirror
Resolving Dependencies
--> Running transaction check
---> Package etcd.x86_64 :2.2.-.el7 will be erased
--> Finished Dependency Resolution
 
Dependencies Resolved
 
===================================================================================================
 Package            Arch                 Version                     Repository               Size
===================================================================================================
Removing:
 etcd               x86_64               2.2.-.el7                 installed                 M
 
Transaction Summary
===================================================================================================
Remove   Package
 
Installed size:  M
Is this ok [y/N]: y
Downloading packages:
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Erasing    : etcd-2.2.-.el7.x86_64                                                         /
warning: /etc/etcd/etcd.conf saved as /etc/etcd/etcd.conf.rpmsave
  Verifying  : etcd-2.2.-.el7.x86_64                                                         / 
 
Removed:
  etcd.x86_64 :2.2.-.el7                                                                        
 
Complete!

安装下载的rpm包

[vagrant@localhost etcd]$ sudo yum localinstall etcd-2.2.-.fc22.x86_64.rpm

验证安装成功

[vagrant@localhost etcd]$ etcdctl --version
etcdctl version 2.2.

创建一个服务描述文件，放入systemd的服务目录下，一般安装完成都会自动创建

[vagrant@localhost etcd]$ sudo vi /usr/lib/systemd/system/etcd.service
[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}\""
Restart=on-failure
LimitNOFILE=
 
[Install]
WantedBy=multi-user.target

修改etcd的配置
一般默认访问的地址是http://localhost:2379，这边我们可以自定义，因为是单机，我们就直接127.0.0.1，有想法的就端口修改下好了
```
[vagrant@localhost etcd]$ sudo vi /etc/etcd/etcd.conf
```
# [member]
ETCD_NAME=default
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
#ETCD_WAL_DIR=""
#ETCD_SNAPSHOT_COUNT="10000"
#ETCD_HEARTBEAT_INTERVAL="100"
#ETCD_ELECTION_TIMEOUT="1000"
#ETCD_LISTEN_PEER_URLS="http://localhost:2380"
ETCD_LISTEN_CLIENT_URLS="http://127.0.0.1:4001"
#ETCD_MAX_SNAPSHOTS="5"
#ETCD_MAX_WALS="5"
#ETCD_CORS=""
#
#[cluster]
#ETCD_INITIAL_ADVERTISE_PEER_URLS="http://localhost:2380"
# if you use different ETCD_NAME (e.g. test), set ETCD_INITIAL_CLUSTER value for this name, i.e. "test=http://..."
#ETCD_INITIAL_CLUSTER="default=http://localhost:2380"
#ETCD_INITIAL_CLUSTER_STATE="new"
#ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_ADVERTISE_CLIENT_URLS="http://127.0.0.1:4001"
#ETCD_DISCOVERY=""
#ETCD_DISCOVERY_SRV=""
#ETCD_DISCOVERY_FALLBACK="proxy"
#ETCD_DISCOVERY_PROXY=""
#
#[proxy]
#ETCD_PROXY="off"
#ETCD_PROXY_FAILURE_WAIT="5000"
#ETCD_PROXY_REFRESH_INTERVAL="30000"
#ETCD_PROXY_DIAL_TIMEOUT="1000"
#ETCD_PROXY_WRITE_TIMEOUT="5000"
#ETCD_PROXY_READ_TIMEOUT="0"
#
#[security]
#ETCD_CERT_FILE=""
#ETCD_KEY_FILE=""
#ETCD_CLIENT_CERT_AUTH="false"
#ETCD_TRUSTED_CA_FILE=""
#ETCD_PEER_CERT_FILE=""
#ETCD_PEER_KEY_FILE=""
#ETCD_PEER_CLIENT_CERT_AUTH="false"
#ETCD_PEER_TRUSTED_CA_FILE=""
#
#[logging]
#ETCD_DEBUG="false"
# examples for -log-package-levels etcdserver=WARNING,security=DEBUG
#ETCD_LOG_PACKAGE_LEVELS=""
如果想要局域网可以访问的话，则将 127.0.0.1 换成宿主机的 ip 即可了，最后外部用 ip 进行接口访问即可。

启动并测试ETCD
首先设置开机启动：systemctl enable etcd

[vagrant@localhost etcd]$ sudo systemctl daemon-reload
[vagrant@localhost etcd]$ sudo systemctl start etcd
[vagrant@localhost etcd]$ sudo  systemctl status etcd
● etcd.service - Etcd Server
   Loaded: loaded (/usr/lib/systemd/system/etcd.service; disabled; vendor preset: disabled)
   Active: active (running) since Fri -- :: UTC; 8s ago
 Main PID:  (etcd)
   Memory: 26.0M
   CGroup: /system.slice/etcd.service
           └─ /usr/bin/etcd --name=default --data-dir=/var/lib/etcd/default.etcd --listen-cl...
 
Mar  :: localhost.localdomain systemd[]: Starting Etcd Server...
Mar  :: localhost.localdomain systemd[]: Started Etcd Server.

查看集群健康状态

[vagrant@localhost etcd]$ sudo etcdctl cluster-health
member ce2a822cea30bfca is healthy: got healthy result from http://127.0.0.1:4001
cluster is healthy

ok，没有问题

卸载与删除etcd

[vagrant@localhost wae]$ yum list installed | grep etcd
etcd.x86_64                      2.2.-.el7                  installed
[vagrant@localhost wae]$ yum remove etcd.x86_64

二、接口测试

etcd的数据形式是以健对值方式存在的。

通过接口获取版本信息

[vagrant@localhost etcd]$ curl http://127.0.0.1:4001/version -XGET
{"etcdserver":"2.2.5","etcdcluster":"2.2.0"}

更新一个健对值信息，并通过 ke y获取到 value

[vagrant@localhost etcd]$ etcdctl set /tmp/message wozainali
wozainali
[vagrant@localhost etcd]$ etcdctl get /tmp/message
wozainali

设置的方式：etcdctl set key value
获取的方式：etcdctl get key

通过接口获取健对值信息

[vagrant@localhost etcd]$ curl http://127.0.0.1:4001/v2/keys/tmp/message -XGET
{"action":"get","node":{"key":"/tmp/message","value":"wozainali","modifiedIndex":,"createdIndex":}}

再看看详细的请求信息

[vagrant@localhost etcd]$ curl http://127.0.0.1:4001/v2/keys/tmp/message -XGET
{"action":"get","node":{"key":"/tmp/message","value":"wozainali","modifiedIndex":,"createdIndex":}}
[vagrant@localhost etcd]$ curl http://127.0.0.1:4001/v2/keys/tmp/message -XGET -vv
* About to connect() to 127.0.0.1 port  (#)
*   Trying 127.0.0.1...
* Connected to 127.0.0.1 (127.0.0.1) port  (#)
> GET /v2/keys/tmp/message HTTP/1.1
> User-Agent: curl/7.29.
> Host: 127.0.0.1:
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Type: application/json
< X-Etcd-Cluster-Id: 7e27652122e8b2ae
< X-Etcd-Index: 12
< X-Raft-Index: 37173
< X-Raft-Term: 3
< Date: Fri, 09 Mar 2018 09:16:15 GMT
< Content-Length: 104
<
{"action":"get","node":{"key":"/tmp/message","value":"wozainali","modifiedIndex":12,"createdIndex":12}}
* Connection #0 to host 127.0.0.1 left intact

通过接口更新一个健对值信息

[vagrant@localhost etcd]$ curl http://127.0.0.1:4001/v2/keys/tmp/message -XPUT -d value=nihaoha
{"action":"set","node":{"key":"/tmp/message","value":"nihaoha","modifiedIndex":,"createdIndex":},"prevNode":{"key":"/tmp/message","value":"wozainali","modifiedIndex":,"createdIndex":}}
[vagrant@localhost etcd]$ curl http://127.0.0.1:4001/v2/keys/tmp/message -XGET
{"action":"get","node":{"key":"/tmp/message","value":"nihaoha","modifiedIndex":,"createdIndex":}}

我们看到更新的时候，会有两条记录，一条是当前记录，一条是之前的记录，多次更新也只会保留最近的信息，获取的时候默认获取最新的信息

[vagrant@localhost etcd]$ curl http://127.0.0.1:4001/v2/keys/tmp/message -XPUT -d value=wowowow
{"action":"set","node":{"key":"/tmp/message","value":"wowowow","modifiedIndex":,"createdIndex":},"prevNode":{"key":"/tmp/message","value":"nihaoha","modifiedIndex":,"createdIndex":}}

具体复杂的操作需要去看官方文档，这边只做了解使用。https://coreos.com/etcd/docs/latest/v2/api.html

通过接口删除健对值信息

[vagrant@localhost etcd]$ curl http://127.0.0.1:4001/v2/keys/tmp/message -XDELETE
{"action":"delete","node":{"key":"/tmp/message","modifiedIndex":,"createdIndex":},"prevNode":{"key":"/tmp/message","value":"wowowow","modifiedIndex":,"createdIndex":}}
[vagrant@localhost etcd]$ curl http://127.0.0.1:4001/v2/keys/tmp/message -XGET
{"errorCode":,"message":"Key not found","cause":"/tmp/message","index":}

可以看到删除之后，重新去获取该 key 的值，提示Key not found，证明我们删除成功了。

以上就是，简单的指定etcd单机安装，以及api的几个简单应用。

三、问题

在修改访问ip问局域网ip之后发现，使用 etcdctl 进行操作的时候会出现如下错误

[vagrant@localhost etcd]$ etcdctl ls
Error:  dial tcp 127.0.0.1:: getsockopt: connection refused
[vagrant@localhost etcd]$
[vagrant@localhost etcd]$
[vagrant@localhost etcd]$ etcdctl cluster-health
cluster may be unhealthy: failed to list members
Error:  client: etcd cluster is unavailable or misconfigured
error #: dial tcp 127.0.0.1:: getsockopt: connection refused
error #: dial tcp 127.0.0.1:: getsockopt: connection refused

查询之后，发现应该是 ETCD_LISTEN_CLIENT_URLS 没有写入 http://127.0.0.1:4001 的原因，追加配置 http://127.0.0.1:4001，重新试一下

[vagrant@localhost etcd]$ etcdctl ls
/test
/test123
/tmp
/test1223
[vagrant@localhost etcd]$ etcdctl cluster-health
member ce2a822cea30bfca is healthy: got healthy result from http://192.168.10.50:4001
cluster is healthy
[vagrant@localhost etcd]$

现在就可以了。
注意，添加配置的时候，用英文的逗号隔开.