安装etcd集群

kuberntes 系统使用 etcd 存储所有数据，是最重要的组件之一，注意 etcd集群只能有奇数个节点(1,3,5…)，本文档使用3个节点做集群。

一、基础环境

软件包

etcd下载地址：https://github.com/coreos/etcd/releases

服务器

架构图

二、生成etcd证书与私钥

创建etcd配置文件

{    "CN": "etcd",    "hosts": [      "127.0.0.1",      "192.168.1.11",      "192.168.1.12",      "192.168.1.13",      "etcd1",      "etcd2",      "etcd3"    ],    "key": {      "algo": "rsa",      "size": 2048    },    "names": [      {        "C": "CN",        "ST": "BeiJing",        "L": "BeiJing",        "O": "Ctyun",        "OU": "ops"      }    ]  }

hosts：定授权使用该证书的 etcd 节点 IP(应包含集群内所有节点的IP与hostname)
C：国家
ST：省份
L：城市
O：公司
OU：部门

生成私钥、证书请求文件、证书

CA证书在前面的章节创建 Kubernetes证书相关(CFSSL)

cfssl gencert -ca=/opt/ssl/k8sca/ca.pem   -ca-key=/opt/ssl/k8sca/ca-key.pem   -config=/opt/ssl/k8sca/ca-config.json   -profile=kubernetes /opt/ssl/etcd/etcd-csr.json | cfssljson -bare etcd

-ca：指定CA证书路径
-ca-key：指定CAKey的路径
-config：指定CA证书签署策略配置文件

二、启动和配置etcd

创建etcd配置文件etcd.conf，此配置文件是定义一些变量，方便etcd.service文件中直接引用、方便后期维护。
配置文件的所有含义都在创建etcd.service配置文件后有详解。

mkdir -p /etc/etcd  vim /etc/etcd/etcd.conf  # [member]  ETCD_NAME=etcd1  ETCD_DATA_DIR="/var/lib/etcd"  ETCD_LISTEN_PEER_URLS="https://192.168.1.11:2380"   ETCD_LISTEN_CLIENT_URLS="https://192.168.1.11:2379" #[cluster]  ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.1.11:2380"  ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"  ETCD_ADVERTISE_CLIENT_URLS="https://192.168.1.11:2379"

创建etcd.service配置文件

etcd.service的变量都是引用etcd配置文件中

mkdir /var/lib/etcd  vim /usr/lib/systemd/system/etcd.service   [Unit]  Description=Etcd Server  After=network.target  After=network-online.target  Wants=network-online.target  Documentation=https://github.com/coreos    [Service]  Type=notify  WorkingDirectory=${ETCD_DATA_DIR}   EnvironmentFile=/etc/etcd/etcd.conf  ExecStart=/usr/local/bin/etcd     --name=etcd1     --cert-file=/opt/ssl/etcd/etcd.pem     --key-file=/opt/ssl/etcd/etcd-key.pem     --peer-cert-file=/opt/ssl/etcd/etcd.pem     --peer-key-file=/opt/ssl/etcd/etcd-key.pem     --trusted-ca-file=/opt/ssl/k8sca/ca.pem     --peer-trusted-ca-file=/opt/ssl/k8sca/ca.pem     --initial-advertise-peer-urls=${ETCD_INITIAL_ADVERTISE_PEER_URLS}     --listen-peer-urls=${ETCD_LISTEN_PEER_URLS}     --listen-client-urls=${ETCD_LISTEN_CLIENT_URLS},http://127.0.0.1:2379     --advertise-client-urls=${ETCD_ADVERTISE_CLIENT_URLS}     --initial-cluster-token=${ETCD_INITIAL_CLUSTER_TOKEN}     --initial-cluster etcd1=https://192.168.1.11:2380,etcd2=https://192.168.1.12:2380,etcd3=https://192.168.1.13:2380     --initial-cluster-state=new     --data-dir=/var/lib/etcd  Restart=on-failure  RestartSec=5  LimitNOFILE=65536    [Install]  WantedBy=multi-user.target

--initial-cluster：集群当中的其他节点
--cert-file：etcd证书路径
--key-file：etcd私钥路径
--peer-cert-file：对等证书(双向证书)路径
--peer-key-file：对等证书(双向证书)私钥路径
--trusted-ca-file：作为客户端时的CA证书路径
--peer-trusted-ca-file：对等证书的CA证书路径
--initial-advertise-peer-urls：列出集群成员通信的URL，用于通告集群其他成员
--listen-peer-urls：用于监听集群其他成员的URL列表
--listen-client-urls：用于监听客户端通讯的URL列表
--advertise-client-urls：通告客户端的URL，用于列出所有客户端
--initial-cluster-token：etcd集群的初始集群令牌，服务器必须通过令牌才能加入etcd集群

启动etcd集群

集群所有节点都配置好配置文件，同时启动。

systemctl daemon-reload && systemctl enable etcd && systemctl start etcd

不使用变量的配置方法

前面分别创建了/etc/etcd/etcd.conf与/var/lib/systemd/system/etcd.service两个配置文件，且etcd.service引用了etcd.conf重定义的变量。

如若不想引用变量，可以不写etcd.conf。仅创建etcd.service如下

[root@etcd1 k8sca]# cat /usr/lib/systemd/system/etcd.service  [Unit]  Description=Etcd Server  After=network.target  After=network-online.target  Wants=network-online.target  Documentation=https://github.com/coreos    [Service]  Type=notify  WorkingDirectory=/var/lib/etcd/  ExecStart=/usr/local/bin/etcd     --name etcd1     --cert-file=/opt/ssl/etcd/etcd.pem     --key-file=/opt/ssl/etcd/etcd-key.pem     --peer-cert-file=/opt/ssl/etcd/etcd.pem     --peer-key-file=/opt/ssl/etcd/etcd-key.pem     --trusted-ca-file=/opt/ssl/k8sca/ca.pem     --peer-trusted-ca-file=/opt/ssl/k8sca/ca.pem     --initial-advertise-peer-urls=https://192.168.1.11:2380     --listen-peer-urls=https://192.168.1.11:2380     --listen-client-urls=https://192.168.1.11:2379,http://127.0.0.1:2379     --advertise-client-urls=https://192.168.1.11:2379     --initial-cluster-token=etcd-cluster-0     --initial-cluster etcd1=https://192.168.1.11:2380,etcd2=https://192.168.1.12:2380,etcd3=https://192.168.1.13:2380     --initial-cluster-state=new     --data-dir=/var/lib/etcd  Restart=on-failure  RestartSec=5  LimitNOFILE=65536    [Install]  WantedBy=multi-user.target  

三、测试集群状态

集群中所有主机配置均一致，仅IP地址不同。

$ etcdctl --ca-file=/opt/ssl/k8sca/ca.pem --cert-file=/opt/ssl/etcd/etcd.pem --key-file=/opt/ssl/etcd/etcd-key.pem cluster-health  member aa869cb0f2e7ed31 is healthy: got healthy result from https://192.168.1.11:2379  member b08a644fd7247c5e is healthy: got healthy result from https://192.168.1.13:2379  member bb9bd2baaebf7d95 is healthy: got healthy result from https://192.168.1.12:2379 

常见问题

• publish error: etcdserver: request timed out
  我部署时先使用一台进行测试，无论如何启动etcd都无法启动，提示publish error: etcdserver: request timed out。后来发现etcd.service中制定了其他etcd主机，所以当单独启动一台是连接其他主机不通，那么etcd就启动失败。所以要把etcd集群中所有主机都配置好，同时启动就OK了。