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。
参考
http://blog.51cto.com/sgk2011/2108542
https://github.com/gjmzj/kubeasz/blob/master/docs/setup/02-install_etcd.md
https://blog.csdn.net/qq_33199919/article/details/80623055
https://skyao.gitbooks.io/learning-etcd3/content/