etcd 3.1 高可用集群搭建

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环境信息

CentOS 7.3

168.61.11 node1
168.61.12 node2
168.61.13 node3

TLS密钥和证书

这里部署的etcd集群使用TLS证书对证书通信进行加密，并开启基于CA根证书签名的双向数字证书认证。

下面介绍使用cfssl生成所需要的私钥和证书.

安装cfssl

cfssl是使用Go语言开发的工具，如果系统中安装了Go，可以使用直接go get安装cfssl:

go get -u github.com/cloudflare/cfssl/cmd/...

会在$GOPATH/bin下安装cfssl, cfssjosn, mkbundle等工具。

CA证书和私钥

创建ca-config.json：

{
  "signing": {
    "default": {
      "expiry": "87600h"
    },
    "profiles": {
      "frognew": {
        "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ],
        "expiry": "87600h"
      }
    }
  }
}

ca-config.json中可以定义多个profile，分别设置不同的expiry和usages等参数。如上面的ca-config.json中定义了名称为frognew的profile，这个profile的expiry 87600h为10年，useages中：

signing表示此CA证书可以用于签名其他证书，ca.pem中的CA=TRUE
server auth表示TLS Server Authentication
client auth表示TLS Client Authentication

创建CA证书签名请求配置ca-csr.json：

{
  "CN": "frognew",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "frognew",
      "OU": "cloudnative"
    }
  ]
}

下面使用cfss生成CA证书和私钥：

cfssl gencert -initca ca-csr.json | cfssljson -bare ca

ls
ca-config.json  ca.csr  ca-csr.json  ca-key.pem  ca.pem

ca-key.pem和ca.pem需要保存在一个安全的地方，后边会用到。

etcd证书和私钥

创建etcd证书签名请求配置etcd-csr.json：

{
    "CN": "frognew",
    "hosts": [
      "127.0.0.1",
      "192.168.61.11",
      "192.168.61.12",
      "192.168.61.13",
      "node1",
      "node2",
      "node3"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "ST": "BeiJing",
            "L": "BeiJing",
            "O": "frognew",
            "OU": "cloudnative"
        }
    ]
}

注意上面配置hosts字段中制定授权使用该证书的IP和域名列表，因为现在要生成的证书需要被etcd集群各个节点使用，所以这里指定了各个节点的IP和hostname。

下面生成etcd的证书和私钥：

cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=frognew etcd-csr.json | cfssljson -bare etcd

ls etcd*
etcd.csr  etcd-csr.json  etcd-key.pem  etcd.pem

对生成的证书可以使用cfssl或openssl查看：

cfssl-certinfo -cert etcd.pem

openssl x509  -noout -text -in  etcd.pem

安装etcd

将CA证书ca.pem, etcd秘钥etcd-key.pem, etcd证书etcd.pem拷贝到各节点的/etc/etcd/ssl目录中。

下载etcd二进制文件包：

wget https://github.com/coreos/etcd/releases/download/v3.1.6/etcd-v3.1.6-linux-amd64.tar.gz

解压缩etcd-v3.1.6-linux-amd64.tar.gz，将其中的etcd和etcdctl两个可执行文件复制到各节点的/usr/bin目录。

在各节点创建etcd的数据目录：

mkdir -p /var/lib/etcd

在每个节点上创建etcd的systemd unit文件/usr/lib/systemd/system/etcd.service，注意替换ETCD_NAME和INTERNAL_IP变量的值：

export ETCD_NAME=node1
export INTERNAL_IP=192.168.61.11
cat > /usr/lib/systemd/system/etcd.service <<EOF
[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
ExecStart=/usr/bin/etcd \
  --name ${ETCD_NAME} \
  --cert-file=/etc/etcd/ssl/etcd.pem \
  --key-file=/etc/etcd/ssl/etcd-key.pem \
  --peer-cert-file=/etc/etcd/ssl/etcd.pem \
  --peer-key-file=/etc/etcd/ssl/etcd-key.pem \
  --trusted-ca-file=/etc/etcd/ssl/ca.pem \
  --peer-trusted-ca-file=/etc/etcd/ssl/ca.pem \
  --initial-advertise-peer-urls https://${INTERNAL_IP}:2380 \
  --listen-peer-urls https://${INTERNAL_IP}:2380 \
  --listen-client-urls https://${INTERNAL_IP}:2379,https://127.0.0.1:2379 \
  --advertise-client-urls https://${INTERNAL_IP}:2379 \
  --initial-cluster-token etcd-cluster-1 \
  --initial-cluster node1=https://192.168.61.11:2380,node2=https://192.168.61.12:2380,node3=https://192.168.61.13:2380 \
  --initial-cluster-state new \
  --data-dir=/var/lib/etcd
Restart=on-failure
RestartSec=5
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

上面在启动参数中指定了etcd的工作目录和数据目录是/var/lib/etcd
--cert-file和--key-file分别指定etcd的公钥证书和私钥
--peer-cert-file和--peer-key-file分别指定了etcd的Peers通信的公钥证书和私钥。
--trusted-ca-file指定了客户端的CA证书
--peer-trusted-ca-file指定了Peers的CA证书
--initial-cluster-state new表示这是新初始化集群，--name指定的参数值必须在--initial-cluster中

启动etcd

在各节点上启动etcd：

systemctl daemon-reload
systemctl enable etcd
systemctl start etcd
systemctl status etcd

检查集群是否健康，在任一节点执行：

etcdctl \
  --ca-file=/etc/etcd/ssl/ca.pem \
  --cert-file=/etc/etcd/ssl/etcd.pem \
  --key-file=/etc/etcd/ssl/etcd-key.pem \
  --endpoints=https://node1:2379,https://node2:2379,https://node3:2379 \
  cluster-health
  
2017-04-24 19:53:40.545148 I | warning: ignoring ServerName for user-provided CA for backwards compatibility is deprecated
2017-04-24 19:53:40.546127 I | warning: ignoring ServerName for user-provided CA for backwards compatibility is deprecated
member 4f2f99d70000fc19 is healthy: got healthy result from https://192.168.61.12:2379
member 99a756f799eb4163 is healthy: got healthy result from https://192.168.61.11:2379
member a9aff19397de2e4e is healthy: got healthy result from https://192.168.61.13:2379
cluster is healthy

确保输出cluster is healthy的信息。

环境信息

TLS密钥和证书

安装cfssl

CA证书和私钥

etcd证书和私钥

安装etcd

启动etcd

参考