# 创建高可用 etcd 集群 kuberntes 系统使用 etcd 存储所有数据,本文档介绍部署一个三节点高可用 etcd 集群的步骤,这三个节点复用 kubernetes master 机器,分别命名为`sz-pg-oam-docker-test-001.tendcloud.com`、`sz-pg-oam-docker-test-002.tendcloud.com`、`sz-pg-oam-docker-test-003.tendcloud.com`: + sz-pg-oam-docker-test-001.tendcloud.com:172.20.0.113 + sz-pg-oam-docker-test-002.tendcloud.com:172.20.0.114 + sz-pg-oam-docker-test-003.tendcloud.com:172.20.0.115 ## TLS 认证文件 需要为 etcd 集群创建加密通信的 TLS 证书,这里复用以前创建的 kubernetes 证书 ``` bash cp ca.pem kubernetes-key.pem kubernetes.pem /etc/kubernetes/ssl ``` + kubernetes 证书的 `hosts` 字段列表中包含上面三台机器的 IP,否则后续证书校验会失败; ## 下载二进制文件 到 `https://github.com/coreos/etcd/releases` 页面下载最新版本的二进制文件 ``` bash wget https://github.com/coreos/etcd/releases/download/v3.1.5/etcd-v3.1.5-linux-amd64.tar.gz tar -xvf etcd-v3.1.5-linux-amd64.tar.gz mv etcd-v3.1.5-linux-amd64/etcd* /usr/local/bin ``` ## 创建 etcd 的 systemd unit 文件 注意替换IP地址为你自己的etcd集群的主机IP。 ``` bash [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/ EnvironmentFile=-/etc/etcd/etcd.conf ExecStart=/usr/local/bin/etcd \ --name ${ETCD_NAME} \ --cert-file=/etc/kubernetes/ssl/kubernetes.pem \ --key-file=/etc/kubernetes/ssl/kubernetes-key.pem \ --peer-cert-file=/etc/kubernetes/ssl/kubernetes.pem \ --peer-key-file=/etc/kubernetes/ssl/kubernetes-key.pem \ --trusted-ca-file=/etc/kubernetes/ssl/ca.pem \ --peer-trusted-ca-file=/etc/kubernetes/ssl/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},https://127.0.0.1:2379 \ --advertise-client-urls ${ETCD_ADVERTISE_CLIENT_URLS} \ --initial-cluster-token ${ETCD_INITIAL_CLUSTER_TOKEN} \ --initial-cluster infra1=https://172.20.0.113:2380,infra2=https://172.20.0.114:2380,infra3=https://172.20.0.115:2380 \ --initial-cluster-state new \ --data-dir=${ETCD_DATA_DIR} Restart=on-failure RestartSec=5 LimitNOFILE=65536 [Install] WantedBy=multi-user.target ``` + 指定 `etcd` 的工作目录为 `/var/lib/etcd`,数据目录为 `/var/lib/etcd`,需在启动服务前创建这两个目录; + 为了保证通信安全,需要指定 etcd 的公私钥(cert-file和key-file)、Peers 通信的公私钥和 CA 证书(peer-cert-file、peer-key-file、peer-trusted-ca-file)、客户端的CA证书(trusted-ca-file); + 创建 `kubernetes.pem` 证书时使用的 `kubernetes-csr.json` 文件的 `hosts` 字段**包含所有 etcd 节点的IP**,否则证书校验会出错; + `--initial-cluster-state` 值为 `new` 时,`--name` 的参数值必须位于 `--initial-cluster` 列表中; 完整 unit 文件见:[etcd.service](../systemd/etcd.service) 环境变量配置文件`/etc/etcd/etcd.conf`。 ```ini # [member] ETCD_NAME=infra1 ETCD_DATA_DIR="/var/lib/etcd" ETCD_LISTEN_PEER_URLS="https://172.20.0.113:2380" ETCD_LISTEN_CLIENT_URLS="https://172.20.0.113:2379" #[cluster] ETCD_INITIAL_ADVERTISE_PEER_URLS="https://172.20.0.113:2380" ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster" ETCD_ADVERTISE_CLIENT_URLS="https://172.20.0.113:2379" ``` 这是172.20.0.113节点的配置,其他两个etcd节点只要将上面的IP地址改成相应节点的IP地址即可。ETCD_NAME换成对应节点的infra1/2/3。 ## 启动 etcd 服务 ``` bash mv etcd.service /etc/systemd/system/ systemctl daemon-reload systemctl enable etcd systemctl start etcd stemctl status etcd ``` 在所有的 kubernetes master 节点重复上面的步骤,直到所有机器的 etcd 服务都已启动。 ## 验证服务 在任一 kubernetes master 机器上执行如下命令: ``` bash $ etcdctl \ --ca-file=/etc/kubernetes/ssl/ca.pem \ --cert-file=/etc/kubernetes/ssl/kubernetes.pem \ --key-file=/etc/kubernetes/ssl/kubernetes-key.pem \ cluster-health 2017-04-11 15:17:09.082250 I | warning: ignoring ServerName for user-provided CA for backwards compatibility is deprecated 2017-04-11 15:17:09.083681 I | warning: ignoring ServerName for user-provided CA for backwards compatibility is deprecated member 9a2ec640d25672e5 is healthy: got healthy result from https://172.20.0.115:2379 member bc6f27ae3be34308 is healthy: got healthy result from https://172.20.0.114:2379 member e5c92ea26c4edba0 is healthy: got healthy result from https://172.20.0.113:2379 cluster is healthy ``` 结果最后一行为 `cluster is healthy` 时表示集群服务正常。 关于如何在etcd中查看kubernetes的数据,请参考[使用etcdctl访问kuberentes数据](../guide/using-etcdctl-to-access-kubernetes-data.md)。