二进制部署一套高可用K8s集群-1.25+（二）

三、部署ETCD集群

etcd 是基于 Raft 的分布式 KV 存储系统，由 CoreOS 开发，常用于服务发现、共享配置以及并发控制（如 leader 选举、分布式锁等）。kubernetes 使用 etcd 集群持久化存储所有 API 对象、运行数据。

本文档 etcd 集群节点名称和 IP规划如下
- k8s-master1：192.168.66.62
- k8s-master2：192.168.66.63
- k8s-master3：192.168.66.64

1、下载和分发 etcd 二进制文件

ETCD仓库地址：https://github.com/etcd-io
如果网络原因，请在本地下载好安装包并上传至服务器
https://etcd.io/docs/v3.3.12/upgrades/upgrade_3_4/ 3.4之后如果使用ETCD V2 API注册Pod集群网络信息会报错，但是flannel网络不支持ETCD v3 API，所以网络我们使用calio，支持更大的集群规模，如果你使用flannel，那么你需要安装ETCDv3.3的版本

1.1：解压安装

[root@k8s-master1 ~]# cd /opt/k8s/work/
[root@k8s-master1 work]# wget https://github.com/etcd-io/etcd/releases/download/v3.5.5/etcd-v3.5.5-linux-amd64.tar.gz

[root@k8s-master1 work]# tar -xvf etcd-v3.5.5-linux-amd64.tar.gz

1.2：分发各ETCD节点

原文链接：https://dqzboy.com

[root@k8s-master1 work]# for node_ip in ${ETCD_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp etcd-v3.5.5-linux-amd64/etcd* root@${node_ip}:/opt/k8s/bin
    ssh root@${node_ip} "chmod +x /opt/k8s/bin/*"
  done

2、创建 etcd 证书和私钥

2.1：创建证书签名请求

[root@k8s-master1 ~]# cd /opt/k8s/work
[root@k8s-master1 work]# cat > etcd-csr.json <<EOF
{
  "CN": "etcd",
  "hosts": [
    "127.0.0.1",
    "192.168.66.62",
    "192.168.66.63",
    "192.168.66.64"
  ],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "ShangHai",
      "L": "ShangHai",
      "O": "k8s",
      "OU": "dqz"
    }
  ]
}
EOF

2.2：生成证书和私钥

[root@k8s-master1 work]# cfssl gencert -ca=/opt/k8s/work/ca.pem \
    -ca-key=/opt/k8s/work/ca-key.pem \
    -config=/opt/k8s/work/ca-config.json \
-profile=kubernetes etcd-csr.json | cfssljson -bare etcd


[root@k8s-master1 work]# ls etcd*pem
etcd-key.pem  etcd.pem

2.3：分发证书和私钥至各etcd节点

[root@k8s-master1 work]# for node_ip in ${ETCD_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p /etc/etcd/cert"
    scp etcd*.pem root@${node_ip}:/etc/etcd/cert/
  done

3、创建 etcd 的 systemd unit 模板文件

[root@k8s-master1 work]# cat > etcd.service.template <<EOF
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target
Documentation=https://github.com/coreos

[Service]
Type=notify
WorkingDirectory=${ETCD_DATA_DIR}
ExecStart=/opt/k8s/bin/etcd \\
  --data-dir=${ETCD_DATA_DIR} \\
  --wal-dir=${ETCD_WAL_DIR} \\
  --name=##ETCD_NAME## \\
  --cert-file=/etc/etcd/cert/etcd.pem \\
  --key-file=/etc/etcd/cert/etcd-key.pem \\
  --trusted-ca-file=/etc/kubernetes/cert/ca.pem \\
  --peer-cert-file=/etc/etcd/cert/etcd.pem \\
  --peer-key-file=/etc/etcd/cert/etcd-key.pem \\
  --peer-trusted-ca-file=/etc/kubernetes/cert/ca.pem \\
  --peer-client-cert-auth \\
  --client-cert-auth \\
  --listen-peer-urls=https://##ETCD_IP##:2380 \\
  --initial-advertise-peer-urls=https://##ETCD_IP##:2380 \\
  --listen-client-urls=https://##ETCD_IP##:2379,http://127.0.0.1:2379 \\
  --advertise-client-urls=https://##ETCD_IP##:2379 \\
  --initial-cluster-token=etcd-cluster-0 \\
  --initial-cluster=${ETCD_NODES} \\
  --initial-cluster-state=new \\
  --auto-compaction-mode=periodic \\
  --auto-compaction-retention=1 \\
  --max-request-bytes=33554432 \\
  --quota-backend-bytes=6442450944 \\
  --heartbeat-interval=250 \\
  --election-timeout=2000
Restart=on-failure
RestartSec=5
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

4、为各ETCD节点创建和分发 etcd systemd unit 文件

4.1：替换模板文件中的变量

[root@k8s-master1 work]# for (( i=0; i < 3; i++ ))
  do
    sed -e "s/##ETCD_NAME##/${ETCD_NAMES[i]}/" -e "s/##ETCD_IP##/${ETCD_IPS[i]}/" etcd.service.template > etcd-${ETCD_IPS[i]}.service 
  done

[root@k8s-master1 work]# ls *.service
etcd-192.168.66.62.service  etcd-192.168.66.63.service  etcd-192.168.66.64.service

4.2：分发生成的 systemd unit 文件

[root@k8s-master1 work]# for node_ip in ${ETCD_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp etcd-${node_ip}.service root@${node_ip}:/etc/systemd/system/etcd.service
  done

5、启动ETCD服务

注意：有可能ETCD节点1启动失败，而另外2个节点启动成功，这是正常情况，请重启ETCD节点1即可

[root@k8s-master1 work]# for node_ip in ${ETCD_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p ${ETCD_DATA_DIR} ${ETCD_WAL_DIR} && chmod 0700 /data/k8s/etcd/data"
    ssh root@${node_ip} "systemctl daemon-reload && systemctl enable etcd && systemctl restart etcd"
  done

6、检查启动结果

文章来源(Source)：https://dqzboy.com

[root@k8s-master1 work]# for node_ip in ${ETCD_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "systemctl status etcd|grep Active"
  done

7、验证服务状态

7.1：任一etcd节点执行以下命令

[root@k8s-master1 work]# for node_ip in ${ETCD_IPS[@]}
  do
    echo ">>> ${node_ip}"
    /opt/k8s/bin/etcdctl \
    --endpoints=https://${node_ip}:2379 \
    --cacert=/etc/kubernetes/cert/ca.pem \
    --cert=/etc/etcd/cert/etcd.pem \
    --key=/etc/etcd/cert/etcd-key.pem endpoint health
  done

各服务节点全部为healthy，则代表etcd集群状态正常

7.2：查看当前leader

[root@k8s-master1 work]# /opt/k8s/bin/etcdctl \
  -w table --cacert=/opt/k8s/work/ca.pem \
  --cert=/etc/etcd/cert/etcd.pem \
  --key=/etc/etcd/cert/etcd-key.pem \
  --endpoints=${ETCD_ENDPOINTS} endpoint status