(五)手动部署k8s之-部署etcd集群

原教程来自 github/opsnull, 现在此基础上记录自己搭建遇到的问题

本文档介绍部署一个三节点高可用 etcd 集群的步骤:

  • 下载和分发 etcd 二进制文件;
  • 创建 etcd 集群各节点的 x509 证书,用于加密客户端(如 etcdctl) 与 etcd 集群、etcd 集群之间的数据流;
  • 创建 etcd 的 systemd unit 文件,配置服务参数;
  • 检查集群工作状态;

下载和分发 etcd 二进制文件

到 etcd 的 release 页面 下载最新版本的发布包:

cd /opt/k8s/work
wget https://github.com/etcd-io/etcd/releases/download/v3.3.13/etcd-v3.3.13-linux-amd64.tar.gz
tar -xvf etcd-v3.3.13-linux-amd64.tar.gz

创建 etcd 证书和私钥

创建证书签名请求

cd /opt/k8s/work
cat > etcd-csr.json <<EOF
{
  "CN": "etcd",
  "hosts": [
    "127.0.0.1",
    "192.168.1.31",
    "192.168.1.32",
    "192.168.1.33"
  ],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "4Paradigm"
    }
  ]
}
EOF
  • hosts 字段指定授权使用该证书的 etcd 节点 IP 或域名列表,需要将 etcd 集群的三个节点 IP 都列在其中

生成证书和私钥:

cd /opt/k8s/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
ls etcd*pem

分发生成的证书和私钥到各 etcd 节点

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p /etc/etcd/cert"
    scp etcd*.pem root@${node_ip}:/etc/etcd/cert/
  done

创建 etcd 的 systemd unit 模板文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
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=${ETCD_WAL_DIR} \\
  --name=##NODE_NAME## \\
  --cert-file=/etc/etcd/cert/etcd.pem \\
  --key-file=/etc/etcd/cert/etcd-key.pem \\
  --trusted-ca-file=/etc/kubernetes/cert/ca.pem \\
  --peer-cert-file=/etc/etcd/cert/etcd.pem \\
  --peer-key-file=/etc/etcd/cert/etcd-key.pem \\
  --peer-trusted-ca-file=/etc/kubernetes/cert/ca.pem \\
  --peer-client-cert-auth \\
  --client-cert-auth \\
  --listen-peer-urls=https://##NODE_IP##:2380 \\
  --initial-advertise-peer-urls=https://##NODE_IP##:2380 \\
  --listen-client-urls=https://##NODE_IP##:2379,http://127.0.0.1:2379 \\
  --advertise-client-urls=https://##NODE_IP##:2379 \\
  --initial-cluster-token=etcd-cluster-0 \\
  --initial-cluster=${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
  • WorkingDirectory、--data-dir:指定工作目录和数据目录为 ${ETCD_DATA_DIR},需在启动服务前创建这个目录;
  • --wal-dir:指定 wal 目录,为了提高性能,一般使用 SSD 或者和 --data-dir 不同的磁盘;
  • --name:指定节点名称,当 --initial-cluster-state 值为 new 时,--name 的参数值必须位于 --initial-cluster 列表中;
  • --cert-file、--key-file:etcd server 与 client 通信时使用的证书和私钥;
  • --trusted-ca-file:签名 client 证书的 CA 证书,用于验证 client 证书;
  • --peer-cert-file、--peer-key-file:etcd 与 peer 通信使用的证书和私钥;
  • --peer-trusted-ca-file:签名 peer 证书的 CA 证书,用于验证 peer 证书;

为各节点创建和分发 etcd systemd unit 文件

替换模板文件中的变量,为各节点创建 systemd unit 文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for (( i=0; i < 3; i++ ))
  do
    sed -e "s/##NODE_NAME##/${NODE_NAMES[i]}/" -e "s/##NODE_IP##/${NODE_IPS[i]}/" etcd.service.template > etcd-${NODE_IPS[i]}.service
  done
ls *.service
  • NODE_NAMES 和 NODE_IPS 为相同长度的 bash 数组,分别为节点名称和对应的 IP;

分发生成的 systemd unit 文件:

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp etcd-${node_ip}.service root@${node_ip}:/etc/systemd/system/etcd.service
  done

文件重命名为 etcd.service

启动 etcd 服务

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p ${ETCD_DATA_DIR} ${ETCD_WAL_DIR}"
    ssh root@${node_ip} "systemctl daemon-reload && systemctl enable etcd && systemctl restart etcd " &
  done
  • 必须先创建 etcd 数据目录和工作目录;
  • etcd 进程首次启动时会等待其它节点的 etcd 加入集群,命令 systemctl start etcd 会卡住一段时间,为正常现象

检查启动结果

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "systemctl status etcd|grep Active"
  done

确保状态为 active (running),否则查看日志,确认原因:

journalctl -u etcd

验证服务状态

部署完 etcd 集群后,在任一 etcd 节点上执行如下命令:

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ETCDCTL_API=3 /opt/k8s/bin/etcdctl \
    --endpoints=https://${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

预期输出:

https://192.168.1.31:2379 is healthy: successfully committed proposal: took = 2.448665ms
>>> 192.168.1.32
https://192.168.1.32:2379 is healthy: successfully committed proposal: took = 3.380867ms
>>> 192.168.1.33
https://192.168.1.33:2379 is healthy: successfully committed proposal: took = 3.034316ms

输出均为 healthy 时表示集群服务正常

查看当前的 leader

source /opt/k8s/bin/environment.sh
ETCDCTL_API=3 /opt/k8s/bin/etcdctl \
  -w table --cacert=/etc/kubernetes/cert/ca.pem \
  --cert=/etc/etcd/cert/etcd.pem \
  --key=/etc/etcd/cert/etcd-key.pem \
  --endpoints=${ETCD_ENDPOINTS} endpoint status 

输出

+---------------------------+------------------+---------+---------+-----------+-----------+------------+
|         ENDPOINT          |        ID        | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
+---------------------------+------------------+---------+---------+-----------+-----------+------------+
| https://192.168.1.31:2379 |  68afffba56612fd |  3.3.13 |   20 kB |     false |         2 |          8 |
| https://192.168.1.32:2379 |  22a9d61e6821c4d |  3.3.13 |   20 kB |      true |         2 |          8 |
| https://192.168.1.33:2379 | ff1f72bab5edb59f |  3.3.13 |   20 kB |     false |         2 |          8 |
+---------------------------+------------------+---------+---------+-----------+-----------+------------+

可见,当前的 leader 为192.168.1.32

最后修改:2019 年 08 月 05 日 05 : 07 PM