k8s1.14集群部署-etcd集群

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简介

ETCD 是一个高可用的分布式键值数据库，可用于服务发现。ETCD 采用 raft 一致性算法，基于 Go 语言实现。

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特点

简单：安装配置使用简单，提供 HTTP API 

安全：支持 SSL 证书 

可靠：采用 raft 算法，实现分布式系统数据的可用性和一致性

kubernetes 使用 etcd 存储所有运行数据

下载和分发 etcd 二进制文件

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

分发二进制文件到集群所有节点：

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cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp etcd-v3.3.13-linux-amd64/etcd* root@${node_ip}:/opt/k8s/bin
    ssh root@${node_ip} "chmod +x /opt/k8s/bin/*"
  done

创建 etcd 证书和私钥

创建证书签名请求：

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cd /opt/k8s/work
cat > etcd-csr.json <<EOF
{
  "CN": "etcd",
  "hosts": [
    "127.0.0.1",
    "192.168.6.101",
    "192.168.6.102"
  ],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "4Paradigm"
    }
  ]
}
EOF

生成证书和私钥：

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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：

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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

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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；

替换模板文件中的变量，为各节点创建 systemd unit 文件：

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cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for (( i=0; i < 2; 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

分发生成的 systemd unit 文件：

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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

启动 etcd 服务

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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

检查结果

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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：

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journalctl -u etcd

验证服务状态

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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

结果显示

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[root@node1 ~]# 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
>>> 192.168.6.101
https://192.168.6.101:2379 is healthy: successfully committed proposal: took = 2.45561ms
>>> 192.168.6.102
https://192.168.6.102:2379 is healthy: successfully committed proposal: took = 3.898134ms

查看当前的 leader

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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

结果为：

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[root@node1 ~]# 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
+----------------------------+------------------+---------+---------+-----------+-----------+------------+
|          ENDPOINT          |        ID        | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
+----------------------------+------------------+---------+---------+-----------+-----------+------------+
| https://192.168.6.101:2379 | 77fff77a6e7d24c5 |  3.3.13 |  864 kB |      true |         8 |      41721 |
| https://192.168.6.102:2379 |  e82e7402173c61e |  3.3.13 |  872 kB |     false |         8 |      41721 |
+----------------------------+------------------+---------+---------+-----------+-----------+------------+

可以看到6.101为leader

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