Etcd 是一个分布式键值存储系统，Kubernetes使用Etcd进行数据存储，所以先准备一个Etcd数据库，为解决Etcd单点故障，应采用集群方式部署，这里使用3台组建集群，可容忍1台机器故障，当然，你也可以使用5台组建集群，可容忍2台机器故障。

节点名称	IP
etcd-1	10.20.17.20
etcd-2	10.20.17.21
etcd-3	10.20.17.22

注：为了节省机器，这里与K8s节点机器复用。也可以独立于k8s集群之外部署，只要apiserver能连接到就行

1 准备cfssl证书生成工具

cfssl是一个开源的证书管理工具，使用json文件生成证书，相比openssl更方便使用。

找任意一台服务器操作，这里用Master节点。

# mkdir -p /opt/tools
# mkdir -p /opt/tools/cfssl
# cd /opt/tools/cfssl/
# wget https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
# wget https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64
# wget https://pkg.cfssl.org/R1.2/cfssl-certinfo_linux-amd64
# chmod +x cfssl_linux-amd64 cfssljson_linux-amd64 cfssl-certinfo_linux-amd64
# mv cfssl_linux-amd64 /usr/local/bin/cfssl
# mv cfssljson_linux-amd64 /usr/local/bin/cfssljson
# mv cfssl-certinfo_linux-amd64 /usr/bin/cfssl-certinfo

2 生成Etcd证书

2.1 自签证书颁发机构（CA）

创建工作目录：

# mkdir -p /root/TLS/{etcd,k8s}
# mkdir -p /root/TLS/{etcd,k8s}
# cd /root/TLS/etcd

自签CA：

cat > ca-config.json << EOF
{"signing": {"default": {"expiry": "87600h"},"profiles": {"www": {"expiry": "87600h","usages": ["signing","key encipherment","server auth","client auth"]}}}
}
EOFcat > ca-csr.json << EOF
{"CN": "etcd CA","key": {"algo": "rsa","size": 2048},"names": [{"C": "CN","L": "Beijing","ST": "Beijing"}]
}
EOF

生成证书：

# cfssl gencert -initca ca-csr.json | cfssljson -bare ca -
# ls *pem
ca-key.pem  ca.pem

2.2 使用自签CA签发Etcd HTTPS证书

创建证书申请文件：

cat > server-csr.json << EOF
{"CN": "etcd","hosts": ["10.20.17.20","10.20.17.21","10.20.17.22"],"key": {"algo": "rsa","size": 2048},"names": [{"C": "CN","L": "BeiJing","ST": "BeiJing"}]
}
EOF

注：上述文件hosts字段中IP为所有etcd节点的集群内部通信IP，一个都不能少！为了方便后期扩容可以多写几个预留的IP。

生成证书：

# cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=www server-csr.json | cfssljson -bare server
# ls server*pem
server-key.pem  server.pem

3 从Github下载etcd二进制文件

下载地址：https://github.com/etcd-io/etcd/releases/download/v3.4.9/etcd-v3.4.9-linux-amd64.tar.gz

4 部署Etcd集群

以下在etcd 节点1上操作，为简化操作，待会将节点1生成的所有文件拷贝到节点2和节点3。

4.1 创建工作目录并解压二进制包

# mkdir -p /opt/etcd/{bin,cfg,ssl} 
# tar zxvf /opt/tools/etcd-v3.4.9-linux-amd64.tar.gz
# mv /opt/tools/etcd-v3.4.9-linux-amd64/{etcd,etcdctl} /opt/etcd/bin/

4.2 创建etcd配置文件

cat > /opt/etcd/cfg/etcd.conf << EOF
#[Member]
ETCD_NAME="etcd-1"
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://10.20.17.20:2380"
ETCD_LISTEN_CLIENT_URLS="https://10.20.17.20:2379"
#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://10.20.17.20:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://10.20.17.20:2379"
ETCD_INITIAL_CLUSTER="etcd-1=https://10.20.17.20:2380,etcd-2=https://10.20.17.21:2380,etcd-3=https://10.20.17.22:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
EOF

• ETCD_NAME：节点名称，集群中唯一
• ETCD_DATA_DIR：数据目录
• ETCD_LISTEN_PEER_URLS：集群通信监听地址
• ETCD_LISTEN_CLIENT_URLS：客户端访问监听地址
• ETCD_INITIAL_ADVERTISE_PEER_URLS：集群通告地址
• ETCD_ADVERTISE_CLIENT_URLS：客户端通告地址
• ETCD_INITIAL_CLUSTER：集群节点地址
• ETCD_INITIAL_CLUSTER_TOKEN：集群Token
• ETCD_INITIAL_CLUSTER_STATE：加入集群的当前状态，new是新集群，existing表示加入已有集群

4.3 systemd管理etcd

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
EnvironmentFile=/opt/etcd/cfg/etcd.conf
ExecStart=/opt/etcd/bin/etcd \
--cert-file=/opt/etcd/ssl/server.pem \
--key-file=/opt/etcd/ssl/server-key.pem \
--peer-cert-file=/opt/etcd/ssl/server.pem \
--peer-key-file=/opt/etcd/ssl/server-key.pem \
--trusted-ca-file=/opt/etcd/ssl/ca.pem \
--peer-trusted-ca-file=/opt/etcd/ssl/ca.pem \
--logger=zap
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
EOF

4.4 拷贝刚才生成的证书

# cp /root/TLS/etcd/ca*pem /root/TLS/etcd/server*pem /opt/etcd/ssl/

4.5 将上面节点1所有生成的文件拷贝到节点2和节点3

scp -r /opt/etcd/ k8s-node1:/opt/
scp /usr/lib/systemd/system/etcd.service k8s-node1:/usr/lib/systemd/system/scp -r /opt/etcd/ k8s-node2:/opt/
scp /usr/lib/systemd/system/etcd.service k8s-node2:/usr/lib/systemd/system/

然后在节点2和节点3分别修改etcd.conf配置文件中的节点名称和当前服务器IP：

[root@k8s-node1 bin]# vim /opt/etcd/cfg/etcd.conf#[Member]
ETCD_NAME="etcd-1"  # 修改此处，节点2改为etcd-2，节点3改为etcd-3
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://10.20.17.20:2380"  # 修改此处为当前服务器IP
ETCD_LISTEN_CLIENT_URLS="https://10.20.17.20:2379"  # 修改此处为当前服务器IP
#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://10.20.17.20:2380"  # 修改此处为当前服务器IP
ETCD_ADVERTISE_CLIENT_URLS="https://10.20.17.20:2379"  # 修改此处为当前服务器IP
ETCD_INITIAL_CLUSTER="etcd-1=https://10.20.17.20:2380,etcd-2=https://10.20.17.21:2380,etcd-3=https://10.20.17.22:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"

4.6 启动etcd服务并设置开机启动

systemctl daemon-reload    # 配置生效
systemctl start etcd       # 启动etcd
systemctl status etcd      # 查看启动状态
systemctl enable etcd      # 设置开机启动

注意：以上三个节点需要先启动其他节点的 etcd 而不是 master 的etcd ！！！

启动master节点的etcd服务后，发现服务无法启动，可使用 journalctl -xe 命令或查看系统日志cat /var/log/messages
看到以下关于etcd的报错信息：

"msg":"prober detected unhealthy status","round-tripper-name":"ROUND_TRIPPER_RAFT_MESSAGE","remote-peer-id":"427a09770fe3b784","rtt":"0s","error":"dial tcp 10.20.17.21:2380: connect: connection refused"

报错原因：分析是因为etcd1的配置文件/etc/systemd/system/etcd.service 启动脚本中的ETCD_INITIAL_CLUSTER_STATE是new，而在配置中ETCD_INITIAL_CLUSTER写入了etcd2/3的IP:PORT，这时etcd1尝试去连接etcd2、etcd3，但是etcd2、3的etcd服务此时还未启动，因此需要先启动etcd2和3的etcd服务，再去启动etcd1。

4.7 查看集群状态

# ETCDCTL_API=3 /opt/etcd/bin/etcdctl --cacert=/opt/etcd/ssl/ca.pem --cert=/opt/etcd/ssl/server.pem --key=/opt/etcd/ssl/server-key.pem --endpoints="https://10.20.17.2017.21:2379,https://10.20.17.22:2379" endpoint healthhttps://10.20.17.20:2379 is healthy: successfully committed proposal: took = 11.989312ms
https://10.20.17.21:2379 is healthy: successfully committed proposal: took = 12.942844ms
https://10.20.17.22:2379 is healthy: successfully committed proposal: took = 29.3212ms

如果输出上面信息，就说明集群部署成功。如果有问题第一步先看日志：/var/log/message 或 journalctl -u etcd