CentOS 7 ETCD 集群配置大全
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Etcd 是 CoreOS 基于 Raft 开发的分布式 key-value 存储，可用于服务发现、共享配置以及一致性保障（如数据库选主、分布式锁等）。Etcd 集群配置分为三种:
静态发现
Etcd 动态发现
DNS 动态发现：通过 DNS 的 SRV 解析动态发现集群
本文主要基于静态发现 和 DNS 动态发现两种方式，并结合自签的TLS证书来创建集群。
环境准备
安装
在三台机器上均执行:
[root@node01 ~]# yum install etcd -y
[root@node01 ~]# rpm -qa etcd
etcd-3.3.11-2.el7.centos.x86_64
创建Etcd所需目录，在三台机器上均执行:
mkdir /data/k8s/etcd/{data,wal} -p
mkdir -p /etc/kubernetes/cert
chown -R etcd.etcd /data/k8s/etcd
静态集群
node01 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="http://192.168.1.91:2380"
ETCD_LISTEN_CLIENT_URLS="http://192.168.1.91:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd1"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.1.91:2380"
ETCD_ADVERTISE_CLIENT_URLS="http://192.168.1.91:2379"
ETCD_INITIAL_CLUSTER="etcd1=http://192.168.1.91:2380,etcd2=http://192.168.1.92:2380,etcd3=http://192.168.1.93:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
node02 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="http://192.168.1.92:2380"
ETCD_LISTEN_CLIENT_URLS="http://192.168.1.92:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd2"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.1.92:2380"
ETCD_ADVERTISE_CLIENT_URLS="http://192.168.1.92:2379"
ETCD_INITIAL_CLUSTER="etcd1=http://192.168.1.91:2380,etcd2=http://192.168.1.92:2380,etcd3=http://192.168.1.93:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
node03 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="http://192.168.1.93:2380"
ETCD_LISTEN_CLIENT_URLS="http://192.168.1.93:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd3"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.1.93:2380"
ETCD_ADVERTISE_CLIENT_URLS="http://192.168.1.93:2379"
ETCD_INITIAL_CLUSTER="etcd1=http://192.168.1.91:2380,etcd2=http://192.168.1.92:2380,etcd3=http://192.168.1.93:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
启动测试：
[root@node01 etcd]# systemctl start etcd
[root@node01 etcd]# systemctl status etcd
● etcd.service - Etcd Server
Loaded: loaded (/usr/lib/systemd/system/etcd.service; disabled; vendor preset: disabled)
Active: active (running) since Thu 2019-11-07 09:28:54 CST; 5s ago
Main PID: 1546 (etcd)
Tasks: 8
Memory: 41.3M
CGroup: /system.slice/etcd.service
└─1546 /usr/bin/etcd --name=etcd1 --data-dir=/data/k8s/etcd/data --listen-client-urls=http://192.168.1.91:2379
Nov 07 09:28:54 node01.k8s.com etcd[1546]: 3b8b38de05e2c497 [term: 1] received a MsgVote message with higher term from 9c64fba479c5e94 [term: 2]
Nov 07 09:28:54 node01.k8s.com etcd[1546]: 3b8b38de05e2c497 became follower at term 2
Nov 07 09:28:54 node01.k8s.com etcd[1546]: 3b8b38de05e2c497 [logterm: 1, index: 3, vote: 0] cast MsgVote for 9c64fba479c5e94 [logterm: 1, index: 3] at term 2
Nov 07 09:28:54 node01.k8s.com etcd[1546]: raft.node: 3b8b38de05e2c497 elected leader 9c64fba479c5e94 at term 2
Nov 07 09:28:54 node01.k8s.com etcd[1546]: published {Name:etcd1 ClientURLs:[http://192.168.1.91:2379]} to cluster 19456f0bfd57284e
Nov 07 09:28:54 node01.k8s.com etcd[1546]: ready to serve client requests
Nov 07 09:28:54 node01.k8s.com etcd[1546]: serving insecure client requests on 192.168.1.91:2379, this is strongly discouraged!
Nov 07 09:28:54 node01.k8s.com systemd[1]: Started Etcd Server.
Nov 07 09:28:54 node01.k8s.com etcd[1546]: set the initial cluster version to 3.3
Nov 07 09:28:54 node01.k8s.com etcd[1546]: enabled capabilities for version 3.3
查看 /var/log/message 日志中，会有如下信息：
Nov 7 09:28:53 node02 etcd: added member 9c64fba479c5e94 [http://192.168.1.92:2380] to cluster 19456f0bfd57284e
Nov 7 09:28:53 node02 etcd: added member 3b8b38de05e2c497 [http://192.168.1.91:2380] to cluster 19456f0bfd57284e
Nov 7 09:28:53 node02 etcd: added member 76ea8679db7365b3 [http://192.168.1.93:2380] to cluster 19456f0bfd57284e
查看集群状态:
[root@node01 etcd]# ETCDCTL_API=3 etcdctl --endpoints=http://192.168.1.91:2379,http://192.168.1.92:2379,http://192.168.1.93:2379 endpoint health
http://192.168.1.92:2379 is healthy: successfully committed proposal: took = 1.103545ms
http://192.168.1.93:2379 is healthy: successfully committed proposal: took = 2.122478ms
http://192.168.1.91:2379 is healthy: successfully committed proposal: took = 2.690215ms
[root@node01 etcd]# etcdctl --endpoints=http://192.168.1.91:2379,http://192.168.1.92:2379,http://192.168.1.93:2379 cluster-health
member 9c64fba479c5e94 is healthy: got healthy result from http://192.168.1.92:2379
member 3b8b38de05e2c497 is healthy: got healthy result from http://192.168.1.91:2379
member 76ea8679db7365b3 is healthy: got healthy result from http://192.168.1.93:2379
cluster is healthy
生成TLS证书
使用自签证书，CA(Certificate Authority)是自签名的根证书，用来签名后续创建的其他证书。本文使用 CloudFlare 的 PKI 工具 cfssl 创建所有证书。
整个证书的创建过程均在 node01 上操作，首先安装 cfssl 工具集：
mkdir -p /opt/k8s/cert && cd /opt/k8s
wget https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
mv cfssl_linux-amd64 /opt/k8s/bin/cfssl
wget https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64
mv cfssljson_linux-amd64 /opt/k8s/bin/cfssljson
wget https://pkg.cfssl.org/R1.2/cfssl-certinfo_linux-amd64
mv cfssl-certinfo_linux-amd64 /opt/k8s/bin/cfssl-certinfo
chmod +x /opt/k8s/bin/*
echo 'export PATH=/opt/k8s/bin:$PATH' >> ~/.bash_profile
source ~/.bash_profile
生成证书
创建根证书 (CA)：CA证书是集群所有节点共享的，只需要创建一个CA证书，后续创建的所有证书都是由它签名。
创建配置文件：CA配置文件用于配置根证书的使用场景(profile)和具体参数(usage、过期时间、服务端认证、客户端认证、加密等)
cd /opt/k8s/work
cat > ca-config.json <<EOF
{
"signing": {
"default": {
"expiry": "87600h"
},
"profiles": {
"kubernetes": {
"usages": [
"signing",
"key encipherment",
"server auth",
"client auth"
],
"expiry": "87600h"
}
}
}
}
EOF
signing 表示该证书可用于签名其它证书，生成的 ca.pem 证书找中 CA=TRUE，server auth 表示client可以用该证书对server提供的证书进行验证，client auth 表示server可以用该证书对client提供的证书进行验证
创建证书签名请求文件
cd /opt/k8s/work
cat > ca-csr.json <<EOF
{
"CN": "kubernetes",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "CN",
"ST": "BeiJing",
"L": "BeiJing",
"O": "k8s",
"OU": "4Paradigm"
}
],
"ca": {
"expiry": "876000h"
}
}
EOF
CN CommonName,kube-apiserver从证书中提取该字段作为请求的用户名(User Name)，浏览器使用该字段验证网站是否合法；O Organization,kube-apiserver 从证书中提取该字段作为请求用户和所属组(Group)，kube-apiserver将提取的User、Group作为RBAC授权的用户和标识
生成CA证书和私钥
cd /opt/k8s/work
cfssl gencert -initca ca-csr.json | cfssljson -bare ca
ls ca*
创建etcd证书和私钥
cd /opt/k8s/work
cat > etcd-csr.json <<EOF
{
"CN": "etcd",
"hosts": [
"127.0.0.1",
"192.168.1.91",
"192.168.1.92",
"192.168.1.93",
"k8s.com",
"etcd1.k8s.com",
"etcd2.k8s.com",
"etcd3.k8s.com"
],
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "CN",
"ST": "BeiJing",
"L": "BeiJing",
"O": "k8s",
"OU": "4Paradigm"
}
]
}
EOF
host 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3个节点都添加其中 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 -l
-rw------- 1 root root 1675 Nov 7 09:52 etcd-key.pem
-rw-r--r-- 1 root root 1444 Nov 7 09:52 etcd.pem
etcd 使用的TLS证书创建完成。然后分发证书到各节点上，要做所有节点上创建对应的目录：
mkdir /data/k8s/etcd/{data,wal} -p
mkdir -p /etc/kubernetes/cert
chown -R etcd.etcd /data/k8s/etcd
分发证书:
cd /opt/k8s/work
scp ca*.pem ca-config.json 192.168.1.91:/etc/kubernetes/cert
scp ca*.pem ca-config.json 192.168.1.92:/etc/kubernetes/cert
scp ca*.pem ca-config.json 192.168.1.93:/etc/kubernetes/cert
scp etcd*pem 192.168.1.91:/etc/etcd/cert/
scp etcd*pem 192.168.1.92:/etc/etcd/cert/
scp etcd*pem 192.168.1.93:/etc/etcd/cert/
在所有节点上执行:
chown -R etcd.etcd /etc/etcd/cert
静态TLS集群
node01 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="https://192.168.1.91:2380"
ETCD_LISTEN_CLIENT_URLS="https://192.168.1.91:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd1"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.1.91:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://192.168.1.91:2379"
ETCD_INITIAL_CLUSTER="etcd1=https://192.168.1.91:2380,etcd2=https://192.168.1.92:2380,etcd3=https://192.168.1.93:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
ETCD_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_CLIENT_CERT_AUTH="true"
ETCD_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_AUTO_TLS="true"
ETCD_PEER_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_PEER_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_PEER_CLIENT_CERT_AUTH="true"
ETCD_PEER_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_PEER_AUTO_TLS="true"
node02 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="https://192.168.1.92:2380"
ETCD_LISTEN_CLIENT_URLS="https://192.168.1.92:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd2"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.1.92:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://192.168.1.92:2379"
ETCD_INITIAL_CLUSTER="etcd1=https://192.168.1.91:2380,etcd2=https://192.168.1.92:2380,etcd3=https://192.168.1.93:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
ETCD_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_CLIENT_CERT_AUTH="true"
ETCD_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_AUTO_TLS="true"
ETCD_PEER_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_PEER_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_PEER_CLIENT_CERT_AUTH="true"
ETCD_PEER_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_PEER_AUTO_TLS="true"
node03 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="https://192.168.1.93:2380"
ETCD_LISTEN_CLIENT_URLS="https://192.168.1.93:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd3"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.1.93:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://192.168.1.93:2379"
ETCD_INITIAL_CLUSTER="etcd1=https://192.168.1.91:2380,etcd2=https://192.168.1.92:2380,etcd3=https://192.168.1.93:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
ETCD_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_CLIENT_CERT_AUTH="true"
ETCD_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_AUTO_TLS="true"
ETCD_PEER_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_PEER_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_PEER_CLIENT_CERT_AUTH="true"
ETCD_PEER_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_PEER_AUTO_TLS="true"
启动测试:
[root@node01 work]# systemctl start etcd
[root@node01 work]# systemctl status etcd
● etcd.service - Etcd Server
Loaded: loaded (/usr/lib/systemd/system/etcd.service; disabled; vendor preset: disabled)
Active: active (running) since Thu 2019-11-07 10:15:58 CST; 5s ago
Main PID: 2078 (etcd)
Tasks: 8
Memory: 28.9M
CGroup: /system.slice/etcd.service
└─2078 /usr/bin/etcd --name=etcd1 --data-dir=/data/k8s/etcd/data --listen-client-urls=https://192.168.1.91:2379
Nov 07 10:15:58 node01.k8s.com etcd[2078]: 2a40d8ba966d12fe [term: 1] received a MsgVote message with higher term from af05139f75a68867 [term: 2]
Nov 07 10:15:58 node01.k8s.com etcd[2078]: 2a40d8ba966d12fe became follower at term 2
Nov 07 10:15:58 node01.k8s.com etcd[2078]: 2a40d8ba966d12fe [logterm: 1, index: 3, vote: 0] cast MsgVote for af05139f75a68867 [logterm: 1, index: 3] at term 2
Nov 07 10:15:58 node01.k8s.com etcd[2078]: raft.node: 2a40d8ba966d12fe elected leader af05139f75a68867 at term 2
Nov 07 10:15:58 node01.k8s.com etcd[2078]: published {Name:etcd1 ClientURLs:[https://192.168.1.91:2379]} to cluster f3e9c54e1aafb3c1
Nov 07 10:15:58 node01.k8s.com etcd[2078]: ready to serve client requests
Nov 07 10:15:58 node01.k8s.com etcd[2078]: serving client requests on 192.168.1.91:2379
Nov 07 10:15:58 node01.k8s.com systemd[1]: Started Etcd Server.
Nov 07 10:15:58 node01.k8s.com etcd[2078]: set the initial cluster version to 3.3
Nov 07 10:15:58 node01.k8s.com etcd[2078]: enabled capabilities for version 3.3
查看 /var/log/message 日志中，会有日下体现：
Nov 7 10:15:57 node01 etcd: added member 2a40d8ba966d12fe [https://192.168.1.91:2380] to cluster f3e9c54e1aafb3c1
Nov 7 10:15:57 node01 etcd: added member af05139f75a68867 [https://192.168.1.92:2380] to cluster f3e9c54e1aafb3c1
Nov 7 10:15:57 node01 etcd: added member c3bab7c20fba3f60 [https://192.168.1.93:2380] to cluster f3e9c54e1aafb3c1
检查TLS集群状态:
ETCDCTL_API=3 etcdctl \
--endpoints=https://etcd1.k8s.com:2379,https://etcd2.k8s.com:2379,https://etcd3.k8s.com:2379 \
--cacert=/etc/kubernetes/cert/ca.pem \
--cert=/etc/etcd/cert/etcd.pem \
--key=/etc/etcd/cert/etcd-key.pem endpoint health
# 输出
https://192.168.1.92:2379 is healthy: successfully committed proposal: took = 1.317022ms
https://192.168.1.91:2379 is healthy: successfully committed proposal: took = 1.59958ms
https://192.168.1.93:2379 is healthy: successfully committed proposal: took = 1.453049ms
ETCD 动态集群基于 DNS 的 SRV 解析自动发现
需要局域网内部有DNS服务器
添加SRV解析
目前常用的内部DNS服务有两种，bind、dnsmasq。
在下面都会列出具体的配置，但只需要配置其中之一即可；
方法一: 使用 bind 配置SRV解析 如果内部没有 bind 服务，可以参考部署文档文章: https://www.cnblogs.com/winstom/p/11806962.html
使用域名为: k8s.com，在 bind 的 zone 文件中添加如下解析:
etcd1 IN A 192.168.1.91
etcd2 IN A 192.168.1.92
etcd3 IN A 192.168.1.93
_etcd-server._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd1
_etcd-server._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd2
_etcd-server._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd3
_etcd-client._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd1
_etcd-client._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd2
_etcd-client._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd3
修改之后重新加载配置文件:
[root@jenkins named]# named-checkzone k8s.com k8s.com.zone
zone k8s.com/IN: loaded serial 0
OK
[root@jenkins named]# rndc reload
server reload successful
方法二: 使用 dnsmasq配置SRV解析如果内部没有dnsmasq 服务，可以参考部署文档文章: https://www.cnblogs.com/winstom/p/11809066.html
使用域名为: k8s.com，具体修改如下，首先在 /etc/dnsmasq_hosts新增下面内容：
192.168.1.91 etcd1 etcd1.k8s.com
192.168.1.92 etcd2 etcd2.k8s.com
192.168.1.93 etcd3 etcd3.k8s.com
在 /etc/dnsmasq.conf 文件中增加下面 SRV 解析内容:
srv-host=_etcd-server._tcp.k8s.com,etcd1.k8s.com,2380,0,100
srv-host=_etcd-server._tcp.k8s.com,etcd2.k8s.com,2380,0,100
srv-host=_etcd-server._tcp.k8s.com,etcd3.k8s.com,2380,0,100
srv-host=_etcd-client._tcp.k8s.com,etcd1.k8s.com,2380,0,100
srv-host=_etcd-client._tcp.k8s.com,etcd2.k8s.com,2380,0,100
srv-host=_etcd-client._tcp.k8s.com,etcd3.k8s.com,2380,0,100
修改之后重启服务:
systemctl restart dnsmasq
验证 SRV 解析是否正常，查询 SRV 记录：
[root@node01 ~]# dig @192.168.1.122 +noall +answer SRV _etcd-server._tcp.k8s.com
_etcd-server._tcp.k8s.com. 3600 IN SRV 2380 0 100 etcd2.k8s.com.
_etcd-server._tcp.k8s.com. 3600 IN SRV 2380 0 100 etcd1.k8s.com.
_etcd-server._tcp.k8s.com. 3600 IN SRV 2380 0 100 etcd3.k8s.com.
查询域名解析结果:
[root@node01 ~]# dig @192.168.1.122 +noall +answer etcd1.k8s.com etcd2.k8s.com etcd3.k8s.com
etcd1.k8s.com. 86400 IN A 192.168.1.91
etcd2.k8s.com. 86400 IN A 192.168.1.92
etcd3.k8s.com. 86400 IN A 192.168.1.93
如上述显示，则表示 SRV 解析正常。
配置ETCD
node01 配置文件：
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="http://192.168.1.91:2380"
ETCD_LISTEN_CLIENT_URLS="http://192.168.1.91:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd1"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://etcd1.k8s.com:2380"
ETCD_ADVERTISE_CLIENT_URLS="http://etcd1.k8s.com:2379"
ETCD_DISCOVERY_SRV="k8s.com"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
node02 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="http://192.168.1.92:2380"
ETCD_LISTEN_CLIENT_URLS="http://192.168.1.92:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd2"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://etcd2.k8s.com:2380"
ETCD_ADVERTISE_CLIENT_URLS="http://etcd2.k8s.com:2379"
ETCD_DISCOVERY_SRV="k8s.com"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
node03 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="http://192.168.1.93:2380"
ETCD_LISTEN_CLIENT_URLS="http://192.168.1.93:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd3"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://etcd3.k8s.com:2380"
ETCD_ADVERTISE_CLIENT_URLS="http://etcd3.k8s.com:2379"
ETCD_DISCOVERY_SRV="k8s.com"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
启动并测试：
[root@node01 etcd]# systemctl start etcd
[root@node01 etcd]# systemctl status etcd
● etcd.service - Etcd Server
Loaded: loaded (/usr/lib/systemd/system/etcd.service; disabled; vendor preset: disabled)
Active: active (running) since Thu 2019-11-07 11:25:29 CST; 4s ago
Main PID: 14203 (etcd)
Tasks: 8
Memory: 16.9M
CGroup: /system.slice/etcd.service
└─14203 /usr/bin/etcd --name=etcd1 --data-dir=/data/k8s/etcd/data --listen-client-urls=http://192.168.1.91:2379
Nov 07 11:25:29 node01.k8s.com etcd[14203]: d79e9ae86b2a1de1 [quorum:2] has received 2 MsgVoteResp votes and 0 vote rejections
Nov 07 11:25:29 node01.k8s.com etcd[14203]: d79e9ae86b2a1de1 became leader at term 2
Nov 07 11:25:29 node01.k8s.com etcd[14203]: raft.node: d79e9ae86b2a1de1 elected leader d79e9ae86b2a1de1 at term 2
Nov 07 11:25:29 node01.k8s.com etcd[14203]: published {Name:etcd1 ClientURLs:[http://etcd1.k8s.com:2379 http://etcd1.k8s.com:4001]} to cluster 42cecf80e3791d6c
Nov 07 11:25:29 node01.k8s.com etcd[14203]: ready to serve client requests
Nov 07 11:25:29 node01.k8s.com etcd[14203]: serving insecure client requests on 192.168.1.91:2379, this is strongly discouraged!
Nov 07 11:25:29 node01.k8s.com systemd[1]: Started Etcd Server.
Nov 07 11:25:29 node01.k8s.com etcd[14203]: setting up the initial cluster version to 3.3
Nov 07 11:25:29 node01.k8s.com etcd[14203]: set the initial cluster version to 3.3
Nov 07 11:25:29 node01.k8s.com etcd[14203]: enabled capabilities for version 3.3
日志 vim /var/log/messages 表现如下:
Nov 7 11:25:27 node01 etcd: got bootstrap from DNS for etcd-server at 0=http://etcd3.k8s.com:2380
Nov 7 11:25:27 node01 etcd: got bootstrap from DNS for etcd-server at 1=http://etcd2.k8s.com:2380
Nov 7 11:25:27 node01 etcd: got bootstrap from DNS for etcd-server at etcd1=http://etcd1.k8s.com:2380
Nov 7 11:25:27 node01 etcd: resolving etcd1.k8s.com:2380 to 192.168.1.91:2380
Nov 7 11:25:27 node01 etcd: resolving etcd1.k8s.com:2380 to 192.168.1.91:2380
Nov 7 11:25:28 node01 etcd: name = etcd1
Nov 7 11:25:28 node01 etcd: data dir = /data/k8s/etcd/data
Nov 7 11:25:28 node01 etcd: member dir = /data/k8s/etcd/data/member
Nov 7 11:25:28 node01 etcd: dedicated WAL dir = /data/k8s/etcd/wal
Nov 7 11:25:28 node01 etcd: heartbeat = 100ms
Nov 7 11:25:28 node01 etcd: election = 1000ms
Nov 7 11:25:28 node01 etcd: snapshot count = 100000
Nov 7 11:25:28 node01 etcd: advertise client URLs = http://etcd1.k8s.com:2379,http://etcd1.k8s.com:4001
Nov 7 11:25:28 node01 etcd: initial advertise peer URLs = http://etcd1.k8s.com:2380
Nov 7 11:25:28 node01 etcd: initial cluster = 0=http://etcd3.k8s.com:2380,1=http://etcd2.k8s.com:2380,etcd1=http://etcd1.k8s.com:2380
测试：
[root@node01 etcd]# etcdctl --endpoints=http://192.168.1.91:2379 cluster-health
member 184beca37ca32d75 is healthy: got healthy result from http://etcd2.k8s.com:2379
member d79e9ae86b2a1de1 is healthy: got healthy result from http://etcd1.k8s.com:2379
member f7662e609b7e4013 is healthy: got healthy result from http://etcd3.k8s.com:2379
cluster is healthy
到这里证明已经成功了。
ETCD TLS 动态集群基于 DNS 的 SRV 解析自动发现
同样需要局域网内部有 DNS 服务器
添加SRV解析
目前常用的内部DNS服务有两种，bind、dnsmasq
在下面都会列出具体的配置，但只需要配置其中之一即可；
方法一: 使用bind配置SRV解析 如果内部没有bind服务，可以参考部署文档文章: https://www.cnblogs.com/winstom/p/11806962.html
使用域名为: k8s.com，在 bind 的 zone 文件中添加如下解析:
etcd1 IN A 192.168.1.91
etcd2 IN A 192.168.1.92
etcd3 IN A 192.168.1.93
_etcd-server-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd1
_etcd-server-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd2
_etcd-server-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd3
_etcd-client-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd1
_etcd-client-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd2
_etcd-client-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd3
修改之后重新加载配置文件:
[root@jenkins named]# named-checkzone k8s.com k8s.com.zone
zone k8s.com/IN: loaded serial 0
OK
[root@jenkins named]# rndc reload
server reload successful
方法二: 使用 dnsmasq 配置 SRV 解析 如果内部没有 dnsmasq 服务，可以参考部署文档文章: https://www.cnblogs.com/winstom/p/11809066.html
使用域名为: k8s.com，具体修改如下，在 /etc/dnsmasq_hosts新增下面内容:
192.168.1.91 etcd1 etcd1.k8s.com
192.168.1.92 etcd2 etcd2.k8s.com
192.168.1.93 etcd3 etcd3.k8s.com
在 /etc/dnsmasq.conf 文件中增加下面 SRV 解析内容:
srv-host=_etcd-server-ssl._tcp.k8s.com,etcd1.k8s.com,2380,0,100
srv-host=_etcd-server-ssl._tcp.k8s.com,etcd2.k8s.com,2380,0,100
srv-host=_etcd-server-ssl._tcp.k8s.com,etcd3.k8s.com,2380,0,100
srv-host=_etcd-client-ssl._tcp.k8s.com,etcd1.k8s.com,2380,0,100
srv-host=_etcd-client-ssl._tcp.k8s.com,etcd2.k8s.com,2380,0,100
srv-host=_etcd-client-ssl._tcp.k8s.com,etcd3.k8s.com,2380,0,100
修改之后重启服务：
systemctl restart dnsmasq
验证 SRV 解析是否正常，查询 SRV记录：
[root@node01 etcd]# dig @192.168.1.122 +noall +answer SRV _etcd-server-ssl._tcp.k8s.com
_etcd-server-ssl._tcp.k8s.com. 3600 IN SRV 2380 0 100 etcd3.k8s.com.
_etcd-server-ssl._tcp.k8s.com. 3600 IN SRV 2380 0 100 etcd2.k8s.com.
_etcd-server-ssl._tcp.k8s.com. 3600 IN SRV 2380 0 100 etcd1.k8s.com.
查询域名解析结果:
[root@node01 ~]# dig @192.168.1.122 +noall +answer etcd1.k8s.com etcd2.k8s.com etcd3.k8s.com
etcd1.k8s.com. 86400 IN A 192.168.1.91
etcd2.k8s.com. 86400 IN A 192.168.1.92
etcd3.k8s.com. 86400 IN A 192.168.1.93
ETCD 配置
node01 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="https://192.168.1.91:2380"
ETCD_LISTEN_CLIENT_URLS="https://192.168.1.91:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd1"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://etcd1.k8s.com:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://etcd1.k8s.com:2379,https://etcd1.k8s.com:4001"
ETCD_DISCOVERY_SRV="k8s.com"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
ETCD_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_CLIENT_CERT_AUTH="true"
ETCD_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_AUTO_TLS="true"
ETCD_PEER_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_PEER_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_PEER_CLIENT_CERT_AUTH="true"
ETCD_PEER_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_PEER_AUTO_TLS="true"
node02 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="https://192.168.1.92:2380"
ETCD_LISTEN_CLIENT_URLS="https://192.168.1.92:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd2"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://etcd2.k8s.com:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://etcd2.k8s.com:2379"
ETCD_DISCOVERY_SRV="k8s.com"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
ETCD_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_CLIENT_CERT_AUTH="true"
ETCD_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_AUTO_TLS="true"
ETCD_PEER_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_PEER_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_PEER_CLIENT_CERT_AUTH="true"
ETCD_PEER_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_PEER_AUTO_TLS="true"
node03 配置文件:
ETCD_DATA_DIR="/data/k8s/etcd/data"
ETCD_WAL_DIR="/data/k8s/etcd/wal"
ETCD_LISTEN_PEER_URLS="https://192.168.1.93:2380"
ETCD_LISTEN_CLIENT_URLS="https://192.168.1.93:2379"
ETCD_MAX_SNAPSHOTS="5"
ETCD_MAX_WALS="5"
ETCD_NAME="etcd3"
ETCD_SNAPSHOT_COUNT="100000"
ETCD_HEARTBEAT_INTERVAL="100"
ETCD_ELECTION_TIMEOUT="1000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://etcd3.k8s.com:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://etcd3.k8s.com:2379"
ETCD_DISCOVERY_SRV="k8s.com"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
ETCD_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_CLIENT_CERT_AUTH="true"
ETCD_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_AUTO_TLS="true"
ETCD_PEER_CERT_FILE="/etc/etcd/cert/etcd.pem"
ETCD_PEER_KEY_FILE="/etc/etcd/cert/etcd-key.pem"
ETCD_PEER_CLIENT_CERT_AUTH="true"
ETCD_PEER_TRUSTED_CA_FILE="/etc/kubernetes/cert/ca.pem"
ETCD_PEER_AUTO_TLS="true"
启动测试:
[root@node03 etcd]# systemctl restart etcd
[root@node03 etcd]# systemctl status etcd
● etcd.service - Etcd Server
Loaded: loaded (/usr/lib/systemd/system/etcd.service; disabled; vendor preset: disabled)
Active: active (running) since Thu 2019-11-07 12:38:37 CST; 4s ago
Main PID: 13460 (etcd)
Tasks: 8
Memory: 16.6M
CGroup: /system.slice/etcd.service
└─13460 /usr/bin/etcd --name=etcd3 --data-dir=/data/k8s/etcd/data --listen-client-urls=https://192.168.1.93:2379
Nov 07 12:38:36 node03.k8s.com etcd[13460]: established a TCP streaming connection with peer 40a8f19a5db99534 (stream Message writer)
Nov 07 12:38:36 node03.k8s.com etcd[13460]: established a TCP streaming connection with peer 40a8f19a5db99534 (stream MsgApp v2 writer)
Nov 07 12:38:37 node03.k8s.com etcd[13460]: 9888555207dbf0e0 [term: 92] received a MsgVote message with higher term from a0d541999e9eb3b3 [term: 98]
Nov 07 12:38:37 node03.k8s.com etcd[13460]: 9888555207dbf0e0 became follower at term 98
Nov 07 12:38:37 node03.k8s.com etcd[13460]: 9888555207dbf0e0 [logterm: 92, index: 9, vote: 0] cast MsgVote for a0d541999e9eb3b3 [logterm: 92, index: 9] at term 98
Nov 07 12:38:37 node03.k8s.com etcd[13460]: raft.node: 9888555207dbf0e0 elected leader a0d541999e9eb3b3 at term 98
Nov 07 12:38:37 node03.k8s.com etcd[13460]: published {Name:etcd3 ClientURLs:[https://etcd3.k8s.com:2379]} to cluster f445a02ce3dc6a02
Nov 07 12:38:37 node03.k8s.com etcd[13460]: ready to serve client requests
Nov 07 12:38:37 node03.k8s.com etcd[13460]: serving client requests on 192.168.1.93:2379
Nov 07 12:38:37 node03.k8s.com systemd[1]: Started Etcd Server.
查看 message 日志：
Nov 7 12:38:36 node01 etcd: added member 40a8f19a5db99534 [https://etcd2.k8s.com:2380] to cluster f445a02ce3dc6a02
Nov 7 12:38:36 node01 etcd: starting peer 40a8f19a5db99534...
Nov 7 12:38:36 node01 etcd: started HTTP pipelining with peer 40a8f19a5db99534
Nov 7 12:38:36 node01 etcd: started streaming with peer 40a8f19a5db99534 (writer)
Nov 7 12:38:36 node01 etcd: started peer 40a8f19a5db99534
Nov 7 12:38:36 node01 etcd: added peer 40a8f19a5db99534
Nov 7 12:38:36 node01 etcd: added member 9888555207dbf0e0 [https://etcd3.k8s.com:2380] to cluster f445a02ce3dc6a02
Nov 7 12:38:36 node01 etcd: starting peer 9888555207dbf0e0...
Nov 7 12:38:36 node01 etcd: started HTTP pipelining with peer 9888555207dbf0e0
Nov 7 12:38:36 node01 etcd: started peer 9888555207dbf0e0
Nov 7 12:38:36 node01 etcd: added peer 9888555207dbf0e0
Nov 7 12:38:36 node01 etcd: added member a0d541999e9eb3b3 [https://etcd1.k8s.com:2380] to cluster f445a02ce3dc6a02
测试集群状态：
ETCDCTL_API=3 etcdctl --endpoints=https://etcd1.k8s.com:2379,https://etcd2.k8s.com:2379,https://etcd3.k8s.com:2379 \
--cacert=/etc/kubernetes/cert/ca.pem \
--cert=/etc/etcd/cert/etcd.pem \
--key=/etc/etcd/cert/etcd-key.pem endpoint health
# 输出
https://etcd1.k8s.com:2379 is healthy: successfully committed proposal: took = 4.269468ms
https://etcd3.k8s.com:2379 is healthy: successfully committed proposal: took = 1.58797ms
https://etcd2.k8s.com:2379 is healthy: successfully committed proposal: took = 1.622151ms
报错解决
证书报错 bad certificate，日志中报错:
Nov 7 12:37:03 node01 etcd: rejected connection from "192.168.1.93:46294" (error "remote error: tls: bad certificate", ServerName "k8s.com")
报错的意思是在生成 ETCD 的 TLS 证书的时候，没有把对应的域名加进去，在创建 ETCD 的 TLS 证书请求的文件中加入对应的域名：
cd /opt/k8s/work
cat > etcd-csr.json <<EOF
{
"CN": "etcd",
"hosts": [
"127.0.0.1",
"192.168.1.91",
"192.168.1.92",
"192.168.1.93",
"k8s.com", # 这里的域名查看是否正确
"etcd1.k8s.com",
"etcd2.k8s.com",
"etcd3.k8s.com"
],
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "CN",
"ST": "BeiJing",
"L": "BeiJing",
"O": "k8s",
"OU": "4Paradigm"
}
]
}
EOF
DNS 的 SRV 解析报错:
etcd: error setting up initial cluster: cannot find local etcd member "etcd1" in SRV records
这里是说 DNS 在配置 SRV 解析的时候报错，请仔细查看解析配置，SRV 解析分为两种，一种是 http 不带证书的解析，一种是 https 带证书的解析，是有区别的，如果配置错误就会包上述错误
http不带证书解析如下：
bind 的解析，编辑 /var/named/k8s.com.zone 文件
etcd1 IN A 192.168.1.91
etcd2 IN A 192.168.1.92
etcd3 IN A 192.168.1.93
_etcd-server._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd1
_etcd-server._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd2
_etcd-server._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd3
_etcd-client._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd1
_etcd-client._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd2
_etcd-client._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd3
dnsmasq 的解析，在/etc/dnsmasq_hosts新增下面内容：
192.168.1.91 etcd1 etcd1.k8s.com
192.168.1.92 etcd2 etcd2.k8s.com
192.168.1.93 etcd3 etcd3.k8s.com
在 /etc/dnsmasq.conf 文件中增加下面SRV解析内容
srv-host=_etcd-server._tcp.k8s.com,etcd1.k8s.com,2380,0,100
srv-host=_etcd-server._tcp.k8s.com,etcd2.k8s.com,2380,0,100
srv-host=_etcd-server._tcp.k8s.com,etcd3.k8s.com,2380,0,100
srv-host=_etcd-client._tcp.k8s.com,etcd1.k8s.com,2380,0,100
srv-host=_etcd-client._tcp.k8s.com,etcd2.k8s.com,2380,0,100
srv-host=_etcd-client._tcp.k8s.com,etcd3.k8s.com,2380,0,100
https带证书解析如下:
bind 的解析，编辑 /var/named/k8s.com.zone 文件：
etcd1 IN A 192.168.1.91
etcd2 IN A 192.168.1.92
etcd3 IN A 192.168.1.93
_etcd-server-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd1
_etcd-server-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd2
_etcd-server-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd3
_etcd-client-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd1
_etcd-client-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd2
_etcd-client-ssl._tcp.k8s.com. 1H IN SRV 2380 0 100 etcd3
dnsmasq 的解析，在/etc/dnsmasq_hosts新增下面内容：
192.168.1.91 etcd1 etcd1.k8s.com
192.168.1.92 etcd2 etcd2.k8s.com
192.168.1.93 etcd3 etcd3.k8s.com
在 /etc/dnsmasq.conf 文件中增加下面 SRV 解析内容:
srv-host=_etcd-server-ssl._tcp.k8s.com,etcd1.k8s.com,2380,0,100
srv-host=_etcd-server-ssl._tcp.k8s.com,etcd2.k8s.com,2380,0,100
srv-host=_etcd-server-ssl._tcp.k8s.com,etcd3.k8s.com,2380,0,100
srv-host=_etcd-client-ssl._tcp.k8s.com,etcd1.k8s.com,2380,0,100
srv-host=_etcd-client-ssl._tcp.k8s.com,etcd2.k8s.com,2380,0,100
srv-host=_etcd-client-ssl._tcp.k8s.com,etcd3.k8s.com,2380,0,100
原文链接：https://www.cnblogs.com/winstom/p/11811373.html
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