背景

今天打算在腾讯云环境上安装k8s（采用ansible脚本自动化部署安装），当安装完etcd之后，发现启动报错。
机器：腾讯云服务器（含内外网两个IP）

问题定位

先查看了下etcd服务的状态，采用如下命令：

systemctl status etcd

查询结果如下：

etcd.service - Etcd Server
   Loaded: loaded (/etc/systemd/system/etcd.service; disabled; vendor preset: disabled)
   Active: activating (auto-restart) (Result: exit-code) since Wed 2022-01-26 13:59:27 CST; 3s ago
  Process: 29215 ExecStart=/usr/bin/etcd --data-dir=/var/lib/etcd --name=etcd0 --cert-file=/etc/kubernetes/pki/etcd.pem --key-file=/etc/kubernetes/pki/etcd-key.pem --trusted-ca-file=/etc/kubernetes/pki/ca.pem --peer-cert-file=/etc/kubernetes/pki/etcd.pem --peer-key-file=/etc/kubernetes/pki/etcd-key.pem --peer-trusted-ca-file=/etc/kubernetes/pki/ca.pem --peer-client-cert-auth --client-cert-auth --listen-peer-urls=https://124.223.82.79:2380 --initial-advertise-peer-urls=https://124.223.82.79:2380 --listen-client-urls=https://124.223.82.79:2379,http://127.0.0.1:2379 --advertise-client-urls=https://124.223.82.79:2379 --initial-cluster-token=etcd-cluster-0 --initial-cluster=etcd0=https://124.223.82.79:2380 --initial-cluster-state=new (code=exited, status=1/FAILURE)
 Main PID: 29215 (code=exited, status=1/FAILURE)

Jan 26 13:59:27 VM-4-9-centos systemd[1]: etcd.service: main process exited, code=exited, status=1/FAILURE
Jan 26 13:59:27 VM-4-9-centos systemd[1]: Failed to start Etcd Server.
Jan 26 13:59:27 VM-4-9-centos systemd[1]: Unit etcd.service entered failed state.
Jan 26 13:59:27 VM-4-9-centos systemd[1]: etcd.service failed.

发现启动失败，但是看不出具体的报错，因此想着查看下日志：

journalctl -xe |grep etcd

查询如下：

Jan 26 13:53:40 VM-4-9-centos etcd[23453]: Git SHA: 9fd7e2b80
Jan 26 13:53:40 VM-4-9-centos etcd[23453]: Go Version: go1.12.17
Jan 26 13:53:40 VM-4-9-centos etcd[23453]: Go OS/Arch: linux/amd64
Jan 26 13:53:40 VM-4-9-centos etcd[23453]: setting maximum number of CPUs to 2, total number of available CPUs is 2
Jan 26 13:53:40 VM-4-9-centos etcd[23453]: peerTLS: cert = /etc/kubernetes/pki/etcd.pem, key = /etc/kubernetes/pki/etcd-key.pem, ca = , trusted-ca = /etc/kubernetes/pki/ca.pem, client-cert-auth = true, crl-file =
Jan 26 13:53:40 VM-4-9-centos etcd[23453]: listen tcp 124.223.82.79:2380: bind: cannot assign requested address
Jan 26 13:53:40 VM-4-9-centos systemd[1]: etcd.service: main process exited, code=exited, status=1/FAILURE
-- Subject: Unit etcd.service has failed
-- Unit etcd.service has failed.
Jan 26 13:53:40 VM-4-9-centos systemd[1]: Unit etcd.service entered failed state.
Jan 26 13:53:40 VM-4-9-centos systemd[1]: etcd.service failed.
Jan 26 13:53:46 VM-4-9-centos systemd[1]: etcd.service holdoff time over, scheduling restart.
-- Subject: Unit etcd.service has finished shutting down
-- Unit etcd.service has finished shutting down.
-- Subject: Unit etcd.service has begun start-up
-- Unit etcd.service has begun starting up.
Jan 26 13:53:46 VM-4-9-centos etcd[23548]: etcd Version: 3.3.20
Jan 26 13:53:46 VM-4-9-centos etcd[23548]: Git SHA: 9fd7e2b80
Jan 26 13:53:46 VM-4-9-centos etcd[23548]: Go Version: go1.12.17
Jan 26 13:53:46 VM-4-9-centos etcd[23548]: Go OS/Arch: linux/amd64
Jan 26 13:53:46 VM-4-9-centos etcd[23548]: setting maximum number of CPUs to 2, total number of available CPUs is 2
Jan 26 13:53:46 VM-4-9-centos etcd[23548]: peerTLS: cert = /etc/kubernetes/pki/etcd.pem, key = /etc/kubernetes/pki/etcd-key.pem, ca = , trusted-ca = /etc/kubernetes/pki/ca.pem, client-cert-auth = true, crl-file =
Jan 26 13:53:46 VM-4-9-centos etcd[23548]: listen tcp 124.223.82.79:2380: bind: cannot assign requested address
Jan 26 13:53:46 VM-4-9-centos systemd[1]: etcd.service: main process exited, code=exited, status=1/FAILURE
-- Subject: Unit etcd.service has failed
-- Unit etcd.service has failed.
Jan 26 13:53:46 VM-4-9-centos systemd[1]: Unit etcd.service entered failed state.
Jan 26 13:53:46 VM-4-9-centos systemd[1]: etcd.service failed.
Jan 26 13:53:51 VM-4-9-centos systemd[1]: etcd.service holdoff time over, scheduling restart.
-- Subject: Unit etcd.service has finished shutting down
-- Unit etcd.service has finished shutting down.
-- Subject: Unit etcd.service has begun start-up
-- Unit etcd.service has begun starting up.

其中很重要的一句便是：

Jan 26 13:53:46 VM-4-9-centos etcd[23548]: listen tcp 124.223.82.79:2380: bind: cannot assign requested address
Jan 26 13:53:46 VM-4-9-centos systemd[1]: etcd.service: main process exited, code=exited, status=1/FAILURE

错误提示地址绑定失败，考虑两个地方：
① 端口被占用了
② IP地址不对（或者说网卡上没有使用的IP）

问题排查

先考虑检查端口，命令如下

netstat -anp|grep 2380

检查后发现端口并未占用，接下来就只能考虑IP的问题了

ip a

发现网卡绑定上并没有我使用的【公网IP】，自然也监听不到了

解决方案

1. 修改etcd.service文件，路径一般为 /etc/systemd/system/etcd.service

vi /etc/systemd/system/etcd.service

将文件内的公网IP地址全部换成内网IP地址

修改完文件后执行如下命令

systemctl daemon-reload
systemctl restart etcd

查看状态

systemctl status etcd

小结

1. 在使用腾讯云、华为云这种云环境时，配置选用内网IP
2. 除etcd外，若其他组件在云环境中遇到bind: cannot assign requested address也可从这两方面（端口、IP）入手查看