参考文档 https://coreos.com/flannel/docs/latest/

1. 基础环境(服务器IP：172.17.0.51,52,53)

    a.系统版本         CentOS Linux release 7.6.1810 (Core)

    b.flannel版本 0.7.1

    c.修改主机名     hostnamectl --static set-hostname node51,修改 /etc/hosts

2. 安装flannel

    yum install -y flannel 

3. 配置flannel

    a.  flannel配置文件/etc/sysconfig/flanneld

        FLANNEL_ETCD_ENDPOINTS="https://172.17.0.51:2379,https://172.17.0.52:2379,https://172.17.0.53:2379"

        FLANNEL_ETCD_PREFIX="/xxx.com/network"

        FLANNEL_OPTIONS="-etcd-cafile=/etc/etcd/ca.pem -etcd-certfile=/etc/etcd/server.pem -etcd-keyfile=/etc/etcd/server-key.pem"

   b.  /usr/lib/systemd/system/flanneld.service

        去掉After=etcd.service

        确认Before=docker.servic

4. 启动配置

    a. 向etcd注册网段(其中一台etcd服务器操作即可)

        etcdctl --ca-file=/etc/etcd/ca.pem --cert-file=/etc/etcd/server.pem --key-file=/etc/etcd/server-key.pem --endpoints="https://172.17.0.51:2379"  set /xxx.com/network/config  '{ "Network": "10.88.0.0/16"}'

    b. 添加快速启动

        systemctl enable flanneld && systemctl daemon-reload

    c. 启动(flannel要关闭docker，覆盖docker网桥)

        systemctl start flanneld && systemctl start docker

    d. 查看节点获得的IP

        [root@node51 docker]# ip a |grep inet

            inet 127.0.0.1/8 scope host lo

            inet 172.17.0.51/24 brd 172.17.0.255 scope global eth0

            inet 10.88.16.0/16 scope global flannel0

            inet 10.88.16.1/24 brd 10.88.16.255 scope global docker0