安装部署 flanneld

# 你可以做如下尝试，21机器：
~]# kubectl get pods -o wide
~]# ping 172.7.21.2
~]# ping 172.7.22.2

你可以发现，两个容器的宿主机之间是不互通的，更别说进入容器里面了。（当然ping10.4.7.22是没问题的）

这时候我们就需要CNI网络插件，CNI最主要的功能是实现POD资源能够跨宿主机进行通信，当然CNI网络插件有很多种，如Flannel、Calico等，而Flannel是目前市场上最为火热的

# 21/22机器：
~]# cd /opt/src/
src]# wget https://github.com/coreos/flannel/releases/download/v0.11.0/flannel-v0.11.0-linux-amd64.tar.gz
src]# mkdir /opt/flannel-v0.11.0
src]# tar xf flannel-v0.11.0-linux-amd64.tar.gz -C /opt/flannel-v0.11.0/
src]# ln -s /opt/flannel-v0.11.0/ /opt/flannel
src]# cd /opt/flannel
flannel]# ll
# out:总用量 34436
flannel]# mkdir cert
flannel]# cd cert/
cert]# scp hdss7-200:/opt/certs/ca.pem . 
cert]# scp hdss7-200:/opt/certs/client.pem .
cert]# scp hdss7-200:/opt/certs/client-key.pem .
cert]# cd ..
# 注意机器名，需要改一处：SUBNET=172.7.21.1/24，需要改成SUBNET=172.7.22.1/24
flannel]# vi subnet.env
FLANNEL_NETWORK=172.7.0.0/16
FLANNEL_SUBNET=172.7.21.1/24
FLANNEL_MTU=1500
FLANNEL_IPMASQ=false

# 21/22机器,注意，我的网络是eth0，新版的是ens33，如果是ens33，则需要改iface，其它需要改一处机器名：ip=10.4.7.21
flannel]# vi flanneld.sh
#!/bin/sh
./flanneld \
  --public-ip=10.4.7.21 \
  --etcd-endpoints=https://10.4.7.12:2379,https://10.4.7.21:2379,https://10.4.7.22:2379 \
  --etcd-keyfile=./cert/client-key.pem \
  --etcd-certfile=./cert/client.pem \
  --etcd-cafile=./cert/ca.pem \
  --iface=eth0 \
  --subnet-file=./subnet.env \
  --healthz-port=2401
  
flannel]# chmod +x flanneld.sh
flannel]# mkdir -p /data/logs/flanneld
flannel]# cd /opt/etcd
# 下面这一步在一部机器上执行即可，只需执行一次，我在21机器做的：
etcd]# ./etcdctl set /coreos.com/network/config '{"Network": "172.7.0.0/16", "Backend": {"Type": "host-gw"}}'
etcd]# ./etcdctl get /coreos.com/network/config
# out:{"Network": "172.7.0.0/16", "Backend": {"Type": "host-gw"}}
# 有一处要修改，21/22机器：flanneld-7-21]
etcd]# vi /etc/supervisord.d/flannel.ini
[program:flanneld-7-21]
command=/opt/flannel/flanneld.sh                             ; the program (relative uses PATH, can take args)
numprocs=1                                                   ; number of processes copies to start (def 1)
directory=/opt/flannel                                       ; directory to cwd to before exec (def no cwd)
autostart=true                                               ; start at supervisord start (default: true)
autorestart=true                                             ; retstart at unexpected quit (default: true)
startsecs=30                                                 ; number of secs prog must stay running (def. 1)
startretries=3                                               ; max # of serial start failures (default 3)
exitcodes=0,2                                                ; 'expected' exit codes for process (default 0,2)
stopsignal=QUIT                                              ; signal used to kill process (default TERM)
stopwaitsecs=10                                              ; max num secs to wait b4 SIGKILL (default 10)
user=root                                                    ; setuid to this UNIX account to run the program
redirect_stderr=true                                         ; redirect proc stderr to stdout (default false)
stdout_logfile=/data/logs/flanneld/flanneld.stdout.log       ; stderr log path, NONE for none; default AUTO
stdout_logfile_maxbytes=64MB                                 ; max # logfile bytes b4 rotation (default 50MB)
stdout_logfile_backups=4                                     ; # of stdout logfile backups (default 10)
stdout_capture_maxbytes=1MB                                  ; number of bytes in 'capturemode' (default 0)
stdout_events_enabled=false                                  ; emit events on stdout writes (default false)
etcd]# supervisorctl update
etcd]# supervisorctl status
# 查看细节信息
etcd]# tail -fn 200 /data/logs/flanneld/flanneld.stdout.log 
# 两部机器完成后，在21和22机器ping对方，已经可以ping通