Docker 网络 Flannel

恒晖瑶

flannel 安装
　　sudo yum install kernel-headers golang gcc
yum install flannel

flannel 配置

在etcd中设置变量
　　etcdctl set /coreos.com/network/config '{ "Network": "172.17.0.0/16" }'

配置flannel
　　vi /etc/sysconfig/flanneld



# Flanneld configuration options
# etcd url location.  Point this to the server where etcd runs
FLANNEL_ETCD="http://10.1.99.13:2379,10.1.99.14:2379,10.1.99.15:2379"
# etcd config key.  This is the configuration key that flannel queries
# For address range assignment
FLANNEL_ETCD_KEY="/coreos.com/network"
# Any additional options that you want to pass
#FLANNEL_OPTIONS=""
重新启动flannel
　　systemctl daemon-reload flanneld
　　systemctl restart flanneld

flannel服务启动
　　flannel服务需要先于docker启动。flannel服务启动时主要做了以下几步的工作：

• 从etcd中获取network的配置信息
  
• 划分subnet，并在etcd中进行注册
  
• 将子网信息记录到/run/flannel/subnet.env中
  

cat /run/flannel/subnet.env


cat /run/flannel/subnet.env
FLANNEL_NETWORK=172.17.0.0/16
FLANNEL_SUBNET=172.17.50.1/24
FLANNEL_MTU=1472
FLANNEL_IPMASQ=false

• 之后将会有一个脚本将subnet.env转写成一个docker的环境变量文件/run/flannel/docker
  

cat /run/flannel/docker



FLANNEL_NETWORK=172.17.0.0/16
FLANNEL_SUBNET=172.17.50.1/24
FLANNEL_MTU=1472
FLANNEL_IPMASQ=false
[iyunv@v4 ~]# cat /run/flannel/docker
DOCKER_OPT_BIP="--bip=172.17.50.1/24"
DOCKER_OPT_IPMASQ="--ip-masq=true"
DOCKER_OPT_MTU="--mtu=1472"
DOCKER_NETWORK_OPTIONS=" --bip=172.17.50.1/24 --ip-masq=true --mtu=1472 "
　　配置docker
　　systemctl show docker 将会发现 在安装flannel后自动生成配置
　　DropInPaths=/usr/lib/systemd/system/docker.service.d/flannel.conf
　　并引用/run/flannel/docker
　　故在docker的systemd文件中应用对应变量 DOCKER_NETWORK_OPTIONS 即可
　　vi /usr/lib/systemd/system/docker.service



ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock $DOCKER_NETWORK_OPTIONS
　　重新启动docker
　　systemctl daemon-reload
　　systemctl restart docker
　　测试
　　分别在两台节点上启动测试容器
　　docker run -d -it --name ip_test busybox
　　后网络互通,测试通过