Docker容器跨主機通訊

默認狀況下Docker容器須要跨主機通訊兩個主機節點都須要在同一個網段下，這時只要兩個Docker容器的宿主機能相互通訊而且該容器使用net網絡模式，改實現方式爲網橋模式通訊；
　　除此以外咱們還能夠經過使用第三方工具爲不一樣主機間建立一個覆蓋網絡，使之可以跨節點通訊，這裏將使用Flanneld實現；

安裝etcd

建立 cat /etc/etcd/etcd.conf文件

# [member]
 ETCD_NAME=infra1
 ETCD_DATA_DIR="/var/lib/etcd"
 ETCD_LISTEN_PEER_URLS="http://192.168.2.150:2380"
 ETCD_LISTEN_CLIENT_URLS="http://192.168.2.150:2379"

 #[cluster]
 ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.2.150:2380"
 ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
 ETCD_ADVERTISE_CLIENT_URLS="http://192.168.2.150:2379"

建立/etc/systemd/system/etcd.service文件

[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target
Documentation=https://github.com/coreos

[Service]
Type=notify
WorkingDirectory=/var/lib/etcd/
EnvironmentFile=-/etc/etcd/etcd.conf
ExecStart=/usr/local/bin/etcd \
  --name ${ETCD_NAME} \
  --initial-advertise-peer-urls ${ETCD_INITIAL_ADVERTISE_PEER_URLS} \
  --listen-peer-urls ${ETCD_LISTEN_PEER_URLS} \
  --listen-client-urls ${ETCD_LISTEN_CLIENT_URLS},http://127.0.0.1:2379 \
  --advertise-client-urls ${ETCD_ADVERTISE_CLIENT_URLS} \
  --initial-cluster-token ${ETCD_INITIAL_CLUSTER_TOKEN} \
  --initial-cluster infra1=http://192.168.2.150:2380,infra2=http://192.168.2.151:2380 \
  --initial-cluster-state new \
  --data-dir=${ETCD_DATA_DIR}
Restart=on-failure
RestartSec=5
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target

啓動systemctl start etcd

在etcd中建立目錄：etcdctl --endpoints=http://192.168.2.150:2379,http://192.168.5.151:2379

mkdir /kube-centos/network

建立config節點並寫入網絡配置信息：

etcdctl --endpoints=http://172.20.0.113:2379,http://172.20.0.114:2379
 mk /kube-centos/network/config '{"Network":"192.167.0.0/16","SubnetLen":24,"Backend":{"Type":"vxlan"}}'

Flanneld

建立 /etc/sysconfig/flanneld文件

# Flanneld configuration options  
# etcd url location.  Point this to the server where etcd runs
FLANNEL_ETCD_ENDPOINTS="http://127.0.0.1:2379"

# etcd config key.  This is the configuration key that flannel queries
# For address range assignment
# FLANNEL_ETCD_PREFIX="/kube-centos/network"
FLANNEL_ETCD_PREFIX="/coreos.com/network"
# Any additional options that you want to pass
FLANNEL_OPTIONS="-iface=eth0"

建立/usr/lib/systemd/system/flanneld.service文件

[Unit]
Description=Flanneld overlay address etcd agent
After=network.target
After=network-online.target
Wants=network-online.target
After=etcd.service
Before=docker.service

[Service]
Type=notify
EnvironmentFile=/etc/sysconfig/flanneld
EnvironmentFile=-/etc/sysconfig/docker-network
#ExecStart=/usr/bin/flanneld-start  $FLANNEL_OPTIONS
ExecStart=/usr/bin/flanneld-start -etcd-endpoints=http://192.168.2.150:2379,http://192.168.2.151:2379 -    iface=ens33
#ExecStart=/usr/bin/flanneld-start -etcd-endpoints=http://192.168.2.150:2379,http://192.168.2.151:2379  -etcd-    prefix=/kube-centos/network
ExecStartPost=/usr/libexec/flannel/mk-docker-opts.sh -k DOCKER_NETWORK_OPTIONS -d /run/flannel/docker
Restart=on-failure

[Install]
WantedBy=multi-user.target
RequiredBy=docker.service

啓動systemctl start flanneld

flannled啓動後會生產/run/flannel/subnet.env文件

修改docker啓動參數配置加上：

EnvironmentFile=/run/flannel/subnet.env
--bip=${FLANNEL_SUBNET} --ip-masq=${FLANNEL_IPMASQ}  --mtu=${FLANNEL_MTU}

重啓docker，此時docker將使用flanneld配置的網段爲container分配ip；

在兩個節點分別啓動容器：docker run -it --rm busybox sh

查看其中一個主機節點的容器IP，ping另外一個主機節點IP

查看其中一個主機節點的容器IP，ping另外一個主機節點IP

此時已可聯通；

注意iptables配置是否正確；

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