Docker容器跨主機通信

預設情況下Docker容器需要跨主機通信兩個主機節點都需要在同一個網段下，這時隻要兩個Docker容器的主控端能互相通信并且該容器使用net網絡模式，改實作方式為網橋模式通信；

　　除此之外我們還可以通過使用第三方工具為不同主機間建立一個覆寫網絡，使之能夠跨節點通信，這裡将使用Flanneld實作；

安裝etcd

建立 cat /etc/etcd/etcd.conf檔案

# [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檔案

[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
           

啟動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節點并寫入網絡配置資訊：

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檔案

# 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檔案

[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
           

啟動systemctl start flanneld

flannled啟動後會生産/run/flannel/subnet.env檔案

修改docker啟動參數配置加上：

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

重新開機docker，此時docker将使用flanneld配置的網段為container配置設定ip；

在兩個節點分别啟動容器：docker run -it --rm busybox sh

檢視其中一個主機節點的容器IP，ping另一個主機節點IP

此時已可聯通；

注意iptables配置是否正确；

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