docker動態映射運行的container端口，最近做項目，對于docker動態映射運行的container端口的資料有必要記錄下，以便以后在用到，
Docker自帶了EXPOSE命令，可以通過編寫dockerfile加-p參數方便的映射Container內部端口，但是對于已經運行的container，如果你想對外開放一個新的端口，只能編輯dockerfile然后重新build，有點不太方便。
其實docker本身使用了iptables來做端口映射的，所以我們可以通過一些簡單的操作來實現動態映射運行中的container端口。
通過運行iptables命令可以看到具體的端口映射(下面的實例中IP為192.168.42.41的container開放了22和20280等端口)
[yaxin@ubox ~]$sudo iptables -nvxL Chain INPUT (policy ACCEPT 262 packets, 529689 bytes) pkts bytes target prot opt in out source destination 14355 789552 DROP tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:25 Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 5479459 653248187 DOCKER all -- * docker0 0.0.0.0/0 0.0.0.0/0 93990 314970368 ACCEPT all -- * docker0 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED 4705395 2183219154 ACCEPT all -- docker0 !docker0 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT all -- docker0 docker0 0.0.0.0/0 0.0.0.0/0 Chain OUTPUT (policy ACCEPT 282 packets, 622495 bytes) pkts bytes target prot opt in out source destination Chain DOCKER (1 references) pkts bytes target prot opt in out source destination 218 13193 ACCEPT tcp -- !docker0 docker0 0.0.0.0/0 192.168.42.41 tcp dpt:22280 4868186 297463902 ACCEPT tcp -- !docker0 docker0 0.0.0.0/0 192.168.42.41 tcp dpt:20280 78663 13128102 ACCEPT tcp -- !docker0 docker0 0.0.0.0/0 192.168.42.41 tcp dpt:22 47 4321 ACCEPT tcp -- !docker0 docker0 0.0.0.0/0 192.168.42.41 tcp dpt:28159 [yaxin@ubox ~]$sudo iptables -t nat -nvxL Chain PREROUTING (policy ACCEPT 210199 packets, 14035875 bytes) pkts bytes target prot opt in out source destination 1219483 82563968 DOCKER all -- * * 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type LOCAL Chain INPUT (policy ACCEPT 197679 packets, 13316595 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 271553 packets, 16671466 bytes) pkts bytes target prot opt in out source destination 1643 99251 DOCKER all -- * * 0.0.0.0/0 !127.0.0.0/8 ADDRTYPE match dst-type LOCAL Chain POSTROUTING (policy ACCEPT 271743 packets, 16682594 bytes) pkts bytes target prot opt in out source destination 13468 811013 MASQUERADE all -- * !docker0 192.168.42.0/24 0.0.0.0/0 0 0 MASQUERADE tcp -- * * 192.168.42.41 192.168.42.41 tcp dpt:22280 0 0 MASQUERADE tcp -- * * 192.168.42.41 192.168.42.41 tcp dpt:20280 0 0 MASQUERADE tcp -- * * 192.168.42.41 192.168.42.41 tcp dpt:22 0 0 MASQUERADE tcp -- * * 192.168.42.41 192.168.42.41 tcp dpt:28159 Chain DOCKER (2 references) pkts bytes target prot opt in out source destination 22 1404 DNAT tcp -- !docker0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:22280 to:192.168.42.41:22280 288 17156 DNAT tcp -- !docker0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:20280 to:192.168.42.41:20280 93 5952 DNAT tcp -- !docker0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:22222 to:192.168.42.41:22 8 512 DNAT tcp -- !docker0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:28159 to:192.168.42.41:28159
我們要做的就是根據自己container的情況配置iptables規則。
首先是filter這個表，我們要配置其放通轉發，docker默認已經將所有的FORWARD規則放到了DOCKER這個自建鏈(chain)中了，這樣方便配置，也方便查看。
然后再配置nat表為其配置DNAT，這個才是端口轉發的核心配置。這個表中只需要配置POSTROUTING和DOCKER鏈即可，這里不講為什么這么配置，如果想要深入了解iptables請google一下。
下面舉個例子：
假如我有一個container，名字為nginx(通過運行docker ps命令即可查詢)，現在我在docker內部運行nginx程序，監聽了8888端口，我希望外網可以通過8899端口(注意一下端口)訪問
找到docker為nginx分配的IP
[yaxin@ubox ~]$sudo docker inspect -f '{{.NetworkSettings.IPAddress}}' nginx192.168.42.43配置iptables中filter表的FORWARD(DOCKER)鏈
[yaxin@ubox ~]$sudo iptables -A DOCKER ! -i docker0 -o docker0 -p tcp --dport 8888 -d 192.168.42.43 -j ACCEPT
配置iptables中nat表的PREROUTING(DOCKER)和POSTROUTING鏈
[yaxin@ubox ~]$sudo iptables -t nat -A POSTROUTING -p tcp --dport 8888 -s 192.168.42.43 -d 192.168.42.43 -j MASQUERADE[yaxin@ubox ~]$sudo iptables -t nat -A DOCKER ! -i dokcer0 -p tcp --dport 8899 -j DNAT --to-destination 192.168.42.43:8888
通過外網訪問curl http://IP:8899就會顯示nginx下配置的html頁面
最后iptables規則
[yaxin@ubox ~]$sudo iptables -nvxL Chain INPUT (policy ACCEPT 67893 packets, 212661547 bytes) pkts bytes target prot opt in out source destination 14364 790008 DROP tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:25 Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 5479682 653269356 DOCKER all -- * docker0 0.0.0.0/0 0.0.0.0/0 94186 314986910 ACCEPT all -- * docker0 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED 4705658 2183254076 ACCEPT all -- docker0 !docker0 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT all -- docker0 docker0 0.0.0.0/0 0.0.0.0/0 Chain OUTPUT (policy ACCEPT 71253 packets, 222512872 bytes) pkts bytes target prot opt in out source destination Chain DOCKER (1 references) pkts bytes target prot opt in out source destination 218 13193 ACCEPT tcp -- !docker0 docker0 0.0.0.0/0 192.168.42.41 tcp dpt:22280 4868186 297463902 ACCEPT tcp -- !docker0 docker0 0.0.0.0/0 192.168.42.41 tcp dpt:20280 78663 13128102 ACCEPT tcp -- !docker0 docker0 0.0.0.0/0 192.168.42.41 tcp dpt:22 47 4321 ACCEPT tcp -- !docker0 docker0 0.0.0.0/0 192.168.42.41 tcp dpt:28159 27 4627 ACCEPT tcp -- !docker0 docker0 0.0.0.0/0 192.168.42.43 tcp dpt:8888 [yaxin@ubox ~]$sudo iptables -t nat -nvxL Chain PREROUTING (policy ACCEPT 232 packets, 16606 bytes) pkts bytes target prot opt in out source destination 1220281 82620790 DOCKER all -- * * 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type LOCAL Chain INPUT (policy ACCEPT 216 packets, 15671 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 317 packets, 19159 bytes) pkts bytes target prot opt in out source destination 1644 99311 DOCKER all -- * * 0.0.0.0/0 !127.0.0.0/8 ADDRTYPE match dst-type LOCAL Chain POSTROUTING (policy ACCEPT 321 packets, 19367 bytes) pkts bytes target prot opt in out source destination 13512 813656 MASQUERADE all -- * !docker0 192.168.42.0/24 0.0.0.0/0 0 0 MASQUERADE tcp -- * * 192.168.42.41 192.168.42.41 tcp dpt:22280 0 0 MASQUERADE tcp -- * * 192.168.42.41 192.168.42.41 tcp dpt:20280 0 0 MASQUERADE tcp -- * * 192.168.42.41 192.168.42.41 tcp dpt:22 0 0 MASQUERADE tcp -- * * 192.168.42.41 192.168.42.41 tcp dpt:28159 0 0 MASQUERADE tcp -- * * 192.168.42.43 192.168.42.43 tcp dpt:8888 Chain DOCKER (2 references) pkts bytes target prot opt in out source destination 22 1404 DNAT tcp -- !docker0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:22280 to:192.168.42.41:22280 288 17156 DNAT tcp -- !docker0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:20280 to:192.168.42.41:20280 93 5952 DNAT tcp -- !docker0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:22222 to:192.168.42.41:22 8 512 DNAT tcp -- !docker0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:28159 to:192.168.42.41:28159 4 208 DNAT tcp -- !dokcer0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:8899 to:192.168.42.43:8888
當然，使用手動配置也是比較麻煩的，所以我寫了一個腳本來自動配置端口映射，使用方法腳本中有說明
#!/bin/bash # filename: docker_expose.sh if [ `id -u` -ne 0 ];then echo "[EROOR] Please use root to run this script" exit 23 fi if [ $# -ne 3 ];then echo "Usage: $0 <container_name> <add|del> [[<machine_ip>:]<machine_port>:]<container_port>[/<protocol_type>]" exit 1 fi IPV4_RE='(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])/.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])' container_name=$1 action=$2 arguments=$3 # check action if [ "$action"x != "add"x -a "$action"x != "del"x ];then echo "[ERROR] Please use add or del parameter to add port map or delete port map" exit 654 fi if [ "$action"x == "add"x ];then action="A" else action="D" fi # get container ip by container name container_ip=`docker inspect -f '{{.NetworkSettings.IPAddress}}' $container_name 2> /dev/null` if [ -z $container_ip ];then echo "[ERROR] Get container's (${container_name}) IP error, please ensure you have this container" exit 2 fi # parse arguments protocol_type=`echo $arguments | awk -F '/' '{print $2}'` if [ -z $protocol_type ];then protocol_type="tcp" fi # check protocol if [ "$protocol_type"x != "tcp"x -a "$protocol_type"x != "udp"x ];then echo "[ERROR] Only tcp or udp protocol is allowed" exit 99 fi machine_ip='' machine_port='' container_port='' # split the left arguments arguments=${arguments%/*} machine_ip=`echo $arguments | awk -F ':' '{print $1}'` machine_port=`echo $arguments | awk -F ':' '{print $2}'` container_port=`echo $arguments | awk -F ':' '{print $3}'` if [ -z $machine_port ];then # arguments is: 234 container_port=$machine_ip machine_port=$machine_ip unset machine_ip elif [ -z $container_port ];then # arguments is: 234:456 container_port=$machine_ip machine_port=$machine_port unset machine_ip fi # check port number function _check_port_number() { local port_num=$1 if ! echo $port_num | egrep "^[0-9]+$" &> /dev/null;then echo "[ERROR] Invalid port number $port_num" exit 3 fi if [ $port_num -gt 65535 -o $port_num -lt 1 ];then echo "[ERROR] Port number $port_num is out of range(1-56635)" exit 4 fi } # check port and ip address _check_port_number $container_port _check_port_number $machine_port if [ ! -z $machine_ip ];then if ! echo $machine_ip | egrep "^${IPV4_RE}$" &> /dev/null;then echo "[ERROR] Invalid Ip Adress $machine_ip" exit 5 fi # check which interface bind the IP for interface in `ifconfig -s | sed -n '2,$p' | awk '{print $1}'`;do interface_ip=`ifconfig $interface | awk '/inet addr/{print substr($2,6)}'` if [ "$interface_ip"x == "$machine_ip"x ];then interface_name=$interface break fi done if [ -z $interface_name ];then echo "[ERROR] Can not find interface bind with $machine_ip" exit 98 fi fi # run iptables command echo "[INFO] Now start to change rules to iptables" echo "[INFO] Changing POSTROUTING chain of nat table" iptables -t nat -${action} POSTROUTING -p ${protocol_type} --dport ${container_port} -s ${container_ip} -d ${container_ip} -j MASQUERADE if [ -z $interface_name ];then echo "[INFO] Changing DOCKER chain of filter table" iptables -${action} DOCKER ! -i docker0 -o docker0 -p ${protocol_type} --dport ${container_port} -d ${container_ip} -j ACCEPT echo "[INFO] Changing DOCKER chain of nat table" iptables -t nat -${action} DOCKER ! -i docker0 -p ${protocol_type} --dport ${machine_port} -j DNAT --to-destination ${container_ip}:${container_port} else echo "[INFO] Changing DOCKER chain of filter table" iptables -${action} DOCKER -i $interface_name -o docker0 -p ${protocol_type} --dport ${container_port} -d ${container_ip} -j ACCEPT echo "[INFO] Changing DOCKER chain of nat table" iptables -t nat -${action} DOCKER -i $interface_name -p ${protocol_type} --dport ${machine_port} -j DNAT --to-destination ${container_ip}:${container_port} fi 感謝閱讀，希望能幫助到大家，謝謝大家對本站的支持！
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