게시 된 각 포트마다 docker-proxy 프로세스가 실행되고 있음을 알았습니다. 이 과정의 목적은 무엇입니까? 여기에 사용자 공간 TCP 프록시가 필요한 이유는 무엇입니까?

$ ps -Af | grep proxy
root      4776  1987  0 01:25 ?        00:00:00 docker-proxy -proto tcp -host-ip 127.0.0.1 -host-port 22222 -container-ip 172.17.0.2 -container-port 22
root      4829  1987  0 01:25 ?        00:00:00 docker-proxy -proto tcp -host-ip 127.0.0.1 -host-port 5555 -container-ip 172.17.0.3 -container-port 5555

docker가 만든 일부 관련 iptable 규칙 :

$ sudo iptables -t nat -L -n -v
Chain PREROUTING (policy ACCEPT 1 packets, 263 bytes)
 pkts bytes target     prot opt in     out     source               destination
    0     0 DOCKER     all  --  *      *       0.0.0.0/0            0.0.0.0/0            ADDRTYPE match dst-type LOCAL

Chain INPUT (policy ACCEPT 1 packets, 263 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain OUTPUT (policy ACCEPT 1748 packets, 139K bytes)
 pkts bytes target     prot opt in     out     source               destination
   32  7200 DOCKER     all  --  *      *       0.0.0.0/0           !127.0.0.0/8          ADDRTYPE match dst-type LOCAL

Chain POSTROUTING (policy ACCEPT 1719 packets, 132K bytes)
 pkts bytes target     prot opt in     out     source               destination
   32  7200 MASQUERADE  all  --  *      !docker0  172.17.0.0/16        0.0.0.0/0

Chain DOCKER (2 references)
 pkts bytes target     prot opt in     out     source               destination
    0     0 DNAT       tcp  --  !docker0 *       0.0.0.0/0            127.0.0.1            tcp dpt:22222 to:172.17.0.2:22
    0     0 DNAT       tcp  --  !docker0 *       0.0.0.0/0            127.0.0.1            tcp dpt:5555 to:172.17.0.3:5555

답변