Ho notato che esiste un processo docker-proxy in esecuzione per ciascuna porta pubblicata. Qual è lo scopo di questo processo? Perché è necessario un proxy tcp dello spazio utente per questo?
$ 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
e alcune regole iptable correlate create dalla finestra mobile:
$ 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