I’m trying to bind two ports from a docker container to a currently unused IP address on one of the host machine’s interfaces.
I’m attempting to start the container (which is based on the centos/systemd image) like this:
sudo docker run --privileged -d -p 172.19.5.1:22:22 -p 172.19.5.1:5432:5432 --name test --hostname test -v /sys/fs/cgroup:/sys/fs/cgroup:ro --net cdnet image_name
and it fails with the message: Error starting userland proxy: listen tcp 172.19.5.1:22: bind: address already in use.
You can see from the settings of the network that this address should be totally valid:
[
{
"Name": "cdnet",
"Id": "c7f58c7f7765b7ee85ffd7638d98c1f73d0abf2393635d26d9634ac94e1c05e9",
"Created": "2018-04-27T20:40:44.542040471Z",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": {},
"Config": [
{
"Subnet": "172.19.0.0/16",
"Gateway": "172.19.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"Containers": {},
"Options": {},
"Labels": {}
}
]
and for good measure, I created the IP on my machine’s main network interface:
6: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 9000 qdisc noqueue state UP qlen 1000
link/ether 0c:c4:7a:8e:f4:f2 brd ff:ff:ff:ff:ff:ff
inet 69.241.118.34/30 brd 69.241.118.35 scope global bond0
valid_lft forever preferred_lft forever
inet 69.241.118.0/30 scope global bond0
valid_lft forever preferred_lft forever
inet 69.241.118.4/30 scope global bond0
valid_lft forever preferred_lft forever
inet 172.19.5.1/25 scope global bond0
valid_lft forever preferred_lft forever
inet 69.241.118.1/30 scope global secondary bond0
valid_lft forever preferred_lft forever
inet 69.241.118.2/30 scope global secondary bond0
valid_lft forever preferred_lft forever
inet 69.241.118.3/30 scope global secondary bond0
valid_lft forever preferred_lft forever
inet6 2001:558:fee8:17a:ec4:7aff:fe8e:f4f2/64 scope global deprecated mngtmpaddr dynamic
valid_lft 1974996sec preferred_lft 0sec
inet6 2001:558:fee8:17a::2/64 scope global
valid_lft forever preferred_lft forever
inet6 fe80::ec4:7aff:fe8e:f4f2/64 scope link
valid_lft forever preferred_lft forever
I have no other containers running (sudo docker ps -aq returns nothing) and I know for sure that no other process is using that address – here’s my output for sudo netstat -anlp (without the Unix domain socket section):
Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 127.0.0.1:199 0.0.0.0:* LISTEN 1406/snmpd tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1/systemd tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN 1763/dnsmasq tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1397/sshd tcp 0 0 0.0.0.0:1691 0.0.0.0:* LISTEN 31215/perl tcp 0 0 0.0.0.0:5662 0.0.0.0:* LISTEN 31215/perl tcp6 0 0 :::111 :::* LISTEN 1/systemd tcp6 0 0 :::22 :::* LISTEN 1397/sshd tcp6 0 920 <IP REDACTED>:22 <IP REDACTED> ESTABLISHED 22357/sshd: <USERNAME REDACTED> tcp6 0 0 <IP REDACTED>:22 <IP REDACTED> ESTABLISHED 22099/sshd: <USERNAME REDACTED> udp 0 0 0.0.0.0:53763 0.0.0.0:* 1406/snmpd udp 0 0 0.0.0.0:57647 0.0.0.0:* 1406/snmpd udp 0 0 192.168.122.1:53 0.0.0.0:* 1763/dnsmasq udp 0 0 0.0.0.0:67 0.0.0.0:* 1763/dnsmasq udp 0 0 0.0.0.0:111 0.0.0.0:* 17684/rpcbind udp 0 0 0.0.0.0:161 0.0.0.0:* 1406/snmpd udp 0 0 0.0.0.0:162 0.0.0.0:* 2589/snmptrapd udp 0 0 0.0.0.0:892 0.0.0.0:* 17684/rpcbind udp 0 0 0.0.0.0:35179 0.0.0.0:* 1406/snmpd udp6 0 0 :::111 :::* 17684/rpcbind udp6 0 0 :::892 :::* 17684/rpcbind
(Neither redacted IP is, needless to say, the one to which I’m trying to bind; they are the real external IPv6 addresses of myself and the machine.)
All of the results for publishing ports of a docker container that I can find in my searches are merely trying to bind a port to localhost, and I really cannot figure out why this is breaking. The system is CentOS Linux release 7.4.1708 (Core), Docker version 17.05.0-ce, build 89658be
NOTE: I’ve tried both with and without EXPOSE 22 5432 in the Dockerfile and I’ve tried different IP addresses (which you can see in the ip addr output above).
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Answer
0.0.0.0 means “all ipv4 interfaces”, so yes, it’s already in use in this line of your output:
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1397/sshd