Unable to SSH to a docker container from docker host - docker

Question

I have created a docker host on openstack and launched a container with it's port 22 mapped to a port on docker host. Followed this link
Still i can't ssh from docker host to container. It gives this error:
$> ssh -v root#172.17.0.9 -p 32775
OpenSSH_6.6.1, OpenSSL 1.0.1e-fips 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 56: Applying options for *
debug1: Connecting to 172.17.0.9 [172.17.0.9] port 32775.
debug1: connect to address 172.17.0.9 port 32775: Connection refused
ssh: connect to host 172.17.0.9 port 32775: Connection refused
Iptables rule is added by default when i used -P option in docker run. It looks like this:
$> iptables -t nat -L -n
Chain PREROUTING (policy ACCEPT)
target prot opt source destination
DOCKER all -- 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type LOCAL
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
DOCKER all -- 0.0.0.0/0 !127.0.0.0/8 ADDRTYPE match dst-type LOCAL
Chain POSTROUTING (policy ACCEPT)
target prot opt source destination
MASQUERADE all -- 172.17.0.0/16 0.0.0.0/0
MASQUERADE tcp -- 172.17.0.3 172.17.0.3 tcp dpt:80
MASQUERADE tcp -- 172.17.0.9 172.17.0.9 tcp dpt:22
Chain DOCKER (2 references)
target prot opt source destination
RETURN all -- 0.0.0.0/0 0.0.0.0/0
DNAT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:9090 to:172.17.0.3:80
DNAT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:32775 to:172.17.0.9:22
And container looks like:
$> docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
46111bb52063 sshns "/usr/sbin/sshd -D" 9 hours ago Up 3 hours 0.0.0.0:32776->22/tcp TestSSHcontainer
I need to have ssh only for my purpose. I'm aware about docker exec option. Tried changes like PermitRootLogin yes on sshd_config and ssh_config on both docker host and container with no success.
bash-4.2# /usr/sbin/sshd -Dd
WARNING: 'UsePAM no' is not supported in Red Hat Enterprise Linux and may cause several problems.
debug1: sshd version OpenSSH_6.6.1, OpenSSL 1.0.1e-fips 11 Feb 2013
debug1: key_parse_private2: missing begin marker
debug1: read PEM private key done: type RSA
debug1: private host key: #0 type 1 RSA
debug1: key_parse_private2: missing begin marker
debug1: read PEM private key done: type ECDSA
debug1: private host key: #1 type 3 ECDSA
debug1: private host key: #2 type 4 ED25519
debug1: rexec_argv[0]='/usr/sbin/sshd'
debug1: rexec_argv[1]='-Dd'
Set /proc/self/oom_score_adj from 0 to -1000
debug1: Bind to port 22 on ::.
Bind to port 22 on :: failed: Address already in use.
debug1: Bind to port 22 on 0.0.0.0.
Bind to port 22 on 0.0.0.0 failed: Address already in use.
Cannot bind any address.
bash-4.2# netstat -anp | grep 22
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN -
tcp6 0 0 :::22 :::* LISTEN -
bash-4.2# ps -eaf | grep ssh
root 1 0 0 19:17 ? 00:00:00 /usr/sbin/sshd -D
root 26 16 0 22:58 ? 00:00:00 grep ssh
Is there something that i'm still missing?

Answer 1

You're using the ip of your container but the host port mapping of container. Try either ssh -v root#172.17.0.9 or ssh -v root#localhost -p <port_mapping_on_host>(Your docker ps -a shows your porting mapping on host is 32776)