I have several web apps running in docker on a ubuntu host. Each app is listening on a different port. When inside any container in the docker network, I can connect and receive data from the service, however, when running a request from the host, I can connect successfully, but no data is received. Why aren't the services returning any data when I connect to them from outside the container???
Docker reports this under "PORTS" when I run docker ps:
0.0.0.0:8080->8080/tcp, :::8080->8080/tcp and netstat reports that the server is listening on that port:
$ netstat -anp | grep 8080 (Not all processes could be identified, non-owned process info will not be shown, you would have to be root to see it all.) tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN - tcp6 0 0 :::8080 :::* LISTEN - However, when I visit localhost:8080 in my browser (I tried both firefox and chrome), the browser hangs, as if it is connected, but no data is being sent. Similarly, curl hangs forever:
$ curl -vvv localhost:8080 * Uses proxy env variable no_proxy == 'localhost,127.0.0.1,::1' * Trying 127.0.0.1:8080... * TCP_NODELAY set * Connected to localhost (127.0.0.1) port 8080 (#0) > GET / HTTP/1.1 > Host: localhost:8080 > User-Agent: curl/7.68.0 > Accept: */* > ^C I also tried connecting to it with telnet with a similar result. I tried running a quick http server directly on the host, and it works fine:
python3 -m http.server 8000 $ curl -vvv localhost:8000 * Uses proxy env variable no_proxy == 'localhost,127.0.0.0/8,::1' * Trying 127.0.0.1:8000... * TCP_NODELAY set * Connected to localhost (127.0.0.1) port 8000 (#0) > GET / HTTP/1.1 > Host: localhost:8000 > User-Agent: curl/7.68.0 > Accept: */* > * Mark bundle as not supporting multiuse * HTTP 1.0, assume close after body < HTTP/1.0 200 OK < Server: SimpleHTTP/0.6 Python/3.8.13 < Date: Fri, 09 Dec 2022 12:36:03 GMT < Content-type: text/html; charset=utf-8 < Content-Length: 16768 < <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> ... I also tried connecting to the docker container ip: (172.17.0.3:8080) with the same results.
However, when I try running curl inside one of the containers, I am able to reach the http endpoints in any container.
All of this leads me to believe that there is a problem with the docker networking on my host (docker bridge?).
I am using docker compose. Docker inspect reports the following (in part):
"HostConfig": { "Binds": [], ... "NetworkMode": "docker-compose-example_default", "PortBindings": { "8080/tcp": [ { "HostIp": "", "HostPort": "8080" } ] }, ... "NetworkSettings": { "Bridge": "", "SandboxID": "1b53a5b6580187b714c6d7d0c9f81a015d585cd0bb0d62da579a4fe7514d47ea", "HairpinMode": false, "LinkLocalIPv6Address": "", "LinkLocalIPv6PrefixLen": 0, "Ports": { "8080/tcp": [ { "HostIp": "0.0.0.0", "HostPort": "8080" }, { "HostIp": "::", "HostPort": "8080" } ] }, "SandboxKey": "/var/run/docker/netns/1b53a5b65801", "SecondaryIPAddresses": null, "SecondaryIPv6Addresses": null, "EndpointID": "", "Gateway": "", "GlobalIPv6Address": "", "GlobalIPv6PrefixLen": 0, "IPAddress": "", "IPPrefixLen": 0, "IPv6Gateway": "", "MacAddress": "", "Networks": { "docker-compose-example_default": { "IPAMConfig": null, "Links": null, "Aliases": [ "dc0813038a3b", "adminer" ], "NetworkID": "65c6700f5445a6ce0f98a0a4e14e3e10577f40706411f639a4f9da5b1cfdd52e", "EndpointID": "0f42ae8ce893fb4f33168c31df0d5de38d2e8ca67521802ba76589a8a0cb1bea", "Gateway": "172.17.0.1", "IPAddress": "172.17.0.3", "IPPrefixLen": 16, "IPv6Gateway": "", "GlobalIPv6Address": "", "GlobalIPv6PrefixLen": 0, "MacAddress": "02:42:ac:11:00:03", "DriverOpts": null } } } Recap: I can connect to these services inside the containers, but I cannot connect to them from the host, even though by all reports, the servers are listening for connections.
What do I need to do so that I can connect to services running inside docker from my host?
