Docker jenkins access port - docker

Question

I am running docker compose of jenkins image by command docker-compose up my config files
Dockerfile:
FROM java:openjdk-8-jre
EXPOSE 50000
docker-compose.yml
version: '3'
services:
jenkins:
image: jenkins:2.60.3-alpine
ports:
- 50000:50000
My container runs docker ps result:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
7dbe18cdbb53 jenkins:2.60.3-alpine "/bin/tini -- /usr/l…" 22 minutes ago Up 22 minutes 8080/tcp, 0.0.0.0:50000->50000/tcp docker_jenkins_1
I checked the docker host by docker inspect 7dbe18cdbb53
Result:
],
"NetworkID": "e3a5461960939397615620f051696f8b78fde9352d0c8b42b4ed679a1e847b9b",
"EndpointID": "999b5d3525b2fe823c5ed0033bb27e85b3ca26356b4bd9f1525de005739fecde",
"Gateway": "172.18.0.1",
"IPAddress": "172.18.0.2",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "02:42:ac:12:00:02",
"DriverOpts": null
`
When i try to access from browser like 172.18.0.2:50000 it doesnt work.

Answer 1

The jenkins image that you have is configured to listen http traffic on port 8080.
Have a look at this: https://github.com/jenkinsci/docker/blob/c2d6f2122fa03c437e139a317b7fe5b9547fe49e/Dockerfile
This is the part where the http port default value is defined
ARG http_port=8080
and this is where it is exposed
# for main web interface:
EXPOSE ${http_port}
Similarly you can find that (slave) Agent port is 50000.
In your docker ps output you can see that the jenkins container is listening on 8080 but this is not publish on the host.
So basically you are trying to connect via http to the agent port and it is not working as expected.
Do change the docker compose file to also publish the 8080 port and use that.