CODEWITHSUNDEEP
proxydockerjenkins
blueFast
blueFast

Reputation: 44371

Jenkins not able to access internet when running as docker container

I am running the jenkins docker image. When starting, it complains that it is not possible to access the internet.

This is how I run it:

docker pull jenkins
mkdir jenkins-shared-volume
docker run -d -p 49001:8080 -p 50000:50000 -v jenkins-shared-volume:/var/jenkins_home -t --name jenkins jenkins

The jenkins instance is then running on http://localhost:49001. But it has connectivity issues:

Offline This Jenkins instance appears to be offline.

For information about installing Jenkins without an internet connection, see the Offline Jenkins Installation Documentation.

You may choose to continue by configuring a proxy or skipping plugin installation.

enter image description here

I have no proxy in my system (home laptop). I guess this is probably an obscure docker problem but:

  1. I can not find any references to this issue
  2. Since this is the usual way in which people would be running the jenkins docker image, I find it surprising that this is not working out of the box

Am I doing something wrong?

EDIT

Just to make sure that indeed the docker container has direct access to the internet:

docker exec -it jenkins /bin/bash
jenkins@4ef4944a7cb7:/$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: icmp_seq=0 ttl=44 time=29.859 ms

EDIT2

Running the container connected to the host network solves the problem and lets jenkins access the internet:

docker run -d --net host -v jenkins-shared-volume:/var/jenkins_home -t --name jenkins jenkins

But I can not map ports: jenkins is directly reachable on http://localhost:8080, which can be a source of conflicts whenever other services are using the 8080 port.

Upvotes: 21

Views: 14521

Answers (3)

derpdewp
derpdewp

Reputation: 207

I had the same error while running nginx & jenkins.Turned out to be a dns issue. I use docker-compose and resolved it by adding dns into the jenkins yaml.

example:

--- 
version: "2.3"
services: 
  jenkins:
    container_name: jenkins
    image: jenkins/jenkins:lts
    restart: unless-stopped
    ports: 
      - "8080:8080"
      - "50000:50000"
    volumes: 
      - "./jenkins/jenkins_home:/var/jenkins_home"
    extra_hosts:
      - "host.docker.internal:host-gateway"
    dns:
      - 8.8.8.8
      - 4.4.4.4
      - host.docker.internal

Upvotes: 0

edumgui
edumgui

Reputation: 151

When you run 'ping 8.8.8.8', you are testing internet connection but not DNS resolution.

Try 'ping www.google.com', I think you are having a DNS issue, thats why Jenkins can't reach the plugins packages.

Edit /etc/docker/daemon.json and set your local DNS servers to avoid Docker using default Google Public DNS. Docker Docs - Daemon configuration file .

Upvotes: 2

voglster
voglster

Reputation: 833

Strangely I ran into the same issue last night using the official Jenkins image:

 docker run -p 8080:8080 --rm jenkins/jenkins

Though I have not figured out why yet or how to permanently fix it, I did find a work around.

Launch the image with the older un-supported image jenkins... do the initial setup.. then shut it down, swap the image and startup the official.

For reference here is my docker-compose.yml:

version: "2"

services:
  app:
    image: jenkins #after booting and initial setup swap to jenkins/jenkins
    ports:
      - "50000:50000"
      - "8080:8080"
    volumes:
      - home:/var/jenkins_home
volumes:
  home:

Upvotes: 2

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