Use hosts file for docker-in-docker container in kubernetes pod

Question

What I want:

Dynamically add hosts in kubernetes pods created by Jenkins master and allow the mounted docker in the pod to use the hosts.

I am using Jenkins to create dynamic slaves for docker build, and created docker-in-docker slave containers for docker build and docker push. The docker-in-docker is created by mounting docker.sock of the VM to the container:

volumeMounts:
- name: hostpathvolume
  mountPath: '/var/run/docker.sock'

I am using hostAliases of kubernetes to append the hosts file with some private docker registries:

hostAliases:
- ip: 9.110.73.11
  hostnames:
  - devopsprod.icp
- ip: 9.119.42.60
  hostnames:
  - devops.icp

I have confirmed that the pods created have these hosts in /etc/hosts, but when I run:

docker login -u xxx -p xxx devops.icp:8500

I got a DNS error:

Error response from daemon: Get https://devops.icp:8500/v2/: dial tcp: lookup devops.icp on 0.0.0.0:00: no such host

This means the docker I run in the container is not using the /etc/hosts in the pod to look up for the ip address. Is there a way to fix this? I don't want to add the hosts manually in the VM's /etc/hosts file.

Artem Golenyaev Artem Golenyaev · Accepted Answer · 2018-10-09T14:29:33

You have mounted docker.sock into the Pod, but Docker still uses the configuration from the Node, not from Pod. There are no other options, you need to add aliases to /etc/hosts on each Node to make it work.

Use hosts file for docker-in-docker container in kubernetes pod

1 Answers