Kubernetes not able pull image from private registry having private domain pointed via /etc/hosts

问题

I am trying to deploy an image from my private registry that's hosted on my local network and pointed using my local machines /etc/hosts file.

I am getting the resolution error as below:

Failed to pull image "gitlab.example.com:5050/group/project:latest": rpc error: code = Unknown desc = failed to resolve image

My /etc/hosts file contains:

192.168.1.100 gitlab.example.com

Using docker the pull/push works perfectly fine as the resolution happens using /etc/hosts

I've tried editing corefile of coredns to make the resolution happen, but it isn't working.

Can someone point me in right direction over here.

回答1:

You can try to use hostAliases 💡 and add a host entry to your pod. Kubernetes will not honor the /etc/hosts file from the hosts/nodes. Either the one in the pod or resolves through CoreDNS. For example:

apiVersion: v1
kind: Pod
metadata:
  name: hostaliases-pod
spec:
  restartPolicy: Never
  hostAliases:
  - ip: "192.168.1.100" 👈
    hostnames:
    - "gitlab.example.com" 👈
  containers:
  - name: gitlab-hosts
    image: myimage
    command:
    - mygitlabjob
    args:
    - "arg1"

Update:

I think see the problem here. microk8s on Ubuntu runs in a snap. That means it's confined/sandboxed in a container of its own. This also means that it probably doesn't care about your machine's /etc/hosts file. Unfortunately, snap's file systems are mounted as read-only for security reasons and to prevent tampering.

○ → pwd
/snap/microk8s/current
○ → sudo touch hosts
touch: cannot touch 'hosts': Read-only file system

If you'd like to use a private registry this way, some recommendations:

Ask your system admin to add that entry into your local DNS server, or add it if you are the system admin.
Use an alternative small K8s distro that uses Docker.
- KinD
- minikube
Build your own microk8s snap with a modified /etc/hosts file (hard)

来源：https://stackoverflow.com/questions/62940403/kubernetes-not-able-pull-image-from-private-registry-having-private-domain-point

标签

Kubernetes

CoreDNS

microk8s