Featured AI Products
Compute
Build, deploy, and scale cloud compute resources
Containers and Images
Safely store and manage containers and backups
Managed Databases
Fully managed resources running popular database engines
Management and Dev Tools
Control infrastructure and gather insights
Networking
Secure and control traffic to apps
Security
Help protect your account and resources with these security features
Storage
Store and access any amount of data reliably in the cloud
Browse all products
AI/ML
CMS
Data and IoT
Developer Tools
Gaming and Media
Hosting
Security and Networking
Startups and SMBs
Web and App Platforms
See all solutions
Community
Documentation
Developer Tools
Get Involved
Utilities and Help
Become a Partner
Marketplace
Pricing

- Community
- DigitalOcean
- Community
- DigitalOcean

Resolving through kube-dns on managed Kubernetes nodes

Posted on June 10, 2019

Hi Digital Ocean,

I am trying to set up an internal Docker registry within a DO managed Kubernetes cluster. I have the registry up and running and can access the registry from the worker nodes by using the service cluster ip, but I can not pull images in deployments through the url provided for the internal Docker registry with kube-dns. I believe the problem is that the worker nodes themselves are not set up to use the kube-dns name server.

As the worker nodes are to be treated as ephemeral, I do not wish to manually set up resolv.conf, as it would probably be overwritten at cluster upgrades, recycles etc.

What can be done? Would it be possible to upgrade the default managed Kubernetes nodes to resolve through kube-dns first?

Thanks for your time and kind regards.

This textbox defaults to using Markdown to format your answer.

You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

cr7392b6b5a2e554b9227c92d1

June 19, 2019

Accepted Answer

I figured out that it was possible to create a privileged DaemonSet putting self-signed certificates into the host nodes’ Docker certificate stores and editing resolv.conf to include the kube-dns nameserver.

However, I ended up exposing the Docker registry on the internet through an HAProxy Ingress, secured with HTTPS and using Basic Auth credentials, as I deemed the registry as being secure enough to be exposed for now (It will be easier to maintain and more easily accessible for other developers/machines/clusters).

John Kwiatkoski

June 11, 2019

You’re correct. The nodes are not setup to use the clusters DNS to hit services. However, what your can do is use the registry services’ clusterIP to specify the internal registry.That IP will not change unless you recreate the service. This way you can use the IP in your deployments to reference the registry and the provide the repo and tag for your image.

Regards,

John Kwiatkoski Senior Developer Support Engineer

andyb

June 17, 2019

You could potentially set up ExternalDNS for your docker registry as discussed in https://github.com/kubernetes-incubator/external-dns/blob/master/docs/tutorials/digitalocean.md. I believe it would mean exposing your registry to the internet, so you’d need to secure it.

The developer cloud

Scale up as you grow — whether you're running one virtual machine or ten thousand.

View all products

Start building today

From GPU-powered inference and Kubernetes to managed databases and storage, get everything you need to build, scale, and deploy intelligent applications.