How to Solve DNS Issues in Rootless Podman Networks on OpenSUSE Micro

Описание: Learn how to resolve DNS issues between pods in rootless Podman on OpenSUSE Micro, ensuring seamless communication between your containers.
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This video is based on the question https://stackoverflow.com/q/77559825/ asked by the user 'Khanetor' ( https://stackoverflow.com/u/1196906/ ) and on the answer https://stackoverflow.com/a/77562896/ provided by the user 'Khanetor' ( https://stackoverflow.com/u/1196906/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the DNS Challenge in Rootless Podman

When deploying containerized applications, efficient communication between services is crucial. In certain scenarios, you may find that containers in different pods are unable to communicate using their names, which can lead to frustrating DNS issues. This is a common challenge faced by many developers using Podman, especially when operating within various operating systems like OpenSUSE Micro.

In this post, we will walk through a specific setup involving two pods — one containing an NginX Proxy Manager and MariaDB, and another running Node-RED. We will explain how to resolve DNS issues encountered when trying to establish communication between these pods by leveraging proper network backend configurations.

The Setup

Your Pod Configuration

You have a well-organized setup as follows:

Network: public

Pod1: containing NginX Proxy Manager and MariaDB, exposing ports 80, 81, and 443

Pod2: running Node-RED

The Issue

Despite successfully pinging the Node-RED service (pod2) via its IP address from the NginX Proxy Manager (NPM) service (pod1), DNS resolution using the pod name was failing. This means that rather than using the IP, you wanted to reference services by their respective pod names which is common practice for ease of access and scalability.

The Solution

Understanding the Network Backend

The main culprit behind the DNS resolution issue was the default network backend used by Podman. As of version 4.4.4 installed on OpenSUSE Leap Micro, the default backend is set to CNI, which is known to not support DNS for containers.

Installing Required Packages

To overcome this limitation, you needed to switch to a network backend that supports DNS. The packages netavark and aardvark-dns are designed to tackle this specific issue.

Installation Steps:

Run the following command to install netavark and aardvark-dns:

[[See Video to Reveal this Text or Code Snippet]]

Resetting Podman

After installing the necessary packages, reset your Podman environment. Be aware that this action will erase existing containers, pods, and images, so ensure to back up any vital data before proceeding.

Creating a New Network

Once reset, you can create a new network that utilizes the netavark backend, which provides DNS capabilities between containers.

Create Your New Network

Run the following command:

[[See Video to Reveal this Text or Code Snippet]]

Verifying DNS Capabilities

With the netavark backend in place, you can now create your rootless containers and pods that can communicate with each other using their pod names. This is a significant improvement over direct IP addressing, allowing for greater flexibility and ease in container management.

Conclusion

By following these steps, you can solve the DNS issues that plagued your initial setup with Podman on OpenSUSE Micro. This adjustment not only enhances inter-pod communication but also improves the overall architecture of your containerized application.

With this newfound capability, feel free to explore further configurations and see how you can optimize your Podman deployments!

Keep engaged with the Podman community as the development continues; improvements and new features are always on the horizon!