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Configuring imagePullPolicy to Pull Latest Image or Fall Back to Local Cache

Core Problem

The current imagePullPolicy only offers three options: Always, IfNotPresent, and Never. While these options provide flexibility, they do not cater to scenarios where developers want to pull the latest image while minimizing single points of failure in production.

Solution & Analysis

To address this issue, we propose adding a fourth option to imagePullPolicy that attempts to pull the image and falls back to using a local cached copy if the image cannot be pulled.

New Option: Pull Latest Image or Fall Back to Local Cache

The new option, which we'll call TryLatest, would first try to pull the latest image from the repository. If the pull is successful, it would use the newly pulled image. If the pull fails due to network issues or other reasons, it would fall back to using a local cached copy.

Here's an example of how this option could be implemented in YAML: 

spec:
  containers:
    - name: my-container
      image: <repository-url>
      imagePullPolicy: TryLatest
In code, the TryLatest option would work as follows:

  1. Check if a cached copy of the image exists locally.
  2. Attempt to pull the latest image from the repository.
  3. If the pull is successful, use the newly pulled image.
  4. If the pull fails, fall back to using the local cached copy.

Benefits

The TryLatest option offers several benefits:

  • Developers can pull the latest changes while minimizing single points of failure in production.
  • The option provides a balance between flexibility and reliability, making it suitable for both development and production environments.
  • It eliminates the need for manual caching or explicit cache management.

Conclusion

Adding a TryLatest option to imagePullPolicy would provide developers with more flexibility and control over image management. By attempting to pull the latest image while falling back to using a local cached copy, this option minimizes single points of failure in production while catering to development needs.

Reference