[IMPORTANT] Use unique tags when deploying application from container registry


This is a little reminder about the importance of using unique tags when deploying applications from a container registry with Qovery.

When working with containerized applications, it is crucial to employ unique image tags for precise version management. This practice ensures complete confidence in the version running within a container. Failing to use unique image tags can lead to adverse consequences due to the image caching mechanisms employed by both the Qovery mirroring system and Kubernetes:

  1. Mirroring Registry: Qovery’s mirroring system stores images in a registry. If an image tag remains the same between two versions, the new version will not be mirrored. Consequently, the new version will not be deployed, affecting the overall application.
  2. Kubernetes: Applications deployed by Qovery on Kubernetes adhere to the “ifNotPresent” image pull policy. This policy means that if the image already exists on the Kubernetes node’s local disk, Kubernetes will not attempt to pull it again. However, if the image tag remains unchanged, the new image version will not be fetched, resulting in your pods running the outdated application code.

In summary, maintaining unique image tags is a critical aspect of effective version control and ensuring that your applications run the intended versions without disruptions caused by caching mechanisms.

A documentation explaining how the Qovery mirroring system works is available here, including a section dedicated to why unique image tags are necessary.

If you have any question, feel free to reply to this post


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