What can be the reason I see many 404 errors on Docker layers before the actual Docker push?

Adi Vizgan
2019-07-22 08:51

Subject

This article explains the reason you can see 404 errors on Docker layers before a Docker push occur.

Description

When pushing a Docker image to Artifactory, the Docker client first sends a HEAD request that contains the checksum of the layer that it needs to upload in order to verify if this layer already exists or not.
If the HEAD request gets a 404 response back, it means that this layer does not exist already and Docker will push it. If it gets a 200 response, it means that the layer already exists and Docker will not push it again.