Caches¶
The time needed to pull and push images is directly influenced by the distance between your users and the geographic location of your MSR deployment. This is because the files need to traverse the physical space and cross multiple networks. You can, however, deploy MSR caches at different geographic locations, to add greater efficiency and shorten user wait time.
With MSR caches you can:
Accelerate image pulls for users in a variety of geographical regions.
Manage user permissions from a central location.
MSR caches are inconspicuous to your users, as they will continue to log in and pull images using the provided MSR URL address.
When MSR receives a user request, it first authenticates the request and verifies that the user has permission to pull the requested image. Assuming the user has permission, they then receive an image manifest that contains the list of image layers to pull and which directs them to pull the images from a particular cache.
When your users request image layers from the indicated cache, the cache pulls these images from MSR and maintains a copy. This enables the cache to serve the image layers to other users without having to retrieve them again from MSR.
Note
Avoid using caches if your users need to push images faster or if you want to implement region-based RBAC policies. Instead, deploy multiple MSR clusters and apply mirroring policies between them. For further details, refer to Promotion policies and monitoring.