Microsoft is committed to making Azure Container Registry (ACR) best-in-class for the storage and distribution of container images. Following this commitment, we’re excited to announce the public preview of Caching for ACR. Once configured, Caching for ACR allows you to cache container images from Docker Hub and Microsoft Artifact Registry in your own ACR instance. This helps you continue using the best in public content and add the speed and reliability of using it from your own networks. 

Why Caching for ACR?  

Caching for ACR is a new feature added to Azure Container Registry (ACR) currently in preview that allows users to cache container images from Microsoft Artifact Registry and Docker Hub.  

Caching container images have three main benefits: 

1.       High-speed and reliable pull operations: Faster pulls of container images are achievable by caching the container images in ACR. Since Microsoft manages the Azure network, pull operations are faster, more reliable, and provide Geo-Replication and Availability Zone support to the customers. 
   
   
2.       Private Network Support: Cached registries are available on private networks. Users can close their firewall to meet compliance standards.
    
3.       Ensuring upstream content is delivered: All registries, especially public ones like Docker Hub and others, have anonymous pull limits in order to ensure they can provide services to everyone. Caching for ACR allows users to pull images from the local ACR–not the upstream registry.  
   
   

Caching for ACR is part of a larger solution to make your upstream content more performant and reliable, and part of your larger secure software supply chain work. If you’d like to learn more about proper usage of upstream artifacts in your infrastructure, see Manage Public Content with Azure Container Registry. In addition to using Caching for ACR, Microsoft suggests you use authenticated pulls for upstream content in line with the industry move to a stronger set of relationships across your supply chain. You can also learn more about Docker Hub and Docker Official images here, and Docker Rate limits here.  

Want to try it out? 

The Public Preview for Caching for ACR is currently only available in the Azure Portal. The CLI version of Caching for ACR will be available in March of 2023. Caching for ACR supports both authenticated and unauthenticated pulls. If you’d like to try out Caching for ACR, please visit our documents page here.

What’s Next?  

We’d encourage you to read the document about managing public content here. 

We’d encourage you to view all the documentation and explore our tutorials at https://aka.ms/acr/docs.    

We're looking forward to hearing all your feedback about Caching for ACR. If you have any questions, feedback, use cases, or concerns please reach out to us at aka.ms/acr/feedback. 

Are you interested in the other features coming to ACR? You can view our public roadmap at aka.ms/acr/roadmap. 

If you would like to inform us of any issues with this feature or any features within ACR. Please file an issue here at aka.ms/acr/issues.  

We are excited about all the new improvements coming to Azure Container Registry. Please stay tuned for all the new improvements.