Microsoft recently announced the public preview for support of Azure Container Registry across Availability Zones. The Zone redundancy provides resiliency and high availability to a registry or replication resource (replica) in a specific region.
Azure Container Registry is a managed service in Azure providing customers with a registry of Docker and Open Container Initiative (OCI) images, with support for all OCI artifacts. The service offers fast, scalable retrieval of container workloads and handles private Docker container images and related content formats, such as Helm charts, OCI artifacts, and images built to the OCI image format specification.
Zone redundancy is a feature in the premium tier of the container registry service in Azure. Customers can enable the availability zones feature to create a resilient and high availability Azure container registry within an Azure region. Since Azure Container Registry also supports geo-replication, which replicates the service across multiple regions, customers can enhance the reliability and performance. Geo-replication enables an Azure container registry to function as a single registry, serving multiple regions with multi-master regional registries.
An Azure docs article on container geo-replication explains what benefits are:
- Single registry, image, and tag names can be used across multiple regions
- Improve performance and reliability of regional deployments with network-close registry access
- Reduce data transfer costs by pulling image layers from a local, replicated registry in the same or nearby region as your container host
- Single management of a registry across multiple regions
Through the Azure Portal or Azure Resource Management (ARM) templates, customers can enable the feature.
Source: https://docs.microsoft.com/en-us/azure/container-registry/zone-redundancy
Other major public cloud providers like AWS and GCP also offer similar container registry services. For instance, the Amazon Elastic Container Registry (ECR) also provides replication of container images across regions since December of last year. Furthermore, Google’s Container Registry service has similar capabilities.
Holger Mueller, principal analyst and vice president at Constellation Research Inc., told InfoQ:
As enterprises build mission-critical applications on containers, they need an infrastructure that supports mission-critical workloads making the core infrastructure of any container-based next-generation application - the registry - a multizone capability is crucial for any IaaS. Good to see Microsoft adding the ability that will make container-based applications more robust and resilient!
Currently, the Azure Container Registry support across Availability Zones is available in East US, East US 2, and West US 2 regions.