Examine the storage mounts in Azure Container Apps

  • 5 minutes

A container app has access to different types of storage. A single app can take advantage of more than one type of storage if necessary.

Storage type Description Usage examples
Container file system Temporary storage scoped to the local container Writing a local app cache.
Ephemeral storage Temporary storage scoped to an individual replica Sharing files between containers in a replica. For instance, the main app container can write log files that are processed by a sidecar container.
Azure Files Permanent storage Writing files to a file share to make data accessible by other systems.

Container file system

A container can write to its own file system.

Container file system storage has the following characteristics:

  • The storage is temporary and disappears when the container is shut down or restarted.

  • Files written to this storage are only visible to processes running in the current container.

  • There are no capacity guarantees. The available storage depends on the amount of disk space available in the container.

Ephemeral volume

You can mount an ephemeral, temporary volume that is equivalent to emptyDir in Kubernetes. Ephemeral storage is scoped to a single replica.

Ephemeral storage has the following characteristics:

  • Files are persisted for the lifetime of the replica.

    • If a container in a replica restarts, the files in the volume remain.

  • Any containers in the replica can mount the same volume.

  • A container can mount multiple ephemeral volumes.

  • The available storage depends on the total number of vCPUs allocated to the replica.

Azure Files volume

You can mount a file share from Azure Files as a volume in a container.

Azure Files storage has the following characteristics:

  • Files written under the mount location are persisted to the file share.

  • Files in the share are available via the mount location.

  • Multiple containers can mount the same file share, including ones that are in another replica, revision, or container app.

  • All containers that mount the share can access files written by any other container or method.

  • More than one Azure Files volume can be mounted in a single container.

To enable Azure Files storage in your container, you need to set up your container in the following ways:

  • Create a storage definition in the Container Apps environment.

  • Define a volume of type AzureFile in a revision.

  • Define a volume mount in one or more containers in the revision.