TimerTrigger in Azure Function in Docker container on Kubernetes runs on every instance (.NET Core)

TimerTrigger to run only once for all instances makes a lease in a BlobStorage. Name of the container depends on a Machine name in case of Kubernetes and it's unique for all instances. Because of that TimerTrigger runs on all instances at the same time.

As temporary solution I have to use env. variables WEBSITE_SITE_NAME and WEBSITE_INSTANCE_ID to make it work as expected, but maybe it's better to provide a way to override default container name for Azure Functions.

Start by reviewing the TimerTrigger lease and default container naming behavior described for Azure Functions running in Docker on Kubernetes. Evaluate how an override for the default container name would coordinate all instances, and consider the issue resolved when one lease reliably prevents duplicate timer execution across instances.

Written by the indexing model from the issue text.