With `ephemeral_disk`, is the persistent `alloc` dir global to all datacenters?

From the docs:

“All tasks in this group will share the same ephemeral disk.”

Since the task groups may span any number of datacenters, I assume the alloc dir to be persisted across datacenters. Is this correct?

Hi @salvor,

Ephemeral disks are not simultaneously persisted across multiple clients. When an allocation is first placed on a client, the allocation directory structure will be built. In the event this allocation fails the local/ and alloc/data directories will be moved/copied depending on where the replacement allocation is placed and how the ephemeral disk in configured.

Datacenters are an abstract concept whereby a client can exist within a single datacenter and an allocation can be eligible for scheduling on any array of datacenters, but only placed within a single one.

I hope this helps. Please let me know if you have any followup questions.

Thanks,
jrasell and the Nomad team

Sorry for my vague question, and thanks for taking the time!

Correction: ‘are ephemeral_disks locked into a DC, or given a sufficient need for it, will the scheduler migrate between available DCs?’

I think the language on the docs indicates that migration between DC’s happens seamlessly, but I was just curious to hear if I was perhaps wrong.