The Deploy VM is not in the Data Path!
I would not expect any interruption of service.
But since it serves as the mediator for HA pairs and as License Manager (LM) for capacity pools, it should not be offline for an extended period of time... From the FAQ:
Does the LM and ONTAP Deploy need to be always running?
Answer: No, but it’s strongly recommended. The LM is critical when deploying new nodes or when making
changes to data aggregates that require a lease update.
After the node is deployed, the aggregate creation process “leases” capacity from the LM for a certain
period—a process analogous to DHCP and IP addresses. When the lease is halfway into its expiration,
the node starts reaching out to the LM to renew the lease.
If the renew request is successful—which means that the LM is available—the node continues to operate
normally. The node does not connect to the LM until the next renewal is required or if the user makes
changes such as creating, deleting, or expanding the aggregates. If the renew request is not successful—which means that the LM was not available—the node continues
with its attempts to renew the lease at regular intervals.
If the lease expires before the LM becomes available, ONTAP Select does not stop serving data and the
aggregate does not go forcibly offline. However, the user might manually offline the aggregates or there
might be an HA event. If so, then aggregates without a valid lease do not come back online unless the LM
is available and the capacity pool has enough free capacity to lease to the aggregates.
Regarding the clusters finding out about the new IP address of the Deploy VM, I have not yet tried it out, but I assume, the Deploy VM tells the clusters about it, since it has all the relevant info to be able to connect to the clusters. I made a note and I'll try it out in our lab one of these days...