Many of operation engineer look for solution how to delete instances in bulk from CLI or CURL call to reduce time effort, here is the filter method to do it, but please make sure that really you want to delete in bulk.
Here the best script method which i follows to do,
Source with required tenant, if you do as admin will delete all projects, so make sure of it.
Now run below CLI, which basically lists servers and grep its ID and do nova delete
nova list | awk '$2 && $2 != "ID" {print $2}' | xargs -n1 nova delete
In particular, the solution from dbxs uses the “name” field. If there are multiple instances with the same name, the “nova delete” operation will fali with:
Multiple server matches found for 'c0', use an ID to be more specific.
ERROR: Unable to delete any of the specified servers.