example of tf map manipulation

main.tf

locals {
  virtual_machines = {
    "test-services1" = {
      vm_instance_group = "instance-group-services"
    },
    "test-services2" = {
      vm_instance_group = "instance-group-services"
    },
    "test-cpu" = {
      vm_instance_group = null
    },
    "test-mdf" = {
      vm_instance_group = null
    },
    "bastion" = {
      vm_instance_group = null
    }
    "test-jupyter" = {
      vm_instance_group = "instance-group-jupyter"
    },
    "test-sbox" = {
      vm_instance_group = "instance-group-sbox"
    }
  }

  test = { for k, v in local.virtual_machines :
    v.vm_instance_group => k...
  if v.vm_instance_group != null }

  test2 = { for k, v in local.test :
  k => { "servers" : v } }

}

output "test2" {
  value = local.test2
}


# Apply complete! Resources: 0 added, 0 changed, 0 destroyed.
# Outputs:
# test2 = {
#   "instance-group-jupyter" = {
#     "servers" = [
#       "test-jupyter",
#     ]
#   }
#   "instance-group-sbox" = {
#     "servers" = [
#       "test-sbox",
#     ]
#   }
#   "instance-group-services" = {
#     "servers" = [
#       "test-services1",
#       "test-services2",
#     ]
#   }