azure: Abort script when no instance ID can be retrieved

We cannot reliably determine if a system is running on Hyper-V
on a private server or on the Azure Cloud.

Therefore, we will have to try to retrieve an IP address
with DHCP and try to connect to the metadata service. If either
of those things is not successful, we will just continue with
the setup process as usual.

So cloud instances should be automatically configured now and
all other systems will continue to boot and call the setup
wizard as usual.

Fixes: #12272
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>

src/initscripts/helper/azure-setup

@@ -58,6 +58,9 @@ prefix2netmask() {
 
 import_azure_configuration() {
 	local instance_id="$(get compute/vmId)"
+	if [ -z "${instance_id}" ]; then
+		return 0
+	fi
 
 	boot_mesg "Importing Microsoft Azure configuration for instance ${instance_id}..."