modules/microvm: add stopTuntap to nomad jobs

modules/microvm.nix

@@ -96,6 +96,13 @@ in
               ip tuntap add ${id} mode tap user microvm
             fi
           '';
+        stopTuntap = { id, ... }:
+          pkgs.writeScript "tuntap-${hostName}-${id}" ''
+            #!${pkgs.runtimeShell} -e
+            if [ -d /sys/class/net/${id} ]; then
+              ip tuntap del ${id} mode tap
+            fi
+          '';
         # change working directory before starting virtiofsd
         runVirtiofsd = { tag, socket, source, ... }:
           pkgs.writeScript "virtiofsd-${hostName}-${tag}" ''
@@ -137,6 +144,16 @@ in
                   command = "${runTuntap interface}"
                 }
               }
+              task "interface-${id}-stop" {
+                lifecycle {
+                  hook = "poststop"
+                }
+                driver = "raw_exec"
+                user = "root"
+                config {
+                  command = "${stopTuntap interface}"
+                }
+              }
             '') config.microvm.interfaces}
 
             ${lib.concatMapStrings (share@{ tag, ... }: ''