Change credentials;Prevent/Delay SSH connectivity

packer/preseed/UbuntuServer20.04/user-data

@@ -1,7 +1,9 @@
 #cloud-config
 autoinstall:
   version: 1
-  locale: en_US
+  early-commands:
+    # Block inbound SSH to stop Packer trying to connect during initial install
+    - iptables -A INPUT -p tcp --dport 22 -j DROP  locale: en_US
   keyboard:
     layout: en
     variant: us
@@ -16,7 +18,7 @@ autoinstall:
       name: lvm
   identity:
     hostname: packer-template
-    username: root
+    username: ubuntu
     password: <<ssh-password>>
   ssh:
     install-server: yes
@@ -25,5 +27,5 @@ autoinstall:
 #      - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCi9eAu6KBaShdcL4pxi6/sJp+IS6nCKexcjQdwFLxg+EoiT2MTAnMsjnfi570het+VV+iOigcZLuRwEcAPh6rSQOtpikmpV6WFjzToWq9aUxDrxWsp/iEPHp+sbjrlsdnGvLGY9XhmPs9s5I8xFQbwF6ilhMIQm+RxtGJJuPUWaF+uXo+3CB91A6bK/rjs97iAjrPZRs0vo5hJGqrIGFi3WP9hf8hF9oWz2BiLRYBib3il6lsAl4Ca0sI//gNM0Ztj4gB7qv1+uPz157bk0IZoN285/72l/rUZVSPIwO+QFZFK07FsyVrpAgMlHk65BiSAO4DtolZEArfXRE1g1DH/ mail@example.com
   user-data:
     disable_root: false
-#  late-commands:
-#    - echo 'ubnt ALL=(ALL) NOPASSWD:ALL' > /target/etc/sudoers.d/ubuntu
+  late-commands:
+    - echo 'ubuntu ALL=(ALL) NOPASSWD:ALL' > /target/etc/sudoers.d/ubuntu