changes

packer/ubuntu-14.04-server-amd64.json

@@ -15,8 +15,8 @@
             "accelerator": "kvm",
             "disk_size": "{{ user `disk_size`}}",
             "headless": true,
-            "iso_url": "http://releases.ubuntu.com/14.04/ubuntu-14.04.4-server-amd64.iso",
-            "iso_checksum": "2ac1f3e0de626e54d05065d6f549fa3a",
+            "iso_url": "http://releases.ubuntu.com/14.04/ubuntu-18.04.4-server-amd64.iso",
+            "iso_checksum": "2ac1f3e0de626e54d055454545454545",
             "iso_checksum_type": "md5",
 
             "http_directory": "http",