This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.
What this hour is for
Packer builds an image from a template. The generator drafts the template. It does not build the image and it does not download an ISO. The ISO is one you already trust and can name. A password, a key, or a token does not go in the template.
The build later runs in a lab you administer. Do not point it at a production network to fetch a file. One image. Do not start the build during the reading.
192.0.2.10/24 and example.com are documentation. They stay in the note.
The change you can finish
Apply nothing while you are writing the note. When the lab window opens, it is one change on the host named in the ticket. Read the draft, then the host, then decide.
Rollback is the file, the package version, or the snapshot you saved first. You do not invent a rollback after the only copy is gone.
- Name the image and the ISO source you trust.
- Draft the template.
- Remove secrets.
- Do not start the build.
- Stop.
Mistakes that outlive the command
Building Golden Images with Packer goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- A secret baked into the image.
- An ISO you cannot name.
- A build started during the reading.
- A fetch from a network you do not administer.
- Production used as the build network.
Decisions to write down
One decision for Building Golden Images with Packer: The ISO source is named. No secret is in the template. The lab is yours. The build was not started. And one image.
Checks before you call it done
Confirm this before you call the change done: The image name is written. The ISO source is written. No secret is present. Nothing was built. And the lab is yours. If one of those fails, stop.
# No secrets in the template.
# Name the ISO source.
# Do not build during the reading.Before you leave the host
Building Golden Images with Packer ends when the hostname in the prompt matches the hostname in the ticket. If it does not, you are on the wrong host. Stop. A command that succeeded on the wrong host is not progress.
The draft stays a draft until a person has read the names in it. A generator does not log into the host and does not know which disk is empty. You delete a line that names a host, a path, or an account you did not write down.
192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. They belong in the note. They are not values you leave on a host because a draft included them.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, or a token you save in the ticket or in git. The real secret stays in the password store.
One change is the window. If two things move and the result is wrong, you will not know which one did it. The next change waits for its own page.
If the same step fails twice, stop for the day. The failure is the result. Adding a forum command beside a half-applied change produces a host nobody can rebuild. Restore the copy you took first.
A second person reads the hostname and the change aloud. If they cannot find them in the ticket, the note is not done. Silence is not agreement. Then leave the host alone.
This page is a planning guide. It is not a vendor manual, not an official standard, and not permission to touch a host you do not administer. You do not disable a firewall, AppArmor, or SELinux to make a check pass.
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