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
A template plus a row of values drafts a config. The renderer does that in the browser. It does not log into a device. The values are hostnames, interfaces, and prefixes from a plan you administer.
Read the output. A secret that the CSV contained is a secret you remove and rotate. prompt-for-this replaces it. A line that permits any source is a line you delete. Documentation prefixes stay out of the production column.
One template, one device class. A template that emits a whole network is how a bad cell becomes a bad network. The backup page owns the copy you take before any later paste.
Do not render someone else's inventory.
The change you can finish
Apply nothing during the writing of the note. When the lab window opens, it is one change on the device named in the ticket. Read the draft, then the device, then decide.
Rollback is the file or the revision you saved first. You do not invent a rollback after the only copy is gone.
- Name the device class.
- Render one row you are allowed to hold.
- Read hostnames and prefixes.
- Remove secrets and any-source permits.
- Keep documentation prefixes out of production rows.
- Do not paste to a device in this hour.
Mistakes that outlive the command
Jinja2 Templates for Network Configs goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- A secret rendered into git.
- An unread loop over every device.
- 0.0.0.0/0 emitted and kept.
- A documentation prefix in a production row.
- Someone else's CSV.
Decisions to write down
One decision for Jinja2 Templates for Network Configs: The row is yours. The output was read. Secrets are gone. Wide permits are gone. And nothing was pasted.
Checks before you call it done
Confirm this before you call the change done: One device is named in the output. The prefix matches the plan. No secret remains. No any-source permit remains. And the device was not touched. If one of those fails, stop.
Before you leave the device
Jinja2 Templates for Network Configs ends when the hostname on the device matches the hostname in the ticket. If it does not, you are on the wrong box. Stop. A command that succeeded on the wrong box is not progress.
The draft stays a draft until a person has read the names in it. A generator does not log into the device and does not know which interface is the uplink. You delete a line that names a device, a zone, or a prefix you did not write down.
0.0.0.0/0 is not kept because a sample included it. A source you can say is the source you keep. 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. They belong in the note. They are not prefixes you type onto a production device because they appeared in a draft.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, a community string, or a pre-shared key you save in the ticket or in git. The real secret stays in the store.
One change is the window. A VLAN and a routing protocol and a VPN do not share it. If two things move and the result is wrong, you will not know which one did it. The next feature 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 config produces a device nobody can rebuild. Restore the copy you took first.
A second person reads the device name and the change aloud. If they cannot find them in the ticket, the note is not done. Silence is not agreement. Then leave the device alone.
This page is a planning guide. It is not a vendor manual, not an official standard, and not a permission to touch a network you do not administer. The pillar guide owns the wider design. This page owns one lab proof.
Tools for this guide
These tools run in the browser on this site. They do not log into your machines.
Related pillar guides
More in this cluster
The pillar for this page, and the next published pages filed with it.