Undo a change#

You will end up with the router running the configuration it had before a change. No file, no backup and no restart are involved: the router keeps every configuration it has applied as a numbered revision, and restoring a revision applies it again.

Before you start#

• The approver, operator or admin role — the History tab offers Restore revision to those — and a licence: restoring changes the router, and an unlicensed router refuses it.
• The router's revisions. The shipped image keeps the last 100.

Know what the numbers mean before you choose one:

Step 1 — Find the change#

System → History. The Configuration history table lists every revision:

By is the router's own record. The Audit log tab on the same page names the Wheelhouse user who applied each change: each Applied changes entry shows the first change in words, and and N more when there were others.

Step 2 — Read what it did#

Select a revision. Its panel, Revision N, opens with What this change did: the change that made that revision, in the same sentences the bar at the bottom of the page uses for pending changes. For example:

• Add VLAN 20 on eth0, with Address 10.20.0.1/24, description “IoT” beneath it
• Change the host name to edge-1

A revision that changed nothing says This revision changed nothing.

So to see what the last change did, open revision 0. Restoring a revision undoes every change made after it, so read the panels of the revisions above the one you mean to restore: to go back to revision 2, read revisions 1 and 0.

Read them for the changes that can cut you off: interface addresses, firewall rules, NAT and SSH. Undoing a change to one of those changes it again.

Step 3 — Restore#

Open the revision from before the change: revision 1 to undo the last change. At the foot of its panel, press Restore revision 1, then Restore revision 1? to go ahead. The second press has to follow within a few seconds, or the button returns to its first state.

Restoring applies this revision at once, without auto-revert. When it is done, the page says Restored revision 1. The configuration it replaced is now revision 1. and offers Review revision 1, which opens the configuration you have just left.

Step 4 — Save it#

Restoring a revision does not save it. The router starts with its saved configuration after a restart, so if the change you undid had been saved, a restart brings it back. Press Save configuration in the System page header once you are satisfied.

What a restore does not bring back#

• Accounts, tokens, two-factor enrolments and the audit log. They are the agent's data, not part of a revision, so a restore cannot bring back a deleted user. A snapshot on the Backup page can: Restore a backup.
• Container images. Restoring a revision restores the configuration that named an image, not the image itself. The catalogue's images are pinned by digest, so the configuration a restore brings back names the exact build.
• Anything that was never applied. Pending changes are not revisions, and neither is a file edited on the router by hand.

Check it worked#

• The note at the top of the System page says the revision was restored.
• The History tab shows the restore as a new revision 0. A restore moves forward to an earlier configuration rather than deleting history, so the table has one more revision than before, not one fewer.
• Open revision 0: What this change did lists the reverse of the change you undid.

If the restore fails#

The page shows the router's reason and nothing changes. The usual cause is a revision the router no longer keeps: it discards the oldest once it holds its limit, and the shipped image keeps 100. For a configuration older than that, restore a backup or a snapshot instead.

Undoing the undo#

Press Review revision 1, or open revision 1 from the History tab, and restore it. The restore was an applied change, so revision 1 is the configuration you left.

Avoid needing this#

For a change that could cut you off, choose Apply with auto-revert on the bar at the bottom of the page instead of Apply changes. The router applies the changes and starts a timer. If the page still responds, press Keep changes. If it does not, the router restarts when the timer runs out and starts with its saved configuration.

• The window is the Auto-revert window under Admin → Agent settings, from 1 to 60 minutes.
• The restart brings back the saved configuration, so a change applied earlier and not saved is undone too. Press Save configuration before applying with auto-revert if earlier changes should survive.
• Keep changes does not save either. Save once the changes are kept.
• Changes that could cut you off are marked, and the bar says These changes could cut off your connection to the router. Apply with auto-revert undoes them if you lose access.

Auto-revert has to be chosen before the change is applied. A restore is for a change that worked, was kept, and turned out to be wrong.

For automation#

R=https://<router>:8443
T=wh_...
curl -sk -H "Authorization: Bearer $T" "$R/api/history"               # the revisions
curl -sk -H "Authorization: Bearer $T" "$R/api/history/diff?rev=0"    # what revision 0 changed
curl -sk -X POST -H "Authorization: Bearer $T" -H 'Content-Type: application/json' \
  -d '{"revision":1}' "$R/api/rollback"                                 # restore revision 1

An empty body restores revision 1. The route needs a licence, and accepts an approver, operator or admin token. It answers 502, with the router's reason, when the revision cannot be loaded.

At the router's console, configure then rollback 1 restores revision 1 the router's own way.

See also#

• Revisions and rollback — the model
• Apply with auto-revert — the undo that needs no reachable router
• Restore a backup — when the change is older than the revisions, or is not in the configuration
• System — history