Flux reconcilation failed after upgrade with "flux install" command

TL;DR

Also follow the version upgrade procedure: before upgrading to v2.7, run flux migrate. See the v2.7.0 upgrade notes at fluxcd.io for the full procedure.

Steps

1. Reported in Flux CD: Flux reconcilation failed after upgrade with "flux install" command.
2. If Flux reconciliation fails after running 'flux install' to upgrade, it is because you bootstrapped Flux in Git and then overwrote the controllers with install. To upgrade a Git-bootstrapped Flux, rerun bootstrap, not install: flux bootstrap github (or your provider) with the same flags. Also follow the version upgrade procedure: before upgrading to v2.7, run flux migrate. See the v2.7.0 upgrade notes at fluxcd.io for the full procedure.

When to use

Use this skill when you run into "Flux reconcilation failed after upgrade with "flux install" command".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

Versions mentioned in the source: v2.7, v2.7.0. If you are on something much newer or older, the details may have shifted.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Edge cases

• Also follow the version upgrade procedure: before upgrading to v2.7, run flux migrate.

In gh:fluxcd/flux2#3622 (https://github.com/fluxcd/flux2/issues/3622), the reporter ran into this: Reported in Flux CD: Flux reconcilation failed after upgrade with "flux install" command. The verified resolution: If Flux reconciliation fails after running 'flux install' to upgrade, it is because you bootstrapped Flux in Git and then overwrote the controllers with install. To upgrade a Git-bootstrapped Flux, rerun bootstrap, not install: flux bootstrap github (or your provider) with the same flags. Also follow the version upgrade procedure: before upgrading to v2.7, run flux migrate. See the v2.7.0 upgrade notes at fluxcd.io for the full procedure.