note the changes that were required fleet-wide (still TODO)

howto/upgrades/bullseye.mdwn

@@ -23,8 +23,49 @@ Notable changes to do, especially on our infra:
  * [merged /usr will be the default in bullseye + 1](https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=978636#178) so our
    (bullseye) installers should be tweaked to remove the
    `--no-merged-usr` everywhere
- * we need to change all installers to switch to bullseye (ganeti and
-   hetzner-robot mostly done, remains tsa-misc/fabric stuff)
+
+# Fleet-wide changes
+
+The following changes need to be performed *once* for the entire
+fleet, generally at the beginning of the upgrade process.
+
+## installer changes
+
+The installer need to be changed to support the new release. This
+includes:
+
+ * the Ganeti installers (add a `gnt-instance-debootstrap` variant,
+   `modules/profile/manifests/ganeti.pp` in `tor-puppet.git`, see
+   commit 4d38be42 for an example)
+ * the (deprecated) libvirt installer
+   (`modules/roles/files/virt/tor-install-VM`, in `tor-puppet.git`)
+ * the wiki documentation:
+   * create a new page like this one documenting the process, linked
+     from [howto/upgrades](howto/upgrades)
+   * make an entry in the `data.csv` to start tracking progress (see
+     below), copy the `Makefile` as well, changing the suite name
+   * change the [Ganeti procedure](howto/ganeti#adding-a-new-instance) so that the new suite is used by
+     default
+   * change the [Hetzner robot](howto/new-machine-hetzner-robot) install procedure
+ * `tsa-misc` and the fabric installer (TODO)
+
+## Debian archive changes
+
+The Debian archive on `db.torproject.org` (currently alberti) need to
+have a new suite added. This can be (partly) done by editing files
+`/srv/db.torproject.org/ftp-archive/`. Specifically, the two following
+files need to be changed:
+
+ * `apt-ftparchive.config`: a new stanza for the suite, basically
+   copy-pasting from a previous entry and changing the suite
+ * `Makefile`: add the new suite to the for loop
+
+But it is not enough: the directory structure need to be crafted by
+hand as well. A simple way to do so is to replicate a previous release
+structure:
+
+    cd /srv/db.torproject.org/ftp-archive
+    rsync -a --include='*/' --exclude='*' archive/dists/buster/  archive/dists/bullseye/
 
 # Per host progress