Document the process to remove a distribution

This is required when the cleaning up and recovering space.
Usually, the beta, development and preview releases are the common
candidates for removal

Signed-off-by: Ritesh Raj Sarraf <ritesh.sarraf@collabora.com>

content/guides/apertis_release_process.md

@@ -250,6 +250,27 @@ The `apply` sub-command does the actual job.
     Package cyrus-sasl2 is NOT IN SYNC in branches: v2020 and v2020-security
     Merging branch v2020-security into v2020
 
+## Removing an old distribution
+
+Perform the following steps to remove an old distribtuion. This would usually be the
+obsolete *Beta* and *Preview* distribution releases, like: `v2019dev0`, `v2019pre`
+
+* Remove the entry for the distribution from the `reprepro` configuration file.
+  Example: `/srv/obs/repos/shared/apertis/internal/apertis/conf/distributions`
+* Run the following `reprepro` command to apply the changes
+
+  ```
+  # sudo -u obsrun reprepro --gnupghome /srv/obs/gnupg/ -Vb /srv/obs/repos/shared/apertis/internal/apertis --delete clearvanished
+  Deleting vanished identifier 'u|v2019dev0|proprietary|amd64'.
+  Deleting vanished identifier 'u|v2019dev0|proprietary|arm64'.
+  Deleting vanished identifier 'u|v2019dev0|proprietary|armhf'.
+  Deleting vanished identifier 'u|v2019pre|demo|amd64'.
+  Deleting vanished identifier 'u|v2019pre|demo|armhf'.
+  Deleting vanished identifier 'u|v2019pre|nothumb|amd64'.
+  Deleting vanished identifier 'u|v2019pre|nothumb|armhf'.
+  Deleting vanished identifier 'u|v2019pre|proprietary|amd64'.
+  Deleting vanished identifier 'u|v2019pre|proprietary|armhf'.
+  ```
 
 # Appendix