XS Blueprints:User account aliasing

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This is an important user administration feature in the XS, affecting the services that rely on the mapping between the laptop identity and the user identity. Currently this means

  • Moodle.
    • automatic sign-on
    • access to the backups is specially important
  • ds-backup which performs backups via ssh+rsync
  • ejabberd - and group management


This feature is available in XS-0.6 onwards.

Use cases

Replacement: A laptop is replaced due to theft of breakage. From the point of view of the XS, the same laptop casing with a different motherboard is a different laptop.

Teachers need to be able to mark the new laptop as associated to the old account so that the user can keep using online tools (moodle et al) under the same account, and has access to the backed up files from the old laptop.


  1. Switch on the new laptop
    1. Initialise it, setting the same "screen name" as the old laptop
    2. Look up the serial number of the laptop in the control panel
    3. Associate to the right Wifi network and register with the XS
  2. On the teacher's laptop
    1. Open Browse.xo and visit Moodle's Admin->Users->Browse to find the 'old' user account.
    2. Select the 'alias' tab
    3. In the alias tab, find the new laptop in the listing by name or serial number, and select it
  3. On the new laptop
    1. Open Browse.xo and visit Moodle. It should auto-login to the "old" user account.
    2. Visit the 'personal profile' page clicking on the top-right link
    3. Click on the 'backup' tab
    4. The backup pages should show a combined view of the backups of the old and new accounts. (You many need to allow for enough time for the backup to run from the old and new laptops to see this in action.)
      1. The initial page will show the latest snapshot from the new XO, followed by the latest snapshot of the old XO.
      2. The 'all snapshots' listing will show two columns. The left one displays the snapshots from the new XO, right one form old XO.
    5. When adding/removing the user from courses, the ejabberd group management will add/remove the new laptop account from the groups.


  • Un-aliasing: You can remove the aliasing by going to the user account -- their alias page offers a remove alias button.
  • Doing it late: the user can no longer access the new account created, but the work done by that user is still available. Ideally, the aliasing is done immediately after registration.

It is relatively easy to make the user aliasing work on the Moodle side, so that's what we do. The ssh / rsync side is client-driven, so we don't alias the accounts there, the new laptop will continue to ssh/rsync to its new identity, unaware of the aliasing.