The 2016.6 release which is currently in preparation adds some important dependencies which some admins may prefer to install ahead of the upgrade.

Debian has the concept of Dependencies which must be installed and Recommends which are optional but expected to be useful by most users of the package in question. The Recommends for GuestFS can be omitted from the installation if admins desire but this needs to be done ahead of the upgrade to 2016.6.

V2 in 2016.6 adds support for GuestFS which removes the need for loopback support for QEMU devices. GuestFS supports a wide range of filesystem utilities and other virtualisation support tools, not all of which will be of interest to LAVA. (Notably, libguestfs Recommends a mail-transport-agent and the default MTA in Debian is exim. With the default exim4 config, this simply adds a local MTA with no external support.)

Debian supports opting out of Recommends when installing packages, so if admins have concerns about extra packages being installed on the dispatchers (e.g. if using ARMv7 dispatchers or simply to reduce the complexity of the install) then Recommends can be omitted for the installation of these dependencies:

The option is:

$ sudo apt --no-install-recommends install python-guestfs

We'll add a note to the installation docs for this too.

With the move to V2 having a dumb dispatcher, the dependencies themselves do need to be installed to allow the server to dictate what jobs the dispatcher can run without the dispatcher failing due to missing support. If later LAVA upgrades need any of the packages that would have been installed as Recommends, LAVA will add an explicit dependency on just those packages and any others will remain optional.