[Pkg-xen-devel] Now is the time! Help testing Xen for Buster.

[Hans van Kranenburg]

Hi all,

The Buster freeze is approaching at full speed! [0]

Now is the time to start upgrading your test environments to Buster to
see how they behave with Xen 4.11 and Linux 4.19. *1)

I've been using these packages for months at work (at Mendix)
successfully already, but that doesn't mean that all the (packaging)
bugs which are lurking in the corner of your specific situation have
been found yet.

Especially full upgrade reports from Stretch to Buster are interesting,
since there's quite some changes made in the packaging. Does it do the
right thing? Is it convenient?

Right now we can still change things, after the Buster release it will
be much harder. So test and report now, instead of doing so after the
release, when it's too late.

While everything is in pretty good shape (especially after the packaging
rewrite by Ian in September, yay), there are still a few issues which
would be nice to improve.

The first one, the init scripts one is the biggest, and if we want to
make changes there, it should happen ASAP.

---- 8< ----

"Review init scripts in the package and see if we can drop modified old
versions and use upstream ones."

The init scripts that we currently ship are some old debian-baked ones,
which are not the ones that are in the upstream source. While things
seem to work (tm) this sounds a bit worrying.

The task here would be to find out what the differences between the init
script collections are, find out that (hopefully) the debian ones can be
thrown in the trash can and be replaced with the upstream ones, and then
test everything and also have it work properly with systemd.

And, the stop/start init scripts need to deal with

There are some related complaints about "warning: something called
deprecated script /usr/lib/xen-common/bin/xen-toolstack" and confusing
"[warn] Not running within Xen or no compatible utils ... (warning)."
that could maybe be solved by this.

---- 8< ----

Command line tab completion doesn't work properly.

Well, it does something, but it completes file paths, which doesn't make
any sense:

-# xen [TAB][TAB]
.bash_aliases  .bashrc        .profile       .vim/          .vimrc
.bash_history  .lesshst       .ssh/          .viminfo

I'd rather have it do nothing than this.

The task here is to find out if we actually ship the right
bash-completion files in the right place and if so, find out why they're
not picked up.

---- 8< ----

pygrub is borken.

See https://bugs.debian.org/912381

We either need to drop pygrub support or fix it. This one is probably
best done by Ian, who touched all of this in september.

---- 8< ----

Have grub (dom0) do the right thing for booting with and without Xen.

The new packaging contains some changes to input files for grub in
/etc/default, which make it possible to have bit of a difference between
linux kernel command line options when starting with and without Xen.
E.g. console settings can be either ttyS0 or hvc0.

I'm planning to look into this one myself, but don't hesitate to explore
when interested.

---- 8< ----

For the Linux kernel part, there's an open issue with live migration [1]
and there's also still an idea to provide better error reporting for the
infamous max grant frames case where domUs stall without any proper
error message for the user. The latter one will maybe happen later
(adding hints which show up in dmesg) but not now.

---- 8< ----

Feel free to reply, and #debian-xen on OFTC IRC is of course also
available for a chat (I'm Knorrie).

Thanks,
Hans

[0] https://release.debian.org/buster/freeze_policy.html
[1]
https://lists.xenproject.org/archives/html/xen-devel/2018-12/msg02167.html

*1) I'm using stretch-backports packages of both Xen and the Linux
kernel that I make myself and use them on Stretch dom0s. The
stretch-backports for Linux 4.19 will be available soon, and if you
don't need to boot PVH with grub, the current ones are also ok. If
anyone wants to use Xen 4.11 (without qemu/HVM) on stretch and doesn't
know how to do that, just ask me.