Let's make use of the new DelegateSubgroup= feature and delegate the
/supervisor/ subcgroup already to nspawn, so that moving the supervisor
process there is unnecessary.
The comment talks about upstream development steps and doesn't make
sense for users. We used special '## ' syntax to strip it out during
build, but it got inadvertently reformatted as a normal comment
in 3982becc92.
We don't need two (and half) templating systems anymore, yay!
I'm keeping the changes minimal, to make the diff manageable. Some enhancements
due to a better templating system might be possible in the future.
For handling of '## ' — see the next commit.
This patch modifies the RequireMountsFor setting in systemd-nspawn@.service to wait for the machine instance directory to be mounted, not just /var/lib/machines.
Closes#14931
This makes things a bit simpler and the build a bit faster, because we don't
have to rewrite files to do the trivial substitution. @rootbindir@ is always in
our internal $PATH that we use for non-absolute paths, so there should be no
functional change.
Devices referred to by `DeviceAllow=` sandboxing are resolved into their
corresponding major numbers when the unit is loaded by looking at
`/proc/devices`. If a reference is made to a device which is not yet
available, the `DeviceAllow` is ignored and the unit's processes cannot
access that device.
In both logind and nspawn, we have `DeviceAllow=` lines, and `modprobe`
in `ExecStartPre=` to load some kernel modules. Those kernel modules
cause device nodes to become available when they are loaded: the device
nodes may not exist when the unit itself is loaded. This means that the
unit's processes will not be able to access the device since the
`DeviceAllow=` will have been resolved earlier and denied it.
One way to fix this would be to re-evaluate the available devices and
re-apply the policy to the cgroup, but this cannot work atomically on
cgroupsv1. So we fall back to a second approach: instead of running
`modprobe` via `ExecStartPre`, we move this out to a separate unit and
order it before the units which want the module.
Closes#14322.
Fixes: #13943.
As discussed on systemd-devel [1], in Fedora we get lots of abrt reports
about the watchdog firing [2], but 100% of them seem to be caused by resource
starvation in the machine, and never actual deadlocks in the services being
monitored. Killing the services not only does not improve anything, but it
makes the resource starvation worse, because the service needs cycles to restart,
and coredump processing is also fairly expensive. This adds a configuration option
to allow the value to be changed. If the setting is not set, there is no change.
My plan is to set it to some ridiculusly high value, maybe 1h, to catch cases
where a service is actually hanging.
[1] https://lists.freedesktop.org/archives/systemd-devel/2019-October/043618.html
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1300212
https://github.com/systemd/systemd/pull/3685 introduced
/run/systemd/inaccessible/{chr,blk} to map inacessible devices,
this patch allows systemd running inside a nspawn container to create
/run/systemd/inaccessible/{chr,blk}.
When a container scope is allocated via machined it gets 16K set already since
cf7d1a30e4. Make sure when a container is run as
system service it gets the same values.
When using `%I` for instances of `systemd-nspawn@.service`, the result
will be `systemd-nspawn` trying to launch a container named e.g.
`fedora/23` instead of `fedora-23`.
Using `%i` instead prevents escaping `-` in a container name and uses
the unmodified container name from the machine store.
