Some VM configurations may result in a large number of threads created by
the associated qemu process which can exceed the system default limit. The
maximum number of threads allowed per process is controlled by the pids
cgroup controller and is set to 16k when creating VMs with systemd's
machined service. The maximum number of threads per process is recorded
in the pids.max file under the machine's pids controller cgroup hierarchy,
e.g.
$cgrp-mnt/pids/machine.slice/machine-qemu\\x2d1\\x2dtest.scope/pids.max
Maximum threads per process is controlled with the TasksMax property of
the systemd scope for the machine. This patch adds an option to qemu.conf
which can be used to override the maximum number of threads allowed per
qemu process. If the value of option is greater than zero, it will be set
in the TasksMax property of the machine's scope after creating the machine.
Signed-off-by: Jim Fehlig <jfehlig@suse.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
When receiving multiple FDs from systemd during service activation it is
neccessary to identify which purpose each FD is used for. While this
could be inferred by looking for the specific IP ports or UNIX socket
paths, this requires the systemd config to always match what is expected
by the code. Using systemd FD names we can remove this restriction and
simply identify FDs based on an arbitrary name.
The FD names are passed by systemd in the LISTEN_FDNAMES env variable
which is populated with the socket unit file names, unless overriden
by using the FileDescriptorName setting.
This is supported since the system 227 release and unfortunately RHEL7
lacks this version. Thus the code has some back compat support whereby
we look at the TCP ports or the UNIX socket paths to identify what
socket maps to which name. This back compat code is written such that
is it easly deleted when we are able to mandate newer systemd.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Require that all headers are guarded by a symbol named
LIBVIRT_$FILENAME
where $FILENAME is the uppercased filename, with all characters
outside a-z changed into '_'.
Note we do not use a leading __ because that is technically a
namespace reserved for the toolchain.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
It is more related to a domain as we might use it even when there is
no systemd and it does not use any dbus/systemd functions. In order
not to use code from conf/ in util/ pass machineName in cgroups code
as a parameter. That also fixes a leak of machineName in the lxc
driver and cleans up and de-duplicates some code.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
So, systemd-machined has this philosophy that machine names are like
hostnames and hence should follow the same rules. But we always allowed
international characters in domain names. Thus we need to modify the
machine name we are passing to systemd.
In order to change some machine names that we will be passing to systemd,
we also need to call TerminateMachine at the end of a lifetime of a
domain. Even for domains that were started with older libvirt. That
can be achieved thanks to virSystemdGetMachineNameByPID(). And because
we can change machine names, we can get rid of the inconsistent and
pointless escaping of domain names when creating machine names.
So this patch modifies the naming in the following way. It creates the
name as <drivername>-<id>-<name> where invalid hostname characters are
stripped out of the name and if the resulting name is longer, it
truncates it to 64 characters. That way we can start domains we
couldn't start before. Well, at least on systemd.
To make it work all together, the machineName (which is needed only with
systemd) is saved in domain's private data. That way the generation is
moved to the driver and we don't need to pass various unnecessary
arguments to cgroup functions.
The only thing this complicates a bit is the scope generation when
validating a cgroup where we must check both old and new naming, so a
slight modification was needed there.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1282846
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
The scope name, even according to our docs is
"machine-$DRIVER\x2d$VMNAME.scope" virSystemdMakeScopeName would use the
resource partition name instead of "machine-" if it was specified thus
creating invalid scope paths.
This makes libvirt drop cgroups for a VM that uses custom resource
partition upon reconnecting since the detected scope name would not
match the expected name generated by virSystemdMakeScopeName.
The error is exposed by the following log entry:
debug : virCgroupValidateMachineGroup:302 : Name 'machine-qemu\x2dtestvm.scope' for controller 'cpu' does not match 'testvm', 'testvm.libvirt-qemu' or 'machine-test-qemu\x2dtestvm.scope'
for a "/machine/test" resource and "testvm" vm.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1238570
systemd-machined introduced a new method CreateMachineWithNetwork
that obsoletes CreateMachine. It expects to be given a list of
VETH/TAP device indexes for the host side device(s) associated
with a container/machine.
This falls back to the old CreateMachine method when the new
one is not supported.
Systemd does not forget about the cases, where client service needs to
wait for daemon service to initialize and start accepting new clients.
Setting a dependency in client is not enough as systemd doesn't know
when the daemon has initialized itself and started accepting new
clients. However, it offers a mechanism to solve this. The daemon needs
to call a special systemd function by which the daemon tells "I'm ready
to accept new clients". This is exactly what we need with
libvirtd-guests (client) and libvirtd (daemon). So now, with this
change, libvirt-guests.service is invoked not any sooner than
libvirtd.service calls the systemd notify function.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The problem is described by [0] but its effect on libvirt is that
starting a container with a full distro running systemd after having
stopped it simply fails.
The container cleanup now calls the machined Terminate function to make
sure that everything is in order for the next run.
[0]: https://bugs.freedesktop.org/show_bug.cgi?id=68370
There are some interesting escaping rules to consider when dealing
with systemd slice/scope names. Thus it is helpful to have APIs
for formatting names
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
To register virtual machines and containers with systemd-machined,
and thus have cgroups auto-created, we need to talk over DBus.
This is somewhat tedious code, so introduce a dedicated function
to isolate the DBus call in one place.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
