Re: [PATCH 11/26] qemu: support automatic VM managed save in system daemon

On Wed, Jan 08, 2025 at 19:42:44 +0000, Daniel P. Berrangé wrote: > Currently automatic VM managed save is only performed in session > daemons, on desktop session close, or host OS shutdown request. > > With this change it is possible to control shutdown behaviour for > all daemons. A recommended setup might be: > > auto_shutdown_try_save = "persistent" > auto_shutdown_try_shutdown = "all" > auto_shutdown_poweroff = "all" > > Each setting accepts 'none', 'persistent', 'transient', and 'all' > to control what types of guest it applies to. > > For historical compatibility, for the system daemon, the settings > currently default to: > > auto_shutdown_try_save = "none" > auto_shutdown_try_shutdown = "none" > auto_shutdown_poweroff = "none" > > while for the session daemon they currently default to > > auto_shutdown_try_save = "all" > auto_shutdown_try_shutdown = "none" > auto_shutdown_poweroff = "none" > > The system daemon settings should NOT be enabled if the traditional > libvirt-guests.service is already enabled. > > Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; > --- > src/qemu/libvirtd_qemu.aug | 3 ++ > src/qemu/qemu.conf.in | 37 ++++++++++++++++++++++ > src/qemu/qemu_conf.c | 51 ++++++++++++++++++++++++++++++ > src/qemu/qemu_conf.h | 3 ++ > src/qemu/qemu_driver.c | 9 +++--- > src/qemu/test_libvirtd_qemu.aug.in | 3 ++ > 6 files changed, 101 insertions(+), 5 deletions(-) > > diff --git a/src/qemu/libvirtd_qemu.aug b/src/qemu/libvirtd_qemu.aug > index 642093c40b..e465a231fc 100644 > --- a/src/qemu/libvirtd_qemu.aug > +++ b/src/qemu/libvirtd_qemu.aug > @@ -98,6 +98,9 @@ module Libvirtd_qemu = > | bool_entry "auto_dump_bypass_cache" > | bool_entry "auto_start_bypass_cache" > | int_entry "auto_start_delay" > + | str_entry "auto_shutdown_try_save" > + | str_entry "auto_shutdown_try_shutdown" > + | str_entry "auto_shutdown_powerdown" Don't forget to merge in the appropriate hunk from the next patch to make tests pass. > > let process_entry = str_entry "hugetlbfs_mount" > | str_entry "bridge_helper" > diff --git a/src/qemu/qemu.conf.in b/src/qemu/qemu.conf.in > index a3e9bbfcf3..d8890c4c32 100644 > --- a/src/qemu/qemu.conf.in > +++ b/src/qemu/qemu.conf.in > @@ -638,6 +638,43 @@ > # > #auto_start_delay = 0 > > +# Whether to perform managed save of running VMs if a host OS > +# shutdown is requested (system/session daemons), or the desktop > +# session terminates (session daemon only). Accepts > +# > +# * "none" - do not try to save any running VMs > +# * "persistent" - only try to save persistent running VMs > +# * "transient" - only try to save transient running VMs > +# * "all" - try to save all running VMs > +# > +# Defaults to "all" for session daemons and "none" > +# for system daemons > +# > +# If 'libvirt-guests.service' is enabled, then this must be > +# set to 'none' for system daemons to avoid dueling actions > +#auto_shutdown_try_save = "all" As demonstrated in previous patch, the 'transient' and 'all' make no sense here, as all you'll get is an error per semantics of managed save. The only way we could make saving of transient VMs work is to invoke the normal save API and dump them in a directory configured for this reason. But then you get problem of what to do at startup as IIUC the native replacement to libvirt-guests will only support startup via 'autostart', thus that'd overcomplicate things a bit more. I'd suggest to simply don't do save for transient VMs.

> + if (virConfGetValueString(conf, "auto_shutdown_try_save", &autoShutdownScope) < 0) > + return -1; > + > + if (autoShutdownScope != NULL && > + (cfg->autoShutdownTrySave = > + virDomainDriverAutoShutdownScopeTypeFromString(autoShutdownScope)) < 0) { > + virReportError(VIR_ERR_INVALID_ARG, > + _("unknown auto_shutdown_try_save '%1$s'"), > + autoShutdownScope); > + return -1; > + } Here it'll need to reject the two unsupported options as well.

> diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h > index 61a2bdce51..5d9ace6dcc 100644 > --- a/src/qemu/qemu_conf.h > +++ b/src/qemu/qemu_conf.h > @@ -201,6 +201,9 @@ struct _virQEMUDriverConfig { > bool autoDumpBypassCache; > bool autoStartBypassCache; > int autoStartDelayMS; > + int autoShutdownTrySave; > + int autoShutdownTryShutdown; > + int autoShutdownPoweroff; Preferrably use the enum type, although that'll make the parser a bit more verbose due to absence of something like virXMLPropEnum.