The Disks tab has a Move button for each disk: it opens a dialog to
choose another storage pool of the same host, and the move runs as a job.
- Running or paused VM: libvirt copies the disk with a block job
(TRANSIENT_JOB, as the VM is persistent) into a file it creates in the
pool, then pivots. The pivot names the copy in both the running and
the next start's definition.
- Shut-off VM: the volume is copied into the pool and the copy named in
the definition.
The source file goes then, unless a VM or volume of any compute uses it
(shared storage holds it for every host that mounts it), a compute
cannot be read, or the delete fails: the job lists such a file under
"Left behind", and the move stands.
A disk moves when:
- the VM is defined and running, paused or shut off, without snapshots,
a saved state or a block job;
- the disk is a writable, unshared, unencrypted raw or qcow2 file of a
storage pool, without a backing file, and the same file in both
definitions;
- the pool keeps disk files, is another directory, and has no file of
that name (libvirt would write into it).
Otherwise it is refused with the reason before anything changes.
The job claims the VM and the file's name in both pools. A cancel aborts
the block copy, and ends the job cancelled once the VM is back on its
file. A failed move deletes the copy it made, unless a definition names
it (a lost reply after the pivot); a file there before the copy began is
never deleted. Recovery after a stopped worker
ends a copy left mirroring, matched by its destination, and reads the
outcome from the definitions.
Superusers only, like the other disk edits.
A migration needed every disk on storage both hosts share: it was refused
when the destination lacked a disk file, and a file of the same name
there was taken for the VM's own disk.
The Migrate tab now lists the VM's disk files for the chosen destination.
For each disk it offers the destination's pools that keep disk files
(directory, filesystem and NFS pools). A disk on storage both hosts share
can also stay where it is.
A directory counts as shared when both hosts have it as a storage pool
and a marker file created on the source exists on the destination. A
directory the probe cannot tell is never taken as shared.
libvirt copies the chosen disks during the migration: migrate3 with
NON_SHARED_DISK for those targets, and destination and persistent
definitions naming the new paths, where libvirt creates the files.
- A shut-off VM is started paused for the copy and shut off on the
destination; its CPUs never run. Its UEFI variables are copied first,
as the destination would start from the firmware's template. If the
migration fails, the VM is shut off on the source again.
- Refused before anything changes, each disk with its reason:
- a disk neither shared nor given a pool, also one only the next
start's definition has;
- CD-ROM images, read-only or encrypted disks, formats other than raw
and qcow2, and disks with a backing file;
- a pool that is not of disk files, or that has a file of that name,
which libvirt would reuse and overwrite;
- two disks copied to one file.
- The job claims each copy's name in its pool, and the source volume.
- A failed or cancelled migration deletes the copies libvirt made, and
the UEFI variables copy, unless a VM on the destination has them.
- The source files stay and are named in the log. With "Delete the
source files of copied disks" they go, except one another VM or volume
uses; a failed delete is logged and the migration stands.
The NVRAM sharing check uses the same probe: a shut-off move stops when
it cannot be told, and the source file stays.
The API's migrate call takes disk_pools ({target: pool}) and
delete_source.
- A running VM gets a PCI device of its host at once and for its next
start, in one libvirt call; a hot plug libvirt could not keep for the
next start says that the device is in the running VM only. A q35 VM
without a free pcie-root-port gets libvirt's error and where a slot
comes from.
- A PCI device is taken from the running VM and from its next start, each
as it has it; a refusal by the guest stops there. When the guest has
not let the device go within libvirt's wait, the page says the removal
is requested and the Logs row records the request: the device stays in
the running VM until the guest lets it go or the VM stops.
- A paused VM, or one with a saved state, does not change its PCI devices.
- A device for a running VM is checked alone too, as libvirt takes only
the hot-plugged device from its host driver.
- The Host devices tab gives a shut-off VM a PCI device of its host and
takes it back; libvirt binds the device to vfio-pci when the VM starts
and gives it back when it stops (managed). The VM's PCI devices are
listed with whether the running VM and its next start have them.
- A device is offered, and accepted on the server under the compute's
claim, only when it is no bridge of any kind (bridge header, PCIe port,
or of the bridge class: host bridge, LPC), the host has none of its own
network interfaces, disks or graphics card on it (else: bind it to
vfio-pci on the host first), no other VM names it, and every other
endpoint of its IOMMU group is the VM's too or has no driver or
vfio-pci and no other VM; bridges in the group stay with pcieport, and
a member that cannot be read keeps the group. Nothing in the group is
taken implicitly.
- A snapshot revert checks the PCI devices of the snapshot with the same
rules; migration and clones already leave host devices out.
- The add forms of the tab load together, when the tab opens.
- A Host devices tab on the VM page lists the VM's USB host devices, each
once: how it is chosen (its address, or any device of its model), the
device the running VM holds and whether its next start has it; its other
host devices (PCI, SCSI, mediated) are listed for the XML editor.
- Superusers add a USB device of the host and take it back, on a running
VM too. The add form is loaded when the tab opens, as its choices read
every VM of the host; a hub, a device the host has its own disks or
network interfaces on, or one another VM names is not offered, with the
reason, and refused on the server under the compute's claim. A device is
chosen by model when the host has one of it, else by its address.
- A VM without a USB controller is refused; a device is taken from each
definition as that definition describes it.
- A clone gets none of the VM's host devices (the clone form says so), and
a VM with host devices is not migrated. A snapshot revert is refused when
it would give the VM a device another VM names or the host uses.
- A NIC that is a host device is no longer edited or removed from the
Network tab: the XML editor changes it.
Plan reviewed with Codex; libvirt's behaviour checked on a host.
- A filter is not deleted while a VM's interface references it, as the
VM runs or as saved for its next boot (a stopped VM too), or while
another filter references it: libvirt refuses only one a running VM
uses, and a VM using a filter that references a deleted one does not
start. The VMs are read from one listing, one or two XML reads each,
instead of a connection per VM; the refusal names them.
- Create refuses a name or UUID the host has, clone a name in use or
one outside the panel's names, and editing the XML must keep the
filter's name and UUID: each would replace another filter or make a
copy. Entered XML is read for these checks without expanding entities
or taking a DTD (util.parse_xml, shared with the network editor),
and a rule is one <rule> element.
- A rule or reference is deleted only while it reads as the page showed
it, not by index and three attributes: a rule alike in those or a
filter changed meanwhile loses nothing.
- A reference is added only to another filter of the host not
referenced yet; the picker offers those.
- References keep their parameters, in order (a name may repeat); a
rule shows every protocol element it has, a rule without one too.
- One change a POST (two would both start from the page's reading,
the second undoing the first); every change redirects and reports its
refusal as a message, a POST for a filter gone meanwhile going to the
list; the catch-all that showed any error goes, and so does
wvmInstance.get_filterrefs, which only the old delete check used. The list reads each filter's
XML once from one listing; a filter's page reads its XML once and
only the other filters' names; the per-filter XML dialog of the list
goes (a filter's page shows its XML). The XML editors send their text
untouched too.
A VM defined with QEMU's own VNC websocket (graphics websocket='...',
which the panel never sets) made the console page connect to that port on
the panel's host name: the port is on the compute, so the console did not
open unless the panel ran on that compute, and then it bypassed novncd and
the panel's console token. Such a VM has its ordinary VNC port too, and
novncd now reaches it there like any other VM.
When the guest agent failed, the Guest Info section stayed empty with no
word: the request's error answer was not handled. An agent without the
time zone or host name command lost the OS details it had answered too.
The section now shows the agent's error, and a missing command leaves out
only its own details.
Only external snapshots had their name checked. An internal one could be
taken with an empty name: libvirt named it, the job and its log row named
nothing, and a recovery looked for "" and marked the job failed though the
snapshot existed. Both kinds now pass the same check when queued, and the
internal form asks for a name as the external one does.
Snapshot dates showed no year, so last year's snapshot looked like this
year's in the list one reverts from; they now read 2026-10-13 23:04:00
under "Date (time zone)", as on the Jobs page.
Cloud images read their first-boot settings with cloud-init. The panel
served them only over HTTP, which a VM reaches only with the network
and a reverse DNS name for its address. A new VM can now carry them
itself: Cloud-init seed (Advanced) on the create form, or cloud_init in
the API.
The job writes a NoCloud seed, an ISO labelled cidata, into the disk's
directory pool as cidata-<uuid>.iso and puts it in the VM's CD-ROM
drive. Its meta-data holds the VM's UUID as instance-id and its name as
hostname, written as JSON so a VM named 123 or yes keeps a string
hostname; its user-data is what the HTTP datasource serves, with the
creating user's SSH keys. The ISO is built with pycdlib and written
through a libvirt stream, as the NVRAM copy is, now one helper for both.
A seed needs a CD-ROM bus and a directory pool, else the create is
refused. A failed create deletes the seed with the new disk, recovery
names one left behind, and deleting the VM with its disks deletes its
seed, found in the pools by name even when ejected. A clone's drive is
left empty: the seed is the source VM's identity.
A quiesced snapshot and a live clone freeze the guest's file systems
through libvirt, which asks the agent without a timeout: with the agent
hung, the job waited, holding the VM, with no end.
The agent must now first answer a guest-ping within 10 s; a frozen or
dead agent fails the job in seconds, before anything is frozen. The
freeze itself stays libvirt's, without a timeout: a timed freeze was
tried and left the guest frozen, since the freeze still ran in the
guest when the agent came back, after its thaw had failed.
The IP search and the VM report read each running VM's addresses and
OS from its guest agent with interfaceAddresses() and guestInfo(),
which wait for a hung agent indefinitely. The search answered by its
deadline, but the thread stayed blocked, counted against the search
thread limit and held up the worker's exit.
They now use the 10 s agent command the VM page uses, shared as
vrtManager.instance.agent_command() and agent_interfaces(). With the
agent frozen, a search answers in 5 s from the leases and the ARP
table, counts the VM unread, and its thread ends about 5 s later.
The VM page read the guest's addresses with interfaceAddresses() from
the agent, and the OS details with agent commands without a timeout.
A connected agent that hangs (a frozen guest) kept the page from
loading at all and held a worker: seen still loading after 120 s.
Both now go through the 10 s guest agent command the root password and
SSH key use. The addresses come from guest-network-get-interfaces, in
the form the page's address code already reads; an agent that does not
answer leaves the ARP address. With the agent frozen the page loads in
about 10 s and the OS details answer with the agent's error (400) in
5 s, instead of a server error.
The Access tab's Root Password and SSH Keys worked only on a shut-off
VM, through gstfsd on the compute. A running VM whose QEMU guest agent
is connected now gets them through the agent: guest-set-user-password
with the SHA-512 crypt hash, and guest-ssh-add-authorized-keys adding
the key to root's keys. A shut-off VM still goes through gstfsd; any
other VM is refused with "Shut the VM down, or start its QEMU guest
agent, and try again", and the buttons are disabled.
Each is one agent command with a 10 s timeout. libvirt's own calls for
them (setUserPassword, authorizedSSHKeysSet) wait for a hung agent
indefinitely, holding a worker and the VM's lock, and the domain's
agent timeout would change every other agent call of the VM too.
The agent's or libvirt's error is shown as is through error_text, so
users who do not see the hosts get no connection details, and the
attempt is logged as failed. The README names the SELinux boolean a
RHEL-family guest needs before its agent may add SSH keys.
libvirt's logical pool cannot change a volume's capacity, so every
resize of such a disk ended in a 500. Disks are resized one at a time;
VIR_ERR_NO_SUPPORT becomes a message naming the disk, and the other
disks still grow.
A live test creates an LVM pool from the storage page on a spare disk
(TEST_LIBVIRT_LVM_DEVICE; the Vagrant computes get /dev/vdb), attaches
new and existing volumes to stopped and running VMs as block disks, and
checks the refused resize in every state.
Settings > Console gets a Console type field. Serial removes the VM's
graphics device (adding a pty console when there is none); VNC adds the
graphics device new VMs get, on localhost, and then applies the form's
VNC fields, so an administrator can open it to all interfaces for a TCP
compute. Serial is offered only while SERIAL_CONSOLE_ENABLED is on.
The move copies the VM's NVRAM file to the destination with libvirt
streams (unless both hosts share the NVRAM directory) and removes the
copy if the move fails; the source's file goes with the existing
cleanup. The undefine keeps the file, as libvirt refuses to undefine a
VM with NVRAM otherwise. A VM with TPM state is still refused.
libvirt's backup copies the disks of a running or paused VM from one
instant into new volumes while it keeps running; the clone is defined
shut off as before. The VM is held for the copy, the copy can be
cancelled, and recovery reads the job's records and libvirt.
The clone's definition is one method for both paths; wvmInstance can check,
start, follow, read and abort a push backup of a VM's disks into new
volumes, and freeze/thaw the guest.
A disk-only snapshot was taken without any space check, though its
overlays grow as the guest writes and a later delete merges them down;
a full pool pauses the guest and can leave the snapshot undeletable.
Only a memory snapshot was checked, for the memory alone.
Before a snapshot, each storage pool with a disk of the VM must have
free a share of those disks' virtual size (10%, at least 1 GiB), and
the pool of the memory file the VM's memory on top. Both values are on
the Settings page (Snapshot Free Percent, Snapshot Free Min GiB; 0
turns a rule off, an invalid value keeps the default). The pools are
refreshed first, and a failed refresh or an unreadable volume refuses
the snapshot instead of skipping the check; a disk in no pool is not
checked. Nothing is reserved: later writes can still fill a pool.
A disk-only snapshot of a running VM is crash-consistent: data the
guest has not written yet is missing from it. With a connected QEMU
guest agent, the snapshot form now offers to freeze the guest's file
systems while the disks are snapshotted (libvirt's QUIESCE flag); the
box is checked by default and can be cleared. It is offered only for a
running VM whose agent is connected, and not together with memory:
libvirt accepts quiesce only for disk-only snapshots, and a memory
snapshot keeps the whole guest state anyway. A request that does not
fit is refused before libvirt is called.
libvirt keeps snapshot metadata on the source host and a migration does
not carry it, even when both hosts share the disks. Only the shut-off
path refused such a VM itself; a running or paused one relied on
libvirt's own refusal. moveto now refuses it for every state, before
any check against the destination, with the same message.
After a snapshot revert or delete, files libvirt could not remove are
named in a warning that says nothing uses them and asks to remove them
by hand. A file another VM on the same host uses (as a disk, a backing
file or a snapshot file) is no longer named: removing it would break
that VM. The warning now says no VM on this host uses the files.
libvirt deletes any volume it is asked to. The storage page and the API
deleted a VM's disk, the base image of another volume or the file a
snapshot was taken on without a check, breaking the VM or its
snapshots.
wvmStorage.del_volume now refuses a volume a domain on the compute uses
as a disk or a backing file of one, a file of a domain's snapshots, or
the backing file of another volume. The check is the one destroy
already used, moved to wvmConnect and extended to snapshot files, so
destroy also keeps the files of another VM's snapshots. The storage
page shows the refusal; the API answers 400 with it, as for other
refusals. Deleting a disk from a VM refuses after the detach when the
VM's own snapshots need the volume, and says the volume was kept.
Network disks count by their source name, pool volume disks by their
volume's path. A volume whose metadata cannot be read stops the check
instead of counting as unused; only one removed meanwhile is skipped.
The check and the delete hold the compute lock, so no VM operation
attaches the volume in between; a busy compute is a message on the page
and 409 in the API.
Deleting a VM with its data deleted only the images its disks pointed
at. With external snapshots that is the newest overlay: the image the
snapshots were taken on, the older overlays and the memory files stayed
on disk, with nothing referring to them once the VM and its snapshot
metadata were gone.
The files the VM's snapshots were taken on, down each disk's backing
chain, the overlays of snapshots kept off the chain after a revert, and
the snapshots' memory files are now the VM's own too. A template the
VM grew from ends the chain and stays, as does an overlay of a disk
detached since. The backing references of the VM's own volumes no
longer count as another domain's use, and a file another VM uses keeps
the files below it.
A backing file that cannot be read (other than one in no pool) stops the
split before anything is deleted, instead of ending the chain there.
The snapshot tab listed the VM's snapshots three times per page: once
per kind and once more for all of them. The list of all is now made
from the two kinds, so the combined flag is no longer used anywhere.
The revert confirm named only the disks the persistent definition
would lose. A disk hot-plugged into the running VM alone is detached
too, so the live definition is compared with what ran when the
snapshot was taken.
A storage pool refresh error after libvirt had already made, reverted
or deleted the snapshot was shown as if the operation had failed. It
is now logged, and the left-behind check is skipped then, since a stale
pool still lists the removed files. A volume removed while that check
reads it is skipped too.
An error reading the block jobs no longer breaks the instance page;
create, revert and delete still query the jobs again and refuse.
When libvirt cannot remove a snapshot file it merged or discarded, it
only logs a warning and the delete or revert still succeeds. On NFS it
removes them as the qemu user, so an image directory the qemu user may
not write to left every merged overlay on disk without a word.
Revert and delete now compare the files in use before and after and
show a warning naming the ones still on disk. Only a snapshot's own
files (overlays, memory) and overlays on a snapshot point count, and a
disk the revert detached is never named, so a kept disk is not offered
for removal.
Create, revert and delete are one libvirt call each. The pflash-to-rom
loader rewrite, the hand-written block commit and the s1./s2. names are
gone, so UEFI VMs can take external snapshots, a revert keeps disks added
later, and deleting an older snapshot keeps the newer one.
Create refuses what libvirt could not revert or delete later: internal
snapshots on the VM, a saved state, a running snapshot job, disks that
are not files, CD-ROM media, a branch after a revert, and memory without
a running VM or room in the first disk's pool. A disk-only revert keeps
the VM running, paused or shut off; one with memory resumes it as saved.
A revert in the same second as the previous one, which libvirt fails
after stopping the VM, is retried once.
A snapshot the old code took of a UEFI VM saved the loader as rom; its
revert is refused (deleting it still works).
The snapshots tab lists internal and external snapshots separately, can
save memory too, shows running snapshot jobs, and the revert confirmation
names the disks it detaches and that NVRAM is not restored.
On an active VM a device was attached in two calls, running VM first.
When the persistent attach was refused, for example because a disk target
or an agent channel was already pending there, the device stayed in the
running VM only and was gone at the next start. A NIC added without a
MAC got a different generated MAC in each definition. One call with
AFFECT_LIVE|AFFECT_CONFIG lets QEMU check the persistent copy before the
hotplug and keeps one MAC. Detach and update still go per definition,
each from its own XML.
On an active VM the boot order editor, the video model select and the
console form showed the running VM: a pending boot order, video model or
console setting looked unset, and the boot order editor offered devices
of the running VM only. Choosing one of those cleared the pending order,
since the setter dropped the old order and skipped devices it could not
find. They now read the persistent definition (get_bootmenu,
get_bootorder, get_media_devices, get_video_model and the console
getters take config=), and set_bootorder refuses a device that is not in
it before it changes anything.
On an active VM the options and CPU forms write the persistent definition
but showed the running VM's title, description and vCPUs, so saving one
posted the live values back over a pending change. They now read the
persistent definition (get_vcpu, get_cur_vcpu, get_title and
get_description take config=).
Buttons in the settings and resize tabs that were disabled only by class
get the disabled attribute: Enter in a field no longer submits a form
the page shows as unavailable while the VM runs.
The QoS table showed the running VM's bandwidth while an edit changes the
definition for the next start. Each row posts average, peak and burst,
so an edit wrote the running values back over a pending change, and a
direction added while the VM ran had no row. The table shows the
persistent definition now. An edit also kept only the posted values and
dropped an inbound floor; it now updates them and keeps the rest.
Enabling hot plug on a stopped VM wrote every vCPU up to the maximum as
enabled, so a VM with 2 of 4 vCPUs booted with 4. The current vCPUs stay
enabled now; libvirt adds the rest as disabled hotpluggable vCPUs.
Only a running VM counted as active, so a paused one (or one blocked,
PM-suspended or shutting down) had its maximum and current memory written
for the next boot and nothing applied live. Every active VM now has its
current memory changed live and in its definition and keeps its maximum;
a paused guest takes the new size once resumed. The quota check follows
the same rule. Checked on a real guest: paused, shrunk, resumed, then
grown back.
The .vv console file is built from the VM found by its UUID, with the
console page's getters, instead of looking the VM up by name five times;
a console without a listen address or password now gives 127.0.0.1 and
an empty password instead of "None". Removed methods nothing calls: the
by-name getters and power methods of wvmInstances, managed save, the vCPU
mode getter (it read the wrong attribute), the old NIC editor and its
bridge lookup. CD-ROM media and NIC hotplug use _definitions() like the
other device edits, the disk editor takes the bus prefix from
util.vol_dev_type, and an unreadable disk is logged, not printed.
Cloning a UEFI VM defined a persistent storage pool on the NVRAM's
directory when no pool held it, and dropped <nvram> from the clone,
which found its copy only because libvirt chose the same file name.
The copy is now made through the NVRAM directory's pool (a transient one
when there is none) or the pool that holds the file, with the original's
format, owner and mode, and the clone's definition names it. A failed
definition removes it with the copied disks. An NVRAM that is not a file
is refused before anything is copied.
A volume of an LVM or iSCSI pool can be attached: by its own path, with
the format its volume reports (raw when the pool knows none). Detaching
a disk takes each definition's own description of it, so a disk only in
the persistent definition goes too. Every NIC type can be a boot device;
bridge and direct NICs were dropped from the boot order. The video model
is a value, never parsed as XML. QoS changes clear the page's read cache.
The NIC model "default" leaves the choice to libvirt instead of writing
model "default", and rt18139 is rtl8139: a VM with either did not start
(checked on a RHEL 10 host). A migration corrects the default NIC type
setting.
A NIC without QoS showed the previous NIC's limits, an empty CD-ROM the
previous drive's pool; a NIC without a source or model broke the page.
The boot order shows the target of block and network disks and of bridge
and direct NICs too. Refreshing the VM's pools before a snapshot or a
delete no longer fails on a disk outside every pool.
The overview read the host's info four times, now once (12 libvirt calls).
A connection object keeps it next to the capabilities, and the VM page and
VM stats take it from there; the VM page's cached_reads block holds only
the VM's own data. Free memory is still read each time.
Measured on the create page: 751 ms and 72 libvirt calls, now 123 ms and
13. Its getters parsed the host's capabilities some 60 times, each read
from libvirt. A connection object (one per request) now reads them once,
and the domain capabilities once per emulator, arch, machine and domain
type. The VM page's cached_reads block no longer needs its own copy.
Each stats answer carries a signed sample of the counters, bound to the VM,
its compute and UUID. The next poll sends it back and the rates are the
averages since then; a sample from another run of the VM (domain ID),
another host CPU count or device list, or older than 30 s falls back to
one second as before. Windows are measured on the monotonic clock.
Now that a poll is cheap, the Stats tab polls every 5 s like the host
graph, the first time as soon as it opens (pollWhileVisible takes the
delay of the first request).
A counter the host reports as unsupported (-1) or that went back gives no
value instead of 0 or a jump; a NIC without a target keeps its chart, a
pool volume disk is measured, and a disk or NIC attached after the page
loaded no longer stops the other charts. Disk rates are MB/s (they were
MiB/s labelled Mb/s), network Mbit/s; the CPU tooltip names the window.
Measured on a VM with two disks, a CD-ROM and a NIC: 70 libvirt calls per
page, now 43. Within the page's cached_reads block the VM's state, the
host's info and domain capabilities, and each disk path's volume are read
once; the running and the persistent disk lists share a path's volume.
The ISO list takes the active pools in one call instead of looking each up
by name; it still refreshes them, so an image copied in by hand shows up.
The opt-in DRBD status waits at most 10 s for the compute's ssh, then
leaves the status unknown instead of holding the page.
The ARP lookup passed 3 as the address source; libvirt's
VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_ARP is 2 and libvirt refused 3 as an
unknown source. The error was suppressed, so a VM without a guest agent
never showed an address.
libvirt keeps a VM's UEFI variables (NVRAM) and emulated TPM state in
files of its host. A live migration carries both: on the test hosts
(libvirt 11.10, QEMU 10.1) the destination got the same NVRAM content
once the VM ran and the same TPM state, and the source TPM state was
removed. Moving a shut-off VM moves only its definition, so neither
went along: on its first start on the destination libvirt made a new
NVRAM from the template and a new TPM. Boot entries and enrolled keys
are lost, and disks sealed to the TPM no longer unlock.
A shut-off VM whose definition has an NVRAM file or an emulated TPM is
now refused before anything changes: "Start the VM and migrate it
live." A passthrough or external TPM keeps no state on the host and
still moves. The check sits in moveto, not in the define/undefine
workaround, as libvirt's own offline migration does not carry the files
either. The keep-NVRAM and keep-TPM undefine flags of that workaround
are gone, as no VM that needs them reaches it.
Checked on the test hosts: a shut-off UEFI VM with a TPM is refused and
stays on the source with nothing defined on the destination; the same
VM migrates live. The new tests fail on the previous code.
A VM that changes its memory faster than the network carries it never
finishes a live migration without auto converge: measured with a guest
rewriting about 1.2 GB/s over an 8.5 Gbit/s link. The migration then
ran until gunicorn ended the request after 600 s. libvirt cancelled it
when the request went away and the VM stayed on the source, but the
user got an error page and nothing was logged.
The app now cancels a migration that has not finished after 540 s
(MIGRATION_TIME_LIMIT, below the 600 s of gunicorn.conf.py; a test
keeps it below). The failure is reported and logged like any other:
the migration was cancelled, the VM stays on the source host, and a
VM like that needs auto converge. A timer that fires as the migration
ends finishes before the compute locks are released, and an error
the cancel did not cause keeps its own message.
Migration needs the VM's disks on storage both hosts reach, and nothing
checked that. A VM with a disk the destination did not have failed
during a live migration; a shut-off VM's definition moved and could not
start there.
moveto now refuses the migration before anything changes, naming each
disk (target and source) that is not a volume of the destination's
active storage pools. Checked: the disks, CD-ROM images and block
devices of the live and the persistent definition, pool volumes, and
backing files, as the definition or the destination's volume lists
them (a shut-off VM's definition does not). Pools are refreshed before
a disk counts as missing, so a file another host made on shared
storage is found. Network disks and network backing images are
reached the same way from every host and are not checked; disk types
that cannot be checked (dir, nvme, ...) are refused.
This checks that the destination knows a volume, not that it is the
same file: shared storage should be a storage pool on each host. A
shared file outside any pool, or a block device no pool covers, is
refused.
