Two disks of a VM with the same file name in different directories
were both offered the same destination pool by default. The form was
sent, and the migration job refused it only then: both copies would
be one file.
The plan now gives each such disk, by default, a pool no earlier disk
of that name is copied into, and says under its choice that another
disk has the file name. A choice that still puts them in one pool is
refused by the job, as before.
Without a migration address libvirt sends a migrating VM to the
destination's own host name, which the source host often cannot resolve:
a live migration to a host added without one failed ("Unable to resolve
address ..."), also when the other host had one. The destination's
address on the Computes page, which the panel reaches it at, is now the
default; the migration address stays for another network. A host the
panel reaches on its loopback keeps libvirt's default.
A live migration whose source host could not resolve the destination's
name for the migration stream failed with "The host of this virtual
machine cannot be reached right now": libvirt reports that failure as a
connection error, and a job's error hides those behind that sentence so
as not to name hosts. Only superusers migrate, so the migration job now
fails with libvirt's own words, here "Unable to resolve address ...",
which points at the destination's Migration address.
The Migrate tab offered every other host alike, and its plan showed
neither a file of the same name in a destination pool nor the disks of
the VM's next start, which the job then refused. Now:
- When the tab opens, the hosts are checked first: one that cannot be
reached, or the VM's own host under another record (the same libvirt
host UUID), is shown with why and cannot be chosen, and the disks of
the first one left are checked. The job refuses the VM's own host
under another name too.
- A pool of the destination that has a file of a disk's name is shown
but cannot be chosen for it; a disk no pool can take refuses the form.
- The next start's file disks the migration does not carry are listed;
one not on storage both hosts share refuses the form, as the job does.
A user who is not a superuser chooses the clone's name from the free
names the clone form lists, or gets the first one with automatic names,
but the server took any posted name. It now refuses a name outside the
list, and with automatic names it takes the first free one whatever is
posted. A superuser still names a clone freely.
The panel checks VM names on every compute, but a job held a name only
on its compute, so two clones from VMs on two hosts could take the same
free name at once; a name claim now holds the name everywhere. A clone
job whose name a VM found on a host took while it was queued stops
before it copies anything.
Settings > Migrate was a horizontal form of six switches without
explanations. The owner chose this layout from three rendered options:
the route on top as "From" (the source host) and "To" (the
destination select) side by side, a "Storage" card with
where each disk goes, a "Transfer settings" card with the switches in
two columns, each with a line saying what it does, and a footer.
Codex reviewed migration end to end; these are fixed:
- No Offline switch: the mode follows the VM's state, and one line says
which. A shut-off VM moved offline whether the switch was on or off.
- Live migration shows for a running or paused VM; Auto converge,
Compressed and Unsafe only for a running VM, the only state the
migration applies them to. Unsafe was offered for a paused or shut-off
VM and ignored.
- Unsafe says it skips libvirt's safety checks; Delete source files
says it deletes only the files of copied disks.
- A VM that cannot migrate anywhere (no other host, a state that does
not migrate, snapshots, host devices) gets the reason and a disabled
button instead of the disk plan and the switches; it learned that
after submitting.
- Migrate stays disabled while the destination did not answer or a disk
cannot go there; it was enabled after any plan.
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.
