refresh_instance_database opened the transaction first and then asked
libvirt for the domain list. A host that goes silent on an established
connection keeps that call waiting until keepalive gives up (30 s). On
SQLite, the default database, the open transaction holds a read lock,
so every other write of the app failed meanwhile with "database is
locked", logins (session writes) included. Reproduced in the test
setup: with a relay to a TCP compute frozen after connecting, three
session writes during the 30 s refresh each failed after 5 s.
- The connection check and listAllDomains run before the transaction,
still under the compute lock, so create, delete and migration of the
compute stay excluded as before.
- The transaction only applies the changes. It checks the compute row
first: a compute deleted while libvirt was asked gets no instances
(this ended in a foreign key error before).
A failed listing still leaves the database untouched. With the change,
the same reproduction writes the sessions at once and keeps the
instances. Both new tests fail on the previous code.
Comments, docstrings and live test names cited item IDs of a roadmap
that is not part of the repository. They now say what is meant, or
nothing where the sentence stands without them. Test assertions and
behavior are unchanged.
The sync deleted the Instance of every VM missing from its compute, and
its owners and rights went with it. A VM moved with virsh, or undefined
and defined again, came back with no owner.
Now, when a VM disappears from a compute:
- if the same UUID is recorded on another compute, it moved: its owners
and template flag go there;
- otherwise they are kept in an InstanceTombstone and restored when the
UUID appears again within INSTANCE_OWNERSHIP_RETENTION_DAYS (30).
A UUID recorded on two computes at the same time is a copy and gets no
owners. VMs deleted through WebVirtCloud leave no tombstone.
Disk edits:
- edit_disk built a new <disk> from the form and replaced the old one,
losing what the form does not show (e.g. encryption and virtio
driver options); a bus change detached and re-attached the disk.
The disk of the persistent definition is now edited in place and the
domain defined once; a bus change picks a free device name and drops
the old address and virtio-only options. Pending persistent changes of
a running VM are kept.
- Clone omits empty disk devices, refuses a disk without a supported
source and destination, and checks the name before allocating storage.
Locks:
- Every VM change held its compute's exclusive lock, so one slow
operation blocked all VMs on that compute. A VM change now holds its
own VM lock plus a shared compute lock; reconciliation, migration and
cloning hold the compute exclusively (two clones of different VMs
must not pass the name check together).
- Quota-checked changes of one user (CPU, memory and disk resize,
clone) run one at a time under a per-user lock, also across computes,
so concurrent requests cannot all pass the check against the old
allocation. It is the outermost lock; superusers, who have no quota,
skip it.
- A busy lock answers 409 to the API and a message in the web UI. API
power and destroy actions return the view's error instead of success.
