The features list still described the panel before jobs, external
snapshots, migration with disk copies, host devices, the serial
console, the address search, the audit log and API tokens; it now
names them. The Updating section gains the behavior changes of the
latest fixes an operator notices: the quota counts next-start values
and queued clones, a non-superuser's clone takes a name the form
offers, deleting a VM's files checks the other computes first, and an
internal snapshot is reverted only on a shut-off VM.
gstfsd, the root service on each compute that rewrites a shut-off VM's
/etc/shadow and authorized_keys, did what any client on its port asked.
Now it needs GSTFSD_KEY (64 hexadecimal characters, in the unit's
/etc/default/webvirt-gstfsd) and does not start without it. Each
connection gets a new challenge; the panel signs its request for it
with HMAC-SHA256 and gstfsd checks the signature before any change, so
a request recorded on one connection is refused on another. gstfsd
signs its reply for the same challenge and the panel's nonce, and the
panel accepts only that reply.
Each compute has a gstfsd key, the host's GSTFSD_KEY: the compute forms
and the API take it and never show it, and an empty value on an edit
keeps it. The bootstrap script makes the key file once, readable by
root only; the README shows how to make it and where the panel takes
it. The traffic is still not encrypted: a remote panel's port stays
open to the panel's address only.
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 Devices section of each host lists its PCI devices by IOMMU group and
its USB devices: what each is (vendor, product, IDs, class, driver), what
the host itself has on it (its network interfaces, disks and graphics
card, anywhere below it) and the VMs whose definitions name it.
- A VM names a PCI device by its address, a USB device by its address or
by its model only; a VM that names a model only is shown on every device
of that model, which one it takes is known only when it starts.
- A host without IOMMU groups says that no PCI device can be given to a VM
and how to turn the IOMMU on.
- One listing of the host's node devices, one XML read each (a device gone
meanwhile is left out), and the VMs' definitions read once; nothing is
shown when they cannot be read, as a device would look free.
- Read only: giving devices to VMs comes in the next layers.
"Type it" sent each character's keysym and let QEMU pick the key from
its own US map, with Shift added for the US shifted characters. A VM
on another layout got other characters: on Turkish Q, '"' typed 'İ',
'@' typed "'", and ğ, ü, ş, ı, ö, ç typed nothing.
The Clipboard dialog now asks for the VM's keyboard layout and
remembers it per browser. Each character is typed as the key that makes
it on that layout (its scancode), with Shift, AltGr or both (AltGr
first: pressed after Shift, the right Alt is Alt on the Linux console),
so the VM's own layout makes the character. The layout is fixed when
typing starts. Text with a character no key types on the layout is not
typed at all, and the dialog lists those characters: a password or a
command with a character left out would be a wrong one.
A layout is one file in console/layouts/: its name and, for each key,
the characters it types plainly, with Shift, with AltGr and with
Shift+AltGr. The view offers every file, US first. dev/console_layout.py
writes a file from the system's XKB data as libxkbcommon computes it
(through ctypes, no new dependency), mapping keys to DOM codes with
noVNC's table from QEMU's keycodemapdb; it lists the dead keys it leaves
out, and drops the keys the keyboard model lacks (the key left of Z on
US pc104 keyboards). English (US) and Turkish Q come with it; the
README says how to add one.
webvirt-novncd and webvirt-socketiod get read-only system directories, no
access to /home and /root, no new privileges, no kernel tunables, modules
or cgroups, and only Unix, IPv4 and IPv6 sockets; socketiod also a private
/tmp. novncd keeps the shared /tmp, where a VM's VNC Unix socket may be.
They keep what they need: a pty and its console worker, TCP and Unix
sockets, ssh with its configuration, writes under /srv/webvirtcloud and
the service user's ~/.ssh. The units installed by the update steps bring
this.
- novncd and socketiod log to stderr: the journal on hosts, docker logs in
the container (runit no longer sends them to unrotated files under
/var/log). Django's settings gave them the panel's own log file, which
every process rotated on its own, and made novncd's -v and -d have no
effect; both work again.
- A refused console says why in the log: novncd's denials are warnings
(they were shown only with -v), socketiod logs each refusal and who
opened which VM's serial console.
- The README's serial console notes say what #228 changed (access
re-checked, superuser takeover, reasons) and where the logs are.
The console pages connect to /novncd/ on the address, scheme and port the
page itself was loaded from; nginx proxies it to novncd, which listens on
the loopback only. There is nothing to configure: the console works on
HTTPS (wss), behind another proxy and on any published port.
Before, the page connected to WS_PUBLIC_HOST/PORT/PATH, port 6080 by
default: straight to novncd, past nginx and without TLS, so an HTTPS panel
and a Docker container published on another port had no console until the
public port was set by hand, and novncd listened on every interface.
Gone: WS_PUBLIC_PORT, WS_PUBLIC_HOST, WS_PUBLIC_PATH and WS_CERT, the
installer's two public console questions and its 6080 firewall rule, the
Docker image's WS_PUBLIC_PORT and its init script lines, the manual
install's firewall rule for 6080 and nginx's unused /websockify location.
WS_HOST defaults to 127.0.0.1. A VM with a QEMU websocket port is still
reached on that port of the panel's host name (left for a separate
decision).
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.
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.
The REST API took only the login session, so a script could not use it
without a browser. A user now makes API tokens on the profile page (API
Tokens tab): a name, and an expiry of 30, 90 or 365 days or none. The
token is shown once, on a page that is not cached, and then kept only as
a SHA-512 digest; the list shows its name, first characters, creation
and expiry, and a token is deleted there. Tools send it as
"Authorization: Token wvc_...", and act as its user, with that user's
permissions. Making and deleting a token is logged, without the token.
A password alone (HTTP Basic) still does not reach the API, as it would
skip the OTP second factor: a token is made in a session that passed the
login and its OTP. The token class comes first, so a refused request gets
401 with its challenge instead of 403.
django-rest-knox 5.1.0 provides the tokens (accounts.ApiToken adds the
name); settings.py takes "knox", KNOX_TOKEN_MODEL and REST_KNOX from the
template.
The step ran `docker compose -p webvirtcloud up -d`. The other Docker
steps let compose name the project after the directory, so in a clone
under another directory name this command started a second deployment
with its own volumes.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
The create page had three tabs (flavor, custom, template), each with its
own copy of the same create form; every flavor rendered one more copy in
a dialog, and fixes had to be made in each copy. All of them posted the
same form to the same job, differing only in where the disk comes from.
The page is now one form in sections: name and size, disk, networks and
an Advanced section. The disk section offers three sources as radio
cards (a new disk, existing volumes, a copy of a template); only the
chosen source's fields are shown, and the others are disabled, so they
are neither sent nor validated. A template's copy goes into the
template's pool unless another is picked. Flavors are presets that fill
vCPU, memory and disk size and pick a new disk; they are added and
deleted in a dialog outside the form. Every source uses the
per-interface network rows, so a new disk no longer requires a MAC:
libvirt gives an interface without one its address, as it did for the
other sources. A refused form comes back with its source, volumes,
template and networks, and the focus on its first error. Without a
storage pool or a network the page shows why instead of the form, and a
host that cannot be read is a message, not a 500.
The host dialog and the machine page share the form's look: hosts are
rows with their CPU and memory use, the machine page is a card with
Cancel/Next and the XML way is a collapsible section. All three steps
show the same step indicator, done steps linking back.
The create job refuses more than one disk source (the page sends one; a
crafted request could send two, and the job would have used the first).
A field with help text is described by its help and its error.
Frontend review fixes: the presets and the disclosure buttons show a
focus ring for keyboard users; a disclosure spans its card and its
chevron turns while open; a preset says it picks a new disk; numeric
fields bring a numeric keyboard and MAC fields no autocorrection; the
machine page's Next waits for a machine type. Tom Select's control
keeps the text colour of the select it replaces: its own fixed colour
made typed text invisible on dark Bootswatch themes, on every page that
uses it.
The Logs page now records every change an admin makes to a compute's
libvirt objects, with the compute's name in the host column:
- networks: add, start, stop, delete, autostart, DHCP range, fixed
addresses, QoS and XML edits;
- storage pools: add, start, stop, delete, autostart, from web and
API; volumes: add and delete (web and API), clone and ISO upload;
- host interfaces: add, start, stop, delete;
- secrets: add, set value (never the value), delete;
- network filters: add, clone, delete, XML edits, rules and
references.
A refused or failed change is a failed row with its reason (libvirt
text through safe_text). The volume clone and upload jobs write their
row when they end; a refused submission is a failed row at once. A
volume row names the volume libvirt created (a dir pool adds .qcow2 or
.img). Volume create or delete through the API on an inactive pool
(409) is a failed row.
Network filters: the rows read "Network filter f1: add" instead of
"f1 network filter is created", and their host is the compute's name
instead of its hostname. A duplicate name or UUID no longer raises a
bare exception, and a filter XML that cannot be parsed no longer ends
in UnboundLocalError.
The Logs page now records the panel's own records too: users (add,
change with the changed fields, delete, block, unblock, an admin's
password set, a user's own password change including the first-login
one, own profile edits), groups with their members and permissions,
VM owners from the accounts pages and from the VM page, OTP QR code
mails, flavors from web and API, app settings and the theme,
removed-VM records and SSH keys. No row carries a password or a key.
- A user is created in one transaction: when a VM named in
NEW_USER_DEFAULT_INSTANCES is missing, no half-made user stays.
- The OTP mail checks the email address before it creates a device;
without one it writes a failed row and makes no device.
- The VM page's owner rows read "VM web-1 owner bob: add" and
"...: remove" instead of "Add owner: bob" and "Delete owner: 17"; a
second owner refused by the single-owner setting is a failed row.
Owner rows keep the VM's host and name, so the VM's log tab shows
them.
- A setting or theme posted with its current value is no change and
writes no row; the old free-text setting rows are gone.
Host-side objects (networks, storage, interfaces, secrets, filters)
follow in the next layer.
The Logs page shows who added, changed or deleted a compute, from web
or API, and every login, failed login, lockout and logout, with the
client address and a Result column (Done, Failed, Unknown for older
rows). A failed change is recorded with its reason and the error still
reaches the user; a refused one is recorded too.
- logs.audit.write saves each row in its own savepoint and never
raises, so a log write cannot break or undo the action it records.
The audit() context manager writes one row when the change ends.
- Logs gains success and ip; user, host and instance are wider and
date is indexed. The page orders by date then id.
- A compute edit names the changed fields; an edit that changes
nothing writes no row, and an empty password field is no change.
- A compute's VMs leaving the panel get a system row each: owners
kept on the Removed VMs page, moved to another compute, restored,
left without owners, or the removed record expired.
- Job rows carry the result. A job's log entry that cannot be
computed is logged and skipped instead of rolling back the finish
(test_service.py changes this on purpose).
- Logins are recorded by signal receivers; CustomLoginView is removed
and the plain LoginView is used. A wrong OTP code is a failed login,
counted by django-axes toward the lockout.
Panel records and host-side objects follow in the next layers.
Deleting a compute removed its VMs from the panel together with their
owners, while the VMs kept running on the host: added again, the host's
VMs came back with no owners. A compute's delete now treats each VM as
one that left its compute: its owners follow the same UUID on another
compute or wait in a tombstone for the retention period. One function,
forget(), does this for the refresh and for the delete; the API's
compute delete goes through the same model delete.
The delete holds the compute exclusive and locks its row before its
VMs', as the reconcile does: a reconcile, VM operation or job on the
compute makes it busy instead of losing owners to a concurrent restore
or deadlocking with it.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Django clones a SQLite test database by copying its main file, while
migrate's writes were still in the WAL file, so every clone had no
tables. The project test runner writes the WAL back before cloning.
Its pool workers are no longer daemonic, so the operations process
tests can start their own workers. tblib carries the traceback of a
failure out of a worker instead of ending the run.
The suite takes 35 s on 8 CPUs instead of 133 s.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
A small middleware sends object-src 'none', base-uri 'self', form-action
'self' and frame-ancestors 'none': no plugin content, no injected <base>
redirecting relative URLs, no form posting to another origin, no framing.
script-src and style-src are left out: the templates still hold inline
scripts, event handlers and javascript: URLs, which an enforced script
policy would block.
The middleware is added to the settings template, which the update steps
and each Docker container rebuild settings.py from.
A socket compute is the panel's own qemu:///system, so the live tests for
it have to run on the libvirt host. Two more lines in the Vagrant block
copy the committed HEAD into compute1, install the dev requirements in a
venv with the distro's libvirt bindings, and run the suite there with
TEST_LIBVIRT_TYPE=4 and the LVM, iSCSI and NFS tests enabled.
The source check of a new logical or NFS pool accepted only letters,
digits and "/", which refused paths such as /dev/mapper/vg0-data,
/dev/disk/by-id/wwn-..., /dev/disk/by-path/pci-0000:00:1f.2-ata-1 or
/export/vm_images. The target check let any first character but "-"
through, so a quote, "<" or "&" reached the pool XML and libvirt failed
on it.
Target and source now share one expression: letters, digits, "/", "_",
".", ":" and "-" (not first, not right after "/"), still in linear time.
The Vagrant computes' NFS export becomes /srv/wvc-nfs, created through the
page in the live pool test.
create_storage_netfs started the pool without a build, so a netfs pool
whose target directory was missing failed to mount ("mount point ... does
not exist"): the page showed the error and the pool stayed defined and
inactive. It now starts with VIR_STORAGE_POOL_CREATE_WITH_BUILD, as the
dir and logical pools do, which makes the mount point.
The Vagrant computes export /srv/wvcnfs to 127.0.0.1, and the live pool
test creates an NFS pool on it at a missing mount point when
TEST_LIBVIRT_NFS_EXPORT is set.
django-auth-ldap, python-ldap and pyasn1 move to
conf/requirements-ldap.txt. Installs without LDAP no longer need the
openldap and sasl headers that pip builds python-ldap with; the
installer and the README's system packages drop them, and the README's
LDAP section installs them with that file. The settings already work
without the module.
The Docker image and dev/requirements.txt keep LDAP, so CI still builds
and audits python-ldap.
A theme change compiled Bootswatch with libsass (34 MB, upstream
deprecated) into two tracked files, which updates, rollbacks and new
Docker containers then reset. The 27 themes now ship as
static/css/themes/<theme>.min.css, built by "manage.py build_themes";
the Settings page only saves the theme name and every page links that
file (zephyr when no settings are in context, as on the 500 page).
libsass moves to dev/requirements.txt; a test checks that each shipped
file is its theme compiled from dev/scss. The "Theme SASS Path" setting
is removed, and the theme default "flaty", a typo that never applied,
becomes zephyr, the theme those installs showed. The update and
rollback steps restore an older version's rewritten theme files only
where they are modified.
With the netcf backend (RHEL/AlmaLinux 8), undefining a bridge also
removes its members' configuration: the device came back without any
after a reboot. Like virsh iface-unbridge, each member is now defined
again on its own after the bridge is undefined, with the bridge's start
mode and, when it is the only member, its addresses. A bond keeps its
mode and devices.
Checked on AlmaLinux 8 (libvirt 8.0, netcf): an ethernet and a bond
member get their ifcfg back, and the bond comes up with the address
after a reboot.
vagrant up makes a throwaway CA and a client certificate in
.vagrant/tls/.pki/libvirt with the host's openssl (Vagrant puts its own
first on PATH). Each compute signs its server certificate for its
address, asks for SASL over TLS like over TCP, and listens on 16514.
libvirt takes a client certificate from $HOME/.pki/libvirt, so the
README's second run uses HOME=.vagrant/tls with TEST_LIBVIRT_TYPE=3 and
leaves the user's own certificates alone.
The Vagrant computes serve a 1 GiB LUN on 127.0.0.1 (targetcli). A live
test, run with TEST_LIBVIRT_ISCSI_TARGET, starts a transient iSCSI pool
on it and attaches the LUN from the VM page to a stopped and a running
VM: both definitions get a raw block disk on its /dev/disk/by-path link.
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.
The Vagrantfile (Ubuntu 18.04, supervisor, a missing requirements file)
is replaced: two AlmaLinux 10 VMs with nested KVM, set up by the
bootstrap, with a SASL user for TCP and the host user's SSH key for
root, so the live suite, migration included, runs without real hosts.
The README's Running tests says what the host needs and how to run it.
The RHEL manual install failed at libvirt-devel, which is in CRB; the
installer already enables it. openSUSE's nginx.conf has its own port-80
server for localhost, which the RHEL steps already warn about. The
bootstrap skipped /etc/os-release as a symlink, which on openSUSE Leap
is the only release file, so it found no distribution.
The compute bootstrap installs gstfsd and webvirt-gstfsd.service in one
helper and no longer installs or restarts supervisor; the README's
compute step does the same, a remote panel's bind goes into a drop-in,
and a compute moving from supervisor removes its gstfsd program.
The installer and the manual installation install four systemd units
(webvirt-cloud, webvirt-novncd, webvirt-socketiod, webvirt-worker) that
run as the web server's user with absolute paths and read
/etc/default/webvirtcloud. gunicorn, socketiod and the worker stop with
KillMode=mixed, so they wind down their own children. supervisor, its
installer code and the contributed systemd files go; the README gets
the update, rollback and a one-time move from supervisor, and the
installer refuses to run over a supervisor install. Docker keeps runit;
novncd's runit script is the one-line form of the others.
Installers before September 2025 ran makemigrations, which left
untracked migration files: one has the name of a tracked accounts
migration (git refuses to check out over it, and once applied it makes
migrate skip the tracked one), the others compete with tracked
migrations. The update now moves them into the backup, marks that
accounts migration unapplied when it was generated locally, and the
rollback puts them back.
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 xterm console never connected: socketiod expected a different token
format, its worker had no compute credentials, one global console was
shared by every client and its output broadcast to all of them, and the
Docker image did not run socketiod at all.
- console/tokens.py: one authorize() for noVNC and socketiod; the signed
token is the only credential, checked at connect time.
- socketiod: one pty worker per client (consolecallback with the
instance id), one session per VM, a session cap, input and resize
checked; the parent never opens libvirt. The engine.io same-origin
check is on.
- consolecallback: opens the console with the compute's credentials and
exits with a message when it cannot.
- Docker runs socketiod as a runit service; nginx proxies /socket.io/
with Host and the scheme for the origin check. Supervisor and systemd
start it as well; WEBVIRTCLOUD_SERIAL_CONSOLE=1 enables it.
- Tests: token and session unit tests, socketiod as a process, and a
live test that reads SeaBIOS from a wvc-test VM on the TCP and SSH
hosts.
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.
The job panel follows an ISO upload, so the dialog closes when the first
chunk is accepted and its progress bar goes; the dialog opens again with
the error if the upload stops. The browser still sends the file, so the
page asks before it is left while an upload runs. The storage page no
longer includes the please-wait dialog, which nothing on it opened.
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 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.
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.
