Select a virtual machine from the guest selector to open its details, actions and Remote Access above the host-wide navigation links. Everything below is also available through the API and command line.

Details and live status

The details page shows power state, guest agent status, SSH reachability, addresses, individual disks, guest filesystems, network interfaces, and disk and network transfer rates. Power state and inventory update through libvirt events over an authenticated WebSocket; browsers do not poll. CPU usage is normalized to the assigned CPUs, and memory usage comes from ten-second balloon reports and excludes reclaimable cache. Filesystem usage and guest OS details require the QEMU Guest Agent and refresh about once a minute.

Power state, guest-agent health, SSH reachability and application health are separate signals. A responding agent does not mean guest setup has finished, and an SSH banner does not mean the first boot is complete.

The overview totals writable data-disk capacity and mounted filesystem usage, excluding read-only media and cloud-init disks. Host disk-image allocation is not guest filesystem usage. When usage is unavailable or stale, summaries show the known capacity alone. Host administrators also see counts of active image imports and unfinished virtual machine jobs from all users.

One host collector shares status results among viewers. Each browser receives an initial snapshot and later changes over an authenticated WebSocket, with session and module permissions checked on connection and while it remains open. Hidden tabs keep their connection but pause updates and guest checks. The collector exits about a minute after its last subscriber leaves; it uses Perl and Webmin’s WebSocket proxy, without a Node.js service.

Visible detail and connection pages share guest-agent and SSH-banner probes because SSH has no libvirt readiness event. Checks back off from five to thirty seconds when SSH responds; the overview does not probe SSH for every guest. Visible pages also share one nonblocking libvirt resource batch every ten seconds. New guests enable ten-second balloon reports; the collector enables them for existing running guests without changing their RAM allocation or saved definition. Host process RSS is not a substitute for guest memory usage.

Filesystem and guest OS checks run in one worker, at most once per second across the host and normally once per minute for each guest. Libvirt events can trigger an earlier refresh; all viewers share the results.

Power controls

Start, shutdown, reboot, suspend, resume and autostart are the ordinary power controls. Hard reset and forced power off are abrupt and require confirmation and a separate permission. Live ISO insertion and ejection work on running guests.

Resources

CPU count and balloon memory can be adjusted on a running virtual machine. Offline settings cover the resource maximums, boot order and firmware. The page explains when a change needs the guest shut down and what still has to be done inside the guest, such as growing a filesystem after a disk was enlarged.

Disks and media

Add extra disks, grow existing disks, attach or detach volumes, and change the CD/DVD media. New disks are QCOW2 files in directory, filesystem and NFS pools, or raw logical volumes in LVM and LVM-thin pools; LVM disks grow only while the machine is shut down. Free-space checks run before every disk operation. Deleting a virtual machine asks which disks to remove, checks shared storage, and recovers an interrupted deletion the next time a host administrator opens Cloudmin.

Network interfaces

Add, change or remove NICs on a stopped guest, choosing a libvirt network or a host bridge. Cloudmin checks for duplicate MACs, duplicate managed addresses and missing networks before allocating resources.

Guest password reset

Reset Password on Edit Virtual Machine changes an existing guest account through the QEMU Guest Agent. The form is always available to permitted users; saving requires a running virtual machine with a responding agent. Passwords are not stored in jobs or logs, and SSH authentication settings stay unchanged.

Snapshots, clones, backups and images

  • Snapshots save a disk state you can restore or delete later.
  • Cloning copies a guest into an independent machine with a fresh identity.
  • Backups write a full archive to local, SSH, S3 or Pro cloud destinations and restore it later.
  • Create Image (Pro) turns a guest’s system disk into a reusable image.

Jobs

Creation, cloning, backups, restores, captures and offline hardware changes run as jobs. The progress page shows each step, the error if one fails, and whether cleanup is pending. Jobs reserve the virtual machine they work on, so conflicting operations wait. Unfinished jobs are recovered when a host administrator with write access visits Cloudmin; read-only and delegated visits never resume jobs.

Changes made outside Cloudmin

Libvirt is the source of truth, so machines changed or created with virsh or virt-manager appear in Cloudmin. Deleting a guest with external tools does not run Cloudmin’s cleanup: remove its managed SSH key, serial logs and Servers Index entry separately in that case. Adopting guests defined outside Cloudmin with full management is Planned .