# qemu-web-desktop: Managing Virtual machines

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<img src="src/html/desktop/images/darts_logo.png" height=200>
<br>

This documentation assumes you already have installed and configured the service. Refer to the [INSTALL.md](INSTALL.md) and [CONFIGURE.md](CONFIGURE.md).

Table of contents:

1. [Creating virtual machines](#creating-virtual-machines)
1. [Adding virtual machines to the service](#adding-virtual-machines-to-the-service)
1. [Automatic configuration of virtual machines via qwdctl](#automatic-configuration-of-virtual-machines-via-qwdctl)
1. [Manual configuration of virtual machines](#manual-configuration-of-virtual-machines)
1. [Starting, sharing, stopping, re-connecting](#starting-sharing-stopping-re-connecting)
1. [Starting sessions manually (command-line)](#starting-sessions-manually-command-line)
1. [Issues: missing QEMU Guest Agent](#issues-missing-qemu-guest-agent)

### Creating virtual machines

It is possible to create a VM from an ISO, just like you would boot physically. An empty disk is first created (here with size 10GB).
```bash
qemu-img create -f qcow2 machine1.qcow2 10G
```
Then you should boot from an ISO file (here indicated as `file.iso`)
```bash
qemu-system-x86_64  -m 4096 -smp 4 -hda machine1.qcow2 -name MySuperbVM -boot d -cdrom file.iso  -device ich9-ahci,id=ahci -enable-kvm -cpu host -vga qxl -netdev user,id=mynet0 -device virtio-net,netdev=mynet0 -device virtio-balloon
```
and install the system on the prepared disk. If you can not start qemu/kvm with a message `Could not access KVM kernel module: Permission denied; qemu-system-x86_64: failed to initialize kvm: Permission denied`, execute the command `sudo /sbin/adduser $USER kvm`, then logout/login.

You may also convert an existing VDI/VMDK file (VirtualBox and VMWare formats - here `file.vmdk`) into QCOW2 for QEMU (here machine1.qcow2`) with command:
```bash
qemu-img convert -f vmdk -O qcow2 file.vmdk machine1.qcow2
```

In case you have an OVA file for VirtualBox, extract it, and convert it afterwards to a QCOW2 file.
```
tar -xvf file.ova
qemu-img convert -f vmdk -O qcow2 file.vmdk machine1.qcow2
```

Last, you may dump an existing physical disk (with a functional system - here from device `dev/sda`) into a QCOW2 format:
```bash
qemu-img convert -o qcow2 /dev/sda machine1.qcow2
```

The QCOW2 format allows to resize disks, for instance with:
```bash
qemu-img resize machine1.qcow2 +50G
```

If a VM file gets too large, you can (re)compress it with command:
```
qemu-img convert -O qcow2 -c image.qcow2 image_compressed.qcow2
```

### Adding virtual machines to the service

The easiest is to make use of the `sudo qwdctl edit machines` tool (see below). Other options are activated by un-commenting sections in the file `/usr/share/qemu-web-desktop/html/desktop/index.html` (can be done with `sudo qwdctl edit web`).

Common virtual machine image file formats are supported (QCOW2, VDI, VMDK, RAW, VHD/VHDX, QED), as well as ISO live images.

#### Automatic configuration of virtual machines via `qwdctl`

Each entry in the configuration file `/etc/qemu-web-desktop/machines.conf` spans on 2 or 3 lines:

-  [name.ext]
-  url=[URL to ISO, QCOW2, VDI, VMDK, RAW, VHD/VHDX virtual machine disk] (optional if the file is already present)
-  description=[description to be shown in the login page] 

Images listed in the configuration file without a `url=` parameter are expected to be downloaded by hand and installed into `/var/lib/qemu-web-desktop/machines` by the local administrator. in this case, just specify the [name.ext] and [description]. 

Images with a `[url]` line are downloaded (requires a configured network connection).

You may edit this file manually, or with the command:
```
sudo -E qwdctl edit machines
```
You may set the **EDITOR** environment variable to select the text editor to use. 

:warning: In case the machine list does not appear in the landing page, first refresh the landing page, or change the `machines_insert=no` to `machines_insert=yes` in `/usr/bin/qwdctl`.


Then actually launch (done automatically with `sudo qwdctl edit machines`):
```
sudo -E qwdctl download
```
or, to only update existing machines, use:
```
sudo -E qwdctl refresh
```

To list active sessions, use:
```
qwdctl status
```

To stop active sessions matching a given TOKEN, use (with caution):
```
sudo qwdctl stop TOKEN
```

The command `qwdctl` alone will display all possible options.

#### Manual configuration of virtual machines

You may also do this by hand. Place any ISO, QCOW2, VDI, VMDK, RAW, VHD/VHDX, QED virtual machine file in e.g.
`/var/lib/qemu-web-desktop/machines`.

```bash
ls /var/lib/qemu-web-desktop/machines

slax.iso  slitaz-rolling.iso  TinyCore-current.iso    machine1.qcow2 ...
```
Then create/edit the `/usr/share/qemu-web-desktop/html/machines.html` (link from `/var/lib/qemu-web-desktop/machines.html`) web page and add entries to reflect the VM files in `html/machines`:
```html
  <option value="slax.iso">Slax (Debian)</option>
  <option value="TinyCore-current.iso">TinyCore Linux</option>
  ...
  <option value="machine1.qcow2">My superb VM</option>
  ...
```

You can also comment/uncomment sections (e.g. GPU, user script, one-shot) at will in the main web page `/usr/share/qemu-web-desktop/html/desktop/index.html` (you may use `sudo qwdctl edit web` for this purpose). Defaults will then be used.

:+1: This project provides minimal ISO's for testing (in `html/desktop/machines`):

- [Slax](https://www.slax.org/) a very compact Debian-based system (265 MB)
- [TinyCore](http://www.tinycorelinux.net/) a very compact, old-style Linux (24 MB - yes)
- [SliTaz](http://www.slitaz.org/) a very compact, old-style Linux (54 MB - yes)

We also recommend other small linux systems:

- https://puppylinux-woof-ce.github.io/index.html (small, comes as Debian and Slackware base)
- https://www.porteus.org/ (small, SlackWare based)
- https://archbang.org/ (Arch based)
- https://www.bodhilinux.com/ (Ubuntu/Debian based)

There exist some virtual machine repositories, for instance:

- https://marketplace.opennebula.systems/appliance
- https://www.osboxes.org

### Starting, sharing, stopping, re-connecting

The DARTS/qemu-web-desktop service allows to connect and re-connect to active sessions (except for one-shot sessions). Each session is by default a **copy** of the given VM, so that changes are not kept (this behaviour can be changed with the `snapshot_use_master=1` option). It is also possible to share the connection link for an active session, so that multiple users can see and interact on the same environment. Last, sessions can be ended either from the sessions themselves (find the 'Shutdown' item), or aborted with the 'Stop' button shown in the session information page.

All of these actions are possible when selecting the 'Manage sessions' button on the right of the service page, with proper credentials. Only your sessions will be listed.

### Starting sessions manually (command-line)

You can also manually start a session from the terminal with command:
```
qwdctl start VM ...
```
Additional arguments override the default configuration, such as:

`qwdctl start VM [option...]` | Description
------------------------------|------------------
`--snapshot_alloc_cpu=VALUE`  | Number of CPU cores to use. Default: 1 (qemu equivalent: `-smp VALUE`)
`--snapshot_alloc_disk=VALUE` | Disk size to create for ISO's, in GB. Default: 10 
`--snapshot_alloc_mem=VALUE`  | Memory to allocate to session, in GB. Default: 4 (qemu equivalent: `-m VALUE*1024`)
`--snapshot_use_master=VALUE` | When 1, do NOT create a snapshot, so that all changes are written to the master VM (not for ISO's). Default: 0 (changes are lost)

A URL is shown. Open a browser to view the session. 
```
$ qwdctl start /var/lib/qemu-web-desktop/machines/TinyCore-current.iso
http://localhost:6005/vnc.html?resize=scale&autoconnect=true&host=localhost&port=6005
```

:warning: All sessions are started in one-shot mode, i.e. closing the browser will end the session. Except when starting with the `--snapshot_use_master=1` option (not for ISO's), the session and the associated snapshot/qcow2 file will be lost. Copy the qcow2 file before ending the session. There is no upport for GPU pass-through with this manual launch.

### Issues: missing QEMU Guest Agent

In some virtual machines or ISO's, you may get errors such as:
- `Dependency failed for QEMU Guest Agent`
- `Time out waiting for device /dev/virtio-ports/org.qemu.guest_agent.0`

In this case, try to boot the VM manually, and install the `qemu-guest-agent` and the `spice-vdagent` packages.

