KasmVNC

https://docs.kasmvnc.com/
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KasmVNC is a modern, secure, and simple web-based VNC server that streams desktops and applications...
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### Install and Configure KasmVNC on Alpine

Source: https://docs.kasmvnc.com/docs/install/index.html

Use these commands to download the package, install it, configure user permissions, and start the VNC server.

```bash
# Please choose the package for your distro here (under Assets):  
# https://github.com/kasmtech/KasmVNC/releases  
wget <package_url>  
  
doas apk add ./kasmvncserver_*.apk --allow-untrusted  
  
# Add your user to the kasmvnc-cert group  
doas adduser $USER kasmvnc-cert  
  
# YOU MUST DISCONNECT AND RECONNECT FOR GROUP MEMBERSHIP CHANGE TO APPLY  
  
# start KasmVNC, you will be prompted to create a KasmVNC user and select a desktop environment  
vncserver  
  
# Tail the logs  
tail -f ~/.vnc/*.log
```

--------------------------------

### Install dbus-x11 package

Source: https://docs.kasmvnc.com/docs/FAQ/index.html

Install the required dbus-x11 package to resolve black screen issues in Gnome.

```bash
sudo apt-get install dbus-x11  
```

--------------------------------

### Install and Configure KasmVNC on Fedora

Source: https://docs.kasmvnc.com/docs/install/index.html

Commands to install the RPM package, configure user permissions, adjust system crypto policies for WebRTC, and manage the service via systemd.

```bash
# Please choose the package for your distro here (under Assets):  
# https://github.com/kasmtech/KasmVNC/releases  
wget <package_url>  
  
sudo dnf install ./kasmvncserver_*.rpm  
  
# Add your user to the kasmvnc-cert group  
sudo usermod -a -G kasmvnc-cert $USER  
  
# YOU MUST DISCONNECT AND RECONNECT FOR GROUP MEMBERSHIP CHANGE TO APPLY  
  
# You might need to relax system crypto policy for full functionality (WebRTC  
# UDP Transit).  
# Print current crypto policy.  
sudo update-crypto-policies --show  
  
# If the current policy is LEGACY or <any_policy>:SHA1, you don't need to change  
# system crypto policy.  
# Otherwise, change the current crypto policy to <your_current_policy>:SHA1:  
# You need to delete ":NO-SHA1" from your crypto policy if it's present.  
sudo update-crypto-policies --set <replace_with_your_current_crypto_policy>:SHA1  
  
# start KasmVNC, you will be prompted to create a KasmVNC user and select a desktop environment  
vncserver  
  
# Tail the logs  
tail -f ~/.vnc/*.log  
  
# Optionally use systemd to start KasmVNC on boot.  
sudo reboot # Needed for systemd to pick up $USER's kasmvnc-cert group  
systemctl --user enable kasmvncserver@:1 # :1 is Xorg DISPLAY number.  
systemctl --user start kasmvncserver@:1  
  
# You can run multiple KasmVNC instances via systemd by passing a different  
# DISPLAY number:  
# systemctl --user enable kasmvncserver@:2  
# systemctl --user start kasmvncserver@:2  
# systemctl --user enable kasmvncserver@:3  
# systemctl --user start kasmvncserver@:3
```

--------------------------------

### Install KasmVNC on Debian/Ubuntu/Kali

Source: https://docs.kasmvnc.com/docs/install/index.html

Commands to download, install, configure user permissions, and manage the KasmVNC service.

```bash
# Please choose the package for your distro here (under Assets):  
# https://github.com/kasmtech/KasmVNC/releases  
wget <package_url>  
  
sudo apt-get install ./kasmvncserver_*.deb  
  
# Add your user to the ssl-cert group  
sudo adduser $USER ssl-cert  
  
# YOU MUST DISCONNECT AND RECONNECT FOR GROUP MEMBERSHIP CHANGE TO APPLY  
  
# start KasmVNC, you will be prompted to create a KasmVNC user and select a desktop environment  
vncserver  
  
# Tail the logs  
tail -f ~/.vnc/*.log  
  
# Optionally use systemd to start KasmVNC on boot.  
sudo reboot # Needed for systemd to pick up $USER's ssl-cert group  
systemctl --user enable kasmvncserver@:1 # :1 is Xorg DISPLAY number.  
systemctl --user start kasmvncserver@:1  
  
# You can run multiple KasmVNC instances via systemd by passing a different  
# DISPLAY number:  
# systemctl --user enable kasmvncserver@:2  
# systemctl --user start kasmvncserver@:2  
# systemctl --user enable kasmvncserver@:3  
# systemctl --user start kasmvncserver@:3
```

--------------------------------

### Install FFmpeg with Extra Codecs

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Command to install FFmpeg with additional codec support on Debian-based systems.

```bash
sudo apt install ffmpeg libavcodec-extra
```

--------------------------------

### Install KasmVNC on RHEL 8

Source: https://docs.kasmvnc.com/docs/install/index.html

Commands to download, install, and configure KasmVNC on RHEL 8, including enabling the powertools repository.

```bash
# Choose the Oracle 8 rpm here:  
# https://github.com/kasmtech/KasmVNC/releases  
wget <package_url>  
  
# Ensure KasmVNC dependencies are available  
sudo dnf config-manager --set-enabled powertools  
sudo dnf install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm  
  
sudo dnf localinstall ./kasmvncserver_*.rpm  
  
# Add your user to the kasmvnc-cert group  
sudo usermod -a -G kasmvnc-cert $USER  
  
# YOU MUST DISCONNECT AND RECONNECT FOR GROUP MEMBERSHIP CHANGE TO APPLY  
  
# start KasmVNC, you will be prompted to create a KasmVNC user and select a desktop environment  
vncserver  
  
# Tail the logs  
tail -f ~/.vnc/*.log  
  
# Optionally use systemd to start KasmVNC on boot.  
sudo reboot # Needed for systemd to pick up $USER's kasmvnc-cert group  
systemctl --user enable kasmvncserver@:1 # :1 is Xorg DISPLAY number.  
systemctl --user start kasmvncserver@:1  
  
# You can run multiple KasmVNC instances via systemd by passing a different  
# DISPLAY number:  
# systemctl --user enable kasmvncserver@:2  
# systemctl --user start kasmvncserver@:2  
# systemctl --user enable kasmvncserver@:3  
# systemctl --user start kasmvncserver@:3
```

--------------------------------

### Configure Runtime Settings

Source: https://docs.kasmvnc.com/docs/configuration/index.html

Example configuration for restricting client overrides and defining allowed runtime modifications.

```yaml
runtime_configuration:  
  allow_client_to_override_kasm_server_settings: false  
  allow_override_standard_vnc_server_settings: true  
  allow_override_list:  
    - pointer.enabled  
    - data_loss_prevention.clipboard.server_to_client.enabled  
    - data_loss_prevention.clipboard.client_to_server.enabled  
    - data_loss_prevention.clipboard.server_to_client.primary_clipboard_enabled
```

--------------------------------

### Install KasmVNC on RHEL 9

Source: https://docs.kasmvnc.com/docs/install/index.html

Commands to download, install, and configure KasmVNC on RHEL 9, including enabling the crb repository.

```bash
# Choose the Oracle 9 rpm here:  
# https://github.com/kasmtech/KasmVNC/releases  
wget <package_url>  
  
# Ensure KasmVNC dependencies are available  
sudo dnf config-manager --set-enabled crb  
sudo dnf install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm  
  
sudo dnf localinstall ./kasmvncserver_*.rpm  
  
# Add your user to the kasmvnc-cert group  
sudo usermod -a -G kasmvnc-cert $USER  
  
# YOU MUST DISCONNECT AND RECONNECT FOR GROUP MEMBERSHIP CHANGE TO APPLY  
  
# start KasmVNC, you will be prompted to create a KasmVNC user and select a desktop environment  
vncserver  
  
# Tail the logs  
tail -f ~/.vnc/*.log  
  
# Optionally use systemd to start KasmVNC on boot.  
sudo reboot # Needed for systemd to pick up $USER's kasmvnc-cert group  
systemctl --user enable kasmvncserver@:1 # :1 is Xorg DISPLAY number.  
systemctl --user start kasmvncserver@:1  
  
# You can run multiple KasmVNC instances via systemd by passing a different  
# DISPLAY number:  
# systemctl --user enable kasmvncserver@:2  
# systemctl --user start kasmvncserver@:2  
# systemctl --user enable kasmvncserver@:3  
# systemctl --user start kasmvncserver@:3
```

--------------------------------

### Install KasmVNC on Oracle Linux 8

Source: https://docs.kasmvnc.com/docs/install/index.html

Commands to install dependencies, the KasmVNC package, and configure systemd for Oracle Linux 8.

```bash
# Please choose the package for your distro here (under Assets):  
# https://github.com/kasmtech/KasmVNC/releases  
wget <package_url>  
  
# Ensure KasmVNC dependencies are available  
sudo dnf config-manager --set-enabled ol8_codeready_builder  
sudo dnf install oracle-epel-release-el8  
  
sudo dnf localinstall ./kasmvncserver_*.rpm  
  
# Add your user to the kasmvnc-cert group  
sudo usermod -a -G kasmvnc-cert $USER  
  
# YOU MUST DISCONNECT AND RECONNECT FOR GROUP MEMBERSHIP CHANGE TO APPLY  
  
# start KasmVNC, you will be prompted to create a KasmVNC user and select a desktop environment  
vncserver  
  
# Tail the logs  
tail -f ~/.vnc/*.log  
  
# Optionally use systemd to start KasmVNC on boot.  
sudo reboot # Needed for systemd to pick up $USER's kasmvnc-cert group  
systemctl --user enable kasmvncserver@:1 # :1 is Xorg DISPLAY number.  
systemctl --user start kasmvncserver@:1  
  
# You can run multiple KasmVNC instances via systemd by passing a different  
# DISPLAY number:  
# systemctl --user enable kasmvncserver@:2  
# systemctl --user start kasmvncserver@:2  
# systemctl --user enable kasmvncserver@:3  
# systemctl --user start kasmvncserver@:3
```

--------------------------------

### Enable Xvnc Debug Logging

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Use this command to start Xvnc with verbose logging directed to stderr.

```bash
Xvnc :1 -Log *:stderr:100  
```

--------------------------------

### Install KasmVNC on Oracle Linux 9

Source: https://docs.kasmvnc.com/docs/install/index.html

Commands to install dependencies, the KasmVNC package, and configure systemd for Oracle Linux 9.

```bash
# Please choose the package for your distro here (under Assets):  
# https://github.com/kasmtech/KasmVNC/releases  
wget <package_url>  
  
# Ensure KasmVNC dependencies are available  
sudo dnf config-manager --set-enabled ol9_codeready_builder  
sudo dnf config-manager --set-enabled ol9_distro_builder  
sudo dnf install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm  
  
sudo dnf localinstall ./kasmvncserver_*.rpm  
  
# Add your user to the kasmvnc-cert group  
sudo usermod -a -G kasmvnc-cert $USER  
  
# YOU MUST DISCONNECT AND RECONNECT FOR GROUP MEMBERSHIP CHANGE TO APPLY  
  
# start KasmVNC, you will be prompted to create a KasmVNC user and select a desktop environment  
vncserver  
  
# Tail the logs  
tail -f ~/.vnc/*.log  
  
# Optionally use systemd to start KasmVNC on boot.  
sudo reboot # Needed for systemd to pick up $USER's kasmvnc-cert group  
systemctl --user enable kasmvncserver@:1 # :1 is Xorg DISPLAY number.  
systemctl --user start kasmvncserver@:1  
  
# You can run multiple KasmVNC instances via systemd by passing a different  
# DISPLAY number:  
# systemctl --user enable kasmvncserver@:2  
# systemctl --user start kasmvncserver@:2  
# systemctl --user enable kasmvncserver@:3  
# systemctl --user start kasmvncserver@:3
```

--------------------------------

### Downloads Directory Listing Response

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Example JSON response returned by the /api/downloads endpoint detailing file metadata.

```json
{
   "files":[
      {
         "filename":"test.txt",
         "date_modified":1727968832,
         "date_created":1727968832,
         "is_dir":false,
         "size":0,
         "owner":"kasm-user",
         "group":"kasm-user",
         "perms":"644"
      },
      {
         "filename":"file2.txt",
         "date_modified":1727969010,
         "date_created":1727969010,
         "is_dir":false,
         "size":0,
         "owner":"kasm-user",
         "group":"kasm-user",
         "perms":"644"
      },
      {
         "filename":"directory",
         "date_modified":1727969024,
         "date_created":1727969024,
         "is_dir":true,
         "size":0,
         "owner":"kasm-user",
         "group":"kasm-user",
         "perms":"755"
      },
      {
         "filename":"important",
         "date_modified":1727969056,
         "date_created":1727969056,
         "is_dir":true,
         "size":0,
         "owner":"kasm-user",
         "group":"kasm-user",
         "perms":"755"
      }
   ]
}
```

--------------------------------

### Implement Containerized Application Unix Socket

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Python example for creating, binding, and communicating via a Unix domain datagram socket.

```python
import os  
import socket  
import time  
  
# create and bind socket  
client_socket = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)  
client_socket_path = f"/tmp/relay-client-{str(time.time())}"  
client_socket.bind(client_socket_path)  
  
# allow others to read/write to the socket  
os.chmod(client_socket_path, 777)  
  
# send data  
server_relay_path = "/tmp/relay"  
request = bytearray(1024)  
sent = client_socket.sendto(request, 0, server_relay_path)  
print(f'sent: {sent}B')  
  
# receive response  
response = bytearray(1024)  
received, server = client_socket.recvfrom_into(response)  
print(f'received: {received}B')  
  
# clean up  
client_socket.close()  
os.unlink(client_socket_path)
```

--------------------------------

### Manage KasmVNC Sessions and Users

Source: https://docs.kasmvnc.com/docs/serverside/index.html

Common command-line operations for starting sessions, managing user credentials, and monitoring logs.

```bash
# Start a session and be guided to setup a user and select a default desktop environment  
vncserver  
  
# Start a session with the mate desktop environment  
vncserver -select-de mate  
  
# Add a new user with read/write permissions  
vncpasswd -u my_username -w -r  
  
# Tail the logs  
tail -f ~/.vnc/*.log  
  
# Get a list of current sessions with display IDs  
vncserver -list  
  
# Kill the VNC session with display ID :2  
vncserver -kill :2
```

--------------------------------

### GET /api/clear_clipboard

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Clears the contents of the KasmVNC and X session clipboard.

```APIDOC
## GET /api/clear_clipboard

### Description
Clears the KasmVNC and X session clipboard contents.

### Method
GET

### Endpoint
/api/clear_clipboard
```

--------------------------------

### GET /api/downloads

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Retrieves a JSON listing of files within the user's downloads directory.

```APIDOC
## GET /api/downloads

### Description
Provides a detailed listing of files in the user's downloads directory, in JSON.

### Method
GET

### Endpoint
/api/downloads

### Parameters
#### Query Parameters
- **path** (string) - Optional - path relative to the user's downloads directory.

### Response
#### Success Response (200)
- **files** (array) - List of file objects containing filename, date_modified, date_created, is_dir, size, owner, group, and perms.
```

--------------------------------

### GET /api/get_screenshot

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Retrieves a screenshot of the current session with optional resizing and deduplication.

```APIDOC
## GET /api/get_screenshot

### Description
Get a screenshot of the current session. You can pass a height and width that do not match the current aspect ratio, it will return the requested width with the height adjusted to keep the aspect ratio.

### Method
GET

### Endpoint
/api/get_screenshot

### Parameters
#### Query Parameters
- **width** (integer) - Optional - Defaults to actual remote screen width
- **height** (integer) - Optional - Defaults to actual remote screen height
- **quality** (integer) - Optional - JPEG quality, defaults to 7
- **deduplicate** (boolean) - Optional - Set to true if you want the API call to return nothing if the screenshot has not changed since the last request
```

--------------------------------

### Retrieve Session Users JSON Response

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Example JSON structure returned by the /api/get_sessions endpoint.

```json
{
   "users": [  
      {"username":"username1", "connected_since":"2025-07-16 08:07:39"},  
      {"username":"username2", "connected_since":"2025-07-16 08:07:39"},  
      {"username":"username3", "connected_since":"2025-07-16 08:07:39"}  
   ]  
}
```

--------------------------------

### Retrieve Frame Statistics

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Example request to the frame stats endpoint and the corresponding JSON response structure.

```text
/api/get_frame_stats?client=auto
```

```json
{
    "frame" : {  
        "resx": 1680,       
        "resy": 971,        
        "changed": 60,      
        "server_time": 45   
    },  
    "server_side" : [  
        { "process_name": "Analysis", "time": 2 },  
	{ "process_name": "Screenshot", "time": 3 },  
	{ "process_name": "Encoding_total", "time": 25, "videoscaling": 17 },  
	{ "process_name": "TightJPEGEncoder", "time": 3, "count": 1, "area": 786432 },  
	{ "process_name": "TightWEBPEncoder", "time": 0, "count": 0, "area": 0 }  
    ],  
    "client_side" : [  
        {  
            "client": "71.61.88.0_1627638469.484285::websocket",  
            "client_time": 1,  
            "ping": 54,  
            "processes" : [  
                { "process_name": "scanRenderQ", "time": 0 }  
            ]  
         }  
     ]  
}
```

--------------------------------

### GET /api/send_full_frame

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Triggers a full frame update to be sent to all users with at least read permission.

```APIDOC
## GET /api/send_full_frame

### Description
Send a full frame to all users with at least read permission.

### Method
GET

### Endpoint
/api/send_full_frame
```

--------------------------------

### Retrieve Bottleneck Statistics JSON

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Example response structure for the /api/get_bottleneck_stats endpoint, showing CPU and network performance metrics per user connection.

```json
{
    "myusername": {  
         "71.61.88.0_1627638421.160028::websocket": [ 8.2, 9.6, 10.0, 9.4 ],  
         "71.61.88.0_1627638469.484285::websocket": [ 8.2, 9.6, 2.6, 8.5 ]  
    }  
}
```

--------------------------------

### GET /api/get_bottleneck_stats

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Retrieves CPU and network bottleneck statistics for all active user connections. Metrics are provided as snapshots and time-averaged values ranging from 0 to 10.

```APIDOC
## GET /api/get_bottleneck_stats

### Description
Returns CPU and network bottleneck statistics to identify performance constraints. Values range from 0 to 10, where 10 represents no constraints.

### Method
GET

### Endpoint
/api/get_bottleneck_stats

### Response
#### Success Response (200)
- **[username]** (object) - A dictionary containing connection identifiers as keys.
- **[connection_id]** (array) - An array containing: [CPU, CPU Average, Network, Network Average].

#### Response Example
{
    "myusername": {
         "71.61.88.0_1627638421.160028::websocket": [ 8.2, 9.6, 10.0, 9.4 ],
         "71.61.88.0_1627638469.484285::websocket": [ 8.2, 9.6, 2.6, 8.5 ]
    }
}
```

--------------------------------

### GET /api/get_sessions

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Retrieves a list of users currently connected to a shared session, including their connection timestamps.

```APIDOC
## GET /api/get_sessions

### Description
Retrieves a list of users connected to a shared session. The `connected_since` field indicates the date and time in UTC that the user connected to the session.

### Method
GET

### Endpoint
/api/get_sessions

### Response
#### Success Response (200)
- **users** (array) - A list of user objects containing username and connection time.

#### Response Example
{
  "users": [
    {"username":"username1", "connected_since":"2025-07-16 08:07:39"},
    {"username":"username2", "connected_since":"2025-07-16 08:07:39"},
    {"username":"username3", "connected_since":"2025-07-16 08:07:39"}
  ]
}
```

--------------------------------

### GET /api/get_frame_stats

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Retrieves timing statistics for frame processing, including server-side encoding processes and client-side performance metrics.

```APIDOC
## GET /api/get_frame_stats

### Description
Returns timings for all major processes with respect to processing a single frame. This helps determine if the network or server-side CPU is causing a bottleneck.

### Method
GET

### Endpoint
/api/get_frame_stats

### Parameters
#### Query Parameters
- **client** (string) - Required - Specifies which client connection to return stats for. Options: 'auto' (first connection for owner), 'all' (all connections), 'none' (no client stats), or a specific connection ID (e.g., '71.61.88.0_1627638421.160028::websocket').

### Response
#### Success Response (200)
- **frame** (object) - Contains frame dimensions (resx, resy), percentage of changes (changed), and total server processing time (server_time).
- **server_side** (array) - List of server-side processes with their respective CPU times, execution counts, and area processed.
- **client_side** (array) - List of client-side metrics including client ID, processing time, and ping.

### Response Example
{
    "frame": {
        "resx": 1680,
        "resy": 971,
        "changed": 60,
        "server_time": 45
    },
    "server_side": [
        { "process_name": "Analysis", "time": 2 },
        { "process_name": "Encoding_total", "time": 25, "videoscaling": 17 }
    ],
    "client_side": [
        {
            "client": "71.61.88.0_1627638469.484285::websocket",
            "client_time": 1,
            "ping": 54
        }
    ]
}
```

--------------------------------

### Set Multiple Fallback Codecs

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Demonstrates how to provide a comma-separated list of codecs for the server to attempt in order.

```bash
Xvnc :1 -VideoCodec h265_nvenc,h265_vaapi,h264_nvenc,h264_vaapi,h264  
```

--------------------------------

### Verify Hardware Acceleration

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Commands to check VAAPI availability, FFmpeg NVENC support, and DRM device permissions.

```bash
vainfo --display drm
```

```text
libva info: VA-API version 1.20.0  
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so  
libva info: Found init function __vaDriverInit_1_20  
libva info: va_openDriver() returns 0  
vainfo: VA-API version: 1.20 (libva 2.12.0)  
vainfo: Driver version: Mesa Gallium driver 25.0.7-0ubuntu0.24.04.2 for AMD Radeon Graphics (radeonsi, renoir, ACO, DRM 3.57, 6.8.0-90-generic)  
vainfo: Supported profile and entrypoints  
      VAProfileMPEG2Simple            : VAEntrypointVLD  
      VAProfileMPEG2Main              : VAEntrypointVLD  
      VAProfileVC1Simple              : VAEntrypointVLD  
      VAProfileVC1Main                : VAEntrypointVLD  
      VAProfileVC1Advanced            : VAEntrypointVLD  
      VAProfileH264ConstrainedBaseline: VAEntrypointVLD  
      VAProfileH264ConstrainedBaseline: VAEntrypointEncSlice  
      VAProfileH264Main               : VAEntrypointVLD  
      VAProfileH264Main               : VAEntrypointEncSlice  
      VAProfileH264High               : VAEntrypointVLD  
      VAProfileH264High               : VAEntrypointEncSlice  
      VAProfileHEVCMain               : VAEntrypointVLD  
      VAProfileHEVCMain               : VAEntrypointEncSlice  
      VAProfileHEVCMain10             : VAEntrypointVLD  
      VAProfileHEVCMain10             : VAEntrypointEncSlice  
      VAProfileJPEGBaseline           : VAEntrypointVLD  
      VAProfileVP9Profile0            : VAEntrypointVLD  
      VAProfileVP9Profile2            : VAEntrypointVLD  
      VAProfileNone                   : VAEntrypointVideoProc
```

```bash
ffmpeg -hide_banner -encoders | grep nvenc
```

```text
V....D h264_nvenc           NVIDIA NVENC H.264 encoder  
V....D hevc_nvenc           NVIDIA NVENC hevc encoder  
V....D av1_nvenc            NVIDIA NVENC av1 encoder
```

```bash
ls -l /dev/dri/
```

```text
crw-rw---- 1 root video  226,   0 Jan  6 18:23 card0  
crw-rw---- 1 root render 226, 128 Jan  6 18:23 renderD128
```

```bash
sudo usermod -aG render $USER
```

--------------------------------

### Configure Xvnc Video Streaming Modes

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Use these command-line arguments to adjust video quality, frame rate, and codec selection for different network conditions.

```bash
Xvnc :1 \
  -VideoCodec h265_nvenc,h265_vaapi,h264_nvenc,h264 \
  -VideoQualityCRFCQP 15 \
  -GroupOfPicture 12 \
  -FrameRate 60
```

```bash
Xvnc :1 \
  -VideoCodec h264_nvenc,h264_vaapi,h264 \
  -VideoQualityCRFCQP 23 \
  -GroupOfPicture 24 \
  -FrameRate 30
```

```bash
Xvnc :1 \
  -VideoCodec h265_nvenc,h265_vaapi,h265,h264 \
  -VideoQualityCRFCQP 30 \
  -GroupOfPicture 60 \
  -FrameRate 24
```

```bash
Xvnc :1 \
  -VideoCodec h264 \
  -VideoQualityCRFCQP 25
```

```bash
Xvnc :1 \
  -VideoCodec h264_nvenc \
  -drinode /dev/dri/renderD129
```

--------------------------------

### Enable GPU Acceleration via CLI

Source: https://docs.kasmvnc.com/docs/gpu_acceleration/index.html

Use the -hw3d flag to enable DRI3 support and specify the render node with -drinode.

```bash
vncserver -hw3d -drinode /dev/dri/renderD128
```

--------------------------------

### Enable GPU Acceleration via YAML Configuration

Source: https://docs.kasmvnc.com/docs/gpu_acceleration/index.html

Configure GPU settings in the kasmvnc.yaml file to enable hardware 3D acceleration.

```yaml
desktop:  
  gpu:  
    hw3d: true  
    drinode: /dev/dri/renderD128
```

--------------------------------

### Configure Group of Pictures (GOP) Size

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Sets the interval between keyframes, affecting responsiveness and bitrate.

```bash
-GroupOfPicture <0-100>  
```

--------------------------------

### Configure Video Quality Parameter

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Sets the CRF or CQP value to control encoding quality, where lower values indicate higher quality.

```bash
-VideoQualityCRFCQP <0-63>  
```

--------------------------------

### Configure Image Watermark

Source: https://docs.kasmvnc.com/docs/configuration/index.html

Sets up a PNG image watermark with tinting and repeat spacing.

```yaml
data_loss_prevention:  
  watermark:  
    image: /data/kasm.png  
    tint: 25,25,255,64  
    repeat_spacing: 20  
```

--------------------------------

### Configure Text Watermark with Template

Source: https://docs.kasmvnc.com/docs/configuration/index.html

Sets up a repeating text watermark using a template string with user and timestamp variables.

```yaml
network:  
  ssl:  
   pem_certificate: ${HOME}/.vnc/self.pem  
   pem_key: ${HOME}/.vnc/self.pem  
  udp:  
    public_ip: 127.0.0.1  
data_loss_prevention:  
  watermark:  
    repeat_spacing: 50  
    tint: 200,200,235,60  
    text:  
      template: "Kasm Workspaces User ${USER} (${KASM_ID}) at %F %H:%M"  
      font: auto  
      font_size: 24  
      timezone_name: Asia/Taipei  
```

--------------------------------

### Create User via POST

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Bulk creation of users using a JSON array in a POST request.

```json
[
   { "user": "username1", "password": "password123", "write": true, "read": true, "owner": false },
   { "user": "username2", "password": "password123", "write": true, "read": true, "owner": false }
]
```

--------------------------------

### KasmVNC Default Configuration File

Source: https://docs.kasmvnc.com/docs/configuration/index.html

The default configuration file defines settings for desktop resolution, network protocols, user sessions, security, and encoding. Many settings can be overridden by the client unless restricted by the runtime configuration.

```yaml
desktop:  
  resolution:  
    width: 1024  
    height: 768  
  allow_resize: true  
  pixel_depth: 24  
  gpu:  
    hw3d: false  
    drinode: /dev/dri/renderD128  
  
network:  
  protocol: http  
  interface: 0.0.0.0  
  websocket_port: auto  
  use_ipv4: true  
  use_ipv6: true  
  udp:  
    public_ip: 127.0.0.1  
    port: auto  
    payload_size: auto  
    stun_server: auto  
  ssl:  
    pem_certificate: /etc/ssl/certs/ssl-cert-snakeoil.pem  
    pem_key: /etc/ssl/private/ssl-cert-snakeoil.key  
    require_ssl: true  
  # unix_relay:  
  #   name:  
  #   path:  
  
  
user_session:  
  new_session_disconnects_existing_exclusive_session: false  
  concurrent_connections_prompt: false  
  concurrent_connections_prompt_timeout: 10  
  idle_timeout: never  
  
keyboard:  
  remap_keys:  
  ignore_numlock: false  
  raw_keyboard: false  
  
pointer:  
  enabled: true  
  game_mode: false  
  
runtime_configuration:  
  allow_client_to_override_kasm_server_settings: true  
  allow_override_standard_vnc_server_settings: true  
  allow_override_list:  
    - pointer.enabled  
    - data_loss_prevention.clipboard.server_to_client.enabled  
    - data_loss_prevention.clipboard.client_to_server.enabled  
    - data_loss_prevention.clipboard.server_to_client.primary_clipboard_enabled  
  
logging:  
  log_writer_name: all  
  log_dest: logfile  
  level: 30  
  
security:  
  brute_force_protection:  
    blacklist_threshold: 5  
    blacklist_timeout: 10  
  
data_loss_prevention:  
  visible_region:  
    # top: 10  
    # left: 10  
    # right: 40  
    # bottom: 40  
    concealed_region:  
      allow_click_down: false  
      allow_click_release: false  
  clipboard:  
    delay_between_operations: none  
    allow_mimetypes:  
      - chromium/x-web-custom-data  
      - text/html  
      - image/png  
    server_to_client:  
      enabled: true  
      size: unlimited  
      primary_clipboard_enabled: false  
    client_to_server:  
      enabled: true  
      size: unlimited  
  keyboard:  
    enabled: true  
    rate_limit: unlimited  
  logging:  
    level: off  
  watermark:  
    # image: /etc/kasmvnc/picture.png  
    # location: 10,10  
    # tint: 255,20,20,128  
    # repeat_spacing: 10  
    # text:  
      # template: "${USER} %H:%M"  
      # font: auto  
      # font_size: 48  
      # timezone_name: Australia/Adelaide  
      # angle: 0  
  
encoding:  
  max_frame_rate: 60  
  full_frame_updates: none  
  rect_encoding_mode:  
    min_quality: 7  
    max_quality: 8  
    consider_lossless_quality: 10  
    rectangle_compress_threads: auto  
  
  video_encoding_mode:  
    jpeg_quality: -1  
    webp_quality: -1  
    max_resolution:  
      width: 1920  
      height: 1080  
    enter_video_encoding_mode:  
      time_threshold: 5  
      area_threshold: 45%  
    exit_video_encoding_mode:  
      time_threshold: 3  
    logging:  
      level: off  
    scaling_algorithm: progressive_bilinear  
  
  video_streaming_mode:  
    codec: auto  
    quality: 17  
    gop: 24  
  
  compare_framebuffer: auto  
  zrle_zlib_level: auto  
  hextile_improved_compression: true  
  
server:  
  http:  
    headers:  
      - Cross-Origin-Embedder-Policy=require-corp  
      - Cross-Origin-Opener-Policy=same-origin  
    httpd_directory: /usr/share/kasmvnc/www  
  advanced:  
    x_font_path: auto  
    kasm_password_file: ${HOME}/.kasmpasswd  
    x_authority_file: auto  
  auto_shutdown:  
    no_user_session_timeout: never  
    active_user_session_timeout: never  
    inactive_user_session_timeout: never  
  allow_environment_variables_to_override_config_settings: false  
  
command_line:  
  prompt: true
```

--------------------------------

### Identify GPU by Path

Source: https://docs.kasmvnc.com/docs/gpu_acceleration/index.html

Use the by-path directory to map render nodes to specific PCI addresses.

```bash
ls -l /dev/dri/by-path/*-render | awk '{print $9,$11}'  
/dev/dri/by-path/pci-0000:04:00.0-render ../renderD128
```

--------------------------------

### Verify GPU Hardware Details

Source: https://docs.kasmvnc.com/docs/gpu_acceleration/index.html

Query PCI information for a specific device ID to confirm the hardware model.

```bash
sudo lspci |grep 04:00.0  
04:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Rembrandt (rev c7)
```

--------------------------------

### Configure DRM Device Node

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Specifies the path to the DRM device for hardware acceleration.

```bash
-drinode <path>  
```

```bash
Xvnc :1 -drinode /dev/dri/renderD128  
```

--------------------------------

### Configure Target Framerate

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Sets the target frames per second for video encoding.

```bash
-FrameRate <10-60>  
```

--------------------------------

### Identify GPU Drivers

Source: https://docs.kasmvnc.com/docs/gpu_acceleration/index.html

List render nodes and their associated drivers to determine which device to use.

```bash
ls -l /sys/class/drm/renderD*/device/driver | awk '{print $9,$11}'  
/sys/class/drm/renderD128/device/driver ../../../bus/pci/drivers/i915  
/sys/class/drm/renderD129/device/driver ../../../../bus/pci/drivers/nvidia  
/sys/class/drm/renderD130/device/driver ../../../../bus/pci/drivers/amdgpu
```

--------------------------------

### Configure Video Codec Parameter

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Defines the syntax for specifying video codecs via command-line parameters.

```bash
-VideoCodec <codec1,codec2,...>  
```

--------------------------------

### VAAPI Initialization Error Log

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Error message displayed when the VAAPI device context fails to initialize.

```text
FFMPEGVAAPIEncoder: Failed to create VAAPI device context  
```

--------------------------------

### Verify FFmpeg Encoder Support

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Command to list available FFmpeg encoders and filter for hardware acceleration support.

```bash
ffmpeg -encoders | grep -E 'vaapi|nvenc'
```

--------------------------------

### Performance Tuning Flags

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Configuration flags for adjusting video quality, framerate, and GOP size to improve encoding performance.

```bash
-VideoQualityCRFCQP 28
```

```bash
-FrameRate 24
```

```bash
-GroupOfPicture 60
```

--------------------------------

### Configure Visible Regions with Percentages

Source: https://docs.kasmvnc.com/docs/configuration/index.html

Defines a rendering region using percentages of the total screen dimensions. Mixing percentage values with absolute or offset values is not supported.

```yaml
data_loss_prevention:  
  visible_region:  
    top: 10%  
    left: 10%  
    right: 20%  
    bottom: 20%  
```

--------------------------------

### System Log Check for DRM

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Command to inspect system logs for DRM-related messages.

```bash
dmesg | grep -i drm
```

--------------------------------

### VAAPI Device Specification Flag

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Command line flag to explicitly set the DRI render node.

```bash
-drinode /dev/dri/renderD128
```

--------------------------------

### Implement noVNC Unix Relay Communication

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

JavaScript implementation using rfb.subscribeUnixRelay and rfb.sendUnixRelayData to handle bidirectional socket communication.

```javascript
rfb.subscribeUnixRelay("relay_name", (payload) => {  
  const buffer = new Uint8Array(Array.from(payload)).buffer;  
  const data = new DataView(buffer);  
  
  // process the incoming data  
  
  // send a response  
  rfb.sendUnixRelayData("relay_name", new Uint8Array([...]));  
});
```

--------------------------------

### Configure Visible Regions with Offset Coordinates

Source: https://docs.kasmvnc.com/docs/configuration/index.html

Defines a rendering region using pixel offsets from the screen edges, useful when resolution is unknown.

```yaml
data_loss_prevention:  
  visible_region:  
    top: -10  
    left: -10  
    right: -10  
    bottom: -10  
```

```yaml
data_loss_prevention:  
  visible_region:  
    top: 50  
    left: 10  
    right: -10  
    bottom: -10  
```

--------------------------------

### Configure KasmVNC Unix Relay

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

YAML configuration settings for enabling the Unix relay in KasmVNC.

```yaml
network:  
   unix_relay:  
      name: relay_name  
      path: relay_path
```

--------------------------------

### POST /api/create_user

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Adds a new user to the session, supporting both individual query parameters and bulk JSON operations.

```APIDOC
## POST /api/create_user

### Description
Add another user to the session. Can be called via query parameters or as a POST with JSON data for bulk operations.

### Method
POST

### Endpoint
/api/create_user

### Parameters
#### Query Parameters
- **name** (string) - Required - The username
- **password** (string) - Required - The requested password
- **write** (boolean) - Optional - Set to 'true' if the user should have write permissions
- **read** (boolean) - Optional - Should the user have read access
- **owner** (boolean) - Optional - Should the owner be able to manage users

### Request Example
[
  { "user": "username1", "password": "password123", "write": true, "read": true, "owner": false }
]
```

--------------------------------

### Update User via POST

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Bulk update of user permissions using a JSON array in a POST request.

```json
[
   { "user": "username1", "write": true, "read": true, "owner": false },
   { "user": "username2", "write": true, "read": true, "owner": false }
]
```

--------------------------------

### rfb.subscribeUnixRelay

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Subscribes to data received from a Unix domain socket relay in noVNC.

```APIDOC
## rfb.subscribeUnixRelay(relay_name, callback)

### Description
Listens for data received from the specified Unix domain socket relay.

### Parameters
- **relay_name** (string) - The identifier for the relay connection.
- **callback** (function) - A function to process the incoming payload.
```

--------------------------------

### rfb.sendUnixRelayData

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Sends data back through the specified Unix domain socket relay in noVNC.

```APIDOC
## rfb.sendUnixRelayData(relay_name, data)

### Description
Sends data back through the relay to the containerized application.

### Parameters
- **relay_name** (string) - The identifier for the relay connection.
- **data** (Uint8Array) - The data payload to send.
```

--------------------------------

### Configure Visible Regions with Absolute Coordinates

Source: https://docs.kasmvnc.com/docs/configuration/index.html

Defines a specific rendering region using absolute pixel coordinates.

```yaml
data_loss_prevention:  
  visible_region:  
    top: 10  
    left: 10  
    right: 1014  
    bottom: 758  
```

--------------------------------

### Software Encoding Fallback Flag

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Flag to force the use of software-based H.264 encoding.

```bash
-VideoCodec h264
```

--------------------------------

### Encoder Not Found Error Log

Source: https://docs.kasmvnc.com/docs/video_streaming_mode/index.html

Error message displayed when the requested VAAPI encoder is missing.

```text
EncoderProbe: Could not find h264_vaapi encoder  
```

--------------------------------

### Remove User via POST

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Use this JSON structure with a POST request to the /api/remove_user endpoint for bulk user removal.

```json
[
   { "user": "username1" },
   { "user": "username2" }
]
```

--------------------------------

### POST /api/update_user

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Updates existing user permissions or credentials, supporting both individual query parameters and bulk JSON operations.

```APIDOC
## POST /api/update_user

### Description
Update an existing user's settings. Can be called via query parameters or as a POST with JSON data for bulk operations.

### Method
POST

### Endpoint
/api/update_user

### Parameters
#### Query Parameters
- **name** (string) - Required - The target username
- **password** (string) - Optional - The password to update
- **write** (boolean) - Optional - Set to true if the user should have write permission
- **read** (boolean) - Optional - Should the user have read access
- **owner** (boolean) - Optional - Should the owner be able to manage users

### Request Example
[
  { "user": "username1", "write": true, "read": true, "owner": false }
]
```

--------------------------------

### GET/POST /api/remove_user

Source: https://docs.kasmvnc.com/docs/developer_api/index.html

Removes a user from the KasmVNC session. Supports query parameters for single users or JSON body for bulk operations.

```APIDOC
## GET/POST /api/remove_user

### Description
Remove a user from the KasmVNC session. Can be called as a GET request or a POST request for bulk operations.

### Method
GET, POST

### Endpoint
/api/remove_user

### Parameters
#### Query Parameters
- **name** (string) - Required - username of the user to remove

#### Request Body
- **Array of objects** (JSON) - Required - List of objects containing "user" keys for bulk removal

### Request Example
[  
   { "user": "username1" },  
   { "user": "username2" }  
]
```
Tokens:
Raw