Using the Linux Service¶

To start, stop, or restart the scyld-cloud-workstation, open a terminal with root or sudo privileges and use the service command:

service scyld-cloud-workstation start
service scyld-cloud-workstation stop
service scyld-cloud-workstation restart

To run scyld-cloud-workstation directly rather than as a service (this is usually only useful for debugging purposes), use the scyld-cloud-workstation.sh start-up script. Usage information can be obtained by passing the --help flag.

usage: scyld-cloud-workstation OPTIONS
scyld-cloud-workstation -- a GPU accelerated remote desktop web service.

--daemon                                   Run application as a daemon.
--pidfile=path                             Write the process ID of the
                                           application to given file.
-h, --help                                 display help information on command
                                           line arguments
-vsvideosource, --videosource=videosource  choose videosource (nvfbc, stream)
-q, --quiet                                hide the console when running
-pwd, --passwd                             update the password

Using the Windows Service¶

To use the scyld-cloud-workstation service, we must verify that the service is registered with the OS and then start the service.

scyld-cloud-workstation.exe /registerService /startup=automatic

'scyld-cloud-workstation.exe' is not recognized as an internal or
 external command, operable program or batch file.

net start scyld-cloud-workstation
net stop scyld-cloud-workstation

Change the Config File Password¶

Scyld Cloud Workstation lets you optionally store a username and hashed password in the config file for authentication. The credentials specified by Server.Auth.Username and Server.Auth.ShadowPassword attributes are entirely independent from LDAP, the remote operating system, and ScyldCloudAuth.

You can change this password by calling scyld-cloud-workstation.sh --passwd in Linux or scyld-cloud-workstation.exe /passwd in Windows from a command line. This password change takes effect without a service restart.

Password strength requirements are described in the Setup chapter under Server.Auth.ShadowPassword.

Log Output¶

Log output is organized by priority levels (from highest to lowest: Fatal, Critical, Error, Warning, Notice, Information, Debug, and Trace). scyld-cloud-workstation by default prints Information level messages to /var/log/messages.

Setting LogLevel to information will log all server starts/stops, sign-in attempts, socket connects/disconnects, video source plays/pauses, and additional warning/error messages. This is usually sufficient for production usage.

To see debug and higher level output, open the scyld-cloud-workstation.xml config file and set LogLevel to debug.

In Linux, debug and higher level log messages can be found at: /opt/scyld-cloud-workstation/bin/scyld-cloud-workstation.log.

In Windows, debug and higher level log messages can be found at: C:\Program Files\Penguin Computing\Scyld Cloud Workstation\log\win-service.log and C:\Program Files\Penguin Computing\Scyld Cloud Workstation\log\scyld-cloud-workstation.log.

By default, Scyld Cloud Workstation does not display a timestamp with each log message. To add a timestamp to all of your output, open the scyld-cloud-workstation.xml and set LogFormat to: %Y-%m-%d %H:%M:%S %q%q: %s:%u: %t.

Selecting a Video Source¶

Scyld Cloud Workstation currently supports two video sources:nvfbc and stream.

For most users an appropriate default video source will be automatically detected based on the system’s configuration. Hosts that have an NVIDIA GRID card with a compatible NVIDIA GRID driver installed default to nvfbc. All other systems will default to stream.

To override the video source, specify --videosource=<nvfbc|stream> or change Server.VideoSource in the config file.

Sign In¶

Once the Scyld Cloud Workstation server has started, users can connect their networked client to the server by typing the server’s URL into the web browser. Servers using the HTTPS protocol (default) have URLs like this: https://<server-hostname-or-ip>.

This will take you to the Scyld Cloud Workstation sign in page. Submit the username and password encrypted in the config file or by ScyldCloudAuth to sign in.

As a third option, you can use your OS specific credentials to sign in.

After signing in you will see a gray canvas that will turn into a remote visualization display within a few seconds. At this point you can interact with the remote operating system. Other users will be prevented from signing into the web service until you sign out.

Main Toolbar¶

The main toolbar gives access to additional Scyld Cloud Workstation features such as signing out. This menu can be hidden or shown by pressing Ctrl+F12 or using the hide/show button at the bottom of the screen.

Paste Text from the Local Clipboard¶

Text can be pasted from the local client into the remote desktop.

To paste text from a local Linux / Windows clipboard into the remote Linux / Windows desktop, press Ctrl+V.

To paste text from a local OS X clipboard to the remote Linux / Windows desktop, use your browser’s menu system to select Edit -> Paste. This transfers the local clipboard to the remote clipboard. Once this is done, you can use Ctrl+V or use your remote application’s paste feature.

Change Screen Resolution¶

In Windows, right click on the desktop and select Screen resolution. Change the resolution dropdown to your desired resolution and then click ‘OK’.

In Linux, if you are using a first generation NVIDIA GRID card (i.e., K1, K2) in a headless configuration (i.e. you are using the UseDisplayDevice none option in your /etc/X11/xorg.conf file), you will have to open a command prompt and use the xrandr --fb <width>x<height> command. For example, if you’d like to change the screen resolution to 1920x1080, you would enter: xrandr --fb 1920x1080.

Otherwise change your screen resolution by using the provided Linux OS tools (dependent on distribution).

Downscale Screen Resolution¶

System administrators have the ability to restrict the maximum screen resolution in the config file at scyld-cloud-workstation.xml using the Server.Video.MaxWidth and Server.Video.MaxHeight settings. This is useful for preventing clients from being overwhelmed by the processing power required to work with high-resolution video.

If the user attempts to use a higher screen resolution, the user will get an alert and the video will be scaled down.

Enable 4K Support¶

As of v7.0.0 it is possible to support 4K desktops with the native, non-browser based client. This feature is not enabled by default and requires a configuration file change to disable the default screen size and bitrate caps. We recommend having a downlink of at least 20 Mbps to support the increased screen size.

In future releases 4K support will be enabled automatically.

The following steps enable 4K support:

1. Open the xml config file.
2. Add the Server.Video.MaxWidth and Server.Video.MaxHeight tags with the value set to -1 to disable the resolution cap.
3. Save the config file and restart the service.

Video Bit-Rate Selection¶

As of v7.1.0, the default video bit-rate is calculated by using a linear regression of two values: 2500 kbps at 1280x720 and 5000 kbps at 1920x1080. A system administrator can customize bit-rates for different resolutions by adding two or more resolution and bit-rate pairings within the Server.Video.AvgBitRate config file setting. The syntax is as follows:

<width>x<height>=<bitrate>,<width>x<height>=<bitrate>,...

Example 1: the following is equivalent to the default bit-rate values: 1280x720=2500k,1920x1080=5000k.

Example 2: the following can be used to specify a single average bit-rate setting across all resolutions: 1024x768=2m,1600x900=2m.

The linear regression algorithm is based on the two closest resolutions to allow a fine-grained bit-rate control. If the value only specifies one resolution and bit-rate, the service will use 0x0=128k as one of the two linear regression points.

Sign Out¶

Windows and Linux users must change users by using the remote OS’s log out / log in feature. Scyld Cloud Workstation does not support “fast user switching” and the service must be restarted if this happens.

Closing your browser or signing out of the Scyld Cloud Workstation session does not sign you out of the remote operating system. Use the remote OS’s signing-out capability to sign out of the remote OS.

Set the maximum number of concurrent clients¶

By default the server only allows 6 users to be signed on at any given time. This number can be changed by a system administrator by adding a Server.MultiUser.MaxClientCount setting in the config file at scyld-cloud-workstation.xml.

Collaboration Quick Start¶

At a high level, adding a new guest involves three steps:

1. A Host creates an Invite Link and sends it to Guest users
2. A Guest opens the Invite Link, enters a Guest name, and attempts to sign in
3. A Host accepts the Guest’s sign in request

Hosts can use the control buttons to pause video to all Guests or ban all Guests and revoke all pending Invites. Hosts can also click on user buttons to kick individual Guests or give keyboard and mouse control.

Control Buttons¶

At the top of the screen there are a row of buttons that allow you to type special keys such as Ctrl + Alt + Del, add guests, pause all guest video, ban all guests, and sign out. Press Ctrl + F12 to show / hide these buttons.

Add New Guests¶

Hosts can invite a group of guests by creating an Invite Link. Click on the ‘Add Guests’ button.

In the form that appears, specify how many guest sign ins you’d like this link to be good for. It is best practice to select the minimum number you will need.

The next form will show the generated Invite Link. Copy and send this link to Guest users and then close the form.

When Guests use this link to request a sign in, an alert will appear to all Hosts asking whehter the user should be Accepted or Declined.

When a Guest signs in, their username becomes reserved until all Hosts sign out. Guest usernames must be unique and consist of only letters, numbers, and underscores. Once the session ends, all Guest usernames are freed again for use.

Pause Guest Video¶

Guest video can be toggled by clicking on the ‘Pause Guests’ button.

Ban Guests and Revoke Invites¶

Guests can be banned for the session either individually or all at the same time using the ‘Ban Guests’ button. Hosts can not be banned.

User Buttons¶

At the bottom of the screen there are a row of buttons containing usernames and status icons. The first button will always be “You”, indicating the user button for the user signing in. Clicking on the user button will show status information (including frame rate) and actions that can be taken on that user, such as banning or giving keyboard / mouse control.

Usernames that end with an asterisk are Hosts. Press Ctrl + F12 to show / hide these buttons.

Give Keyboard and Mouse Control¶

A Host can give any other user control of the keyboard and mouse using the ‘Give Keyboard and Mouse Control’ button.