About Scyld Cloud Workstation¶

Scyld Cloud Workstation 13.0.4, commit 5779650cbd286d1411c6d427837b8d6733819b9d.

Introduction¶

Scyld Cloud Workstation is a web server that provides secure, easy remote access to teams working on Linux, Windows, and MacOS workstations through standard web browsers, eliminating the need for client-side installations and changes to firewall policies.

This document describes system requirements, installation, configuration, and usage.

Server Requirements¶

This section describes the hardware and software requirements for the workstation hosting the Scyld Cloud Workstation server.

Server OS¶

Scyld Cloud Workstation is supported and tested on the following 64-bit operating systems:

CentOS 7
Rocky Linux 8 and 9
Windows 10, 11, and Windows Server 2019
Windows Server 2022 (server-side only)
MacOS Catalina 10.15 to MacOS Ventura 13
Ubuntu 20 and 22

Important

Rocky Linux users: XWayland is not currently supported. Please see Installing the Server on Rocky Linux for instructions on enabling Xorg as the default X server.

Attention

There is a known graphics issue with older GNOME 3 Shell based systems (GNOME 3 and GDM) on machines that don’t have an attached monitor. We recommend upgrading to GNOME 3.28+ or using the MATE desktop environment and LightDM as a workaround.

If you require other versions of Windows, RedHat, and Debian based flavors of Linux, please contact Penguin Computing for additional support.

Server Hardware¶

We recommend the following CPU, Memory, and GPU:

Server-Side	Recommended
CPU	Intel Core i5, one core per monitor + 1
Memory	2 GB
GPU	Any

Server Network¶

The server’s bandwidth (BW) requirements are the sum of the bandwidth required by all connected clients.

A client’s bandwidth requirements are the sum of the video bandwidth and the audio bandwidth. Video bandwidth depends on the display resolutions, the selected video encoding, and the number of displays. These bandwidth values can be found in Client Requirements. Note that even though multiple clients may be sharing the same desktop, each client needs its own connection to that screen with its own bandwidth usage.

By default, audio bandwidth is 1.411 Mbps when it is enabled by the end-user. When audio is disabled by the end-user, it consumes no bandwidth.

To calculate the maximum server bandwidth (BW) requirements, use the following equations:

Video BW Per User = Displays per User * BW per Display

Audio BW Per User = 1.411 Mbps

Max Server BW = Users * (Video BW per User + Audio BW per User)

For example, if we want to plan for a single user to have video and audio access to a server that has a single display showing at 1080p with our normal (lossy) encoding:

Video BW Per User = 1 display * 6 Mbps = 6 Mbps

Audio BW Per User = 1.411 Mbps

Max Server BW = 1 user * (6 Mbps + 1.411 Mbps) = 7.411 Mbps

As a second example, if we want to plan for three users to have video and audio access to a server that has dual displays showing at 2K with our normal (lossy) encoding:

Video BW Per User = 2 displays * 12 Mbps = 24 Mbps

Audio BW Per User = 1.411 Mbps

Max Server BW = 3 users * (24 Mbps + 1.411 Mbps) = 76.233 Mbps

Server Screen Resolutions¶

The performance of the remote access is partly dependent on the server’s screen resolution and the client’s ability to process that resolution quickly.

Scyld Cloud Workstation allows system administrators to pick a maximum screen resolution width and height in the config file (by default 1920x1080). If the user attempts to change the screen resolution above this setting, then the video scales down automatically. This can alleviate situations where users set the screen resolution so high that their client machine becomes unusable.

For most users, we recommend our default values. If you’d like to test higher screen resolutions, we recommend doing so with gradual increases.

Warning

Changing screen resolutions has two known issues:

Multiple rapid resolution changes may lead to service instability. Changing the screen resolution more than 5 times over a few seconds may cause the service to restart or quit.

For more information about changing screen resolutions, see Change Screen Resolution.

Server Audio¶

Scyld Cloud Workstation will stream audio from a remote server if it has a functional audio device and proper drivers. In Linux, pulseaudio is required and is already installed by default in CentOS 7+ and Ubuntu 16+.

MacOS users must follow the instructions in Install BlackHole for MacOS Audio to add MacOS Audio Support.

OpenSSL¶

OpenSSL is an open source implementation of the SSL and TLS protocols and must be installed on the server host. Most Linux distributions have this installed by default, but in Windows this is installed by the Scyld Cloud Workstation server-side installer.

SSL Certificate¶

An SSL certificate signed by a trusted certificate authority is used to provide encryption and authentication for a client’s HTTPS connection to the Scyld Cloud Workstation web server. By default, Scyld Cloud Workstation comes with a self-signed SSL certificate and private key that should not be used in secure production environments.

For more information on generating SSL certificates, see Setup.

Client Requirements¶

You can connect to the server using either an HTML5 browser or our native client (Scyld Cloud Workstation Client).

Client Hardware and Network¶

Client-side hardware and network requirements are largely based on the server’s screen resolution and the number of pixels changing on the screen at a given time.

The table below shows CPU and Network requirements when remoting a single full screen movie using our normal video encoder at 24-30 frames per second. Turning on audio streaming will consume an additional 1.411 Mbps of bandwidth.

Normal Video Recommendations¶
Server Resolution	Network (Mbps)	CPU, Native Client	CPU, Chrome
1280 x 720	3	Intel Core i5	Intel Core i5
1920 x 1080	6	Intel Core i5	Intel Core i7-3520M
2560 x 1440	12	Intel Core i7-3520M	Intel Core i7-2600K
3840 x 2160	25	Intel Core i7-2600K	Intel Core i7-5775C

The tables below show recommendations for visually lossless and lossless video encodings, respectively. These options are only accessible with the native client.

Visually Lossless Video Recommendations¶
Server Resolution	Network (Mbps)	CPU, Native Client
1280 x 720	11	Intel Core i7-3520M
1920 x 1080	22	Intel Core i7-3520M
2560 x 1440	32	Intel Core i7-3520M
3840 x 2160	64	Intel Core i7-2600K

Lossless Video Recommendations¶
Server Resolution	Network (Mbps)	CPU, Native Client
1280 x 720	65	Intel Core i7-2600K
1920 x 1080	125	Intel Core i7-2600K
2560 x 1440	200	Intel Core i7-5775C
3840 x 2160	400	Intel Core i7-5775C

Note

The Scyld Cloud Workstation Client is more optimized than the Chrome Browser so it requires lower CPU resources to achieve the same frame rate.

Note

Acceptable network latency is application and workflow dependent. In some cases, 150ms may be acceptable. Performance may degrade if the client is running background applications that consume significant amounts of CPU time, memory, or network bandwidth.

Web Browser Support¶

The following web browsers are supported and listed in order of performance:

Chrome 59+
FireFox 56+
Microsoft Edge Legacy 44.17763.1.0+
Microsoft Edge 79+
Safari 7+

Note

Chrome provides the best performance and is recommended.

Note

FireFox 52.4.0 in CentOS 7 is known to have screen flickering issues. Please update to 60.8 and above.

These browsers by default enable TLS 1.2, WebGL and WebSocket features that are necessary for security and optimal Scyld Cloud Workstation performance. While WebSocket support is a hard requirement, Scyld Cloud Workstation is capable of running without WebGL support at reduced performance levels.

The following links can be used to determine if your browser supports necessary features for an optimal Scyld Cloud Workstation experience:

Browser Feature	Test for Browser Support
Security Protocol TLS 1.2	https://www.ssllabs.com/ssltest/viewMyClient.html
WebGL	https://get.webgl.org/
WebSockets	http://websocketstest.com/

Note

TLS 1.2 is the current standard used to secure HTTPS connections as of the writing of this document.

Scyld Cloud Workstation Client¶

Scyld Cloud Workstation Client is a native client that requires a separate application installation on the client side. It is similar to the web browser, but it includes some additional benefits:

faster frame rates at higher screen resolutions
lossless and visually lossless video support
support for keyboard shortcuts reserved by web browsers (for example: Ctrl + T, Ctrl + N, Ctrl + W)

Scyld Cloud Workstation Client is supported and tested on the following 64-bit operating systems:

CentOS 7
Rocky Linux 8 and 9
Windows 10, 11, and Windows Server 2019
MacOS Catalina 10.15 to MacOS Ventura 13
Ubuntu 20 and 22

Note

OpenGL 2.1 support is required.

Note

New in v11.2: Scyld Cloud Workstation Client can also be launched from URI links such as: scw://<server>

Server-Client Version Compatability¶

Scyld Cloud Workstation and Scyld Cloud Workstation Client versions are compatible if they are from the same compatible range. The current list of compatible version ranges is given below.

v11.0 and later

v9.1 until v11.0

Feature Requirements and Setup¶

Scyld Cloud Workstation features are designed to be ready to use across all platforms that meet the recommended hardware and operating systems listed above. Some of these features include:

Authentication over Active Directory, LDAP, PAM, SCAuth, RHV OAuth2, and more
Secure HTTPS communication
Video playback up to 1440p
Audio
Multi-display support
Text paste
Quality of Service adaptation
US keyboard and mouse support
Collaboration

Some features have additional requirements. These are organized by server-side operating system below:

All Operating Systems
- Enabling 4K Video on all OSes
- Enabling Lossless and Visually Lossless Video on all OSes
CentOS 7
- Enabling USB Forwarding on CentOS 7
Rocky Linux
- Enabling USB Forwarding on Rocky Linux
- Enabling Xorg X server as the default on Rocky Linux
Windows
- Enabling Audio on Windows VMs
MacOS

All Operating Systems¶

Enabling 4K Video on all OSes
Enabling Lossless and Visually Lossless Video on all OSes

Enabling 4K Video on all OSes¶

Set Server.Video.MaxWidth and Server.Video.MaxHeight to -1 in the XML config file.

Connect with the native client instead of a browser for best performance.

Enabling Lossless and Visually Lossless Video on all OSes¶

Connect with the native client instead of a browser.

CentOS 7¶

Enabling USB Forwarding on CentOS 7

Enabling USB Forwarding on CentOS 7¶

USB devices can be forwarded between native clients and remote servers that meet the following requirements:

The server’s license file must have a valid ‘scw-usb’ entitlement. If you do not see this entitlement in your license file, please contact Penguin Computing sales for more information.
The Server-USB module must be installed on the remote server. See Installing Server-USB Module on CentOS 7 for more information on this step.
The Client-USB module must be installed on the client side. See Installing Client-USB Module on the Client for more information on this step.

Rocky Linux¶

Enabling USB Forwarding on Rocky Linux
Enabling Xorg X server as the default on Rocky Linux

Enabling USB Forwarding on Rocky Linux¶

USB devices can be forwarded between native clients and remote servers that meet the following requirements:

The server’s license file must have a valid ‘scw-usb’ entitlement. If you do not see this entitlement in your license file, please contact Penguin Computing sales for more information.
The Server-USB module must be installed on the remote server. See Installing Server-USB Module on Rocky Linux for more information on this step.
The Client-USB module must be installed on the client side. See Installing Client-USB Module on the Client for more information on this step.

Enabling Xorg X server as the default on Rocky Linux¶

XWayland is not currently supported. Please see Installing the Server on Rocky Linux for instructions on enabling Xorg as the default X server.

Windows¶

Enabling Audio on Windows VMs

Enabling Audio on Windows VMs¶

Only if you are running the server on a Windows Virtual Machine: Download and install Screen Capture Recorder 0.12.10.

MacOS¶

Enabling Audio on MacOS
Enabling USB Forwarding on MacOS Big Sur
Re-Enabling USB Forwarding after Updating to MacOS Monterey

Enabling Audio on MacOS¶

Download and install BlackHole 0.2.9. See Install BlackHole for MacOS Audio for more information.
Note: Audio is not supported on MacOS Virtual Machines.

Enabling USB Forwarding on MacOS Big Sur¶

USB Forwarding to Big Sur servers is no longer supported due to a change in Big Sur. Please update to MacOS Monterey or later for USB Forwarding support. NOTE: Big Sur clients can still forward USB devices to other servers.

Re-Enabling USB Forwarding after Updating to MacOS Monterey¶

If you have an existing Scyld Cloud Workstation installation and you’ve updated from Big Sur (or earlier) to Monterey (or later), follow these steps to install ‘VirtualHereUniversal’ and re-enable USB forwarding:

Use a Finder window to open the Applications folder
Right-click on ‘scyld-cloud-workstation’ and select ‘Show Package Contents’
Open ‘Contents’ and then ‘Resources’
Open the VirtualHereUniversal dmg by double-clicking on ‘VirtualHereUniversal.dmg’
Drag the ‘VirtualHereUniversal’ application into the Applications folder
Move the deprecated ‘VirtualHere’ application to the Trash