Important Instructions: CKS

The Linux Foundation has a zero tolerance rule in regard to anyone who engages in Exam Misconduct. Our exams are administered under strict supervision and exam rules, and are carefully monitored during the live exam, and upon completion of the exam, the session recording is reviewed.

Any suspicious activity will be addressed and will result in consequences including, but not limited to, revoking a passing score and restricting an individual’s ability to take an exam again.

Exam Details

  • The exams are delivered online and consist of performance-based tasks (problems) to be solved on the command line running Linux.

  • The exams consist of 15-20 performance-based tasks.

  • Candidates have 2 hours to complete the CKS exam.

  • The exam is proctored remotely via streaming audio, video, and screen sharing feeds.

  • Results will be emailed 24 hours from the time that the exam is completed.

System Requirements to take the exam

IMPORTANT! Changes to Operating System Support

Beginning October 14, 2025, PSI – our exam proctoring partner - will no longer support Windows 10 or MacOS Ventura (13.x) for ANY online proctored exams

Click here to learn more

Candidates should run the PSI Online Proctoring System Check to verify that their machine meets the technical requirements for taking a proctored exam.

The online proctored exam is taken on PSI's proctoring platform "Bridge", using the PSI Secure Browser (a web browser created to guarantee a secure exam delivery over a virtual connection).

PSI Secure Browser Download is made available to candidates at Exam Launch Time.

Candidates should review the Bridge FAQ Information, published by PSI, to prepare for the Secure Browser installation and be aware of how to resolve issues with the Installation/download or launch of their exam:

PSI Secure Browser FAQ (General) PSI Secure Browser - Linux OS Troubleshooting

Candidates must provide their own computer with:

  • Supported OS: Please review the System Requirements, published by PSI, in particular the supported Operating System Information.

  • All browsers are supported, however PSI highly recommends using the latest version of Google Chrome for the best exam scheduling experience, and because the secure browser is Chrome-based and will give a more accurate experience.

  • Reliable internet access

    • Ensure others on the same internet connection are not performing activities that use excessive bandwidth (i.e. holding conference calls, streaming content, gaming, etc.)

    • A wired connection is often more stable and robust than a wireless connection

    • Turn off bandwidth-intensive services (e.g. file sync, dropbox, BitTorrent)

    • HTTPS connectivity to AWS S3 endpoints like https://*.s3.amazonaws.com/* is required, make sure your network environment is not blocking those requests (e.g. Firewall rules, HTTP Proxy, etc)

  • One active monitor (either built in or external) (NOTE: Dual Monitors are NOT supported). The Linux Foundation recommends a screen size of 15” or higher to support the ExamUI. The Linux Foundation recommends a screen resolution of 1080p.

  • Microphone

  • Please check to make sure it is working before you start your exam session.

  • Webcam

    • Ensure the webcam is capable of being moved as you will have to pan your surroundings to check for potential violations of exam policy.

    • If you will be testing from an employer-provide ISP or will use an employer provided machine, please ensure that streaming will be allowed using WebRTC.

    Candidates are not allowed to have other applications or browser windows running except the one on which the Exam is being shown.

    Please review the PSI Bridge Platform: System Requirements to ensure your machine will meet the requirements of our online proctor.

Important Information to Consider:

  • Please disable firewalls or use a computer without a corporate firewall. Firewalls may interfere with installing the secure browser needed to take the test.

  • You should use a computer on which you have the privileges needed to install applications AND end system process' and services.

  • You cannot take an exam using a virtual machine even though the compatibility check may not display any issues

  • If possible, stop any antivirus software from running, and antivirus scanning during the exam time.

  • If you are using a laptop, make sure that it's plugged into a power socket, so that the battery does not run out during the exam.

Acceptable Testing Location

Below are the expectations for an acceptable testing location::

  • Clutter-free work area

    • No objects such as paper, writing implements, electronic devices, or other objects on top of surface

    • No objects such as paper, trash bins, or other objects below the testing surface

  • Clear walls

    • No paper/print outs hanging on walls

    • Paintings and other wall décor is acceptable

    • Candidates will be asked to remove non-décor items prior to the exam being released

  • Lighting

    • Space must be well lit so that proctor is able to see candidate’s face, hands, and surrounding work area

    • No bright lights or windows behind the examinee

  • Other

    • Candidate must remain within the camera frame during the examination

    • Space must be private where there is no excessive noise. Public spaces such as coffee shops, stores, open office environments, etc. are not allowed.

Please see the Candidate Handbook for additional information covering policies, procedures and rules during the exam

Taking the Exam

We recommend that candidates review the Take Exam section of our Candidate handbook, to become familiar with the PSI Secure Browser Download and Installation steps, and the candidate's Self Check-In Process.

ID Requirements to take the Exam

Candidates need to provide identification (ID) that meets the requirements outlined below:

  • All IDs must be a valid (unexpired) Government-issued original, physical document (not photocopied or electronic)

  • IDs must include the candidate's name, photo, and signature*

    • *Government-issued biometric IDs that do not contain signature will be accepted

  • The first and last name on the ID must exactly match the verified name entered on your exam checklist

  • Acceptable forms of ID:

    • International travel passport

    • Government-issued driver’s license/permit

    • Government-Issued local language ID (with photo and signature)

    • National identity card State or province-issued identity card

    • Alien registration card (green card or permanent resident/visa)

    • 住民基本台帳 (Basic Resident Register with photo) or マイナンバーカード(My Number Card)

  • Minors, between the age of 16-18, are permitted to take an online proctored exam with PSI, provided they complete the following requirements:

    • A Parent/Guardian must complete the Parental Release for Testing of Minors form, and submit it to trainingsupport.linuxfoundation.org, at least 2 weeks prior to the scheduled date of the exam

    • At check in, the minor candidate must present a valid student ID as a form of identification

    • During the PSI check-in process, the candidate's guardian must also present a valid ID and must provide verbal consent during the PSI check-in process.

Sanctioned Countries

Exams may be administered to citizens of a sanctioned country listed below PROVIDED the citizens are tested OUTSIDE the sanctioned country and their exam registration and current ID show an address OUTSIDE the sanctioned country.

  • Cuba

  • Iran

  • Syria

  • North Korea

  • Crimea Region of Ukraine

Resources allowed during exam

Please review the Resources Allowed information published here: CKS Resources Allowed

Exam Technical Instructions

  1. Root privileges can be obtained by running 'sudo −i'.

  2. Rebooting of your server IS permitted at any time.

  3. Do not stop or tamper with the certerminal process as this will END YOUR EXAM SESSION.

  4. Do not block incoming ports 8080/tcp, 4505/tcp and 4506/tcp. This includes firewall rules that are found within the distribution's default firewall configuration files as well as interactive firewall commands.

  5. Use Ctrl+Alt+W instead of Ctrl+W.

    5.1 Ctrl+W is a keyboard shortcut that will close the current tab in Google Chrome.

  6. The Terminal (Terminal Emulator Application) is a Linux Terminal, to copy & paste within the Linux Terminal you need to use LINUX keyboard shortcuts: Copy = Ctrl+Shift+C Paste = Ctrl+Shift+V (Or use the right-click context menu and select Copy or Paste)

  7. In other applications on the Remote Desktop (which is on a Linux Desktop), you'll want to use: Copy = Ctrl+C

    Paste = Ctrl+V

  8. Some keys on international keyboards may not work as expected on the remote desktop. An on-screen virtual keyboard is provided for any special characters that may be needed. To access the on-screen keyboard, double-click the "Virtual Keyboard" icon on the desktop.

  9. For security reasons, the INSERT key is prohibited within the Remote Desktop. Candidates can Type i to switch into insert mode so that you can start editing the file. Once you're done, press the escape key Esc to get out of insert mode and back to command mode.

  10. Installation of services and applications included in this exam may require modification of system security policies to successfully complete.

CKS Environment

  • Each task on this exam must be completed on a designated host.

  • An infobox at the start of each task provides you with the host name.

  • hosts can be reached via ssh, using a command such as the following: ssh <nodename>

  • You must return to the base node (with hostname base) after completing each task.

    • Nested ssh is not supported

  • You can assume elevated privileges on any node by issuing the following command: sudo -i

  • You can also use sudo to execute commands with elevated privileges at any time

  • For your convenience, all SSH hosts have the following additional command-line tools pre-installed and pre-configured:

    • kubectl with kalias and Bash autocompletion

    • yq for YAML processing

    • curl and wget for testing web services

    • man and man pages for further documentation

    Warning: The base system (with hostname base) does not have any of the above tools pre-installed as all tasks on this exam must be completed on a designated SSH host

  • The CKS environment is currently running Kubernetes v1.33.

Adjusting Font and Windows in the ExamUI

  • The “+” or “-” buttons (zoom in / zoom out) on the PSI Secure Browser Toolbar, can be used to increase or decrease the font size presented in the Remote Desktop.

  • The Firefox browser window can be maximized or minimized by double-clicking within the browser header or use the maximize or minimize buttons located in the top right corner of the browser header. If the top right corner of the browser window is off-screen, you can drag the browser window to bring the top right corner into view).

  • The Content Panel (the panel on the left-hand side that displays the exam items) can be resized by dragging the border that separates the content panel from the remote desktop.

  • Use Ctrl+F in the Firefox Browser to activate the "Find in Page" feature. A Find bar will appear at the bottom of the window. (Please be sure to resize the Firefox browser so that you can see the full browser window before using the “Find” feature.)

  • You can maximize the PSI Secure Browser to fit your full screen. You can also use the toggle to the right of your video thumbnail in the Secure Browser tool bar to shrink the toolbar. This will allow more real estate for the display of the ExamUI.

Additional Resources

If you need additional help, please login with your LF Account to https://trainingsupport.linuxfoundation.org and use the search bar to find an answer to your question, or select your request type from the categories provided.

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