Bug 57631 - Offline computers can cause large response times of the computer room functionalities.
Summary: Offline computers can cause large response times of the computer room functio...
Status: CLOSED FIXED
Alias: None
Product: UCS@school
Classification: Unclassified
Component: UMC - Computer room
Version: UCS@school 5.0
Hardware: Other Linux
: P5 normal
Target Milestone: UCS@school 5.0 v6-errata
Assignee: Johannes Königer
QA Contact: Jürn Brodersen
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Keywords:
Depends on:
Blocks:
 
Reported: 2024-09-30 12:05 CEST by Johannes Königer
Modified: 2024-10-01 11:43 CEST (History)
1 user (show)

See Also:
What kind of report is it?: Bug Report
What type of bug is this?: 4: Minor Usability: Impairs usability in secondary scenarios
Who will be affected by this bug?: 2: Will only affect a few installed domains
How will those affected feel about the bug?: 2: A Pain – users won’t like this once they notice it
User Pain: 0.091
Enterprise Customer affected?:
School Customer affected?:
ISV affected?:
Waiting Support:
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Bug group (optional): Regression
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Description Johannes Königer univentionstaff 2024-09-30 12:05:44 CEST
Problem: Offline computers can cause large response times of the computer room functionalities.

There are two causes for this:
- When the computer room manager tries to ping an offline computer, it will take around 3 seconds to time out (depending on kernel parameters)
- When the computer room manager tries to set a feature of a computer which is offline, it will take `WebAPI/ConnectionAuthenticationTimeout` (Veyon proxy setting, by default 15) seconds to time out

For example, this can be seen when doing the following:
- On room acquisition (ping causes delay)
- On starting demo mode (auth time out)

This can be solved by:
- The pinging takes always place in a thread, not in request handlers, and a connected property is available for the request handler to get the latest state
- The request handler only sets features if the computer is connected/available
Comment 3 Johannes Königer univentionstaff 2024-09-30 17:40:59 CEST
Connection checks are now done only in the `VeyonComputer` threads.
Features will now only be set if the computer instance is connected.

Successful build
Package: ucs-school-umc-computerroom
Version: 12.0.22
Branch: 5.0-0
Scope: ucs-school-5.0
User: jkoeniger

Successful build
Package: ucs-test-ucsschool
Version: 7.3.193
Branch: 5.0-0
Scope: ucs-school-5.0
User: jkoeniger
Comment 4 Jürn Brodersen univentionstaff 2024-10-01 11:13:01 CEST
Basic functionality testing: All features in the computer room can be used.

* [x] Watching a student works.
* [x] Locking and unlocking a screen works.
* [x] Shutdown works.
* [~] Switching on works. (This cannot be tested at the moment within our infrastructure)
* [x] Restart works
* [x] Logout works.
* [x] Locking and unlocking input devices works.
* [x] Presentation mode works.
* [x] Exam mode start and finish works
* [x] Restarting the Veyon proxy is handled gracefully by the UMC module
Comment 5 Jürn Brodersen univentionstaff 2024-10-01 11:43:30 CEST
Errata updates for UCS@school 5.0 v6 have been released.

https://docs.software-univention.de/ucsschool-changelog/5.0v5/en/changelog.html
https://docs.software-univention.de/ucsschool-changelog/5.0v5/de/changelog.html

If this error occurs again, please clone this bug.