[SOLR-16644] Entropy warning thresholds need to be revisited

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 9.4
• Labels: newdev
• Assignee: Unassigned
• Reporter: Ishan Chattopadhyaya
• Created: 03/Feb/23 08:46
• Updated: 18/Oct/23 13:58
• Resolved: 29/Sep/23 17:32

Description

As per the following, newer kernels (5.15+) have recalibrated the entropy levels from 0-4096 to 0-256. Hence, everything is throwing a warning:

Warning: Available entropy is low. As a result, use of the UUIDField, SSL, or any other features that require
RNG might not work properly. To check for the amount of available entropy, use 'cat /proc/sys/kernel/random/entropy_avail'.

Here's where I found out about this change:
https://askubuntu.com/questions/1427470/entropy-is-stuck-at-256-after-upgrading-to-kernel-5-15-0-47

We might need to intelligently report the low entropy (based on kernel version).

Issue Links

• breaks: SOLR-17039 Entropy calculation fails in Docker due to missing 'bc' cmd
• links to: GitHub Pull Request #1842
• links to: GitHub Pull Request #2000