Update splaylimit during daemon run

[ImpBY]

This issue was originally filed due to a regression after merging #9345 and released in 8.7.0/7.31.0. The change was reverted in #9415 and released in 8.8.1 and 7.32.1. Since this issue contains a possible fix for the regression, we're repurposing this ticket for the original issue described in PUP-11728.

Describe the Bug

splay is recalculated even if the splay_limit has not changed
https://puppetcommunity.slack.com/archives/C0W298S9G/p1721059192632569

Expected Behavior

this leads to the fact that the probability of the first launch of the puppet increases over time.
upon reaching 1/3 of the time from the splay_limit it becomes almost 100%.
as a result the agent will perform the first run within 1/3 of the splay_limit. by default it is 10 min (splay_limit 30 min)

Steps to Reproduce

Steps to reproduce the behavior:

1. add code to lib/puppet/scheduler/splay_job.rb

    def ready?(time)
     def ready?(time)
+      File.open("/tmp/splay", "a+") do |f|
+        f.write("splay: #{@splay}\n")
+        f.close
+      end
      if last_run
        super
      else
        start_time + splay <= time
      end
    end

3. watch realtime changes of splay

# systemctl restart puppet
# tail -f /tmp/splay | awk -e '{ print strftime("%Y-%m-%d_%H:%M:%S",systime()) "\t" $0}'
2024-07-16_10:48:40	splay: 532
2024-07-16_10:48:44	splay: 532
2024-07-16_10:48:44	splay: 532
2024-07-16_10:48:49	splay: 532
2024-07-16_10:48:49	splay: 532
2024-07-16_10:48:53	splay: 1065
2024-07-16_10:48:53	splay: 1065
2024-07-16_10:48:54	splay: 1065
2024-07-16_10:48:54	splay: 1065
2024-07-16_10:48:59	splay: 1065
2024-07-16_10:48:59	splay: 1065
2024-07-16_10:49:04	splay: 1065
2024-07-16_10:49:04	splay: 1065
2024-07-16_10:49:08	splay: 847
2024-07-16_10:49:08	splay: 847
2024-07-16_10:49:09	splay: 847
2024-07-16_10:49:09	splay: 847
^C

Environment

• Version 7.31.0
• Platform Oracle Linux Server 9.4 (5.15.0-207.156.6.el9uek.x86_64)

Additional Context

suggested patch:

diff --git lib/puppet/scheduler/splay_job.rb lib/puppet/scheduler/splay_job.rb
index b44e08bad6..d2a5643324 100644
--- lib/puppet/scheduler/splay_job.rb
+++ lib/puppet/scheduler/splay_job.rb
@@ -1,6 +1,7 @@
 module Puppet::Scheduler
   class SplayJob < Job
     attr_reader :splay
+    attr_reader :splay_limit_previous

     def initialize(run_interval, splay_limit, &block)
       @splay = calculate_splay(splay_limit)
@@ -29,7 +34,10 @@ module Puppet::Scheduler
     # @return @splay [Integer] a random integer less than or equal to the splay limit that represents the seconds to
     # delay before next agent run.
     def splay_limit=(splay_limit)
-      @splay = calculate_splay(splay_limit)
+      if @splay_limit_previous != splay_limit
+        @splay_limit_previous = splay_limit
+        @splay = calculate_splay(splay_limit)
+      end
     end

[ImpBY]

jruby consumption before and after patch

~1200 agents

server params

# (optional) maximum number of JRuby instances to allow
max-active-instances: 32
max-queued-requests: 64
max-retry-delay: 120 ## seconds before retry

agents params

splay = true
splaylimit = 30m
runinterval = 30m

[sharewax]

issue has been added by this pull request #9345

[sharewax]

how it looks like before/after and downgrade.

[github-actions]

Migrated issue to PUP-12061