Red Hat Bugzilla – Bug 971610
Scaled app head gear hits nofile ulimits...
Last modified: 2015-05-14 19:21:07 EDT
Description of problem:
We found while trying to scale the summit presentation that the head haproxy gear is hitting the nofile ulimit (which is set to 4096 by default).
We added these lines to this file /etc/security/limits.d/84-51ae792fe0b8cdddf2000177.conf:
51ae792fe0b8cdddf2000177 soft nofile 16384
51ae792fe0b8cdddf2000177 hard nofile 16384
And that helped out tremendously.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. create a scaled app with at least 4 backed gears (5 gears total)
2. pound on the app
3. watch netstat -nap on the head gear's node and notice that the connections are being limited to the head gear.
4. bump the limit
5. notice that the head gear can scale better
Slow head gear because of file descriptors are being limited. This makes the backend gears not be able to contribute enough.
Only the hard limit needs to be increased. Haproxy will request an increase up to the hard limit based on the number of connections its configured for.
Release ticket updated.
Pull request for devenv:
1. create a scaled app.
2. log into your gear and edit haproxy/conf/haproxy.cfg
3. change the value of "maxconn" to 8000
4. restart your app
5. log back into the gear and inspect haproxy/logs/haproxy.log
No errors like "FD limit (1024) too low for maxconn=8000..."
Commit pushed to master at https://github.com/openshift/li
Bug 971610 - Increase the hard limit on file descriptors to 16k
Checked on devenv_3360,
Step as comment#1,
After restart app, no such errors in haproxy.log
Move bug to verified.