#2485: Encourage leak containment by limiting the number of requests a CKAN process serves

nils.toedtmann — Fri, 01 Jun 2012 11:47:09 GMT

CKAN has memory leaks. They can be contained by limiting the time-to-live of a ckan process. An easy way to achieve this is to limit the number of requests a ckan server process can serve before it gets killed and replaced.

One should ...

research ways to limit requests-per-process with the different web servers (see below for a start);
explain these safeguards in the CKAN documentation and encourage users to apply them;
consider the helper script ckan-create-instance to generate Apache configs with WSGIDaemonProcess ... maximum-requests=XY being active instead of commented out. Or at least let it warn the user to use MaxRequestsPerChild;
Investigate current CKAN deployments whether they suffer from mem leaks, and if so contain them.

How to limit requests-per-process

Apache:
- Use WSGIDaemonProcess with maximum-requests=50 or whatever limit is appropriate. We did this sucessfully on datahub.io and the ckan farm
- (This need to be verified) Without WSGIDaemonProcess, MaxRequestsPerChild 50 should achieve the same.
nginx/supervisord: to be researched.

CKAN: Ticket Query

#2485: Encourage leak containment by limiting the number of requests a CKAN process serves