https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=37087 Bug ID: 37087 Summary: Add support for TCP keepalive to SIP server Change sponsored?: --- Product: Koha Version: Main Hardware: All OS: All Status: NEW Severity: enhancement Priority: P5 - low Component: SIP2 Assignee: koha-bugs@lists.koha-community.org Reporter: dcook@prosentient.com.au QA Contact: testopia@bugs.koha-community.org Some computing platforms like Microsoft Azure (and some corporate firewalls) enforce idle timeouts which silently kill long-running/persistent TCP connections. In the case of Microsoft Azure, this idle timeout occurs after 4 minutes. In production, this has been massively disruptive to circulation operations using self-checkout kiosks that connect to Koha using SIP2. Fortunately, this problem is easily solvable by using TCP keepalives. When TCP keepalives are used, after X seconds a TCP ACK message will be sent from the SIP server to the SIP client, which will then send back a TCP ACK. Nothing happens at the application level. It's just at the lower network level. And this prevents idle timeouts. I'll provide more technical information in code comments. -- I've already successfully implemented this strategy in Azure for managing persistent Elasticsearch TCP connections simply by tweaking the "net.ipv4.tcp_keepalive_time" kernel parameter, which is automatically used by the HTTP::Tiny connection library used by Search::Elasticsearch, since it implements the SO_KEEPALIVE socket option out of the box by default. With the SIP server, we have a lot more control than we do with third-party software, so I'm planning to implement a more fine-grained approach, which won't require any kernel parameter changes. Instead, it will be manageable by application configuration alone. (Note: this is partially because testing in koha-testing-docker would be difficult where it's not easy/possible to tweak kernel parameters.) -- You are receiving this mail because: You are watching all bug changes. You are the assignee for the bug.