On Tue, Oct 11, 2016 at 12:55:13PM -0400, Alex Hall wrote: > Hello list, > This may be off-topic, but I'm serving RT with Nginx and FCGI. Randomly, it > seems, the FCGI server is failing. Nginx works, but users see "error 502: > bad gateway". I see the same in the logs, with connect() failing. All I > have to do is run the spawn-fcgi command to get things back. > > Why this is happening, with some frequency, is the question. My Nginx, RT, > and system logs all show nothing, and to my knowledge, there are no FCGI > logs at all. The first error for today in Nginx is when a client failed to > connect after the server went down; there's nothing that says what the > actual problem was. This happened Saturday, then again today. > > The server has the latest updates for Debian 8.6, and has 4GB of ram. It's > serving a few dozen users at most, so the load can't be the problem. I'm > using Nginx 1.6.2 with four workers and 768 threads per worker. Users see > nothing unusual before this happens, just a 502 instead of the page they > expected. > > If anyone else is using Nginx and has ever seen this, I'd love some input. > As this could be considered off topic, feel free to respond directly to > [email protected]. If I need to provide more details, please let me know. > Thank you. > > -- > Alex Hall > Automatic Distributors, IT department > [email protected]
Hi Alex, You will get the 502 error when there are no more RT backends running. I tracked down verious errors in the RT logs that resulted in a backend exits. Most were of the 'cannot believe I did that type' by people setting up the system, i.e. not really fixable with a distributed management environment. We ended up using 'multiwatch' in RHEL6 and systemd in RHEL7 to keep an appropriate number of backends always available. Regards, Ken --------- RT 4.4 and RTIR training sessions, and a new workshop day! https://bestpractical.com/training * Boston - October 24-26 * Los Angeles - Q1 2017
