Does anyone have advice for me regarding custom headers in mod_proxy health check? Thank you :-)
On Wed, Aug 7, 2024 at 2:31 PM Aaron Rosenzweig <justrosenzw...@gmail.com> wrote: > We have mod_proxy doing balancing and working great with the exception of > one thing, the health check. I'm talking about the heartbeat interval that > tells mod_proxy if our java app instances are ok. > > I read the docs here: > https://httpd.apache.org/docs/current/mod/mod_proxy_hcheck.html > > I'm pretty sure the issue is that the health check is not picking up the > custom header I need to talk to a WebObjects application (java). I'm > wondering if there is a way to configure it or if it simply isn't possible > and am looking for advice on appending this header. > > When setting up the proxy balancer, I initially had the same problem but > it was quickly solved by adding the following line before the proxy > balancer definition: > RequestHeader append x-webobjects-adaptor-version "mod_proxy" > > What that did was add an arcane header that the java app (NeXT/Apple > WebObjects) instances need to see in order for them to want to respond. > Without it, they will drop the connection. Essentially what I'm doing here > is replacing a special mod_webobjects Apache module with the built-in > mod_proxy. This header is just something WO needs to see to allow > communication. > > But now, when I add health check parameters to the proxy balancer it > thinks the app instances are all dead. It's because, for some reason, the > custom header is not being used for the health check and the connection > immediately drops. To confirm that was true, I modified the java > application to force the header to be set when an incoming java HTTP > request was received. While that did allow communication with health check, > it causes other problems for me so is not a good workaround. > > Does anyone know how to configure the mod_proxy health check to use a > custom header? Or is it not possible currently? Thank you :-) >
