Mod_jk 和 Tomcat 卡在发送回复

Question

Currently, the server at work is underperforming and the way it's set up is not ideal either. For this reason I'm trying to find a new way to do things that will hopefully help with both, performance and deployment.

The approach I decided for is to have tomcat instances for our webapps (currently there are two, so it'd be an instance per webapp) and use Apache as a "front". I'm not experienced in this, so It's normal I'm having issues here and there, but so far I've manage to get this going.

What I expect is to redirect from mysite.com index page to either mysite.com/service1 or mysite.com/service2. Service1 was setup in out test server at port 8080 and service2 at 8081. I installed Apache2 and mod_jk yesterday and set up apache with the contents of mysite.com. Today I started the configurations, that ended up as follow:

workers.properties

worker.list=s1

worker.s1.type=ajp13
worker.s1.port=8009

#host is localhost by default according to the documentation

jk.load

LoadModule jk_module /usr/lib/apache2/modules/mod_jk.so

JkWorkersFile /etc/apache2/workers.properties

JkLogFile /var/log/apache2/mod_jk.log
JkLogLevel debug
JkMount /service1/* s1

Service1's server.xml connector (The rest is all default)

<Connector protocol="AJP/1.3" port="8009" redirectPort="8443" />

I had more, but because of the errors, I took a step back and tried with only one tomcat for now. I will add the second tomcat and a loadbalancer.

Ok, so what's going on?

I can access the server and the index page of our system with no problem. The problem is when I try to redirect to service1. It just loads without response, but if I try to access service1 directly by port 8080, it works properly (I tired commenting out this connector. No luck).

Looking at server-status, I see the request stuck at w/sending reply, and in mod_jk.log I see that the worker properly matches the request. So while my configurations seem to be right, there is something in between happening. I don't really know if it's something with Apache, Tomcat or Mod_jk. I also tried to follow several guides of how to do this, but all of them got me to 404s. Looking around here and ServerFault didn't shed much light unfortunately so I'm the one asking now.

Am I missing something? Should I just use another approach? I'm very new at this and I'm at loss right now. The configuration and the logs show that nothing is really wrong (at first glance, at least...) so I'm entirely sure if my case scneario is even posible with mod_jk... HOnestly to run it back and try with proxy is very tempting at this point, but if I am, I'd rather know where Im wrong.

Additional info: Running on Ubuntu Server 18.04, lastest apache2 and mod_jk avaliable from apt (as of Apr 14), java 1.8 and Tomcat 8.5.64.

Answer 1

There was a change in Tomcat last year (from version 8.5.51 and version 9.0.31 ), which introduced a secretRequired attribute to the AJP connector with a default of true (cf. documentation ). Hence you can either:

• add a shared secret between the AJP connector and mod_jk

• or add secretRequired="false" to the AJP connector:

   <Connector protocol="AJP/1.3" port="8009" secretRequired="false" redirectPort="8443" />

Remark: AJP is a very old protocol and rarely used. Since your installation is pretty new, you might consider using directly HTTP (cf. this talk ).