Issue Description:

Apache Load balancer failed to connect to tomcat. As a result, users are kicking out of application.

Error Message from Apache mod_jk.log

timeout with waiting reply from tomcat. tomcat is down, stopped or network problems (errno=60).

Error at tomcat at the same time

java.io.IOException: An established connection was aborted by the software in your host machine

Environment:

Apache Web server as Load Balancer, version 2.4
Apache Tomcat 9
JDK 1.8

We have 4 tomcats configured connecting from load balance ( Apache Web server) Tomcat context.xml setting

<Connector port="xxx" protocol="AJP/1.3" redirectPort="8443" connectionTimeout="600000" />

Our workers.properties settings

worker.list=loadbalancer,stat
worker.stat.type=status 

# Set properties for loadbalancer (ajp13 )

worker.loadbalancer.sticky_session=1

# Set properties for worker1 (AppServer1)
worker.worker1.type=ajp13
worker.worker1.host=192.168.1.21
worker.worker1.port=8009
worker.ajp13.socket_keepalive=True
worker.ajp13.connection_pool_timeout=600
worker.worker1.lbfactor=1
worker.worker1.local_worker=0
worker.worker1.sticky_session=0

worker.worker1.reply_timeout=120000
worker.worker1.socket_timeout=150000

All other workers has same settings as worker1

Settings in httpd.conf for Apache

<IfModule prefork.c>
StartServers       16 
MinSpareServers   10 
MaxSpareServers   40
ServerLimit      512 
MaxClients       512
MaxRequestsPerChild  4000
</IfModule>