Hey all,
Recently migrated a production site (mixture of Servlets and JSPs)
from Oracle Application Server to Apache/Tomcat. Since then we have
seen numerous HTTP Error 503 - Service unavailable errors at peak
times when site is under load. mod_jk.log has the following error
message(s):
[2184:1952] [error] jk_lb_worker.c (1473): All tomcat instances
failed, no more workers left
I'm looking for help in trying to tweak settings to prevent this, or
confirmation that I've configured the setup correctly.
Many thanks
Rob
Platform:
Windows Server 2003 SP2
Setup:
Two tomcat instances with a single Apache front end, all on the same server
Versions
Tomcat: 6.0.24
Apache: 2.2.16
mod SSL: 2.2.16
Open SSL: 0.9.8
mod_JK:1.2.30
Conf:
httpd.conf:
<IfModule mod_jk.c>
JkWorkersFile conf/workers.properties
JkLogFile logs/mod_jk.log
JkLogLevel error
JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "
JkOptions +ForwardKeySize +ForwardURICompat -ForwardDirectories
JkRequestLogFormat "%w %V %T"
<Location /*/WEB-INF/*>
AllowOverride None
deny from all
</Location>
JkMount /examples balancer
JkMount /examples/* balancer
JkMount /App1/* balancer
JkMount /App2/* balancer
</IfModule>
Workers.properties:
workers.tomcat_home="C:\tomcat1"
workers.java_home="C:\Program Files\Java\jdk1.6.0_18"
ps=\
# Define workers
#worker.list=worker1,worker2
worker.list=balancer
# Set properties for worker worker1 (ajp13)
worker.worker1.type=ajp13
worker.worker1.host=localhost
worker.worker1.port=8009
worker.worker1.lbfactor=1
worker.worker1.cachesize=10
worker.worker1.connection_pool_timeout=300
worker.worker1.socket_keepalive=FALSE
#worker.worker1.recycle_timeout=300
# Set properties for worker worker2 (ajp13)
worker.worker2.type=ajp13
worker.worker2.host=localhost
worker.worker2.port=8019
worker.worker2.lbfactor=1
worker.worker2.cachesize=10
worker.worker2.connection_pool_timeout=300
worker.worker2.socket_keepalive=FALSE
#worker.worker2.recycle_timeout=300
worker.balancer.type=lb
worker.balancer.balance_workers=worker1,worker2
worker.balancer.method=R
worker.balancer.sticky_session=True
Server.xml (same for both tomcat instances apart from jvmRoute):
<?xml version='1.0' encoding='utf-8'?>
<Server port="8005" shutdown="SHUTDOWN">
<Listener className="org.apache.catalina.core.AprLifecycleListener"
SSLEngine="on" />
<Listener className="org.apache.catalina.core.JasperListener" />
<Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener"
/>
<Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" />
<Listener
className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"
/>
<GlobalNamingResources>
<Resource name="UserDatabase" auth="Container"
type="org.apache.catalina.UserDatabase"
description="User database that can be updated and saved"
factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
pathname="conf/tomcat-users.xml" />
</GlobalNamingResources>
<Service name="Catalina">
<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="40000"
redirectPort="8443" />
<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />
<Engine name="Catalina" defaultHost="localhost" jvmRoute="worker1">
<Realm className="org.apache.catalina.realm.UserDatabaseRealm"
resourceName="UserDatabase"/>
<Host name="localhost" appBase="webapps"
unpackWARs="true" autoDeploy="true"
xmlValidation="false" xmlNamespaceAware="false">
</Host>
</Engine>
</Service>
</Server>
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