I reverted the ports back to the way they were and the SEVERE error goes away.
I also get some lateral caching going on but its very erratic. In my test,
server A is the only instance that writes to the cache.
Scenario 1 - success
- Start server A, B, C
- Access server B
- Access server C
- Access server A to put value in cache
- Server B and C display the value put by A
Scenaio 2 - fail
- Start server A, B, C
- Access server A to put value in cache
- console displays connection exceptions
- Access server B
- Access server C
- Access server A to remove then put value to cache
- Server B and C displays null
Scenaio 3 - fail
- Start server A, B, C
- Access server B
- Access server C
- Access server A to put value in cache
- Server B and C display the value put by A
- Restart server B
- Access server A to put value in cache
- server A displays exception about connection to B
- Server B displays null
Just wondering if perhaps I have some fundamental misunderstanding about how
the lateral caching should be working. I would assume that values written to
any of the local caches would be pushed into the other two. When a instance
restarts it would rejoin the group etc. Am I missing something?
Thanks
> On Jul 27, 2017, at 12:00 PM, Mat Jaggard <[email protected]> wrote:
>
> Have you tested to see if any of the the TcpListenerPorts are open on your
> server? If you're on Linux you can try `netstat -l`
>
> On Thu, 27 Jul 2017 at 15:52 Russell Sherk <[email protected]>
> wrote:
>
>> Hi Greg,
>>
>> Don't know much about JCS. Just general Tomcat stuff.
>>
>> See if this helps:
>> http://sentineltechsupport.gemalto.com/2013/10/java-runtime-log-error-could-not-instantiate-auxfactory-named-dc/
>>
>> If not, maybe someone else in the list can help.
>>
>> Cheers,
>>
>> --Russ
>>
>> -----Original Message-----
>> From: Greg Parker [mailto:[email protected]]
>> Sent: July-27-17 10:07 AM
>> To: Commons Users List <[email protected]>
>> Subject: Re: JCS LateralTCPCacheFactory
>>
>> Thanks Russ,
>>
>> So the TcpListenerPort value should match the tomcat port? So if tomcat
>> is running on port 6080 the cache.ccf on that instance should set
>> TcpListenerPort=6080? I set things up this way and nothing seems to
>> complain; however, now I get a SEVERE error on first access and caching is
>> not working across the three instances. Here are the details:
>>
>> SEVERE [ajp-nio-6009-exec-1]
>> org.apache.commons.jcs.engine.control.CompositeCacheConfigurator.parseAuxiliary
>> Could not instantiate auxiliary cache named "hello".
>>
>> jcs.region.hello=LTCP
>>
>> jcs.region.hello.cacheattributes=org.apache.commons.jcs.engine.CompositeCacheAttributes
>> jcs.region.hello.cacheattributes.MaxObjects=1000
>>
>> jcs.region.hello.cacheattributes.MemoryCacheName=org.apache.commons.jcs.engine.memory.lru.LRUMemoryCache
>> jcs.region.hello.cacheattributes.UseMemoryShrinker=true
>> jcs.region.hello.cacheattributes.MaxMemoryIdleTimeSeconds=3600
>> jcs.region.hello.cacheattributes.ShrinkerIntervalSeconds=60
>> jcs.region.hello.cacheattributes.MaxSpoolPerRun=500
>>
>> jcs.region.hello.elementattributes=org.apache.commons.jcs.engine.ElementAttributes
>> jcs.region.hello.elementattributes.IsEternal=false
>>
>>
>>
>> jcs.auxiliary.LTCP=org.apache.commons.jcs.auxiliary.lateral.socket.tcp.LateralTCPCacheFactory
>>
>> jcs.auxiliary.LTCP.attributes=org.apache.commons.jcs.auxiliary.lateral.socket.tcp.TCPLateralCacheAttributes
>> jcs.auxiliary.LTCP.attributes.UdpDiscoveryEnabled=false
>> jcs.auxiliary.LTCP.attributes.AllowGet=true
>> jcs.auxiliary.LTCP.attributes.Receive=true
>> jcs.auxiliary.LTCP.attributes.TcpListenerPort=6080
>> jcs.auxiliary.LTCP.attributes.TcpServers=localhost:7080,localhost:8080
>>
>> Thanks
>>
>>
>>
>>> On Jul 27, 2017, at 8:57 AM, Russell Sherk <[email protected]>
>> wrote:
>>>
>>> Hi Greg,
>>>
>>> Tomcat uses two consecutive ports. The one you specify and the next one
>> for shutdown. E.g if you specify 8020, the shutdown port by default is 8021.
>>>
>>> Try spacing your ports out: 8020, 8022, 8024.
>>>
>>> --Russ
>>>
>>>
>>> On Jul 26, 2017 10:11 PM, Greg Parker <[email protected]> wrote:
>>> I'm trying to get a sample cluster of tomcat servers (server A, B and C)
>> to use a distributed cache. The ‘hello’ cache is configured on each server
>> with a different TcpListenerPort on each server (8020, 8021, 8022) like
>> this:
>>>
>>> jcs.region.hello=LTCP
>>> …
>>>
>>> jcs.auxiliary.LTCP=org.apache.commons.jcs.auxiliary.lateral.socket.tcp
>>> .LateralTCPCacheFactory
>>> jcs.auxiliary.LTCP.attributes=org.apache.commons.jcs.auxiliary.lateral
>>> .socket.tcp.TCPLateralCacheAttributes
>>> jcs.auxiliary.LTCP.attributes.UdpDiscoveryEnabled=false
>>> jcs.auxiliary.LTCP.attributes.AllowGet=true
>>> jcs.auxiliary.LTCP.attributes.Receive=true
>>> jcs.auxiliary.LTCP.attributes.TcpListenerPort=8020
>>> jcs.auxiliary.LTCP.attributes.TcpServers=localhost:8020,localhost:8021
>>> ,localhost:8022
>>>
>>>
>>> Server A has a page that sets a value in the cache like this:
>>>
>>> cache = JCS.getInstance("hello");
>>> cache.put(“message", “Hello from server A");
>>>
>>>
>>> Server B, and C try to get the value without setting it:
>>>
>>> cache = JCS.getInstance("hello");
>>> add(new Label("message", "Server B -> cache has : " +
>>> cache.get(“message");));
>>>
>>>
>>> The first time I access the page on server A I get an exception -
>> "Cannot connect to localhost:8021”. If I access the page on each server
>> then things appear to start communicating; however, the “message” entry
>> from the “hello” region is set on server A and null on B and C. Sometimes
>> I see the value on server C displayed properly but never on server B.
>>>
>>> With a configuration like this should I expect to see values immediately
>> distributed to the other servers?
>>>
>>> Is there a way I should be bootstrapping the cache when the server
>> starts? If the servers need to communicate with one another it would seem
>> to me that they need to be listening long before the first time the server
>> tries to access the cache.
>>>
>>> For performance I would like to use the cache to store serialized XML
>> data instead of storing it in the session or a database. The data remains
>> in the cache while the user transforms it through several request cycles.
>> So during a request cycle the XML data would be retrieved, transformed, and
>> stored back in the cache. In a clustered environment I need the XML data
>> available on every server in the cluster. Is this an acceptable use case
>> for JCS?
>>>
>>> Thanks
>>>
>>>
>>>
>>>
>>
>>
