Soft Limits and Hard Limits in HortonWorks - hadoop-yarn

I am trying to figure out how to configure soft limits and hard limits for the memory subsystem (Cgroups) in Hortonworks. I was successful in configuring it in Cloudera. But, I haven't found anything as such in Horton Works.
Can anyone let me know, is there a way to configure at all, as I couldn't find anything related to this in any of the Hortonworks documentation?
If yes, How?
Thank you.

Related

RabbitMQ configuration for Wildfly

Does anyone successfully replace HornetQ by RabbitMQ in Wildfly 8?
I'm trying to use our enterprise messaging system and extract the logic of messaging from our base app server to separate the concern between messaging and our core product.
I looked on the web and did not find anything useful as how to change the standalone.xml
Any help, even if the answer is - it is not possible - would be great.
Thank you
My bounty is about to expire and I don't see help until now. So, I am answering as per my experience.
From question:
Any help, even if the answer is - it is not possible - would be great.
Don't know, but we don't need to do that. I have found a work around for that.
Answer is RUN RABBITMQ's OWN SERVER
I followed this link to install it on ubuntu server. Then I read these awesome and simple tutorials. Those six tutorials were great base to start with.
I am now integrating the project with my Java EE project which runs on Wildfly 9 server.
Best of luck to anyone who ends up here. Any constructive edits and answers are welcomed.

Which AMQPSpout are you using?

I would like to consume messages from the RabbitMQ using a an AMQP Spout.
Can you recommend me some good one (meaning tested also on the production)?
I found this spout https://github.com/ppat/storm-rabbitmq suitable for my project. I didn't tested yet in production, but it behaves well in the development phase.
I hope that this answer will help others.
Good luck.
Florin

Disable "ping" response in Apache

I saw that many sites don't respond at "ping call"; I read that is possible disable this function in Server Apache.
My questions are very easy:
- Is it a good choose? If yes, why?
Thanks
this has nothing to do with the apache software. The network service is answering the ICMP-Protocol, which means the PING-command. This happens on the operation systems level.
There are tutorials how to do this on Linux. (e.g. http://www.tech-recipes.com/rx/40/).
Also there are tutorials how to do this on Windows (e.g. http://technet.microsoft.com/en-us/library/cc786463(v=ws.10).aspx)
There are lots of goals to disable it. To pronounce an example, there could be a lower threat of flooding.

Apache Tomcat 6.0.35 is taking 100% CPU in prodcution

I have been using apache-tomcat-6.0.35 in production environment. Our application is hosted on Amazon EC2 using Small Instance. The problem we are facing is that the apache tomcat is using 100% CPU. We have verified it by running htop and it shows multiple threads of tomcat running.
Out application has been developed in Grails 2.0.1.
We are puzzled that why it is happening? Can any body suggest any solutions?
Thanks
Probable Cause
Most likely this has been caused by the recent Leap Second and its impact on quite some unaware/unprepared IT systems, including parts of Linux, MySQL, Java and indeed Tomcat - see the Wired article about the ‘Leap Second’ Bug Wreaks Havoc Across Web for the whole story:
[...], saying it experienced the leap bug problem with the
Java-happy Tomcat web servers it uses to serve up its site. “Our web
servers running tomcat came close to zero response (we were able to
handle some requests),” read an e-mail from a site spokesman. “We were
able to connect to servers in order to reset them. Only rebooting the
servers cleared up the issue.” [emphasis mine]
Workaround / Fix
Accordingly, the solution usually boils down to turning it off and on again, i.e. restarting the server in question, though you might be able to avoid this by simply setting the date, as suggested e.g. in the context of:
Linux/Tomcat, see July 1 2012 Linux problems? High CPU/Load? Probably caused by the Leap Second!:
Apparently, simply forcing a reset of the date is enough to fix the
problem:
date -s "`date`"
MySQL, see MySQL and the Leap Second, High CPU and the Fix (also linked from the comments on wwwhizz' answer to MySQL high CPU usage, where you'll find two specific variations how to do this depending on your OS):
The fix is quite simple – simply set the date. Alternatively, you can
restart the machine, which also works. Restarting MySQL (or Java, or
whatever) does NOT fix the problem.
Background / Proposed Solutions
Please note that while the underlying issue is utterly tricky, it is all but unknown in principle, hence there have been prominent posts/users warning about and explaining this and offering suggestions on how to deal with it in principle, in particular:
An humble attempt to work around the leap second by Marco Marongiu
Time, technology and leaping seconds by Christopher Pascoe
We can't say anything for sure with the information provided. For performance issue, I would recommend a profiler, especially JProfiler, to investigate the cause of this problem. By this way you will be able to locate where the problem is.
This program has a trial license, I think that's enough for a quick look.
UPDATE: after carefully read your question, I see that you have many tomcat instance running for a website? It means that the previous tomcat instances failed to stop; they still run and hog up all the resources. This is possible. You must kill all the old tomcat process before trying to start a new one.
You can kill the processes by hand by "kill -9 " if you are on Linux, before trying to start the server again.

Does Alfresco 3.4e CE support clustering?

I have just a simple question to answer !
Does Alfresco 3.4e Community Edition support clustering ?
If yes, then what are the supported clustering methods (e.g is JGroups supported?) ?
Regards,
It will work with Community, yes. There are a few little bits in Enterprise that'll make the setup and monitoring easier, which coupled with the support you get may mean you'd be better off going to Enterprise if you can.
You should probably start with this presentation to get you through the basics of Alfresco clustering. Once you've understood that, you likely want to read the Alfresco documentation on Setting up high availability systems which covers the concepts, initial cluster config, setting up JGroups etc.
You may also find it useful to read this guide on the Alfresco Wiki for instructions on setting it up, including how to configure JGroups as part of that process, if you haven't already.