Friday, November 29, 2013

Post perihelion, ISON is still alive

I know that everyone things the ISON comet is dead, but I think it is still alive even post perihelion.

Check out these images taken from: http://soho.esac.esa.int/data/realtime/c2/1024/latest.html










Tuesday, August 14, 2012

Monitoring Tomcat 7 on RHEL / AWS using JConsole/VisualVM over SSH

Problem:

  • you have a Tomcat running on Red Hat Enterprise Linux (RHEL) on Amazon Web Services (AWS) and you want to monitor it or investigate some issue via JMX.
  • you want to use JConsole and/or VisualVM and you want to do it at least partially secure
  • you already have ssh access to the AWS Linux machine running your Tomcat.
I lost a couple of hours to find this out and I wanted to share it with everyone.

The solution implies 3 steps (excluding Tomcat restart) on server side and 3 steps on client side:

Server side:
  1. download http://archive.apache.org/dist/tomcat/tomcat-7/v7.0.23/bin/extras/catalina-jmx-remote.jar and put it in tomcat/lib
  2. add following listener to server.xml: 

    <listener classname="org.apache.catalina.mbeans.JmxRemoteLifecycleListener"
        rmiregistryportplatform="10001"
        rmiserverportplatform="10002"
        uselocalports="true" />


  3. add following settings in tomcat/bin/setenv.sh:

    CATALINA_OPTS="-Dcom.sun.management.jmxremote
        -Dcom.sun.management.jmxremote.ssl=false
        -Dcom.sun.management.jmxremote.authenticate=false"
        $CATALINA_OPTS


>>> Restart tomcat

Client side:
  1. download http://archive.apache.org/dist/tomcat/tomcat-7/v7.0.23/bin/extras/catalina-jmx-remote.jar and put it in JDK/JRE/lib/ext (same file as downloaded at Server step 1)
  2. start ssh tunnel with:

        ssh user@aws-host -L10001:127.0.0.1:10001 -L10002:127.0.0.1:10002

  3. Start JConsole and enter the following remote service URL:

        service:jmx:rmi://127.0.0.1:10002/jndi/rmi://127.0.0.1:10001/jmxrmi
>>> You have JConsole connected over SSH to your tomcat running on AWS.

Of course, if you want to configure plain authentication or even SSL for even greater security, all you have to do is add the corresponding standard JMX settings on the server side, and client side.

Happy monitoring.

Monday, October 10, 2011

'Pumped Up Kicks' by Foster The People (3 + 1 versions)

Here is one song 'Pumped Up Kicks' by Foster The People and three versions:
#1 Original:


#2 Cover:

#3 DubStep remix and crazy moves:
#4 and the unplugged version of course




Tuesday, June 14, 2011

windows 7 sp1 vs genuine check vs WAT (Windows Activation Technologies)

Problem:
You just applied the latest updates from  MS and now you have Windows 7 with Service Pack 1 but your system is no longer 'genuine' and it fails this check. This may happen if you had a really 'genuine' installation or an 'adjusted' one and then you bought your legal copy.

Solution:
step 1: Uninstall "Update for Microsoft Windows (KB971033) (Control Panel->Programs and Features->"View Installed Updates"). This will uninstall WAT but you still have the WGA stuff in your system so you can re-activate your Windows safely (using your legit, previous installation, or newly acquired license)..
step 2: Restart system
step 3: Activate Windows
step 4: Start Windows Update and install all the critical and needed updates as usual (this will re-install WAT - KB971033). Windows will remain Activated.

This worked on a system I use and may not work on yours. The fact that it worked at least once, made me share this.

Good luck.