Inventor's Paradox

Background Sometimes I need to run a long-running background process in the server, and I need to know when does the CPU usage returns to (almost) 0, indicating the process finished. I know there are other options, like sending myself an email when the process finished, but currently I am satisfied with monitoring the CPU usage. The old way I have an android cellphone, which allows me to : Launch ConnectBot, type ssh username and password connect to the server type top watch the top result The new way Because I am more familiar with PHP than with anything else right now (ok, there are times I am more familiar with C Sharp, but it is another story), I  do a quick google search for 'php cpu usage' and found  http://stackoverflow.com/questions/13131003/get-cpu-percent-usage-in-php . Using stix's solution I created this simple JSON web service using PHP : For displaying the CPU as a graph, another google search pointed me to Flot, a javascript l...

This post describes steps that can be taken for sysadmins to peek inside an ActiveMQ server. We assume root capability, otherwise we need a user which has access to ActiveMQ configuration files. Step 1. Determine running ActiveMQ process ps auxw | grep activemq We got a java process running ActiveMQ : [root@broker ~]# ps auxw | grep activemq activemq  1236  0.1  0.0  19124   696 ?        Sl   07:00   0:02 /usr/lib/activemq/linux/wrapper /etc/activemq/wrapper.conf wrapper.syslog.ident=ActiveMQ wrapper.pidfile=/var/run/activemq//ActiveMQ.pid wrapper.daemonize=TRUE wrapper.lockfile=/var/lock/subsys/ActiveMQ activemq  1243  3.2 12.2 2016568 125264 ?      Sl   07:00   1:06 java -Dactivemq.home=/usr/share/activemq -Dactivemq.base=/usr/share/activemq -Djavax.net.ssl.keyStorePassword=password -Djavax.net.ssl.trustStorePassword=password -Djavax.net.ssl.keyStore=/usr/share/activemq/conf/broker.ks...

All Cloud Foundry components communicates with each other using NATS publish-subscribe mechanism. Lets see in detail what is NATS like. Cloud Foundry Router as NATS client During startup of Cloud Foundry Router ( router.rb ), there is a call to start NATS client below : NATS . start ( :uri => config [ 'mbus' ] ) It means that NATS client will be started with the uri parameter obtained from configuration parameter 'mbus'.  config_path = ENV [ "CLOUD_FOUNDRY_CONFIG_PATH" ] || File . join ( File . dirname ( __FILE__ ), '../config' ) config_file = File . join ( config_path , 'router.yml' ) ... opts . on ( "-c" , "--config [ARG]" , "Configuration File" ) do | opt |      config_file = opt    end ... We find that the configuration parameter will be read from a YAML (yet Another Markup Language) that whose location could came from multiple sources, in these order : specified fro...