Massoud Mazar

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Monitoring hadoop data nodes using nagios

if you already have nagios setup to monitor your servers, it's a good idea to use it to monitor your hadoop data nodes as well. you can use nrpe to call your dfs monitoring plugin. I found this blog post about setting up nrpe on CentOS extremely useful. The only trick to get it to work was to also setup rpmforge repositories for yum, so it finds the nrpe packages (nagios-nrpe and nagios-plugins-nrpe). 

The next step was to add monitoring script for hadoop dfs, which I found here. Since I was using hadoop 0.20.2, I had to make some changes to the script to correctly parse values out of the dfs report:More...

Setting up Hadoop/Hive to use MySQL as metastore

In a previous post I showed how to setup Hadoop/Hive to use Derby in server mode as the metastore. Many believe MySQL is a better choice for such purpose, so here I'm going to show how we can configure our cluster which we created previously to use a MySQL server as the metastore for Hive.

First we need to install MySQL. In this scenario, I'm going to install MySQL on our Master node, which is named centos1. More...

setting up hadoop/hive cluster on Centos 5

If you are reading this post chances are you are trying to setup a hadoop/hive cluster. I hope these instructions save you some time with your installation.

Install CentOS:

I assume you are starting from scratch and want to setup a small cluster with minimum OS components (as far as I could minimize it). To start, download the OS setup media, and boot each machine with it. Go through the More...

CSS Friendly Menu, Problems with Chrome and IE6

After realizing that asp.net menu is generating a huge HTML and causes the application pages to be large and slow, I decided to use CSS friendly control adapters. It reduced the page size by 50 KB, but I had some challenges to get it to show the way I wanted it. Here I want to share some of the things I learned along the way:More...

ReportViewer control toolbar in Google Chrome browser

SQL Server Reporting Services ReportViewer control has a toolbar that is not displayed correctly in Google Chrome browser. You will see something like this:


 The correct display looks like this:


A workaround I'm using is to use JavaScript to find DIV and TABLE elements in the above toolbar and change their "display" style to "inline-block".

Following code can be added to the bottom of the page to accomplish this:More...



Showing animated icon while populating TreeView with PopulateOnDemand

TreeView server control in asp.net can use AJAX behind the scenes to populate child nodes when user clicks on the expand icon next to each node. If the loading process is fast, it works perfectly. But when child nodes are generated by a slow process (like a slow database query) then user experience is unacceptable. User would click on the expand and nothing would happen for a long time, leaving user wondering if the click really did anything.

In such scenarios, an animated icon that lets user know data is being loaded would help a lot. More...