FreshDream Blogger Template

4/04/2015 1 Comment

3-column SEO Optimized Blogger Template - FreshDream.

FreshDream is a 3-column Blogger template for personal blogs and article publishing websites. This template is a perfect choice for those who want to make a elegant and fresh looking blog. This simple yet beautiful interface is designed by our team with focus is on user-experience and usability. The theme is highly SEO optimized, and the websites using this template has experienced increase in traffic and pageviews. Template Features: Wordpress Look, 3 Columns, Right Sidebar and Left Sidebar,  Featured Content Slider,  Top Navigation Menu, SEO ready,  Awesome Fonts and thumbnails FreshDream Blogger Theme

FreshDream Core Features

  • Lightweight fresh and clean looking interface with grey background.
  • Related posts widgets with Thumbnails and Hover effect.
  • Highly SEO Optimized.
  • Lightweight Top navigation Menu with CSS3 +HTML Dropdown Menu.
  • Clean Looking threaded comments.
  • Advertisements banner ready - Perfect for Adsense users, right sidebar for Square ad, left sidebar for Skyscraper ad
  • Simple User Friendly Search Box.
  • Numbered Pagination using CSS.
  • Custom Widgets (Facebook Likebox, Recent Comment)
  • Social Share Counter Widget.
  • Auto Blog Post summarize And “Read More” Button.
  • Social Media Buttons integrated below each post.
  • Cool Image Slider for Blogger Posts.

Theme Customization

Configure Dropdown Menu:

Login to blogger dashboard --> Template--> Edit HTML. Find and scroll down to where you see the codes below: Input your menu item by replacing the YOUR_URL with your Content URL and YOUR DESC with the title of the content below.
<div id='cssmenu'> ...... ...... <li> <a expr:href='YOUR_URL'>YOUR DESC</a> </li>

Configure Content Slider:

Login to blogger dashboard --> Layout--> Add a Gadget. Add a HTML/Javascript widget above the Blog Posts and add the below code. Replace the URL with the content URL, IMAGE_URL  with the source path of the image file and TITLE with the content title.
 <script src="http://dimpost.googlecode.com/files/js-image-slider.js" 
 type="text/javascript"></script>
 <div id="sliderFrame">
 <div id="slider">
 <a href="URL_1"><img src="IMAGE_URL_1" alt="TITLE_1" /></a>
 <a href="URL_2"><img src="IMAGE_URL_2" alt="TITLE_2" /></a>
 <a href="URL_3"><img src="IMAGE_URL_3" alt="TITLE_3" /></a>
 <a href="URL_4"><img src="IMAGE_URL_4" alt="TITLE_4" /></a>
 </div></div>
If you face any problems during installation, or find any bugs and errors, please use the comment section to report them, I would be glad to help you. Please also provide your feedback about the template, the improvements that can be made.

CSS Drop Down Menu Without Javascript

12/17/2014 No Comment

Lightweight and Pure CSS Drop Down Menu without Javascript

The menu is created in CSS3 which consists of a nested ul structure to create the second level of the menu. Just copy the below code below to give your website a beautiful, light-weight and flexible Drop down Menu.

HTML Code for CSS Drop Down Menu

<cssmenu>
<ul class="cf">
<li><a href="#">Menu 1</a></li>
<li><a class="dropdown" href="#">Menu 2</a>
<ul>
<li><a href="#">Sub Menu 1</a></li>
<li><a href="#">Sub Menu 2</a></li>
<li><a href="#">Sub Menu 3</a></li>
</ul>
</li>
<li><a href="#">Menu 3</a></li>
<li><a href="#">Menu 4</a></li>
</ul>
</cssmenu>

CSS Code for Drop Down Menu

cssmenu ul {
 text-shadow:0 1px 0 #FFF;
    background: #ddd;
    list-style: none;
    margin: 0;
    padding: 0;
    width: 100%;
}
cssmenu li {
    float: left;
    margin: 0;
    padding: 0;
    position: relative;
    min-width: 24.5%;
}
cssmenu a {
    background: #ddd;
    color: #444;
    display: block;
    font: bold 16px/50px sans-serif;
    padding: 0 25px;
    text-align: center;
    text-decoration: none;
    -webkit-transition: all .30s ease;
    -moz-transition: all .30s ease;
    -ms-transition: all .30s ease;
    -o-transition: all .30s ease;
    transition: all .30s ease;
}
cssmenu .dropdown:after {
    content: &#39; ▶&#39;;
}
cssmenu .dropdown:hover:after{
 content:&#39;\25bc&#39;
}
cssmenu li:hover a {
    background: #ccc;
}
cssmenu li ul {
    float: left;
    left: 0;
    opacity: 0;
    position: absolute;
    top: 35px;
    visibility: hidden;
    z-index: 1;
    -webkit-transition: all .30s ease;
    -moz-transition: all .30s ease;
    -ms-transition: all .30s ease;
    -o-transition: all .30s ease;
    transition: all .30s ease;
}

How to float DIV side by side using CSS

11/22/2014 No Comment

In this article, we will discuss how to place 3 DIV side by side using CSS.

You need to have a container with a width greater than the sum of the widths of the all the 3 DIV elements. For this purpose, we have kept width of the container element as 520px and the individual DIVs as 170px. Use the float as left, the DIVs will be arranged side by side.
<div style="width: 520px;">
<div style="float: left; width: 170px;">Left DIV</div>
<div style="float: left; width: 170px;">Middle DIV</div>
<div style="float: left; width: 170px;">Right DIV</div>
<br style="clear: left;" /></div>
</div>
If the page is to be expanded in the future, the sizes need to be re-adjusted. So, it is advisable to use percentage (%) instead of px for the DIVs. This will also help in adjusting to screens of different sizes
<div style="width: 100%;">
<div style="float: left; width: 32%;">Left DIV</div>
<div style="float: left; width: 32%;">Middle DIV</div>
<div style="float: left; width: 32%;">Right DIV</div>
<br style="clear: left;" /></div>
</div>
 You can also do the same in a CSS file for modularity
#container{
    width: 100%;
    overflow: hidden; /* contain floated elements */
}
#left{
    float: left;
    width: 32%;
}
#center{
    float: left;
    width: 32%;
}
#right{
    float: left;
    width: 32%;
}

How to disable Copy, Paste and Text Selection using CSS

4/04/2014 No Comment

Disable Copy/Paste and Text Selection using CSS and Javascript.

CSS Code to disable text selection and highlighting.

This CSS code will disable text highlighting and selecting for your website/blog post. This CSS code works perfectly in Internet Explorer, Mozilla Firefox and Google Chrome. In blogger you may put the code inside the .post-body section.
-webkit-user-select: none;
-khtml-user-drag: none;
-khtml-user-select: none;
-moz-user-select: none;
-moz-user-select: -moz-none;
-ms-user-select: none;
-o-user-select: none;
user-select: none;
One thing to note about the above CSS code is that in Firefox, it will also disable Copy/Paste of the content of your post/website. However, the copy will still be possible in Chrome browser.

CSS Code to enable text selection in Blockquote.

There may be cases where a certain portion of your post may still need the highlighting and selection, let say in the blockquote area where you may write certain sample code. In that case just you need to put
.post blockquote {
-webkit-touch-callout: text;
-khtml-user-select: text;
 -moz-user-select: text;
 -ms-user-select: text;
 user-select: text;
 -o-user-select:text;
 -webkit-user-select: text;
}

Disable Copy/Paste of you content.

To disable copy/paste in the blogger and Wordpress posts copy the below code into you theme template. This will make the task of copying text a little complex for content scrappers.
<script type='text/JavaScript'>
function killCopy(e){
return false
}
function reEnable(){
return true
}
document.onselectstart=new Function (&quot;return false&quot;)
if (window.sidebar){
document.onmousedown=killCopy
document.onclick=reEnable
}
</script>

CSS Code to make the footer stay at the bottom of a page

2/14/2014 No Comment

CSS - HTML page footer stay at bottom of the page.

CSS code for Footer at the bottom of a page.

Main body page is stretched to a 100% of the page. The footer is then given the below CSS rules
#footer {
clear: both;
position: relative;
z-index: 10;
text-align: center;
height:30px;
}

CSS code for Fixed Footer at the bottom.

There is another approach which will work on all browsers, though it will appear at the bottom, the footer will be placed over the content. As such, the footer will be at the bottom of the window even when you scroll.
#footer {
position:fixed;
bottom:0;
left:0;
right:0;
width:100%;
z-index: -999;
overflow: hidden;
}

Hadoop Cluster Interview Questions Answers

9/25/2013 No Comment

Apache Hadoop Cluster Interview Questions.

Explain about the Hadoop-core configuration files?
Answer : Hadoop core is specified by two resources. Its is configured by two well written xml files which are loaded from the classpath:
1. hadoop-default.xml  -  Read-only defaults for Hadoop, suitable for a single machine instance
2. hadoop-site.xml. - It specifies the site configuration for Hadoop distribution. The cluster specific information is also provided by the Hadoop administrator.

Explain in brief the three modes in which Hadoop can be run?
Answer : The three modes in which Hadoop can be run are:
1. Standalone (local) mode - No Hadoop daemons running, everything runs on a single Java Virtual machine only
2. Pseudo-distributed mode - Daemons run on the local machine, thereby simulating a cluster on a smaller scale.
3. Fully distributed mode - Runs on a cluster of machines.

Explain what are the features of Stand alone (local) mode?

Answer : In stand-alone or local mode there are no Hadoop daemons running,  and everything runs on a single Java process. Hence, we don't get the benefit of distributing the code across a cluster of machines. Since, it has no DFS, it utilizes the local file system. This mode is suitable only for running MapReduce programs by developers during various stages of development. Its the best environment for learning and good for debugging purposes.

What are the features of Fully Distributed mode?

Answer : In Fully Distributed mode, the clusters range from a few nodes to 'n' number of nodes. It is used in production environments, where we have thousands of  machines in the Hadoop cluster. The daemons of Hadoop run on these clusters.We have to configure separate masters and separate slaves in this distribution, the implementation of which is quite complex. In this configuration, Namenode and Datanode runs on different hosts and there are nodes on which task tracker runs. The root of the distribution is referred as HADOOP_HOME.

Explain what are the main features of Pseudo mode?


Answer : In Pseudo-distributed mode, each Hadoop daemon runs in a separate Java process, as such it simulates a cluster though on a small scale. This mode is used both for development and QA environments. Here, we need to do the configuration changes.

What are the Hadoop configuration files at present?
Answer : There are 3 configuration files in Hadoop:
1. conf/core-site.xml:
<configuration><property><name>fs.default.name</name>         <value>hdfs://localhost:9000</value>     </property></configuration>
2. conf/hdfs-site.xml:
<configuration><property><name>dfs.replication</name> <value>1</value></property></configuration>
3. conf/mapred-site.xml:
<configuration><property><name>mapred.job.tracker</name>         <value>localhost:9001</value></property></configuration>
Can you name some companies that are using Hadoop ?
Answer :  Numerous companies are using Hadoop, from large Software Companies, MNCs to small organizations. Yahoo is the top contributor with many open source Hadoop Softwares and frameworks. Social Media Companies like Facebook and Twitter have beein using for a long time now for storing their mammoth data. Apart from that Netflix, IBM, Adobe and e-commerce websites like Amazon and eBay are also using multiple Hadoop technologies.

Which is the directory where Hadoop is installed?

Answer :  Cloudera and Apache has the same directory structure. Hadoop is installed in cd
/usr/lib/hadoop-0.20/.

What are the port numbers of Namenode, job tracker and task tracker?

The port number for Namenode is ’70′, for job tracker is ’30′ and for task tracker is ’60′.

Tell us what is a spill factor with respect to the RAM?
Answer : Spill factor is the size after which your files move to the temp file. Hadoop-temp directory is used for this. Default value for io.sort.spill.percent is 0.80. A value less than 0.5 is not recommended.

Is fs.mapr.working.dir a single directory?

Yes, fs.mapr.working.dir it is just one directory.

Which are the three main hdfs-site.xml properties?

The three main hdfs-site.xml properties are:
1. dfs.name.dir which gives you the location on which metadata will be stored and where
DFS is located – on disk or onto the remote.
2. dfs.data.dir which gives you the location where the data is going to be stored.
3. fs.checkpoint.dir which is for secondary Namenode.

How to come out of the insert mode?

To come out of the insert mode, press ESC, type :q (if you have not written anything) OR
type :wq (if you have written anything in the file) and then press ENTER.

Tell us what is Cloudera and why it is used in Big Data?

Answer : Cloudera is the leading Hadoop distribution vendor on the Big Data market, its termed as the next-generation data management software that is required for business critical data challenges that includes access, storage, management, business analytics, systems security, and search. 

We are using Ubuntu operating system with Cloudera, but from where we can

download Hadoop or does it come by default with Ubuntu?
This is a default configuration of Hadoop that you have to download from Cloudera or from
Edureka’s dropbox and the run it on your systems. You can also proceed with your own
configuration but you need a Linux box, be it Ubuntu or Red hat. There are installation
steps present at the Cloudera location or in Edureka’s Drop box. You can go either ways.

What is the main function of the ‘jps’ command?

Answer : The "jps" command checks whether the Datanode, Namenode, task tracker, job tracker, and other components are working or not in Hadoop. One thing to remember is that if you have started Hadoop services with sudo then you need to run JPS with sudo privileges else the status will be not shown.

How can I restart Namenode?

1. Click on stop-all.sh and then click on start-all.sh OR
2. Write sudo hdfs (press enter), su-hdfs (press enter), /etc/init.d/ha (press enter) and
then /etc/init.d/hadoop-0.20-namenode start (press enter).

How can we check whether Namenode is working or not?
To check whether Namenode is working or not, use the command /etc/init.d/hadoop-

0.20-namenode status or as simple as jps.

What is "fsck" and what is its use?

Answer : "fsck" is File System Check. FCSK is used to check the health of a Hadoop Filesystem. It generates a summarized report of the overall health of the filesystem. 
Usage :  hadoop fsck /

At times you get a ‘connection refused java exception’ when you run the File System Check command Hadoop fsck /?
Answer :  The most possible reason is that the Namenode is not working on your VM.

What is the use of the command mapred.job.tracker?

Answer : The command mapred.job.tracker is used by the JobTracker to list out which host and port that the MapReduce job tracker runs at. If it is "local", then jobs are run in-process as a single map and reduce task.

What does /etc /init.d do?

/etc /init.d specifies where daemons (services) are placed or to see the status of these
daemons. It is very LINUX specific, and nothing to do with Hadoop.

How can we look for the Namenode in the browser?

If you have to look for Namenode in the browser, you don’t have to give localhost:8021, the
port number to look for Namenode in the brower is 50070.

How to change from SU to Cloudera?

To change from SU to Cloudera just type exit.

Which files are used by the startup and shutdown commands?

Slaves and Masters are used by the startup and the shutdown commands.

What do masters and slaves consist of?

Masters contain a list of hosts, one per line, that are to host secondary namenode servers.
Slaves consist of a list of hosts, one per line, that host datanode and task tracker servers.

What is the function of hadoop-env.sh? Where is it present ?
Answer :  This file contains some environment variable settings used by Hadoop, it provides the environment for Hadoop to run. The path of JAVA_HOME is set here for it to run properly. hadoop-env.sh file is present in the conf/hadoop-env.sh location. You can also create your own custom configuration file conf/hadoop-user-env.sh, which will allow you to override the default Hadoop settings

Can we have multiple entries in the master files?
Yes, we can have multiple entries in the Master files.

In Hadoop_PID_DIR, what does PID stands for?
PID stands for ‘Process ID’.

What does hadoop-metrics.properties file do?
hadoop-metrics.properties is used for ‘Reporting‘ purposes. It controls the reporting for
Hadoop. The default status is ‘not to report‘.

What are the network requirements for Hadoop?

The Hadoop core uses Shell (SSH) to launch the server processes on the slave nodes. It
requires password-less SSH connection between the master and all the slaves and the
secondary machines.

Why do we need a password-less SSH in Fully Distributed environment?

We need a password-less SSH in a Fully-Distributed environment because when the cluster
is LIVE and running in Fully Distributed environment, the communication is too frequent. The job tracker should be able to send a task to task tracker quickly.

What will happen if a Namenode has no data?
Answer : If a Namenode has no data it cannot be considered as a Namenode. In practical terms, Namenode needs to have some data.

What happens to job tracker when Namenode is down?

Answer :  Namenode is the main point which keeps all the metadata, keep tracks of failure of datanodes with the help of heart beats. As such when a namenode is down, your cluster will be completely down, because Namenode is the single point of failure in a Hadoop Installation.

Explain what do you mean by formatting of the DFS?

Answer : Like we do in Windows, DFS is formatted for proper structuring of data. It is not usually recommended to do as it formats the Namenode too in the process, which is not desired.

We use Unix variants for Hadoop. Can we use Microsoft Windows for the same?
Answer : In practicality, Ubuntu and Red Hat Linux are the best Operating Systems for Hadoop. On the other hand, Windows can be used but it is not used frequently for installing Hadoop as there are many support problems related to it. The frequency of crashes and the subsequent restarts makes it unattractive. As such, Windows is not recommended as a preferred environment for Hadoop Installation, though users can give it a try for learning purposes in the initial stage.

Which one decides the input split - HDFS client or Namenode ?
Answer : The HDFS Client does not decide. It is already specified in one of the configurations through which input split is already configured.

Lets take a scenario, lets say we have 
already Cloudera in a cluster, now if we want to form a cluster on Ubuntu can we do it. Explain in brief ?
Answer : Yes, we can definitely do it. We have all the useful installation steps for creating a new cluster. The only thing that needs to be done is to uninstall the present cluster and install the new cluster in the targeted environment.

Can you tell me if we can create a Hadoop cluster from scratch?

Answer : Yes, we can definitely do that.  Once we become familiar with the Apache Hadoop environment, we can create a cluster from scratch.

Explain the significance of SSH? What is the port on which port does SSH work? Why do we need password in SSH localhost?
Answer : SSH is a secure shell communication, is a secure protocol and the most common way of administering remote servers safely,  relatively very simple and inexpensive to implement. A single SSH connection can host multiple channels and hence can transfer data in both directions. SSH works on Port No. 22, and it is the default port number. However, it can be configured to point to a new port number, but its not recommended. In localhost, password is required in SSH for security and in a situation where passwordless communication is not set.

What is SSH. Explain in detail about SSH communication between Masters and
the Slaves?
Answer : Secure Socket Shell or SSH is a password-less secure communication that provides administrators with a secure way to access a remote computer and data packets are sent across the slave. This network protocol also has some format into which data is sent across. SSH communication is not only between masters and slaves but also between two hosts in a network.  SSH appeared in 1995 with the introduction of SSH - 1. Now SSH 2 is in use, with the vulnerabilities coming to the fore when Edward Snowden leaked information by decrypting some SSH traffic

Can you tell is what will happen to a Namenode, when job tracker is not up and running?
Answer : When the job tracker is down, it will not be in functional mode, all running jobs will be halted because it is a single point of failure. Your whole cluster will be down but still Namenode will be present. As such the cluster will still be accessible if Namenode is working, even if the job tracker is not up and running. But you cannot run your Hadoop job.

Dear Readers, please provide us with your own Hadoop and Big Data interview experience in the comments section.

Big Data Resources - Interview Questions, Downloads, Tutorials

9/22/2013 No Comment

Big Data Interview Questions, Downloads, Tutorials.

Apache Hadoop Interview Questions Answers

MapReduce Interview Questions

Apache Pig Interview Questions Answers

Big Data Downloads 

 

Siebel Server Down Troubleshooting

9/22/2013 No Comment

Siebel Server is not coming up in Linux/Unix and Windows.

Server Busy Error for Siebel Server. Steps for Troubleshooting. There could be several cases where Siebel servers are not coming up or Siebel services are not running properly. We are discussing in detail about those scenarios and the solutions.

1. The first step is to ensure that you validate the .srf file is not corrupt by placing the SRF on a dedicated environment. If the dedicated client is facing issues there could be possibly two reasons as cited below.
  • The SRF file in the server machine got corrupt. Replace your SRF with the backup.
  • The Oracle Database Server itself is down. Restart the same.
2. Any changes or modification which lead to the corruption of Siebel Gateway Name Server information file siebns.dat will also result in the Siebel Servers not coming up. In general, NameSrvr logs tell us the connectivity related information and common errors like license key not found. Since there are multiple copies of siebns.dat, you can try to revert to an old working siebns.dat file. The servers will come up.

3. Stop Siebel servers after you set Siebel environment variables using the script ./siebenv.sh and then use the command stop_server all 

Unix/Linux/Solaris: Execute ps -ef | grep [directory path] (eg. ps -ef | grep /app/siebel/siebsrvr).
ps -ef | grep sieb
Ensure that all processes for that enterprise are killed.
use kill -9 pid
4. Delete OSDF files that exists in directory %SIEBEL_ROOT%\sys with name like the ones below:
osdf.[SiebelEnterprise].[SiebelServer]
Where [SiebelEnterprise] = The Siebel Enterprise name
[SiebelServer] = The Siebel Server name.

You can also use the command as below to clean OSDF files
  • % cleansync -f $SIEBEL_ROOT/siebsrvr/sys/osdf.<enterprise_name>.<server_name> -d 
5. After OSDF files, please also ensure that you delete any shared memory files that exists in directory %SIEBEL_ROOT%\admin with name like:*.shm files This shared memory file is maintained by each Siebel Server under the "admin" directory of its root installation. Though this file is automatically deleted when the Siebel server is shut down, if it still exists when the Siebel server is down then there is the likely possibility that it has been corrupted and has to be removed. You can delete it manually or by the command using below. Please ensure that if you have more than one Siebel Server, you have to delete the files from each server.

  • % siebclean -f $SIEBEL_ROOT/siebsrvr/admin/<enterprise_name>.<server_name>.shm -q 
6. Another quick test is to check for the Siebel enterprise logs. If there are no enterprise logs are getting generated then there are connectivity issues with the Siebel database. One of the possible reason is the change of Database password for SADMIN user.

You just need to run odbcsql from siebsrvr/bin to check connectivity issues. The command is as cited below.
odbcsql /u SADMIN /p SADMIN /s DSN Name

7. Ensure that you do cleanup of unwanted logarchive and log files so that fresh logs can be monitored and space can be freed up accordingly. It is recommended to move the Log Archives to a different machine if they are required from the Business point of view

8. Please ensure that you delete FDR and core files as these files consume large amounts of memory in the machines leading to servers not getting started.

9. In a Unix environment you can try to restart server after executing Siebel environment variable script ./siebenv.sh and then use the command start_server all
However, if the server still does not restart, you need to check the enterprise logs for it for any possible errors. 
The enterprise log lies in the following location in the server machine.
%SIEBEL_ROOT%\enterprises\[SiebelEnterprise]\[SiebelServer]\log
The enterprise log has name with format:
[SiebelEnterprise].[SiebelServer].log

10. Check that there is no Siebel processes for the enterprise that are still running. For Windows: Check Task Manager for any Siebel process for the enterprise still in running state.

11.If the Siebel environment has LDAP authentication, any changes and modification in the LDAP tree structure can also affect the environment to go down. This usually happens when you make the changes and propagate it across. Please verify if this is the case.

12. Use the command netstat -an|grep 2321 and verify that the SRBroker/SCBroker port is listening. 
You may get error messages like "SBL-NET-01218: The connection was refused by server crm. No component is listening on port 2321."

13. Use the command netstat -an|grep 2320 and verify that the Gateway Service port is open and listening.

14. Increase the log level of the server components so that SCBroker and SRBroker can be monitored From the log you would get very vital information that can be used for debugging.

In many of the troubleshooting steps mentioned above, it requires generation of Enterprise Server logs for finding the possible cases of errors. Please monitor the logs so there there is no disk space issue. 

 

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