As the image is built, we shall go back to the monitoring screen (the first screen that you have seen).
Now press "Esc" or click "Cancel" to close the current dialog.
A the monitoring screen, click on the "Start all" button at the bottom center area. See the screenshot below (mouse over image):
When prompted click on "Yes" button. Then, please, wait until all the three gears under the "Status" turn green and rotating...
If you get the green gears on "Status" and "Software on instance" (see the screenshot above, mouse-over image) then ...
CONGRATULATIONS !!! You have got your Hadoop cluster up and running.
Now, let's have some fun with it!
Click on the green gear "Apache Hadoop (2.8.5)" on the row of "Dobby (master)", see the screenshot below:
This will open a new popup which displays the running processes on "Dobby" - the master node running on Ubuntu.
Click on the active link "HDFS Namenode Web UI". See the screenshot below:
A new browser window pops up with the Hadoop's web application for Namenode information at http://localhost:50070
You are now able to browse HDFS and perform many operations related to Hadoop's file system. The slaves nodes "Kreacher" and "Winky" are displayed. See the screenshot below:
Next, we shall open a new handy Web management screen of Hadoop - Yarn ResourceManager UI. From the open popup click on the active link "Yarn ResourceManager Web UI". See the image below.
A new browser window pops up with the Hadoop's web application for ResourceManager information at http://localhost:8088
Now, you can look at the YARN web GUI to observe your Hadoop applications (ex. MapReduce, Pig jobs, etc.). You can monitor the application submission ID, the user who submitted the application, the name of the application, the queue in which the application is submitted, the start time and finish time in the case of finished applications, and the final status of the application, using the ResourceManager UI.
The screenshot below shows the information you can get from the YARN web UI: