I installed the Cloudera CDH on my laptop with a Core i5 processor, 512GB SSD, and 3 GB allocated to the VM (out of 4GB RAM). I could start VirtualBox, but could not launch the Hadoop VM until I upgraded to 8GB RAM, and allocated 6GB RAM to the VM.

I hope this gives you an idea.

Hi Srujan,
You can't run hadoop cluster with these configuration.
You can either use hadoop pseudo distributed mode for practice or you can upgrade your RAM to 8GB to run hadoop cluster.
I recommend you to upgrade your RAM only. Your processor is good enough to handle 5 node cluster only if upgrade RAM.
Thanks.