Before we even start with Hadoop, it is important to secure at the operating system and network level. It is expected of the users to have prior knowledge for securing Linux and networks, and in this recipe, we will only look at disk encryption.
It is good practice to encrypt the data disk, so that even if they are stolen, the data is safe. The entire disk can be encrypted or just the disk where critical data resides.
To step through the recipes in this chapter, make sure you have at least one node with CentOS 6 and above installed. It does not matter which flavor of Linux you choose, as long as you are comfortable with it. Users must have prior knowledge of Linux installation and basic commands. The same settings apply to all the nodes in the cluster.
