NetworkPolicies

NetworkPolicy objects in Kubernetes are essentially Network Access Control Lists but at the Pod and namespace level. They work by using label selection (such as Services) or by indicating a CIDR IP address range to allow on a particular port/protocol.

This is immensely helpful for ensuring security, especially when you have multiple microservices running on a cluster. Now, imagine you have a cluster that hosts many applications for your company. It hosts a marketing website that runs an open-source library, a database server with sensitive data, and an application server that controls access to that data. If the marketing website doesn't need to access the database, then there should be no reason for it to be allowed access to the database. By using a NetworkPolicy, we can prevent an exploit or a bug in the marketing website from allowing an attacker to expand that attack so that they can access your business data by preventing the marketing website Pod from...