Project Calico is the world's simplest, most scalable, open networking solution for OpenStack”. 

Calico, a pure layer3 approach to Virtual Networking for highly scalable & flexible Data centers. It is a open-source technology, that implements large, standards-based cloud data center infrastructures Calico supports rich and flexible network policy that enforces on every node in a cluster, to provide tenant isolation, security groups, and external reachability constraints.

There is security layer into Calico that enables developers and operations staff to easily define with fine granularity which connections are allowed, and which are not. These rules implement and extend the Kubernetes Network Policy API.

There are basically 3 policy demo we can configure:

  • Simple Policy Demo
  • Stars Policy Demo
  • Advanced Policy Demo

We will discuss on the overview of Simple Policy Demo. Lastime, we discussed Star Policy here:

Simple Policy Demo

It includes demo try out Kubernetes NetworkPolicy with Calico, as well as a client service for all running on Kubernetes.

It requires a Kubernetes cluster configured with Calico networking, and expects that you have kubectl configured to interact with the cluster.

We need to install Kubernetes in the system which includes Network Policy API.

We need to get the following thing: Calico and then need to get into star-policy directory of Calico 1.png

We need to create some nginx pods in the policy-demo Namespace, and expose them through a Service.: 2.png

Also we need to ensure the nginx service is accessible: 3.png

Enable isolation:

Now this is the important part…. let’s turn on isolation in our policy-demo Namespace which will then prevent connections to pods in this Namespace. We will now run the command that creates a NetworkPolicy which implements a default deny behavior for all pods in the policy-demo Namespace. 5.png

Allow Access using a NetworkPolicy :

Now, let’s enable access to the nginx Service using a NetworkPolicy. This will allow incoming connections from our access Pod, but not from anywhere else.We need to now create a network policy access-nginx with the following contents: 6.png

That’s it! We should now be able to access the Service from the access Pod. 7.png

We can remove the policy using following: 8.png

As you can see, this is just a simple example of the Kubernetes NetworkPolicy API and how Calico can secure your Kubernetes cluster.

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