Which is better for Kubernetes calico or flannel

Which is better for Kubernetes calico or flannel CNI network ?

In Kubernetes, you have several options for Container Network Interface (CNI) plugins to manage cluster networking.

What is CNI in Kubernetes ?

A Container Network Interface (CNI) plugin in Kubernetes is a tool that offers a simplified approach to networking. It provides administrators with greater control over network configurations, ensuring consistency across all pods and enhancing security and performance1. These plugins are essential for creating and managing network interfaces for your pods

These plugins handle communication between Pods, services, and nodes.

When comparing Calico and Flannel as Container Network Interface (CNI) plugins for Kubernetes, both have their strengths and use cases:

1. Calico:
   • Performance: Calico is known for its high performance. It efficiently handles network traffic between hosts and pods.
   • Flexibility: Calico provides flexibility and a holistic view of networking. It not only ensures connectivity but also focuses on network security and administration.
   • Network Policies: Calico offers advanced network administration features, including network policy enforcement, service discovery, and load balancing.
   • Use Cases: Consider Calico when you need robust performance, fine-grained network policies, and a comprehensive networking solution.
   • Provides network policies, security, and observability features.

2. Flannel:

• Simplicity: Flannel takes a more straightforward approach. It’s lightweight and easy to set up.
• Quick Start: If getting up and running quickly is your priority, Flannel is a good choice.
• Scenarios: Flannel is suitable for smaller clusters or scenarios where simplicity outweighs advanced features.
• Simple and lightweight, suitable for small clusters.

3. Cloud provider CNI

Amazon VPC CNI Plugin:

• The Amazon VPC CNI plugin is specifically designed for Amazon EKS (Elastic Kubernetes Service) clusters.
• It creates elastic network interfaces (ENIs) on each Amazon EC2 node in your EKS cluster.
• The plugin assigns private IPv4 or IPv6 addresses from your VPC to each Pod and service.
• Recently, it gained native support for enforcing Kubernetes network policies, allowing you to secure traffic within your EKS clusters

1. Install Calico:

Initialize the control plane using the following command:

sudo kubeadm init --pod-network-cidr=10.244.0.0/16

Note: If 10.244.0.0/16 is already in use within your network, choose a different pod network CIDR.

Install the Tigera Calico operator and custom resource definitions:

sudo kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.27.2/manifests/tigera-operator.yaml 

Note: Use kubectl create instead of kubectl apply due to the large size of the CRD bundle.

Create the necessary custom resource to install Calico:

kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.27.2/manifests/custom-resources.yaml 

Before creating this manifest, review its contents and ensure its settings match your environment (e.g., adjust the default IP pool CIDR to match your pod network CIDR).

Confirm Installation:

Confirm that all pods are running with the following command:

kubectl get pods -n kube-system

2.Install Flannel

Initialize the control plane using the following command

sudo kubeadm init --pod-network-cidr=10.244.0.0/16

Note: If 10.244.0.0/16 is already in use within your network, choose a different pod network CIDR.

Deploy Flannel using the following command

kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml

Note: If you use a custom podCIDR (not 10.244.0.0/16), download the above manifest and modify the network to match your custom one.

Verify that all pods are running with the following command:

kubectl get pods -n kube-system

See Also :- What is Docker?