Completek8s Classroomnotes 07/Sep/2023

Elastic Kubernetes Services (EKS)

eksctl is a cli tool developed by Weaveworks & is easiest way to deploy all components needed to run EKS
Refer Here for official site of eksctl
eksctl defaults to creating a cluster with following default paramters
- An autogenerated cluster name
- Two m5.large worker nodes
- Use of official AWS EKS AMI
- us-west-2 defaul region
- dedicated vpc
Network information
- dedicated vpc 192.168.0.0/16 with three private, three public subnets
- NAT Gateway & Internet gateway to enable acess needed for container images & communication to AWS S3 and ECR API
- Two security groups are setup for eks cluster
  - Ingress internode group SG: Allows nodes to communicate with each other on all ports
  - Control Plane security group: Allows communication between the control plane and worker node groups
One node group containing two m5.large nodes is default, but how many pods can that node run? AWS has a formula based on the node type and number of interfaces and Ip Adddresses it supports.
((Number of network interfaces for the instance type) * (Number of Ip Addresses per network interface -1)) + 2
m5 large can support a maximum of 29 pods

This is an open source implementation of CNI built for AWS
This includes native AWS Services like VPC Flow logs, VPC routing policies, security groups for network traffic isolation
Refer Here for VPC CNI
Two components of VPC CNI
- CNI Plugin: responsible for host and pod’s network stack
- ipamd: IPAM dameon responsible for maintaining warm pool of available IP addresses and assign and IP to pod
refer class room video for demonstration of the above