🕵️ Investigate the Usage of an Alternative CNI for EKS cluster to be built in MP

[julialawrence]

As a DevOps Engineer, I would like to investigate which alternative container network interface implementation I can use in preference to deault vpc-cni which ships with EKS.
vpc-cni while simple to use, assigns pod IP addresses out of the general subnet CIDR ranges. Since we're sharing networking with the rest of Modernisation Platform, this is not a viable strategy as there are not enough IP addresses available in those CIDR ranges for our workloads.

Definition of Done:

• Identify an appropriate replacement for the CNI plugin to use instead of vpc-cni
• Determine the best way to deploy
• Capture the decision in our ADR

[jacobwoffenden]

VPC CNI has been chosen