Are you interested in bypassing the complexities of Network Address Translation (NAT) and deploying containers without the need for IP address translation? The solution lies in acquiring ample public IP addresses, although the high cost of each IPv4 address makes it impractical to assign one to every container. Conversely, IPv6 offers an abundance of addresses, allowing for unique assignments to multiple containers without constraints.

Originally defined in 1981, the Internet Protocol (IP) utilized fixed-length addresses composed of four octets (32 bits), known as IPv4 addresses. As the depletion of IPv4 addresses became apparent in the early 1990s, reusable private IP addresses were introduced in March 1994 to conserve address space. This necessitated Network Address Translation (NAT) for communication between internal and external hosts, which was standardized shortly after.

In response to IPv4 limitations, IPv6 was introduced in 1995, featuring expanded addressing capabilities with a 128-bit address size. However, the transition to IPv6 has been sluggish due to the lack of backward compatibility, with current adoption standing at around 22% after over two decades.

The objective of this post is to illustrate the process of deploying containers on a Cloud Provider (AWS) using IPv6, building upon the simplified Kubernetes multi-cluster networking discussed previously. The proposed topology involves creating EC2 instances with Elastic Network Interfaces (ENI) attached, enabling the allocation of a contiguous block of IPv6 addresses to each instance.

Although the allocation of smaller subnets (/64) to AWS instances is not currently feasible, Elastic Network Interfaces facilitate the association of a block of IPv6 addresses with each instance. Despite the less-than-optimal IPv6 prefix length, this approach enables the deployment of containers exclusively using IPv6.

The process entails several steps:

1. Creation of EC2 instances with ENIs attached, allocating a block of IPv6 addresses.
2. Installation of Docker and configuration of IPv6 addressing on the instances.
3. Running containers exclusively using IPv6 addresses.
4. Testing connectivity between containers and to external hosts over IPv6.

Here’s the coding part:

# Create EC2 instances with ENIs attached
eni1=`aws ec2 create-network-interface \
  --subnet-id $subnetId \
  --description "My IPv6 ENI 1" \
  --groups $sgId \
  --ipv6-addresses \
  Ipv6Address=2600:1f18:47b:ca03::1:1 \
  Ipv6Address=2600:1f18:47b:ca03::8 \
  Ipv6Address=2600:1f18:47b:ca03::9 \
  Ipv6Address=2600:1f18:47b:ca03::a \
  Ipv6Address=2600:1f18:47b:ca03::b \
  --query 'NetworkInterface.NetworkInterfaceId' \
  --output text`

# Repeat for the second ENI
eni2=`aws ec2 create-network-interface \
  --subnet-id $subnetId \
  --description "My IPv6 ENI 2" \
  --groups $sgId \
  --ipv6-addresses \
  Ipv6Address=2600:1f18:47b:ca03::2:2 \
  Ipv6Address=2600:1f18:47b:ca03::c \
  Ipv6Address=2600:1f18:47b:ca03::d \
  Ipv6Address=2600:1f18:47b:ca03::e \
  Ipv6Address=2600:1f18:47b:ca03::f \
  --query 'NetworkInterface.NetworkInterfaceId' \
  --output text`

# Launch instances with ENI attached
vm1=`aws ec2 run-instances \
  --key-name $AWS_SSH_KEY \
  --image-id ami-0ac019f4fcb7cb7e6 \
  --instance-type r5d.large \
  --network-interfaces DeviceIndex=0,NetworkInterfaceId=$eni1 \
  --query 'Instances[0].InstanceId' \
  --output text`

# Similarly for instance-2
vm2=`aws ec2 run-instances \
  --key-name $AWS_SSH_KEY \
  --image-id ami-0ac019f4fcb7cb7e6 \
  --instance-type r5d.large \
  --network-interfaces DeviceIndex=0,NetworkInterfaceId=$eni2 \
  --query 'Instances[0].InstanceId' \
  --output text`

# Get public IPv6 addresses for instances
ip1=`aws ec2 describe-instances \
  --filter Name=instance-id,Values=$vm1 \
  --output text \
  --query 'Reservations[].Instances[].NetworkInterfaces[].\
Ipv6Addresses[0].Ipv6Address'`

# Similarly for instance-2
ip2=`aws ec2 describe-instances \
  --filter Name=instance-id,Values=$vm2 \
  --output text \
  --query 'Reservations[].Instances[].NetworkInterfaces[].\
Ipv6Addresses[0].Ipv6Address'`

These steps involve creating EC2 instances with ENIs attached, launching instances with the ENIs, and retrieving public IPv6 addresses for each instance.

The process continues with configuring IPv6 addressing and installing Docker on the instances, followed by running containers exclusively using IPv6 addresses. Testing connectivity between containers and external hosts over IPv6 ensures the successful deployment of IPv6-only containers in the cloud.