Ensure IP subnet allocation accounts for expansion and availability

As workloads evolve and expand, a robust network topology is key to maintaining high availability and reliability. Proper IP subnet allocation allows for seamless scaling and effective management of resources across multiple environments, ensuring that future growth does not compromise network integrity.

Best Practices

Plan for Future Growth

• Analyze current and expected workload sizes to determine appropriate IP address ranges for your VPCs.
• Select a sufficient CIDR block for your VPCs based on anticipated growth, ensuring you have enough IP addresses for all potential resources and future expansion.
• Consider using larger CIDR blocks to allow for subnet diversification across multiple Availability Zones to improve fault tolerance and availability.
• Regularly review and adjust your subnet allocations as your service requirements evolve, taking care to document changes to your network topology.

Utilize Multi-AZ Deployments for High Availability

• Design your network topology to span multiple Availability Zones (AZs) for redundancy and fault tolerance.
• Allocate subnets across different AZs to ensure even distribution of resources, minimizing the impact of failures in a single AZ.
• Use AWS services that inherently support high availability, such as Elastic Load Balancing and Auto Scaling, which can spread workloads across AZs.

Implement IP Address Management

• Use a structured IP address management strategy to keep track of allocations and availability of IPs per subnet.
• Incorporate automation tools and scripts to assist in monitoring and managing IP address usage within your VPCs.
• Consider tools such as AWS Resource Groups and AWS Config Rules to help ensure compliance with your IP address management policy.

Effective Domain Name Resolution

• Leverage Amazon Route 53 for domain name system (DNS) services to ensure reliable and scalable DNS resolution.
• Implement private hosted zones in Route 53 for internal domain name resolution among your VPC resources, ensuring public and private IPs are easily manageable.
• Regularly audit and update DNS entries to reflect any changes in your network topology, minimizing downtime caused by incorrect resolutions.

Questions to ask your team

• Have you conducted an analysis to determine the maximum IP address requirements for your workloads?
• Is your IP plan documented, and does it include future growth scenarios?
• Are your IP subnets designed to allow for the addition of new resources without reconfiguration?
• How often do you review and update your IP addressing strategy to accommodate new services?
• Do you have controls in place to prevent IP address exhaustion as your workloads scale?

Who should be doing this?

Network Architect

• Design and implement the overall network topology considering reliability and future scalability.
• Analyze current workloads to determine appropriate IP address range allocations.
• Ensure subnet allocations across Availability Zones to maximize resilience and availability.
• Coordinate with teams to understand their networking needs and provide necessary infrastructure.
• Evaluate and select appropriate technologies for intra- and inter-system connectivity.

Infrastructure Engineer

• Deploy and maintain the virtual private cloud (VPC) infrastructure based on the designed topology.
• Implement IP address management strategies for public and private IPs.
• Regularly monitor and adjust subnet sizes to accommodate changes in application architecture.
• Troubleshoot and resolve network-related issues impacting workload availability.

DevOps Engineer

• Collaborate with the Network Architect to integrate network considerations into CI/CD pipelines.
• Implement monitoring solutions for network performance and reliability.
• Automate the provisioning and management of networking resources in alignment with best practices.
• Ensure that workload deployments follow established network guidelines and configurations.

Security Engineer

• Evaluate and ensure that network designs adhere to security protocols and standards.
• Implement network access controls and monitor for unauthorized changes.
• Collaborate with the Network Architect to design network security layers.
• Conduct regular audits of network infrastructure and address security vulnerabilities.

What evidence shows this is happening in your organization?

• IP Address Management Plan: A detailed document outlining the strategy for IP address allocation, subnetting, and addressing future growth to ensure that all workloads have sufficient IP ranges across different environments.
• Network Topology Diagram: Visual representation of the network architecture, including VPC configurations, IP subnets, and the connectivity between components to illustrate future scalability and reliability.
• Subnet Allocation Strategy Checklist: A checklist ensuring that subnets are allocated efficiently, considering future expansion needs and best practices for high availability across multiple Availability Zones.
• Capacity Planning Document: A report detailing the anticipated workload growth and corresponding network requirements, ensuring IP subnet allocations are aligned with projected needs.
• Network Design Policy: A policy document that governs how network topology is planned, including guidelines for IP address management, subnet sizing, and future expansion considerations.

Cloud Services

AWS

• Amazon VPC: Amazon VPC allows you to create a virtual network in your AWS account, where you can manage IP address ranges, subnets, and route tables, enabling efficient planning for network topology.
• AWS IP Address Manager (IPAM): AWS IPAM simplifies the management of IP addresses and helps you monitor IP address usage across your Amazon VPC, facilitating effective IP subnet allocation and planning.
• AWS Network Manager: AWS Network Manager provides a centralized view of your global network and network topology, which is essential for planning connectivity across multiple environments.

Azure

• Azure Virtual Network: Azure Virtual Network enables the creation of isolated virtual networks, allowing for precise IP address management and subnet configurations to cater for expanding workloads.
• Azure Network Watcher: Azure Network Watcher provides tools to monitor and diagnose networking issues in your Azure environments, helping you ensure proper connectivity and IP management.

Google Cloud Platform

• Google Cloud VPC: Google Cloud VPC enables you to create a virtual networking environment with control over IP address allocation and flexible subnetting for your applications and services.
• Cloud DNS: Cloud DNS is a scalable, reliable, and managed authoritative Domain Name System (DNS) service that allows you to manage DNS records, essential for IP address management and network planning.

Question: How do you plan your network topology?
Pillar: Reliability (Code: REL)