AWS VPC Configuration: 5 Kick-Yourself Mistakes

AWS VPC configuration: getting it right.

AWS VPC logoThe great thing about an AWS VPC is the incredible flexibility and security it offers. Amazon’s VPCs allow you to provision compute resources, like EC2 instances and RDS deployments, inside Amazon’s isolated virtual networks, giving you complete control over all inbound and outbound network traffic. You can select IP address ranges, subnet association, and route table and network gateway configuration. You’re really in control.

Here’s what’s great about the VPCs:

  • Since instances launched into an AWS VPC aren’t directly accessible from the internet, they are by default more secure.
  • VPCs simplify security, allowing seamless integration with ACLs, Routing rules, and security groups.
  • You can attach multiple network interfaces.
  • You can directly connect your on-premise network to an AWS VPC.
  • VPCs simplify secure, multi-tier web deployments (like connecting a public app to a private database server living in a private subnet).
  • Disaster recovery backup images built on VPC connectivity through private connections can make recovering mission-critical data simpler and more reliable.
  • Launch-dedicated instances running on hardware dedicated to a single customer gain additional isolation.

On the other hand…

As well-designed as VPCs are, they’re not bulletproof. Especially when human beings get involved. Since you should be aiming for absolute perfection for all your deployments, make sure that you avoid these configuration blunders:

Five AWS VPC config mistakes

  1. Poor subnet/CIDR Block planning: Administrators often fail to keep network compatibility and future needs in mind while designing their VPC subnets and CIDR blocks. Bearing in mind that AWS VPC subnet blocks, once assigned, can’t be modified, you should carefully calculate how many nodes each subnet might need. Remember: creating a /24 or /27 CIDR might not leave you enough addresses. Also, choosing, say, a 10.0.0.0/16 block for your VPC subnet when the local data center you want to connect to uses 10.0.26.0/24 won’t end happily.
  2. Public IP addresses: When you launch an instance into the public subnet of a nondefault VPC (using it’s default settings), it will not get a public IP or hostname the way it would use the old EC2-Classic. Once it’s created, the only way to make your instance publicly addressable is by assigning an elastic IP to the node. Elastic IPs are not free and, by default, you are limited to five per account (although you can always request more).
  3. Sharing Production and Development Environments: Putting all your staging, dev, and production environments into a single VPC will pretty much guarantee loads of confusion and endless security group and routing table conflicts.
  4. Not considering distributed redundancy for NAT instances: Smart admins always build High-Availability into their applications. But then some of them place their applications or database servers inside private subnets that will access remote services (S3, SQS, patches, and updates) through stand-alone NAT instances. When the NAT instance goes down, your whole application will break. Here’s a quick tutorial to build and configure a NAT Instance.
  5. Assuming an AWS VPC requires complex networking skills: VPCs are not switches. VPCs are not routers. VPCs are not firewalls. Even if they perform the work of all three of those hardware tools, VPCs are really software-defined networks (SDN). AWS designed them from the bottom up to be straightforward and uncomplicated. You do need to understand a few very basic networking concepts like routing, NAT, VPN, and ACL, but AWS itself does most of the heavy lifting.

Conclusion

If you’re still hosting your applications within EC2-Classic, you should seriously consider migrating to AWS VPC to leverage the huge benefits of VPC. But always stick with Best Practices…and think ahead!

And by the way, Cloud Academy has a full video course on AWS VPCs.

Avatar

Written by

Nitheesh Poojary

My professional IT career began nine years back when I was just out of my college. I worked with a great team as an infrastructure management engineer, managing hundreds of enterprise application servers. I found my passion when I got the opportunity to work with Cloud technologies: I'm addicted to AWS Cloud Services, DevOps engineering, and all the cloud tools and technologies that make engineers' lives easier. Currently, I am working as a Solution Architect in SixNines IT. We are an experienced team of engineers that have helped hundreds of customers move to the cloud responsibly. I have achieved 5 AWS certifications, happily helping fellow engineers across the globe through my blogs and answering questions in various forums.


Related Posts

Patrick Navarro
Patrick Navarro
— January 22, 2020

Top 5 AWS Salary Report Findings

At the speed the cloud tech space is developing, it can be hard to keep track of everything that’s happening within the AWS ecosystem. Advances in technology prompt smarter functionality and innovative new products, which in turn give rise to new job roles that have a ripple effect on t...

Read more
  • AWS
  • salary
Alisha Reyes
Alisha Reyes
— January 6, 2020

New on Cloud Academy: Red Hat, Agile, OWASP Labs, Amazon SageMaker Lab, Linux Command Line Lab, SQL, Git Labs, Scrum Master, Azure Architects Lab, and Much More

Happy New Year! We hope you're ready to kick your training in overdrive in 2020 because we have a ton of new content for you. Not only do we have a bunch of new courses, hands-on labs, and lab challenges on AWS, Azure, and Google Cloud, but we also have three new courses on Red Hat, th...

Read more
  • agile
  • AWS
  • Azure
  • Google Cloud Platform
  • Linux
  • OWASP
  • programming
  • red hat
  • scrum
Alisha Reyes
Alisha Reyes
— December 24, 2019

Cloud Academy’s Blog Digest: Azure Best Practices, 6 Reasons You Should Get AWS Certified, Google Cloud Certification Prep, and more

Happy Holidays from Cloud Academy We hope you have a wonderful holiday season filled with family, friends, and plenty of food. Here at Cloud Academy, we are thankful for our amazing customer like you.  Since this time of year can be stressful, we’re sharing a few of our latest article...

Read more
  • AWS
  • azure best practices
  • blog digest
  • Cloud Academy
  • Google Cloud
Avatar
Guy Hummel
— December 12, 2019

Google Cloud Platform Certification: Preparation and Prerequisites

Google Cloud Platform (GCP) has evolved from being a niche player to a serious competitor to Amazon Web Services and Microsoft Azure. In 2019, research firm Gartner placed Google in the Leaders quadrant in its Magic Quadrant for Cloud Infrastructure as a Service for the second consecuti...

Read more
  • AWS
  • Azure
  • Google Cloud Platform
Alisha Reyes
Alisha Reyes
— December 10, 2019

New Lab Challenges: Push Your Skills to the Next Level

Build hands-on experience using real accounts on AWS, Azure, Google Cloud Platform, and more Meaningful cloud skills require more than book knowledge. Hands-on experience is required to translate knowledge into real-world results. We see this time and time again in studies about how pe...

Read more
  • AWS
  • Azure
  • Google Cloud
  • hands-on
  • labs
Alisha Reyes
Alisha Reyes
— December 5, 2019

New on Cloud Academy: AWS Solution Architect Lab Challenge, Azure Hands-on Labs, Foundation Certificate in Cyber Security, and Much More

Now that Thanksgiving is over and the craziness of Black Friday has died down, it's now time for the busiest season of the year. Whether you're a last-minute shopper or you already have your shopping done, the holidays bring so much more excitement than any other time of year. Since our...

Read more
  • AWS
  • AWS solution architect
  • AZ-203
  • Azure
  • cyber security
  • FCCS
  • Foundation Certificate in Cyber Security
  • Google Cloud Platform
  • Kubernetes
Avatar
Cloud Academy Team
— December 4, 2019

Understanding Enterprise Cloud Migration

What is enterprise cloud migration? Cloud migration is about moving your data, applications, and even infrastructure from your on-premises computers or infrastructure to a virtual pool of on-demand, shared resources that offer compute, storage, and network services at scale. Why d...

Read more
  • AWS
  • Azure
  • Data Migration
Wendy Dessler
Wendy Dessler
— November 27, 2019

6 Reasons Why You Should Get an AWS Certification This Year

In the past decade, the rise of cloud computing has been undeniable. Businesses of all sizes are moving their infrastructure and applications to the cloud. This is partly because the cloud allows businesses and their employees to access important information from just about anywhere. ...

Read more
  • AWS
  • Certifications
  • certified
Avatar
Andrea Colangelo
— November 26, 2019

AWS Regions and Availability Zones: The Simplest Explanation You Will Ever Find Around

The basics of AWS Regions and Availability Zones We’re going to treat this article as a sort of AWS 101 — it’ll be a quick primer on AWS Regions and Availability Zones that will be useful for understanding the basics of how AWS infrastructure is organized. We’ll define each section,...

Read more
  • AWS
Avatar
Dzenan Dzevlan
— November 20, 2019

Application Load Balancer vs. Classic Load Balancer

What is an Elastic Load Balancer? This post covers basics of what an Elastic Load Balancer is, and two of its examples: Application Load Balancers and Classic Load Balancers. For additional information — including a comparison that explains Network Load Balancers — check out our post o...

Read more
  • ALB
  • Application Load Balancer
  • AWS
  • Elastic Load Balancer
  • ELB
Albert Qian
Albert Qian
— November 13, 2019

Advantages and Disadvantages of Microservices Architecture

What are microservices? Let's start our discussion by setting a foundation of what microservices are. Microservices are a way of breaking large software projects into loosely coupled modules, which communicate with each other through simple Application Programming Interfaces (APIs). ...

Read more
  • AWS
  • Docker
  • Kubernetes
  • Microservices
Nisar Ahmad
Nisar Ahmad
— November 12, 2019

Kubernetes Services: AWS vs. Azure vs. Google Cloud

Kubernetes is a popular open-source container orchestration platform that allows us to deploy and manage multi-container applications at scale. Businesses are rapidly adopting this revolutionary technology to modernize their applications. Cloud service providers — such as Amazon Web Ser...

Read more
  • AWS
  • Azure
  • Google Cloud
  • Kubernetes