Architecting on AWS: Dynamic Configuration vs Master AMIs

Infrastructure as a Service holds the promise of reduced costs and increased flexibility that is enabled through ease of operation and management. To seize that opportunity as IT professionals when we are architecting on AWS though, we need to adapt how we view, manage and operate today’s technology.

The desire to respond more agile to changing business needs and the ever-increasing pace in innovation has helped to form the DevOps service delivery model where the development and operations domains moved closer together.

Modern cloud service providers support and continuously advance the model of coded infrastructure. As part of that, they keep abstracting further away from our traditional understanding of IT infrastructure. This is reaching a point, where computing services become a true commodity similar to power or tap water.

If you are new to cloud computing and coded infrastructure, it is important for you to understand those underlying basics as we are going to build on them at the later stage.

When you create a new AWS EC2 instance from one of the (admitting large variety) of Amazon Machine Images (AMIs) you will eventually require to customize certain configuration settings or deploy additional applications to tailor it for your solution. The Base Microsoft Windows Server AMI, for example, doesn’t have a web server pre-installed. This provides you with the flexibility to configure the web server of your choice.

While we could log-on to the machine after launch and manually deploy and configure our web server, this is obviously not going to be good enough long term. Particular not, if we eventually want to be able to dynamically scale our environment. Even if you just want to make a single instance more fault tolerant as described in Architecting on AWS: How to use autoscaling to achieve elastic computing post in this series, you would need to employ a basic level of automation.

Architecting on AWS: the options continuum

As with any good IT problem, there is more than one solution to the problem. Naturally, those options are kind of on opposing ends of a scale. Your task is to weigh off the advantages and disadvantages of each option to find the optimal solution for your needs.

Dynamic configuration

The standard AWS AMIs can be instructed to perform automated tasks or configuration actions at launch time. This is enabled by the EC2Config service for Windows and cloud-init scripts under Linux. You provide those instructions as “user data” as part of the advanced launch configuration of your instances.

The user data instructions can either contain Microsoft script commands and PowerShell scripts on Windows or Shell Script and cloud-init directives on Linux based AMIs. The actual types of actions performed are only limited by your imagination and the total size limit of 16 kilobyte (a minor but important detail).

Pre-baked AMIs

Instead of configuring your instances dynamically at launch time, you can also create your own version of an Amazon Machine Image. Just launch a new instance, ensure that all your ‘static’ applications and settings have been applied, to finally create a new image from that instance. This is done in the AWS console using the Create Image option from the Instance Actions menu or using the create-image command from the Command Line Interface.

Trade-offs

Your decision to decide for a dynamic configuration or master image approach depends on your individual use case. Each of the options does have its advantages and disadvantages that you need to understand and assess against each other in order to find the best solution for your scenario.
One advantage of using pre-baked AMIs is the reduced time to get a new instance from ‘launch’ to ‘ready’. With all components pre-configured and applications installed, you just need to wait for the instance to launch.

This obviously comes at a cost as the image requires constant maintenance. Even if your application code is fairly static, you still need to ensure that you keep your images patched regularly to ensure the resulting instances are not exposed to any new security threats.

On the other hand, the dynamic configuration provides you with a lot of flexibility. Every instance you launch can have an ever so slightly different configuration.
Since you always ever start with an AWS managed AMI your security patches are ‘reasonable’ up-to-date (i.e. usually within 5 business days after Microsoft’s patch Tuesday for Windows AMIs).
You are ‘paying’ for this additional service through the time it takes for your instance to get itself ‘ready’ while executing all launch scripts. You also need to be aware that the ID of the AMI image changes whenever AWS releases a new version of the patched image. This is particularly important to note for your scripted launches or AutoScaling configurations as described in our previous post on this topic.

Fortunately, we are able to combine the two options to get the best of two worlds. For this scenario, you would create an AMI image that contains the applications and configurations items that are changing infrequently (e.g. Internet Information Server, Windows update configuration, etc.). Items that are changing frequently (e.g. your own application) are then injected as part of the dynamic launch configuration.

This approach minimizes the time to get a new instance to the ‘ready’ state, yet still provides you with a level of flexibility to influence the final result through the user data instructions.

Outlook

While this post provided you with an introduction to the entry-level functionality provided to you by AWS this is really just the tip of the iceberg to get your head into the right space towards the concept of a coded infrastructure.

Auxiliary configuration management solutions like Chef, Puppet and PowerShell DSC provide you with additional flexibility and control over your larger deployments.

Based on Chef, AWS OpsWorks also provides you with an application management solution, which is currently limited to Linux based AMIs.

At re:Invent 2014 AWS also released AWS CodeDeploy, supporting the automated deployment of code updates to your Linux and Windows environments, which is currently available for the North Virginia and Oregon regions. Knowing AWS though this is only going to be a short term limitation and we’ll be looking at this service, probably also in combination with Elastic Beanstalk and CloudFormation at a later stage. In the interim, you can start to learn more about the individual AWS services using the AWS training material on the Cloud Academy library.

Avatar

Written by

Christian Petters

As a Solutions Architect, Christian is helping organisations to find the most appropriate solution to address their unique business problems. He is passionate about the opportunities that are provided by modern cloud services and covers topics in AWS and MS Azure with a particular focus on Microsoft technologies.


Related Posts

Avatar
Cloud Academy Team
— July 9, 2020

Which Certifications Should I Get?

As we mentioned in an earlier post, the old AWS slogan, “Cloud is the new normal” is indeed a reality today. Really, cloud has been the new normal for a while now and getting credentials has become an increasingly effective way to quickly showcase your abilities to recruiters and compan...

Read more
  • AWS
  • Azure
  • Certifications
  • Cloud Computing
  • Google Cloud Platform
Alisha Reyes
Alisha Reyes
— July 2, 2020

New Content: AWS, Azure, Typescript, Java, Docker, 13 New Labs, and Much More

This month, our Content Team released a whopping 13 new labs in real cloud environments! If you haven't tried out our labs, you might not understand why we think that number is so impressive. Our labs are not “simulated” experiences — they are real cloud environments using accounts on A...

Read more
  • AWS
  • Azure
  • DevOps
  • Google Cloud Platform
  • Machine Learning
  • programming
Joe Nemer
Joe Nemer
— June 19, 2020

Kickstart Your Tech Training With a Free Week on Cloud Academy

Are you looking to make a jump in your technical career? Want to get trained or certified on AWS, Azure, Google Cloud Platform, DevOps, Kubernetes, Python, or another in-demand skill?Then you'll want to mark your calendar. Starting Monday, June 22 at 12:00 a.m. PDT (3:00 a.m. EDT), ...

Read more
  • AWS
  • Azure
  • cloud academy content
  • complimentary access
  • GCP
  • on the house
Alisha Reyes
Alisha Reyes
— June 11, 2020

New Content: AZ-500 and AZ-400 Updates, 3 Google Professional Exam Preps, Practical ML Learning Path, C# Programming, and More

This month, our Content Team released tons of new content and labs in real cloud environments. Not only that, but we introduced our very first highly interactive "Office Hours" webinar. This webinar, Acing the AWS Solutions Architect Associate Certification, started with a quick overvie...

Read more
  • AWS
  • Azure
  • DevOps
  • Google Cloud Platform
  • Machine Learning
  • programming
Rebecca Willis
Rebecca Willis
— June 3, 2020

Azure vs. AWS: Which Certification Provides the Brighter Future?

More and more companies are using cloud services, prompting more and more people to switch their current IT position to something cloud-related. The problem is most people only have that much time after work to learn new technologies, and there are plenty of cloud services that you can ...

Read more
  • AWS
  • Azure
  • certification
Alisha Reyes
Alisha Reyes
— June 2, 2020

Blog Digest: 5 Reasons to Get AWS Certified, OWASP Top 10, Getting Started with VPCs, Top 10 Soft Skills, and More

Thank you for being a valued member of our community! We recently sent out a short survey to understand what type of content you would like us to add to Cloud Academy, and we want to thank everyone who gave us their input. If you would like to complete the survey, it's not too late. It ...

Read more
  • AWS
  • Azure
  • blog digest
  • Certifications
  • Cloud Academy
  • OWASP
  • OWASP Top 10
  • Security
  • VPCs
Alisha Reyes
Alisha Reyes
— May 11, 2020

New Content: Alibaba, Azure Cert Prep: AI-100, AZ-104, AZ-204 & AZ-400, Amazon Athena Playground, Google Cloud Developer Challenge, and much more

This month, our Content Team released 8 new learning paths, 4 courses, 7 labs in real cloud environments, and 4 new knowledge check assessments. Not only that, but we introduced our very first course on Alibaba Cloud, and our expert instructors are working 'round the clock to create 6 n...

Read more
  • alibaba
  • AWS
  • Azure
  • gitops
  • Google Cloud Platform
  • lab playground
  • programming
Avatar
Rhonda Martinez
— May 4, 2020

Top 5 Reasons to Get AWS Certified Right Now

Cloud computing trends are on the rise and have been for some time already. Fortunately, it’s never too late to start learning cloud computing. Skills like AWS and others associated with cloud computing are in high demand because cloud technologies have become crucial for many businesse...

Read more
  • Amazon Elastic Book Store
  • Amazon Elastic Compute Cloud (EC2)
  • AWS
  • AWS Certifications
  • Glacier
Alisha Reyes
Alisha Reyes
— May 1, 2020

Introducing Our Newest Lab Environments: Lab Playgrounds

Want to train in a real cloud environment, but feel slowed down by spinning up your own deployments? When you consider security or pricing costs, it can be costly and challenging to get up to speed quickly for self-training. To solve this problem, Cloud Academy created a new suite of la...

Read more
  • AWS
  • Azure
  • Docker
  • Google Cloud Platform
  • Java
  • lab playgrounds
  • Python
Alisha Reyes
Alisha Reyes
— April 30, 2020

Blog Digest: AWS Breaking News, Azure DevOps, AWS Study Guide, 8 Ways to Prevent a Ransomware Attack, and More

  New articles by topicAWS Azure Data Science Google Cloud  Cloud Adoption Platform Updates & New Content Security Women in TechAWSBreaking News: All AWS Certification Exams Now Available Online As an Advanced AWS Technology Partner, C...

Read more
  • AWS
  • Azure
  • blog digest
  • Certifications
  • Cloud Academy
  • programming
  • Security
Avatar
Stuart Scott
— April 27, 2020

AWS Certified Solutions Architect Associate: A Study Guide

Want to take a really impactful step in your technical career? Explore the AWS Solutions Architect Associate certificate. Its new version (SAA-C02) was released on March 23, 2020, though you can still take SAA-C01 through July 1, 2020. This post will focus on version SAA-C02.The AWS...

Read more
  • AWS
  • AWS Certifications
  • AWS Certified Solutions Architect Associate
Alisha Reyes
Alisha Reyes
— April 9, 2020

New on Cloud Academy: AWS Solutions Architect Exam Prep, Azure Courses, GCP Engineer Exam Prep, Programming, and More

Free content on Cloud Academy More and more customers are relying on our technology and content to keep upskilling their people in these months, and we are doing our best to keep supporting them. While the world fights the COVID-19 pandemic, we wanted to make a small contribution to he...

Read more
  • AWS
  • Azure
  • Google Cloud Platform
  • programming