In the ultra-competitive world of software development, getting your product through the development process safely and efficiently is crucial for success.
This is where choosing the correct deployment strategy comes in. Not only does the right strategy help you to deploy your application faster, increase user experience, and generate greater business revenue, it also helps avoid disaster. After all, testing and deployment errors recently led to one of history’s largest IT disasters, the 2024 global CrowdStrike/Microsoft outage.
In this article, we’ll take a little look at that recent outage and what caused it before diving deep into deployment strategies. We’ll look at what they are, the most popular types, and help you decide the best approach to turbocharge and de-risk your deployment process.
The 2024 CrowdStrike/Microsoft Outage Explained
On July 19th 2024, many of us woke to the news that airlines had grounded flights, police were unable to respond to emergency calls, hospitals were canceling surgeries, and retailers couldn’t take payments. And all of this was due to a software error, causing Windows-based devices to experience the dreaded blue screen of death.
But what really happened?
CrowdStrike, a market-leading cybersecurity tool, installs sensors to monitor devices and prevent harmful activities taking place. To achieve that monitoring, CrowdStrike sits at the heart of the operating system, with permissions to oversee the critical operations of each device.
Unfortunately, an update to these sensors contained a problem, causing it to crash. Given the sensor and the Windows OS were so tightly linked, when the sensor crashed, so did the Microsoft Windows kernel, resulting in an unusable system and the blue screen of death.
In total, 8.5 million Windows devices were directly affected, impacting users across the globe. Because industries such as airlines, emergencies services, and payment providers are critical infrastructure services, they take application version updates as soon as they’re available to help them guard against outsider threats. But, in this instance, taking those updates straight away left them vulnerable to the issue, whereas those still on the previous version of the software remained unaffected.
Experts are estimating up to $5.4 billion dollars of damages to Fortune 500 companies resulting from the incident, with the true cost across the world expected to far exceed that number. The outage brings to life how critical the software deployment process is, and how your strategy may directly help to reduce the risk you face when you deploy the new version of any software package. This is true whether it’s in-house development or updates from a 3rd party supplier.
In the rest of this article, we’ll help you make informed decisions on the approach to deployment by looking at what each deployment strategy involves, the pros and cons of each one, and how they help lower the risk of errors.
What is a Deployment Strategy?
A deployment strategy is a planned approach to releasing new features or updates to a new or existing application.
Once a new software or feature has been developed and tested, the deployment strategy is the method by which developers roll out changes and put it into the hands of users. The right strategy ensures that the transition from the old to the new version is smooth, efficient, and causes minimal downtime for users – all while minimizing the risk of disaster!
In the simplest terms, you can think of software delivery like a classic postal delivery service, with your deployment strategy the difference between sending a parcel by air, rail, or road – with each of those methods having pros and cons around speed, cost, and reliability.
As deployment strategies get move advanced and embedded, organizations can get to a state of rolling updates, where they deploy an application with zero downtime for the user – pretty cool, right?
8 Most Popular Types of Deployment Strategies Explained
Let’s take a closer look at some of the most widely used deployment strategies in the software development world. Each of these is applicable for launching a new application or making changes to an existing application, depending on where you are in your software development life cycle.
1. Big Bang Deployment
The big-bang deployment is perhaps the simplest strategy, but it’s also the riskiest. In this approach, the software is delivered all at once, replacing the old version in an instantaneous transition. Essentially, it’s like flipping a switch – one moment you have the old version, and the next, everything is new.
Pros:
- Simple to implement and understand
- Suitable for small and un-complex applications or those with a limited user base
Cons:
- High risk of system-wide failures – requires a lot of testing and validation to mitigate this
- Difficult to rollback if issues occur
- Can lead to significant downtime
2. Continuous Deployment
Continuous Deployment (CD) is an approach where every change that passes automated testing is automatically deployed to production. It’s all about speed and automation without human intervention. This is great for organizations that need fast, light touch deployment management, most likely on existing applications with a well-established team and infrastructure.
Pros:
- Faster time-to-market for new features through continuous delivery
- Encourages smaller, more manageable updates
- Reduces manual intervention, testing, and human intervention
Cons:
- Requires robust automation for testing and deployment – which can be costly or take time to develop
- May not be suitable for all types of applications
- Can be challenging to implement in large, complex systems with many interdependencies
3. Blue-Green Deployment
Blue-Green deployment involves maintaining two identical production environments, where you deploy the new version alongside the old version – one in each environment. These environments are called Blue and Green environments. At any time, only one of these is ‘live’ and serving users, with the other being updated to reflect new changes. When you want to update your application, you do so in the environment that isn’t live – e.g., the blue environment is live, the green environment is updated, then users switch over to the green environment.
Pros:
- Allows for easy rollback as you can simply swap back to the older version in the other environment
- Minimizes downtime and works as a load balancer
- Provides an opportunity for final testing in a production-like environment
Cons:
- Requires double the IT resources to run two environments
- Can be complex to set up and manage one at a time
- Often requires effort around data synchronization between environments
4. Canary Deployment
Canary deployment allows you to dip your toe in the water before jumping in. A small subset of users or servers receives the new updates first (the canary release), allowing you to test the functionality and assess how it may impact the user experience before increasing traffic to the updated server (and thus the number of users) over time. The canary deployment strategy is especially popular with large organizations that have defined or separate groups of users.
Pros:
- Allows for real-world testing while reducing the risk to the wider organization
- Easy to roll back if issues are detected
- Can be used to gather a subset of user’s feedback on new features
Cons:
- Can be complex to manage and redirect traffic
- Often requires double the IT resources to run multiple environments
- Slower than some other deployment methods
5. Shadow Deployment / Dark Launching
In a shadow deployment, also known as dark launching, the new version runs alongside the current version but doesn’t receive any real user traffic. Instead, it receives a copy of the production traffic, allowing DevOps engineers to test how it performs under real conditions without affecting users. This shadow deployment allows teams to test performance without the need to run dedicated QA testing, helping speed up the path to a new application version.
Pros:
- Allows for performance testing under real conditions
- No risk to actual users
- Can identify issues before they impact real traffic
Cons:
- Requires significant additional resources
- Complex to set up and manage
- May not catch all potential issues, especially those related to user interaction and experience
6. Ramped Deployment & Rolling Deployment
Ramped deployment and rolling deployment both involve gradually replacing instances of the old version with the new version. Like canary deployments, this strategy is often used in environments with multiple servers. There are some slight nuances with a ramped or rolling approach, though. The ramped option gradually increases the percentage of each server running the new version, whereas the rolling approach takes turns to update each server in one go. Choosing between the two will depend on the number of servers and the flexibility of the technologies within them.
Pros:
- Incremental deployments reduce risk to different sets of users
- Can be stopped or rolled back at any point
- Minimizes downtime at large
Cons:
- Can be slow, especially for large-scale applications
- May require running and maintaining multiple versions simultaneously
- Can be complex to manage in highly interconnected systems
7. Recreate Deployment
In a recreate deployment, the old version is completely shut down, the new version is deployed, and then the server is turned back on for users. Like big-bang, this is quite a simple approach but inevitably results in downtime. The recreate deployment strategy is commonly used for non-critical applications, where downtime can be managed in the business operation.
Pros:
- Ensures a clean environment for the new version
- Simple to implement and requires less resources than other strategies
- Useful for large changes such as complete version changes or database schema updates
Cons:
- You can’t use this strategy unless you can accept application downtime.
- All-or-nothing approach increases risk
- Not suitable for applications requiring high availability
8. A/B Testing Deployment
A/B testing deployment involves running two versions of the application side by side and directing a portion of traffic to a select group of users. This allows you to compare the performance or user acceptance of different versions side-by-side. Similar to Blue-Green deployments, it also helps with load balancing and can supplement the broader software deployment strategy.
Pros:
- Allows for data-driven decision-making
- Can be used to test user preferences
- Useful for optimizing features or user interfaces
Cons:
- Requires sophisticated traffic routing
- Can be complex to set up, analyze results, and requires significant additional resources
- May confuse users if the differences are significant
How to Pick The Best Application Deployment & Roll Out Strategy For DevOps & Software Development
Selecting the best deployment strategy is crucial for the success of your software project. Now that we know the deployment strategies to choose from, here are some factors to consider:
- Application Complexity: More complex applications may benefit from strategies that allow for gradual rollout, like Blue-Green or Canary deployments. If the application is less complex, big-bang or recreate deployments may be better.
- Team Size and Expertise: Certain strategies, like Continuous Deployment, require a high level of automation and expertise. Make sure your team is equipped to handle the chosen strategy.
- Risk Tolerance: If your application is critical and downtime is not an option, choose a strategy that’s low-risk, like Blue-Green or Canary deployments.
- Release Frequency: For applications that require continuous deployment, an automated deployment pipeline through Continuous Deployment (CD) or Ramped and Rolling Deployment might be more suitable to complement the broader software delivery process.
- Infrastructure size and costs: Some strategies require additional resources or specific infrastructure setups. Ensure your infrastructure can support your chosen strategy, and that you have the budget available to operate it going forward.
- User Base: Consider the size and nature of your user base. Strategies like A/B Testing or Canary Deployment can be particularly useful for applications with large, diverse user bases where lots of feedback can be gathered.
- Monitoring and Rollback Capabilities: Ensure you have robust monitoring in place and the ability to quickly roll back changes if needed. This is important for various deployment strategies, but especially those with high-risk, such as big-bang.
- Regulatory Requirements: Some industries have strict regulations about software updates. Make sure your chosen strategy complies with any relevant regulations and all modern standards for software development.
Remember, there’s no one-size-fits-all solution when choosing the right deployment strategy. You might even use different strategies for different parts of your application or at different stages of your project’s lifecycle.
Partner With Experts to Master Software Delivery and Choose The Best Approach to Deployment
Like many things in IT, you’re likely to get the best results when you work with experts in a chosen field. This is especially true when it comes to the deployment strategy for your application, as years of expert knowledge can help you streamline the entire process, including defining software goals, optimizing development practices, and decoupling deployment from release to speed up your release cycle.
At Inetum, we have many years of experience helping customers optimize their software development lifecycle, including helping customers to determine which deployment strategy is right for their business, their people, and their application. This includes advising on technology too, with a broad range of expertise in Microsoft Azure, AWS, Kubernetes, and other leading deployment and hosting technologies.
So, if you’re looking for advice to help turbocharge and de-risk your deployment process, why not check out reach out to our consulting team at Inetum to explore the world of software deployment together?
Architect, developer, designer and manager of division responsible for delivering projects in Microsoft technology stack. For almost ten years I has been involved in creating software for the .NET platform for the world's largest companies from different sectors (food and beverage, banking, aerospace). During this time, I participated in the development of desktop, mobile and web applications, performing various roles. Since 2015 I specialize in Microsoft Azure solutions, in particular related to Cloud migration and building innovate Azure native solutions.