Simple to execute, especially for small applications.
Full control over each step of the deployment process.
Minimal setup or tooling required.
Cons:
Prone to human error, such as forgetting steps or misconfiguring environments.
Downtime is unavoidable, as the application must be stopped and restarted.
No automated rollback — recovery from errors requires manual intervention which will result in more down time.
Not scalable for large systems with high availability requirements.
Ensures continuous availability during the deployment process.
Allows for gradual deployment, reducing the risk of widespread failures.
Integrated rollback mechanisms in orchestrated environments like Kubernetes
Slower deployment compared to updating all instances at once.
For stateful applications, ensuring data consistency across rolling updates adds complexity.
Blue-Green Deployment is a deployment strategy that utilizes two identical production environments, referred to as “blue” and “green.” At any given time, only one of these environments serves live traffic (say, the “blue” environment). When a new version of the application is ready, it is deployed to the idle environment (the “green” environment). Once the update is confirmed to be successful, traffic is switched from the blue environment to the green environment.
When to Use?
Canary releases are ideal for introducing new features or updates in high-traffic applications where minimizing risk is crucial. They are frequently used in environments that rely on continuous delivery or microservices architectures, where frequent updates are part of the process.
Reduces the risk of widespread issues by limiting exposure to a small group of users.
Allows real-time monitoring and gathering of feedback before committing to a full rollout.
Simple rollback by directing traffic back to the old version.
Safely tests the new version under real-world traffic conditions without affecting users.
Allows teams to validate the performance of new features or system improvements.
No risk of negatively impacting the user experience since the shadow system doesn’t serve live traffic.
Requires additional infrastructure to run the shadow environment.
Mirroring live traffic can be resource-intensive, especially for high-traffic applications.
Doesn’t test user-facing interactions directly, as the shadow deployment doesn’t interact with users.
Requires sophisticated traffic management and monitoring tools.
High Infrastructure cost
Rollout complexity increases with the number of versions being managed simultaneously.
Pros:
Cons:
Shadow Deployment is an advanced technique where live traffic is mirrored to a new version of the application running in parallel with the old version. The key difference between this and other deployment methods is that the new version doesn’t serve users directly; instead, it receives the same requests as the old version, but the responses are discarded.
This method allows teams to observe how the new version behaves under production conditions without affecting the live system. It is particularly useful for validating large-scale changes, such as architecture updates, performance optimizations, or complex feature rollouts.
For instance, using tools like Envoy or Istio, real user traffic can be mirrored to both the live system and the shadow system, allowing for side-by-side performance comparisons.
The switch between environments is often handled by load balancers or DNS configuration, making the transition seamless for users. If an issue arises with the new version, it’s easy to revert by switching traffic back to the previous environment.
When to Use?
Blue-Green deployment is perfect for mission-critical applications where zero downtime is a requirement, such as in e-commerce, financial services, or any high-availability environment. It is particularly useful when you need to guarantee that new updates won’t disrupt live users and need a fail-safe rollback option.
Recreate Deployment is simple but best suited for small, non-critical applications.
Rolling Deployment ensures minimal downtime, making it a good fit for distributed systems that require continuous availability.
Blue-Green Deployment offers zero-downtime updates but requires additional infrastructure.
Canary Releases are excellent for minimizing risk during feature rollouts, but they require advanced traffic management.
Shadow Deployment is a powerful tool for validating system performance and large-scale changes without affecting live users.
Requires maintaining two full production environments, which increases infrastructure costs.
Consistency between the two environments must be strictly maintained to avoid discrepancies.
