Description:

The “big bang” approach involves switching from the old system to the new one in a single, decisive action. All users begin using the new version at once.

Use Case:

• Simple applications with limited users

• Internal tools where brief downtime is acceptable

• Projects with limited budget and complexity

Pros:

• Straightforward implementation

• No need to maintain two versions in parallel

Cons:

• High risk — if something goes wrong, it affects all users

• Potentially longer downtime

• Rollback can be complex and time-consuming

Description:
Involves maintaining two identical environments — “blue” (live) and “green” (staging or updated version). The traffic is switched from blue to green once the new version is ready and tested.

Use Case:

• Systems requiring high availability

• Environments where rollback needs to be fast

• Large-scale web applications

Pros:

• Instant cutover with minimal downtime

• Easy rollback by redirecting traffic back to the blue environment

• Testing can be done on a live-like system

Cons:

• Requires duplication of infrastructure

• Higher operational costs

• Complexity in maintaining environment parity

Description:

Rolls out the new version to a small subset of users first (the “canaries”). If successful, the deployment is gradually extended to the remaining users.

Use Case:

• Applications with large user bases

• Systems where issues must be detected early

• Scenarios requiring progressive rollout

Pros:

• Reduces risk by exposing new features incrementally

• Issues can be detected early and rollback can be limited in scope

• Real-time monitoring of impact on users

Cons:

• More complex automation and routing required

• Slower deployment timeline

• Rollback procedures need to be carefully planned.

Description:

Deploy new code to production but hide it behind feature flags. The feature is turned on or off dynamically without redeploying.

Use Case:

• Testing features in production

• A/B testing and gradual enablement

• Coordinating frontend/backend releases

Pros:

• Allows safe deployment of incomplete features

• Enables real-time user targeting

• Immediate rollback of features without redeploying

Cons:

• Adds complexity to codebase

• Technical debt if flags aren’t cleaned up

• Risk of exposing unfinished or buggy features accidentally

Description:

Replaces instances of the old version with new ones in batches until all have been updated.

Use Case:

• Stateless services

• Cloud-native or container-based applications

• Environments where high availability must be maintained

Pros:

• No downtime when properly orchestrated

• Controlled rollout with monitoring

• Good balance between risk and speed

Cons:

• Requires careful coordination and orchestration

• Rollback can be complex once partial deployment occurs

• Temporary inconsistencies if not managed well