What are shadow deployment and canary deployment?

Shadow deployment is a deployment strategy where a new version of a service is launched in parallel with the current one but does not affect real user traffic. The new service receives copies of requests (shadow traffic) for testing in real conditions without risking users. This helps identify errors and test performance.

Canary deployment is a gradual rollout of a new version to a small portion of users (for example, 5-10%) to verify stability and correctness. If no issues arise, the share of users with the new version gradually increases. This approach reduces risks during updates.

Both methods are widely used in MLOps for the safe deployment of new models and services.