Traffic splitting: This allows the DevOps team to incrementally shift traffic from v1 to v2. They can start with a small percentage of traffic going to v2 (e.g., 5%), monitor its performance, and gradually increase the percentage (e.g., 10%, 25%, 50%, 100%) as confidence grows. This is crucial for a controlled rollout.
Fault injection: This enables the team to introduce controlled failures (like latency, errors, or timeouts) into the system, specifically targeting v2. This helps them assess how the new version behaves under stress and ensure it meets their resilience requirements. They can verify that circuit breakers, retries (if configured), and other resilience mechanisms function as expected.
Linkerd is a lightweight service mesh that can be used to implement traffic splitting and fault injection. → https://linkerd.io/
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B) Load balancing and automatic retry: While load balancing distributes traffic across instances of a service and automatic retry handles transient errors, these features don't directly address the gradual migration or targeted resilience testing needed for a rollout. Load balancing would distribute traffic across all available instances (both v1 and v2 if both are running), not allow for a controlled shift.
C) Automatic retry and fault injection: Fault injection is useful, but without traffic splitting, you can't control which version receives the injected faults. You'd be testing both v1 and v2 simultaneously, making it harder to isolate the impact on the new version.
D) Load balancing and traffic splitting: Load balancing, as explained above, isn't the primary tool for a gradual rollout. Traffic splitting is essential, but without fault injection, you're only testing normal traffic patterns, not how the system handles failures, which is critical for resilience testing.