Applications hosted in cloud providers achieve high availability via redundancy across different Availability Zones. Ensure that failover works seamlessly by simulating Zone outages.

Motivation

Cloud provider can host your deployments and services across multiple locations worldwide. From a reliability standpoint, cloud provider's regions and availability zones are most interesting. While the former refers to separate geographic areas spread worldwide, the latter refers to an isolated location within a region. For most use cases, applying deployments across availability zone is sufficient. Given that failures may happen at this level quite frequently, you should verify that your applications are still working in case of an outage.

Structure

We leverage the Container block traffic attack to simulate an availability zone outage just for a specific deployment. Before the simulated outage, we ensure that a load-balanced user-facing endpoint works appropriately. During an availability zone's unavailability, the HTTP endpoint must continue operating but may suffer from degraded performance (e.g., lower success rate or higher response time). The performance should recover as soon as the zone is back again.

Solution Sketch

• AWS regions and zones
• Azure regions
• Azure availability zones
• GCP regions and Zones
• Kubernetes liveness, readiness, and startup probes