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Working with Frames and Multiple Windows

Learn how to switch WebDriver's context into iframes and nested frames, and how to detect, switch between, and close multiple browser windows and tabs.

Checkpointing

How Flink takes consistent, distributed snapshots of a running job's state to enable automatic recovery from failures.

Scaling with the Redis Adapter

Learn how the Redis adapter uses Redis's pub/sub to synchronize rooms and broadcasts across multiple Socket.IO server instances, enabling true horizontal scali…

Controlling Motors and Servos

Drive DC motors, servos, and stepper motors from an Arduino using transistors, H-bridge drivers, and the Servo library, and understand why motors must not be p…

Proxying WebSockets with Nginx

Configure nginx to correctly upgrade and proxy long-lived WebSocket connections, including timeouts and load-balancing considerations.

Testing Roles with Molecule

Learn how Molecule automates spinning up test instances, converging a role, and verifying results to give roles real automated tests.

Vault and Secrets Management

How Ansible Vault encrypts sensitive data at rest, how vault IDs support multiple passwords, and how to integrate vault into automated pipelines safely.

Orchestrating Microservices with Kubernetes

Learn how Kubernetes deploys, scales, heals, and load-balances containerized microservices using Deployments, Services, and self-healing controllers.

Nested Aggregations

Learn how the nested and reverse_nested aggregations let Elasticsearch correctly aggregate over arrays of objects mapped with the nested field type.

What Is Version Control?

An introduction to version control systems, why teams need them, and the difference between centralized and distributed approaches to tracking change over time.