Agile Software Testing — Session 1

Overview

This session is a hands-on technical course segment focused on setting up and interacting with a K6 container for performance testing, using Docker and docker-compose. The instructor guides participants through verifying container access, executing K6 commands, and understanding the limitations of running Docker inside a container. The session emphasizes practical navigation, prompt awareness, and correct command usage within containerized environments.

Topic (Timeline)

1. Introduction and Time Allocation [00:00:03 - 00:00:23]

The instructor opens by inviting participants to ask questions, offering to remotely connect to their machines for troubleshooting. A 11-minute window (remaining Pomodoro interval) is allocated for the current task, with an expectation that it will be completed quickly.

2. Clarification of Command Syntax [00:00:26 - 00:00:32]

The instructor confirms the correct command for permanent deletion, referencing a red button labeled “delete forever,” likely in a UI context preceding this segment.

3. K6 Container Access and Version Verification [00:00:35 - 00:02:33]

Participants are instructed to access the K6 container (part of Grafana’s performance testing toolset) and verify its version using the appropriate K6 command. The instructor emphasizes that Docker cannot be executed from within the K6 container, as it lacks Docker installation — comparing it to running a VM inside a VM. Participants are reminded to check their shell prompt to confirm they are inside the K6 container, not the host system.

4. Host System Setup and docker-compose Execution [00:02:33 - 00:03:33]

Participants are directed to switch to their host machine’s terminal (CMD or shell) and confirm the presence of the docker-compose.yaml file within the course directory. The instructor demonstrates running docker-compose up -d to start containers, noting that image and volume caching make the process fast in this environment, though initial runs may take minutes. After successful execution, participants are confirmed to have running containers.

5. Entering K6 Container and Command Validation [00:03:33 - 00:04:30]

Participants are guided to enter the K6 container and verify the version again, now observing the changed prompt as confirmation of successful entry. The instructor poses a question: whether a JMeter command (line 42) would work inside the K6 container. The correct response is confirmed — it would not, as JMeter is not installed in the K6 container, reinforcing the principle that only K6-specific commands are available within this environment.

6. Final Check and Transition [00:04:30 - 00:04:30]

The instructor confirms all participants successfully completed the task, with no reported issues. The session concludes with a transition to the next topic.

Appendix

Key Principles

• Container Isolation: Containers do not inherit host tools (e.g., Docker) unless explicitly installed. Running Docker inside a container requires privileged mode and is not standard practice.
• Prompt Awareness: The shell prompt indicates the execution context (host vs. container); always verify before running commands.
• Tool-Specific Environments: Each container is purpose-built (e.g., K6 for load testing); only its native commands are available.

Tools Used

• K6 (Grafana’s performance testing tool)
• Docker
• docker-compose

Common Pitfalls

• Attempting to run docker commands from within a non-Docker container.
• Misinterpreting container prompts as host shell prompts.
• Assuming tools from other environments (e.g., JMeter) are available in unrelated containers.

Practice Suggestions

• Always run docker ps from the host to verify container status.
• Use docker exec -it <container_name> /bin/sh to enter containers and verify installed tools with which <command> or <command> --version.
• Keep a cheat sheet of container-specific commands and their expected outputs.