Enhance Orchestrator Flow: Persist Hhfab Session

Hey guys! Today, we're diving deep into enhancing our orchestrator flow to make it more robust and user-friendly. We'll be focusing on reordering the flow and ensuring that the hhfab session persists, which will significantly improve the reliability and accessibility of our lab environment. Let's get started!

Summary

Our primary goal is to enforce a VLAB-first boot by ensuring that EMC (Elastic Management Console) and GitOps steps are blocked until hhfab reports a healthy lab. This means no more premature EMC initializations! We'll also launch hhfab vlab up --controls-restricted=false --ready wait via a persistent systemd+tmux service. This way, it survives reboots but stays accessible via tmux attach. Think of it as making our lab setup super resilient and easy to monitor. Finally, we'll update the documentation and tests to guarantee this behavior moving forward.

Background

The current orchestrator (packer/scripts/hedgehog-lab-orchestrator) has a couple of key issues. It initializes the k3d EMC before VLAB, and it runs hhfab in the foreground. This makes the entire process fragile. If something goes wrong, you're likely starting from scratch. Additionally, this setup prevents the EMC from using the controller’s host-facing interface, which isn't ideal. PM guidance from 2025-11-08 emphasizes the need for a detached tmux session and host-network connectivity to achieve a more realistic environment. Essentially, we need a system that's more stable, more accessible, and more representative of real-world conditions.

Acceptance Criteria

To ensure we're on the right track, we have a few key acceptance criteria:

1. VLAB-First Orchestration: The orchestrator should refuse to start EMC/GitOps modules until VLAB initialization and hhfab vlab inspect succeed. This guarantees that our lab environment is healthy before we move on to other components.
2. Robust VLAB Launch: VLAB launch must use --controls-restricted=false --ready wait, and its logs should be stored under /var/log/hedgehog-lab/modules/vlab.log. This gives us better control and easier debugging.
3. Systemd + Tmux Persistence: We'll introduce a systemd unit (e.g., hhfab-vlab.service) that spawns a detached tmux session named hhfab-vlab running hhfab. This service should auto-restart and expose its status via systemctl. Think of it as a reliable background process that keeps our lab running.
4. Orchestrator Coordination: Instead of forking hhfab directly, the orchestrator will wait on the systemd unit. The state will be recorded in /var/lib/hedgehog-lab/state.json, providing a clear picture of what's happening behind the scenes.
5. Clear Documentation: Our documentation (docs/build/BUILD_GUIDE.md, docs/INSTALL.md) needs to explain how students can view the session using tmux ls and tmux attach -t hhfab-vlab. We want to make it as easy as possible for users to interact with the lab.
6. Comprehensive Testing: We'll write or update tests (Bats/Python or similar) to fail on incorrect ordering or missing services. These tests will be wired into our CI pipeline (make test or a new target) to catch issues early.
7. Successful Implementation: All changes will land via a PR with all GitHub Actions workflows passing and full code review. This ensures that our code is high-quality and well-vetted.

Diving Deeper into the Acceptance Criteria

To truly appreciate the significance of these acceptance criteria, let's delve a bit deeper into why each one is crucial for the overall improvement of our orchestrator flow.

VLAB-First Orchestration:

Why it matters: Imagine starting a car without checking if the engine is running smoothly. That's essentially what we're doing if we initialize EMC/GitOps before ensuring VLAB is healthy. By prioritizing VLAB, we prevent potential cascading failures and ensure that all subsequent steps are built on a solid foundation. This approach reduces debugging time and enhances the overall reliability of our lab environment.

Implementation details: The orchestrator will include checks to verify that VLAB has been successfully initialized and that hhfab vlab inspect returns the expected results. If VLAB is not healthy, the orchestrator will pause and provide informative error messages to guide users in troubleshooting the issue. This proactive approach minimizes frustration and ensures a smoother user experience.

Robust VLAB Launch:

Why it matters: The --controls-restricted=false --ready wait flags are essential for giving us the necessary control and feedback during the VLAB launch process. By disabling controls restriction, we gain more flexibility in configuring the lab environment. The --ready wait flag ensures that the orchestrator waits until VLAB is fully initialized before proceeding to the next steps. Logging to /var/log/hedgehog-lab/modules/vlab.log provides a centralized location for debugging and monitoring VLAB's behavior.

Implementation details: The systemd service will be configured to launch hhfab with these specific flags. Additionally, we'll implement robust logging to capture any errors or warnings during the VLAB launch process. This detailed logging will be invaluable for diagnosing issues and improving the stability of our lab environment.

Systemd + Tmux Persistence:

Why it matters: Running hhfab in a detached tmux session managed by systemd is a game-changer for the persistence and accessibility of our lab environment. Systemd ensures that the hhfab process automatically restarts if it crashes, providing a self-healing mechanism. Tmux allows users to easily attach to the hhfab session, monitor its progress, and interact with the lab environment in real-time. This combination of systemd and tmux creates a robust and user-friendly experience.

Implementation details: The systemd unit file will be carefully crafted to ensure that the hhfab process is launched correctly and that it restarts automatically if necessary. We'll also configure tmux to create a persistent session that users can easily attach to. This seamless integration of systemd and tmux will significantly enhance the reliability and accessibility of our lab environment.

Orchestrator Coordination:

Why it matters: By having the orchestrator wait on the systemd unit, we create a clear dependency chain that ensures VLAB is fully operational before moving on to other components. Recording the state in /var/lib/hedgehog-lab/state.json provides a centralized location for tracking the progress of the orchestration process. This enhanced coordination and state management improve the overall transparency and maintainability of our lab environment.

Implementation details: The orchestrator will use systemd's API to monitor the status of the hhfab-vlab.service. If the service fails to start or encounters an error, the orchestrator will pause and provide informative error messages to guide users in troubleshooting the issue. The state.json file will be updated to reflect the current status of the VLAB initialization process, providing a clear audit trail for debugging purposes.

Clear Documentation:

Why it matters: Comprehensive documentation is essential for empowering students and users to effectively interact with our lab environment. By clearly explaining how to view the hhfab session using tmux ls and tmux attach -t hhfab-vlab, we lower the barrier to entry and enable users to take full advantage of the lab's capabilities. Well-documented processes also reduce the support burden and promote self-sufficiency.

Implementation details: The documentation will be updated with step-by-step instructions on how to access the hhfab session using tmux. We'll also include screenshots and examples to make the process as clear and intuitive as possible. The goal is to create documentation that is both comprehensive and easy to understand, empowering users to confidently navigate the lab environment.

Comprehensive Testing:

Why it matters: Rigorous testing is crucial for ensuring that our orchestrator flow behaves as expected and that all components are properly integrated. By writing or updating tests to fail on incorrect ordering or missing services, we can catch potential issues early and prevent them from impacting users. Integrating these tests into our CI pipeline ensures that every change is thoroughly vetted before it is deployed.

Implementation details: We'll create unit tests to verify the order of execution of the orchestrator steps. We'll also write integration tests to confirm that the systemd service is running correctly and that tmux is properly configured. These tests will be automated and run as part of our CI pipeline, providing continuous feedback on the health of our orchestrator flow.

Successful Implementation:

Why it matters: A successful implementation is the ultimate measure of our efforts. By requiring all changes to land via a PR with passing GitHub Actions workflows and full code review, we ensure that our code is high-quality, well-tested, and thoroughly vetted. This rigorous process minimizes the risk of introducing bugs and ensures that our orchestrator flow is reliable and maintainable.

Implementation details: We'll establish clear guidelines for code review and testing. We'll also configure our CI pipeline to automatically run all tests and checks before a PR can be merged. This comprehensive approach ensures that every change is carefully scrutinized and that only high-quality code is deployed to our lab environment.

Implementation Notes

Here are some key implementation notes to keep in mind:

• Tmux Installation: Ensure that tmux is installed during the provisioning process. It's a critical dependency for managing the hhfab session.
• Wrapper Script: Consider creating a wrapper script like /usr/local/bin/hhfab-vlab-runner. This script can handle retries and log redirection, making the system more resilient.
• Error Output: Provide helpful error output when the orchestrator detects a failure. Tailoring the service logs can significantly aid in troubleshooting.

Elaborating on Implementation Notes

Let's break down these implementation notes further to understand their importance and how they contribute to the overall success of our orchestrator flow.

Tmux Installation:

Why it matters: Tmux is the cornerstone of our persistent session management. Without it, we lose the ability to easily attach to and monitor the hhfab process. Ensuring that tmux is installed during provisioning is a fundamental requirement for achieving our goals.

Implementation details: The provisioning scripts will be updated to include the installation of tmux. This can be achieved through package managers like apt or yum, depending on the underlying operating system. We'll also verify that tmux is properly configured and that it is running as expected.

Wrapper Script:

Why it matters: A wrapper script like /usr/local/bin/hhfab-vlab-runner provides an additional layer of robustness and flexibility. It can handle retries in case of transient errors, redirect logs to the appropriate location, and perform other tasks that enhance the reliability of the system. This script acts as a safeguard against unexpected issues and ensures that the hhfab process runs smoothly.

Implementation details: The wrapper script will be written in a scripting language like bash or Python. It will include logic to retry the hhfab command if it fails, with appropriate backoff intervals. The script will also redirect standard output and standard error to the log file, providing a comprehensive record of the hhfab process.

Error Output:

Why it matters: Clear and informative error output is essential for efficient troubleshooting. When the orchestrator detects a failure, it's crucial to provide users with the information they need to diagnose the issue and take corrective action. Tailoring the service logs to include relevant details can significantly reduce debugging time.

Implementation details: The orchestrator will be configured to capture and display the output of the systemd service when it encounters an error. This output will include the contents of the log file, providing a detailed view of what went wrong. We'll also provide specific error messages that guide users in troubleshooting common issues.

Testing

Our testing strategy will include:

• Unit Tests: Covering orchestrator step order and service dependency checks.
• Integration Smoke Test (Optional): Confirming that systemctl status hhfab-vlab returns active and tmux ls lists the session.

By following these steps, we'll create a more reliable, accessible, and user-friendly lab environment. Let's get to work!