Address raciness in starting sriov services

[apdibbo]

Address raciness in starting sriov services

With some of our hosts on rocky 9 we see some raciness where if 2 of the nvidia-sriov services try to start at the same time then 1 or both of the GPUs are rendered unresponsive. A reboot is then required to get the GPU back

This change will bring up each of the nvidia-sriov services in series which seems to prevent the raciness we were seeing

[gemini-code-assist]

Summary of Changes

Hello @apdibbo, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves an issue on Rocky 9 systems where concurrent initialization of NVIDIA SR-IOV services could cause GPUs to become unresponsive, necessitating a system reboot. The solution ensures that these services are brought up one after another, preventing the race condition and enhancing system stability for GPU operations.

Highlights

• Race Condition Fix: Addressed a race condition where multiple nvidia-sriov services starting concurrently could lead to unresponsive GPUs on Rocky 9 hosts.
• Sequential Service Startup: Implemented a mechanism to ensure nvidia-sriov services start sequentially by dynamically adding dependencies to their systemd unit files.
• Ansible Task for Dependency Tracking: Introduced a new Ansible set_fact task to build a list of previously configured nvidia-sriov services, which is then used to enforce startup order.

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[gemini-code-assist]

Code Review

This pull request addresses a race condition when starting multiple nvidia-sriov services by introducing a mechanism to start them sequentially. The approach of dynamically adding dependencies to the systemd service units is a good solution. My review includes a suggestion to refine the Ansible task that builds the list of services, making the implementation more robust and idiomatic. Overall, the change effectively resolves the reported issue.

[jovial]

Nice solution - thanks - I'll make a new release that includes this now.

[jovial]

Included in https://github.com/stackhpc/ansible-collection-linux/releases/tag/v1.5.1