Job slicing does not respect host limit, leading to unnecessary job failures

[jangel97]

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Bug Summary

I have a job template that runs against approximately 50 hosts. To speed up execution, I've set Job Slicing to 5, which effectively runs 5 parallel jobs against 10 hosts each.

However, when I run this job template with a limit set to target only 2 hosts, the job still creates 5 slices. As a result:

• 1 slice succeeds (processing the 2 limited hosts).
• 4 slices fail because they have no hosts to run against.

This behavior causes the overall job to report failures, and since I have alerting configured, I receive unnecessary failure notifications.

My deployment of AAP is in VMs.

AWX version

AAP 2.4

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Installation method

N/A

Modifications

no

Ansible version

No response

Operating system

RHEL 8

Web browser

No response

Steps to reproduce

1. Create a job template with Job Slicing set to 5.
2. Set a limit to target a small number of hosts (e.g., 2 hosts).
3. Launch the job template.
4. Observe that multiple slices fail due to having no hosts assigned.

Expected results

When a limit is set that results in fewer hosts than the number of slices, AWX should adjust the number of slices accordingly. In this case, it should:

• Create only 1 slice to handle the 2 hosts.
• Avoid creating additional slices that have no hosts to process.

Actual results

• AWX creates the maximum number of slices specified (5 in this case), regardless of the number of hosts after applying the limit.
• Slices without any hosts assigned fail, impacting the overall job status.

Additional information

Perhaps this is fixed in AAP 2.5?

[jangel97]

I am willing to discuss about implementation details and create PR for this, if it makes sense to fix this