Regarding runner and pipeline

[Sashikanta Mohanty]

I have a question regarding Add Runner/Runner installation. When I Add a runner for Example: select Windows(64bit) for System and Architecture, I see Runner labels comes "self.hosted" and "windows". 
Question1: It is not allowed to delete these default labels. Is it actual behaviour or any way to delete any one runner from these two?

When I run the pipeline and passing 
runs-on:
- self.hosted
- windows
It is working.
Question2: When I keep both Its working and when I delete "windows" and kept "self.hosted", It gives error "no runner is active" even my window runner is on. But when I have put only "windows" as runner It works. Is it the behaviour?

Question 3:
How operating system is getting detect. If I have 2 steps and in one step I am taking 
runs-on:
- self.hosted
- windows
means with runs-on and trying get OS type by using windows command, It is giving me proper result. and in second step I am not passing any runner. when I am trying to execute 
- OS_TYPE=$(uname -s)
- echo "Detected OS- $OS_TYPE"
It gives me "Linux".
Not able to understand in second step how It is getting operating system?

Question 4-  
I have a scenario when I am not passing anything through runs-on then we are considering it as cloud runner. So, In this case   how a system will understand which command to execute If Its window/linux/mac. Please suggest. As per my understanding It will run only linux command . So in case of windows cloud - how can I manage?

Please check those scenarios and give me some solution. I am getting stuck because of this clarification.

[Ben · Accepted solution]

Hi @Sashikanta Mohanty 

To answer your questions:

Question 1:

• When you add a self-hosted runner (e.g., Windows 64-bit), it is automatically assigned the labels:

  • self.hosted

  • windows

• These labels are default and required for the runner to be discoverable and selectable by jobs.

• You cannot remove these default labels. They are enforced by the system to ensure correct runner targeting and OS matching.

• You can add custom labels, but the system labels (self.hosted, windows, etc.) are not removable.

References:

• Runners | Bitbucket Cloud | Atlassian Support

Question 2:

• The runner selection is based on label matching.

• If you specify:

  runs-on:
- self.hosted
- windows

  The job will run on any runner that has both labels (in this case any Windows runners you configure).

• If you specify only self.hosted, the system looks for any self-hosted runner, regardless of OS. If your only available runner is Windows, but the job expects a generic self-hosted runner, it may not match due to additional internal constraints (e.g., job requirements, shell type).

• If you specify only windows, it will match any runner labeled windows (including both self-hosted and cloud runners, if available).

• If you remove "windows" and keep only "self.hosted", and your runner is Windows, it should still match—but if your pipeline or job requires a specific shell or OS, it may fail if the runner doesn't meet those requirements.

• Both labels are required for precise targeting.

• If you want to target a Windows self-hosted runner, you must use both labels.

Question 3:

• Runners are assigned on a per-step basis, meaning you need to define the runs-on parameter for each build step that you wish to execute on a self-hosted runner
• If no runs-on parameter is given, the build will execute on Atlassian infrastructure and not self-hosted, which will always be Linux platform

Question 4:

• See Question 3 above, if you wish your builds to run on Windows architecture only, you must always specify the runs-on parameter in the build step with the two minimum required labels:
  runs-on:
- self.hosted
- windows

Hope this helps!

Cheers!

- Ben (Bitbucket Cloud Support)

[Sashikanta Mohanty]

Thanks @Ben  Thanks, Its really helpful. Thanks for your help.