> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/open-source/use-harness-open-source/pipelines-1/reference.md).

# Reference

- [Expression Variables](https://developer.harness.io/open-source/use-harness-open-source/pipelines-1/reference/expression-variables.md)
- [Container](https://developer.harness.io/open-source/use-harness-open-source/pipelines-1/reference/container.md)
- [Volume](https://developer.harness.io/open-source/use-harness-open-source/pipelines-1/reference/volume.md)
- [Pipeline Options](https://developer.harness.io/open-source/use-harness-open-source/pipelines-1/reference/pipeline-options.md)
- [Stage: type ci](https://developer.harness.io/open-source/use-harness-open-source/pipelines-1/reference/stage-type-ci.md)
- [Step: plugin](https://developer.harness.io/open-source/use-harness-open-source/pipelines-1/reference/step-plugin.md)
- [Step: background](https://developer.harness.io/open-source/use-harness-open-source/pipelines-1/reference/step-background.md)
- [Step: run](https://developer.harness.io/open-source/use-harness-open-source/pipelines-1/reference/step-run.md)