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What is H2O Workflows?

H2O Workflows is the workflow orchestration component of H2O AI Cloud (HAIC). It is basically a definition language inspired by GitHub Actions, implemented with CUE for type safety and validation. You can use it to define, run, and manage multi-step computational workflows using declarative YAML definitions.

Overview​

Workflows are defined in YAML and validated against a CUE schema. A workflow consists of:

  • Workflow: The top-level container with a name and jobs.
  • Jobs: Independent units of work that can run in parallel or sequentially.
  • Steps: Sequential actions within a job.

What you can do with H2O Workflows​

  • Define workflows as YAML files with jobs, steps, inputs, and triggers.
  • Run workflows manually or on a schedule using CRON triggers.
  • Use matrix jobs to fan out work across parameter combinations.
  • Share logic across teams with reusable workflows.
  • Monitor runs, attempts, and individual steps through the API.

How it works​

  1. You write a YAML workflow definition specifying jobs and steps.
  2. The Workflows server validates your YAML against the schema and stores it as a revision.
  3. When triggered, the orchestrator schedules and executes jobs across available runners.
  4. Each run creates attempts, and each attempt executes the jobs and steps defined in your workflow.

Workflows replaces H2O Orchestrator​

H2O Workflows is the successor to H2O Orchestrator. If you previously used H2O Orchestrator, Workflows provides the same orchestration capabilities with a YAML-based declarative model. The documentation structure mirrors the H2O Orchestrator docs for familiarity.

Next steps​

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