Inferensys

Glossary

Argo Workflows

An open-source, container-native workflow engine for orchestrating parallel jobs on Kubernetes, often used to define Directed Acyclic Graphs (DAGs) for complex ML training and data processing pipelines.
Data scientist building training data pipeline on laptop, data preprocessing visible, technical workspace.
Container-Native Workflow Engine

What is Argo Workflows?

Argo Workflows is an open-source, container-native workflow engine for orchestrating parallel jobs on Kubernetes. It enables users to define complex, multi-step pipelines as Directed Acyclic Graphs (DAGs) using custom resources, making it a standard tool for machine learning training and data processing.

Argo Workflows is a Kubernetes-native workflow engine that defines each step in a pipeline as an individual container. It orchestrates complex jobs by modeling them as Directed Acyclic Graphs (DAGs) , where each node is a containerized task with defined dependencies. This architecture allows for the parallel execution of compute-intensive steps, such as hyperparameter tuning or distributed model training, directly on a cluster without external orchestration servers.

The engine is implemented as a Custom Resource Definition (CRD) , extending the Kubernetes API to manage Workflow objects. Users specify pipelines declaratively in YAML, enabling version control and GitOps practices. Argo handles artifact passing between steps, retries, and conditional logic, making it a robust execution layer for Kubeflow pipelines and standalone data engineering tasks in both connected and air-gapped environments.

Container-Native Workflow Engine

Core Capabilities of Argo Workflows

Argo Workflows orchestrates parallel jobs on Kubernetes by defining complex pipelines as Directed Acyclic Graphs (DAGs), making it the standard engine for ML training, data processing, and infrastructure automation in disconnected environments.

01

DAG-Based Pipeline Definition

Define complex multi-step workflows as Directed Acyclic Graphs (DAGs) using YAML manifests. Each step runs in its own container with explicit dependency declarations.

  • Parallel execution: Run independent steps simultaneously to maximize GPU utilization
  • Conditional branching: Implement if/else logic based on step outputs or exit codes
  • Recursive DAGs: Nest workflows within workflows for modular, reusable pipeline components

Example: A training pipeline that fans out hyperparameter sweeps across 16 GPUs, then aggregates results in a final evaluation step.

02

Artifact Passing and Data Management

Automatically pass files and data between workflow steps without manual volume mounting. Argo integrates with S3-compatible object stores, GCS, and Azure Blob Storage.

  • Input/Output artifacts: Declare files that steps produce or consume
  • Artifact repositories: Configure MinIO or local S3 endpoints for air-gapped clusters
  • Compression and archiving: Automatic tarball creation for directory artifacts

Critical for disconnected environments: configure an on-premises artifact repository to store intermediate model checkpoints and training datasets without external network access.

03

Template Composability and Reuse

Encapsulate logic into reusable WorkflowTemplates and ClusterWorkflowTemplates that can be referenced across teams and namespaces.

  • Steps template: Define sequential or parallel execution blocks
  • DAG template: Specify complex dependency graphs between tasks
  • Script template: Run inline scripts with custom images
  • Resource template: Directly create and manage Kubernetes resources

This composability enables platform teams to build a library of approved ML pipeline components that data scientists can assemble without writing infrastructure code.

04

Exit Handlers and Lifecycle Hooks

Implement robust error handling and cleanup logic with exit handlers that execute regardless of workflow success or failure.

  • On-exit hooks: Run cleanup containers to release GPU allocations or delete temporary volumes
  • Retry strategies: Configure exponential backoff with max retry limits per step
  • Timeout controls: Set active deadline seconds to prevent runaway training jobs

Example: A workflow that automatically archives training logs to a local persistent volume and cordons failed GPU nodes when a distributed training job crashes.

05

CronWorkflows for Scheduled Execution

Run workflows on a time-based schedule using CronWorkflow resources, a first-class custom resource that extends Argo's capabilities.

  • Standard cron syntax: Define schedules with minute-hour-day-month-weekday precision
  • Concurrency policy: Allow, forbid, or replace overlapping workflow runs
  • Starting deadline: Set maximum tolerated delay for missed triggers
  • Time zone support: Schedule based on local time zones for regional data processing

Ideal for periodic model retraining pipelines, nightly data aggregation jobs, or scheduled inference batch processing in air-gapped environments.

06

Workflow Observability and Archival

Monitor and debug pipelines with built-in visualization and persistent logging capabilities.

  • Argo UI: Interactive DAG visualization showing real-time step status and logs
  • Workflow archive: Persist completed workflow records with TTL-based cleanup
  • Prometheus metrics: Export custom metrics for integration with existing monitoring stacks
  • Pod annotations: Propagate metadata to underlying pods for log aggregation

Configure the workflow controller to archive completed runs to an on-premises PostgreSQL database, enabling audit trails for compliance without external SaaS dependencies.

ARGO WORKFLOWS EXPLAINED

Frequently Asked Questions

Clear, technical answers to the most common questions about orchestrating complex, container-native Directed Acyclic Graphs (DAGs) on Kubernetes for machine learning and data processing pipelines.

Argo Workflows is an open-source, container-native workflow engine for orchestrating parallel jobs on Kubernetes. It functions by defining a workflow as a Kubernetes Custom Resource Definition (CRD), where each step in the workflow executes inside its own dedicated container. The engine is designed to run complex Directed Acyclic Graphs (DAGs) and simple step-based jobs, making it ideal for multi-step ML training and data processing pipelines. Users define workflows using YAML manifests, specifying a list of templates that can be steps, DAGs, or resource templates. The Argo controller continuously watches for new Workflow CRs and orchestrates the creation of pods, monitors their status, and manages artifact passing between steps using a configured artifact repository like S3 or MinIO. This architecture ensures that each task has isolated dependencies, immutable execution environments, and declarative retry strategies, providing a native Kubernetes experience without external dependencies for scheduling logic.

Prasad Kumkar

About the author

Prasad Kumkar

CEO & MD, Inference Systems

Prasad Kumkar is the CEO & MD of Inference Systems and writes about AI systems architecture, LLM infrastructure, model serving, evaluation, and production deployment. Over 5+ years, he has worked across computer vision models, L5 autonomous vehicle systems, and LLM research, with a focus on taking complex AI ideas into real-world engineering systems.

His work and writing cover AI systems, large language models, AI agents, multimodal systems, autonomous systems, inference optimization, RAG, evaluation, and production AI engineering.