The orchestration engine supports three execution backends. The planner and step contracts stay the same; only how each step runs changes.

Comparison

Backend Env value How steps run Good for
CrewAI in-process inprocess (default) Whole crew in one Python process Local dev, single machine
Subprocess subprocess + AGENTIC_SUBPROCESS_WORKERS=1 One python main.py --execute-step worker per step Step isolation, container testing
Kubernetes kubernetes K8s Job per step, PVC run store Production, multi-tenant

In-process (default)

No extra configuration. CrewAIExecutionBackend runs agents in the coordinator process.

# implicit default
AGENTIC_EXECUTION_BACKEND=inprocess

Subprocess

Each step spawns a worker subprocess that reads a StepSpec JSON file and writes result.json to the shared run store.

export AGENTIC_EXECUTION_BACKEND=subprocess
export AGENTIC_SUBPROCESS_WORKERS=1
export AGENTIC_RUN_STORE_PATH=/tmp/agentic-run-store
python main.py --dynamic "Smoke test subprocess isolation"

Status: F0–F4 complete — subprocess path proven in CI.

Kubernetes

Each step becomes a one-shot K8s Job mounting a ReadWriteMany PVC at AGENTIC_K8S_RUN_STORE_MOUNT (default /run/store).

export AGENTIC_EXECUTION_BACKEND=kubernetes
export AGENTIC_K8S_WORKER_IMAGE=agentic-orchestrator-worker:local
export AGENTIC_K8S_RUN_STORE_PVC=agentic-run-store
export AGENTIC_RUN_STORE_PATH=/run/store   # coordinator must share the same store

Deploy manifests: agentic-orchestration-tool/deploy/k8s/.

Concern Notes
MCP stdio Worker-native stdio or cluster sidecar gateways
Run store hostPath (kind), NFS, or GKE Filestore
CI kind e2e with stub worker image

Status: K3 MVP implemented (kind CI e2e). K5 operational polish (warm pool, structured logs) optional.

Run store layout

{AGENTIC_RUN_STORE_PATH}/{run_id}/{step_id}/result.json
{AGENTIC_RUN_STORE_PATH}/{run_id}/{step_id}-spec.json

Workers and coordinator must share this path (bind mount, PVC, or NFS).

What stays the same

  • YAML agent and MCP catalogs
  • Planner JSON plan format
  • Session, KB, learning, and QA hooks
  • --execute-step worker contract

See Architecture for the full pipeline.

Deep dives: Dual execution framework (F0–F5 code seam) and Kubernetes execution upgrade (cluster delivery, K3–K5).