davila7/skypilot-multi-cloud-orchestration

SkyPilot Multi-Cloud Orchestration

Comprehensive guide to running ML workloads across clouds with automatic cost optimization using SkyPilot.

When to use SkyPilot

Use SkyPilot when:

• Running ML workloads across multiple clouds (AWS, GCP, Azure, etc.)
• Need cost optimization with automatic cloud/region selection
• Running long jobs on spot instances with auto-recovery
• Managing distributed multi-node training
• Want unified interface for 20+ cloud providers
• Need to avoid vendor lock-in

Key features:

• Multi-cloud: AWS, GCP, Azure, Kubernetes, Lambda, RunPod, 20+ providers
• Cost optimization: Automatic cheapest cloud/region selection
• Spot instances: 3-6x cost savings with automatic recovery
• Distributed training: Multi-node jobs with gang scheduling
• Managed jobs: Auto-recovery, checkpointing, fault tolerance
• Sky Serve: Model serving with autoscaling

Use alternatives instead:

• Modal: For simpler serverless GPU with Python-native API
• RunPod: For single-cloud persistent pods
• Kubernetes: For existing K8s infrastructure
• Ray: For pure Ray-based orchestration

Quick start

Installation

pip install "skypilot[aws,gcp,azure,kubernetes]"

# Verify cloud credentials
sky check

Hello World

Create hello.yaml:

resources:
  accelerators: T4:1

run: |
  nvidia-smi
  echo "Hello from SkyPilot!"

Launch:

sky launch -c hello hello.yaml

# SSH to cluster
ssh hello

# Terminate
sky down hello

Core concepts

Task YAML structure

# Task name (optional)
name: my-task

# Resource requirements
resources:
  cloud: aws              # Optional: auto-select if omitted
  region: us-west-2       # Optional: auto-select if omitted
  accelerators: A100:4    # GPU type and count
  cpus: 8+                # Minimum CPUs
  memory: 32+             # Minimum memory (GB)
  use_spot: true          # Use spot instances
  disk_size: 256          # Disk size (GB)

# Number of nodes for distributed training
num_nodes: 2

# Working directory (synced to ~/sky_workdir)
workdir: .

# Setup commands (run once)
setup: |
  pip install -r requirements.txt

# Run commands
run: |
  python train.py

Key commands

| Command | Purpose | |---------|---------| | sky launch | Launch cluster and run task | | sky exec | Run task on existing cluster | | sky status | Show cluster status | | sky stop | Stop cluster (preserve state) | | sky down | Terminate cluster | | sky logs | View task logs | | sky queue | Show job queue | | sky jobs launch | Launch managed job | | sky serve up | Deploy serving endpoint |

GPU configuration

Available accelerators

# NVIDIA GPUs
accelerators: T4:1
accelerators: L4:1
accelerators: A10G:1
accelerators: L40S:1
accelerators: A100:4
accelerators: A100-80GB:8
accelerators: H100:8

# Cloud-specific
accelerators: V100:4         # AWS/GCP
accelerators: TPU-v4-8       # GCP TPUs

GPU fallbacks

resources:
  accelerators:
    H100: 8
    A100-80GB: 8
    A100: 8
  any_of:
    - cloud: gcp
    - cloud: aws
    - cloud: azure

Spot instances

resources:
  accelerators: A100:8
  use_spot: true
  spot_recovery: FAILOVER  # Auto-recover on preemption

Cluster management

Launch and execute

# Launch new cluster
sky launch -c mycluster task.yaml

# Run on existing cluster (skip setup)
sky exec mycluster another_task.yaml

# Interactive SSH
ssh mycluster

# Stream logs
sky logs mycluster

Autostop

resources:
  accelerators: A100:4
  autostop:
    idle_minutes: 30
    down: true  # Terminate instead of stop

# Set autostop via CLI
sky autostop mycluster -i 30 --down

Cluster status

# All clusters
sky status

# Detailed view
sky status -a

Distributed training

Multi-node setup

resources:
  accelerators: A100:8

num_nodes: 4  # 4 nodes × 8 GPUs = 32 GPUs total

setup: |
  pip install torch torchvision

run: |
  torchrun \
    --nnodes=$SKYPILOT_NUM_NODES \
    --nproc_per_node=$SKYPILOT_NUM_GPUS_PER_NODE \
    --node_rank=$SKYPILOT_NODE_RANK \
    --master_addr=$(echo "$SKYPILOT_NODE_IPS" | head -n1) \
    --master_port=12355 \
    train.py

Environment variables

| Variable | Description | |----------|-------------| | SKYPILOT_NODE_RANK | Node index (0 to num_nodes-1) | | SKYPILOT_NODE_IPS | Newline-separated IP addresses | | SKYPILOT_NUM_NODES | Total number of nodes | | SKYPILOT_NUM_GPUS_PER_NODE | GPUs per node |

Head-node-only execution

run: |
  if [ "${SKYPILOT_NODE_RANK}" == "0" ]; then
    python orchestrate.py
  fi

Managed jobs

Spot recovery

# Launch managed job with spot recovery
sky jobs launch -n my-job train.yaml

Checkpointing

name: training-job

file_mounts:
  /checkpoints:
    name: my-checkpoints
    store: s3
    mode: MOUNT

resources:
  accelerators: A100:8
  use_spot: true

run: |
  python train.py \
    --checkpoint-dir /checkpoints \
    --resume-from-latest

Job management

# List jobs
sky jobs queue

# View logs
sky jobs logs my-job

# Cancel job
sky jobs cancel my-job

File mounts and storage

Local file sync

workdir: ./my-project  # Synced to ~/sky_workdir

file_mounts:
  /data/config.yaml: ./config.yaml
  ~/.vimrc: ~/.vimrc

Cloud storage

file_mounts:
  # Mount S3 bucket
  /datasets:
    source: s3://my-bucket/datasets
    mode: MOUNT  # Stream from S3

  # Copy GCS bucket
  /models:
    source: gs://my-bucket/models
    mode: COPY  # Pre-fetch to disk

  # Cached mount (fast writes)
  /outputs:
    name: my-outputs
    store: s3
    mode: MOUNT_CACHED

Storage modes

| Mode | Description | Best For | |------|-------------|----------| | MOUNT | Stream from cloud | Large datasets, read-heavy | | COPY | Pre-fetch to disk | Small files, random access | | MOUNT_CACHED | Cache with async upload | Checkpoints, outputs |

Sky Serve (Model Serving)

Basic service

# service.yaml
service:
  readiness_probe: /health
  replica_policy:
    min_replicas: 1
    max_replicas: 10
    target_qps_per_replica: 2.0

resources:
  accelerators: A100:1

run: |
  python -m vllm.entrypoints.openai.api_server \
    --model meta-llama/Llama-2-7b-chat-hf \
    --port 8000

# Deploy
sky serve up -n my-service service.yaml

# Check status
sky serve status

# Get endpoint
sky serve status my-service

Autoscaling policies

service:
  replica_policy:
    min_replicas: 1
    max_replicas: 10
    target_qps_per_replica: 2.0
    upscale_delay_seconds: 60
    downscale_delay_seconds: 300
  load_balancing_policy: round_robin

Cost optimization

Automatic cloud selection

# SkyPilot finds cheapest option
resources:
  accelerators: A100:8
  # No cloud specified - auto-select cheapest

# Show optimizer decision
sky launch task.yaml --dryrun

Cloud preferences

resources:
  accelerators: A100:8
  any_of:
    - cloud: gcp
      region: us-central1
    - cloud: aws
      region: us-east-1
    - cloud: azure

Environment variables

envs:
  HF_TOKEN: $HF_TOKEN  # Inherited from local env
  WANDB_API_KEY: $WANDB_API_KEY

# Or use secrets
secrets:
  - HF_TOKEN
  - WANDB_API_KEY

Common workflows

Workflow 1: Fine-tuning with checkpoints

name: llm-finetune

file_mounts:
  /checkpoints:
    name: finetune-checkpoints
    store: s3
    mode: MOUNT_CACHED

resources:
  accelerators: A100:8
  use_spot: true

setup: |
  pip install transformers accelerate

run: |
  python train.py \
    --checkpoint-dir /checkpoints \
    --resume

Workflow 2: Hyperparameter sweep

name: hp-sweep-${RUN_ID}

envs:
  RUN_ID: 0
  LEARNING_RATE: 1e-4
  BATCH_SIZE: 32

resources:
  accelerators: A100:1
  use_spot: true

run: |
  python train.py \
    --lr $LEARNING_RATE \
    --batch-size $BATCH_SIZE \
    --run-id $RUN_ID

# Launch multiple jobs
for i in {1..10}; do
  sky jobs launch sweep.yaml \
    --env RUN_ID=$i \
    --env LEARNING_RATE=$(python -c "import random; print(10**random.uniform(-5,-3))")
done

Debugging

# SSH to cluster
ssh mycluster

# View logs
sky logs mycluster

# Check job queue
sky queue mycluster

# View managed job logs
sky jobs logs my-job

Common issues

| Issue | Solution | |-------|----------| | Quota exceeded | Request quota increase, try different region | | Spot preemption | Use sky jobs launch for auto-recovery | | Slow file sync | Use MOUNT_CACHED mode for outputs | | GPU not available | Use any_of for fallback clouds |

References

• Advanced Usage - Multi-cloud, optimization, production patterns
• Troubleshooting - Common issues and solutions

Resources

• Documentation: https://docs.skypilot.co
• GitHub: https://github.com/skypilot-org/skypilot
• Slack: https://slack.skypilot.co
• Examples: https://github.com/skypilot-org/skypilot/tree/master/examples