Write a SpecConfig

Overview

A job specification defines how Bacalhau should execute your workload. This guide provides a complete reference of all supported options, configurations, and their valid values.

Basic Structure

A job specification is a JSON document with the following structure:

{
  "Name": "my-job",
  "Type": "batch",
  "Count": 1,
  "Tasks": [{
    "Name": "main",
    "Engine": {
      "Type": "docker",
      "Params": {
        "Image": "ubuntu:latest"
      }
    },
    "Resources": {
      "CPU": "1",
      "Memory": "1GB"
    }
  }]
}

Field Reference

Job Level Fields

Field	Type	Required	Default	Valid Values
Name	string	Yes	-	Alphanumeric with - and _
Type	string	Yes	batch	batch, service, daemon, ops
Count	integer	No	1	1 or greater
Priority	integer	No	0	0-100
Namespace	string	No	default	Valid DNS label
Labels	object	No	{}	Key-value string pairs
Tasks	array	Yes	-	Array of task objects

Types

These are the types of jobs:

• batch: Run once and complete

• service: Run continuously with specified replica count

• daemon: Run continuously on all matching nodes

• ops: Run once on all matching nodes

Task Configuration

Tasks define the actual work to be performed. Each task requires:

1. Engine configuration (how to run)

2. Resource requirements (what it needs)

3. Data handling (inputs/outputs)

Inside tasks, there are a number of fields.

Task Level Fields

Field	Type	Required	Default	Valid Values
Name	string	Yes	-	Alphanumeric with - and _
Engine	object	Yes	-	Engine configuration
Resources	object	Yes	-	Resource requirements
InputSources	array	No	[]	Array of input sources
ResultPaths	array	No	[]	Array of result paths
Network	object	No	{"Type": "none"}	Network configuration
Timeouts	object	No	-	Timeout settings
Env	object	No	{}	Key-value string pairs
Meta	object	No	{}	Key-value string pairs

Additionally, there are sub-fields to fill in.

Engine Types

• docker: Docker container execution

• wasm: WebAssembly module execution

Engine Configuration

Docker Engine Parameters

Parameter	Type	Required	Description
Image	string	Yes	Docker image name
Entrypoint	array	No	Container entrypoint
Parameters	array	No	Command parameters
WorkingDirectory	string	No	Working directory
EnvironmentVariables	object	No	Environment variables
Ports	array	No	Port mappings

Example:

"Engine": {
  "Type": "docker",
  "Params": {
    "Image": "python:3.9-slim",
    "Entrypoint": ["python"],
    "Parameters": ["-c", "print('hello')"],
    "WorkingDirectory": "/app",
    "EnvironmentVariables": {
      "PYTHONUNBUFFERED": "1"
    }
  }
}

Common Edge Cases:

• Images without default entrypoints require explicit entrypoint

• Environment variables with spaces or special characters need proper escaping

• Working directory must exist in container

• Large images may exceed node storage limits

WASM Engine Parameters

Parameter	Type	Required	Description
EntryModule	string	Yes	WASM module path
EntryPoint	string	Yes	Exported function name
Parameters	array	No	Function arguments
EnvironmentVariables	object	No	Environment variables

Example:

"Engine": {
  "Type": "wasm",
  "Params": {
    "EntryModule": "app.wasm",
    "EntryPoint": "_start",
    "Parameters": ["--verbose"],
    "EnvironmentVariables": {
      "MEMORY_LIMIT": "512MB"
    }
  }
}

Storage Types

• ipfs: IPFS content (you must provide your own IPFS endpoint)

• s3: Amazon S3 storage

• local: Local filesystem

• urlDownload: HTTP/HTTPS URLs

• s3PreSigned: Pre-signed S3 URLs

Network Types

• none: No network access (default)

• http: Limited HTTP/HTTPS access

• full: Unrestricted network access

Publisher Types

• ipfs: Publish to IPFS

• s3: Upload to S3

• local: Store locally

• noop: Discard results

Resource Requirements

Resource Fields

Field	Type	Required	Format	Range
CPU	string	Yes	Decimal	0.1 to node max
Memory	string	Yes	Size + Unit	1MB to node max
Disk	string	Yes	Size + Unit	10MB to node max
GPU	string	No	Integer	0 to node max

Example:

"Resources": {
  "CPU": "1.5",
  "Memory": "2GB",
  "Disk": "10GB",
  "GPU": "1"
}

Data Handling

Input Source Fields

Field	Type	Required	Description
Source.Type	string	Yes	One of: ipfs, s3, local, urlDownload, s3PreSigned, inline
Source.Params	object	Yes	Source-specific parameters
Target	string	Yes	Absolute mount path
Alias	string	No	Friendly identifier

Source Type Parameters

IPFS:

{
  "CID": "string",
  "Gateway": "string"
}

S3:

{
  "Bucket": "string",
  "Key": "string",
  "Region": "string",
  "Endpoint": "string",
  "AccessKeyID": "string",
  "SecretAccessKey": "string"
}

URL:

{
  "URL": "string",
  "Headers": {
    "string": "string"
  }
}

Inline:

{
  "Content": "string"
}

Example:

"InputSources": [
  {
    "Source": {
      "Type": "ipfs",
      "Params": {
        "CID": "QmHash..."
      }
    },
    "Target": "/inputs/data",
    "Alias": "dataset"
  }
]

This can accept multiple sources - for example:

"InputSources": [
  {
    "Source": {"Type": "ipfs", ...},
    "Target": "/inputs/data1"
  },
  {
    "Source": {"Type": "s3", ...},
    "Target": "/inputs/data2"
  }
]

Network Configuration

"Network": {
  "Type": "http",
  "Domains": ["api.example.com"],
  "EnableIPv6": true,
  "DNS": ["8.8.8.8"],
  "Policies": {
    "Egress": {
      "Ports": ["80", "443"]
    }
  }
}

Timeout Configuration

"Timeouts": {
  "ExecutionTimeout": 3600,
  "QueueTimeout": 300,
  "TotalTimeout": 4000
}

Validation and Testing

Pre-Submission Validation

You can test your job schema by running the validatecommand. E.g.

bacalhau validate job.json

Test Runs

Bacalhau also supports --dry-runfor testing, though this is only done locally. It does not test against the network.

bacalhau run --dry-run job.json

Troubleshooting Guide

Common Error Messages

1. Resource Errors

   Error: insufficient resources: CPU request exceeds node capacity

   Solution: Check node capabilities and adjust requests

2. Network Errors

   Error: network access denied: domain not in allowlist

   Solution: Verify network policy and domain lists

3. Timeout Errors

   Error: job exceeded ExecutionTimeout

   Solution: Adjust timeouts or optimize job