Configuration

Campers uses a YAML configuration file (campers.yaml) with four main sections: variables, playbooks, defaults, and camps.

File Location

By default, Campers looks for campers.yaml in the current directory. Override with:

export CAMPERS_CONFIG=/path/to/config.yaml

Structure Overview

vars:
  # Reusable variables

playbooks:
  # Ansible playbooks for provisioning

defaults:
  # Base settings for all camps

camps:
  # Named configurations

Variables

Define reusable values that can be referenced anywhere using ${var_name}:

vars:
  project: my-ml-project
  remote_dir: /home/ubuntu/${project}
  python_version: "3.12"

Variables support:

• Nested references: ${remote_dir}/data expands to /home/ubuntu/my-ml-project/data
• Environment variables: ${oc.env:HOME} or ${oc.env:MY_VAR,default_value}

Playbooks

Ansible playbooks for provisioning instances. Define once, reuse across camps:

playbooks:
  base:
    - name: Base system setup
      hosts: all
      become: true
      tasks:
        - name: Update apt cache
          apt:
            update_cache: yes
            cache_valid_time: 3600

        - name: Install packages
          apt:
            name: [git, htop, tmux, curl]
            state: present

  python-dev:
    - name: Python environment
      hosts: all
      tasks:
        - name: Install uv
          shell: curl -LsSf https://astral.sh/uv/install.sh | sh
          args:
            creates: ~/.local/bin/uv

Defaults

Base settings inherited by all camps:

defaults:
  region: us-east-1
  instance_type: t3.medium
  disk_size: 50
  ssh_username: ubuntu

  sync_paths:
    - local: .
      remote: /home/ubuntu/${project}

  ports:
    - 8888

  ignore:
    - "*.pyc"
    - __pycache__
    - .venv/
    - .git/

  env_filter:
    - AWS_.*
    - HF_TOKEN

  ansible_playbook: base
  on_exit: stop

Camps

Named configurations that override defaults:

camps:
  dev:
    instance_type: t3.large
    ansible_playbooks: [base, python-dev]
    command: cd ${remote_dir} && bash

  jupyter:
    instance_type: m5.xlarge
    disk_size: 200
    ports: [8888, 6006]
    ansible_playbooks: [base, python-dev]
    command: jupyter lab --ip=0.0.0.0 --port=8888 --no-browser

  gpu:
    instance_type: g5.xlarge
    region: us-west-2
    ansible_playbooks: [base, python-dev]
    env_filter:
      - AWS_.*
      - CUDA_.*
      - HF_.*

Settings Reference

Instance Settings

Setting	Type	Default	Description
region	string	us-east-1	AWS region
instance_type	string	t3.medium	EC2 instance type
disk_size	integer	50	Root volume size in GB
ssh_username	string	ubuntu	SSH username for connection
ami	object	—	AMI selection (see below)

AMI Selection

ami:
  name: "ubuntu/images/hvm-ssd/ubuntu-*-24.04-amd64-server-*"
  owner: "099720109477"  # Canonical

File Synchronization

Setting	Type	Default	Description
sync_paths	list	—	Local/remote directory pairs
include_vcs	boolean	false	Include .git directories
ignore	list	[]	File patterns to exclude

sync_paths:
  - local: .
    remote: /home/ubuntu/project
  - local: ~/data
    remote: /home/ubuntu/data

Port Forwarding

Setting	Type	Description
port	integer	Single port to forward
ports	list	Multiple ports to forward

ports:
  - 8888   # Jupyter
  - 6006   # TensorBoard
  - 5432   # PostgreSQL

Ports are forwarded from localhost:<port> to the remote instance.

Environment Variables

Setting	Type	Description
env_filter	list	Regex patterns matching env vars to forward

env_filter:
  - AWS_.*       # All AWS credentials
  - HF_TOKEN     # Hugging Face token
  - WANDB_.*     # Weights & Biases
  - ^DB_.*       # Database credentials

Security Note

Be careful with environment forwarding. Campers warns when forwarding variables containing SECRET, PASSWORD, TOKEN, or KEY.

Commands and Scripts

Setting	Type	Description
command	string	Command to execute after setup
setup_script	string	One-time setup script (runs once per instance)
startup_script	string	Script to run before each command

setup_script: |
  pip install -r requirements.txt

startup_script: |
  source ~/.bashrc
  cd ${remote_dir}

command: python train.py

Provisioning

Setting	Type	Description
ansible_playbook	string	Single playbook name
ansible_playbooks	list	Multiple playbooks (run in order)

ansible_playbooks:
  - base
  - python-dev
  - jupyter

Lifecycle

Setting	Type	Default	Description
on_exit	string	stop	Action when session ends: stop or terminate

• stop: Instance stops, data preserved, can be restarted
• terminate: Instance and data destroyed

Environment Variables

Variable	Description
CAMPERS_CONFIG	Path to configuration file
CAMPERS_DIR	Data directory for keys (default: ~/.campers)
CAMPERS_DEBUG	Enable debug logging (1 to enable)
AWS_PROFILE	AWS credentials profile
AWS_REGION	Default AWS region

Configuration Merging

Settings are merged in this order (later overrides earlier):

1. Built-in defaults
2. defaults: section in config
3. Camp-specific settings
4. CLI arguments

# CLI arguments override everything
campers run dev --instance-type t3.xlarge --disk-size 100