# Role: datascience

## Description
Installs and configures a complete data science environment including Anaconda/Conda, Jupyter Notebook, and R statistical computing language. This role is optional and separate from general development tools for faster deployments when data science capabilities are not needed.

## Requirements
- Ansible 2.9+
- Debian/Ubuntu systems
- At least 5GB free disk space (Anaconda is ~700MB)
- Root or sudo access

## Installed Components

### Anaconda/Conda
- Full Anaconda3 distribution (latest version)
- Python data science packages (pandas, numpy, matplotlib, scikit-learn)
- Conda package manager
- Initialized for bash (zsh initialization via shell role)

### Jupyter Notebook
- Jupyter Notebook server
- IPython kernel
- JupyterLab interface
- Systemd service for automatic startup
- Web-based access on configurable port

### R Language
- R base and development packages
- R recommended packages
- CRAN repository configuration
- IRkernel for Jupyter integration
- Common R packages

## Variables

| Variable | Default | Description |
|----------|---------|-------------|
| `install_conda` | `false` | Install Anaconda/Conda |
| `conda_install_path` | `{{ ansible_env.HOME }}/anaconda3` | Conda installation directory |
| `install_jupyter` | `false` | Install Jupyter Notebook (requires conda) |
| `jupyter_port` | `8888` | Jupyter web server port |
| `jupyter_bind_all_interfaces` | `true` | Listen on all network interfaces |
| `jupyter_allow_remote` | `true` | Allow remote connections |
| `install_r` | `false` | Install R language |
| `r_packages` | `[r-base, r-base-dev, r-recommended]` | R packages to install |

## Dependencies
- `base` role (for core utilities)

## Example Playbook

### Full Data Science Stack
```yaml
- hosts: datascience_servers
  roles:
    - role: datascience
      install_conda: true
      install_jupyter: true
      install_r: true
```

### Conda + Jupyter Only
```yaml
- hosts: jupyter_servers
  roles:
    - role: datascience
      install_conda: true
      install_jupyter: true
      install_r: false
```

### R Only (no Python)
```yaml
- hosts: r_servers
  roles:
    - role: datascience
      install_conda: false
      install_r: true
```

## Usage

### Installation
```bash
# Install full data science stack
make datascience HOST=server01

# Install on specific host with custom vars
ansible-playbook playbooks/development.yml --limit server01 --tags datascience \
  -e "install_conda=true install_jupyter=true install_r=true"
```

### Post-Installation

#### Set Jupyter Password
```bash
jupyter notebook password
```

#### Access Jupyter
```bash
# Local
http://localhost:8888

# Remote
http://your-server-ip:8888
```

#### Verify Installations
```bash
conda --version
jupyter --version
R --version
```

## Tags
- `datascience`: All data science tasks
- `conda`: Conda/Anaconda installation only
- `jupyter`: Jupyter Notebook installation only
- `r`, `rstats`: R language installation only

## Services

### Jupyter Notebook Service
- **Service name**: `jupyter-notebook.service`
- **Start**: `systemctl start jupyter-notebook`
- **Status**: `systemctl status jupyter-notebook`
- **Logs**: `journalctl -u jupyter-notebook`

## Performance Notes

### Installation Times
- **Anaconda**: 5-10 minutes (700MB download)
- **Jupyter**: 2-5 minutes (if Anaconda already installed)
- **R**: 10-30 minutes (compilation of packages)

### Disk Space
- **Anaconda**: ~2.5GB after installation
- **R + packages**: ~500MB
- **Total**: ~3GB for full stack

## Security Considerations

1. **Jupyter Password**: Always set a password after installation
2. **Firewall**: Ensure port 8888 (or custom port) is properly firewalled
3. **HTTPS**: Consider using HTTPS for remote access
4. **User Isolation**: Jupyter runs as the ansible user by default

## Troubleshooting

### Conda Not in PATH
```bash
# Add to .bashrc or .zshrc
export PATH="$HOME/anaconda3/bin:$PATH"
```

### Jupyter Service Won't Start
```bash
# Check logs
journalctl -u jupyter-notebook -n 50

# Verify conda is accessible
/root/anaconda3/bin/jupyter --version
```

### R Package Installation Fails
```bash
# Install manually in R
R
> install.packages("IRkernel")
```

## Integration with Other Roles

- **Shell Role**: Provides zsh with conda integration
- **Monitoring**: btop/htop for resource monitoring
- **Docker**: Can run Jupyter in containers alternatively

## Notes
- Anaconda installer is cleaned up after installation
- Conda init for zsh is handled by the shell role
- IRkernel is automatically installed if both Jupyter and R are enabled
- R packages are compiled during installation (can be slow)
- Jupyter service starts on boot automatically