Spack Repository Integration

Slurm Factory uses a custom Spack repository (vantagecompute/slurm-factory-spack-repo) to provide specialized package definitions and patches optimized for relocatable, production-ready Slurm builds.

Repository Purpose

The custom Spack repository provides:

1. Custom Slurm Package (slurm_factory.slurm)

   • Optimized build variants for HPC deployments
   • Patches for improved relocatability
   • Enhanced configuration options
   • Better integration with OpenMPI and PMIx
   • RPATH fixes for true relocatability

2. Custom cURL Package (slurm_factory.curl)

   • Additional protocol support (LDAP, RTMP, SSH, etc.)
   • Optimized for Slurm REST API requirements
   • Consistent TLS backend (OpenSSL)
   • Enhanced security features

3. Build Optimizations

   • CPU-specific optimizations (x86_64_v3 target by default)
   • Shared library preferences for smaller packages
   • RPATH/RUNPATH configurations for relocatability
   • Compiler wrapper improvements
   • Enhanced module generation

Integration Flow

How It's Used

Slurm Factory automatically integrates the custom repository during the Docker build process:

Automatic Integration

1. Clones the repository during Docker container initialization
2. Registers it with Spack as a custom package source with higher priority
3. Uses the custom packages when building Slurm and dependencies
4. Applies patches and variants specific to relocatable builds

The integration happens in the Dockerfile:

# Clone custom Spack repository
RUN git clone https://github.com/vantagecompute/slurm-factory-spack-repo.git \
    /root/slurm-factory-spack-repo && \
    spack repo add /root/slurm-factory-spack-repo

Repository Priority

Custom packages take precedence over upstream Spack packages:

# Spack will prefer custom packages when available
$ spack repo list
==> 2 package repositories.
slurm-factory-spack-repo    /root/slurm-factory-spack-repo  # Higher priority
builtin                      /opt/spack/var/spack/repos/builtin

When you request slurm@25.11, Spack automatically selects slurm_factory.slurm@25.11 if it's in the custom repo.

Package Namespacing

The custom packages use the slurm_factory namespace to avoid conflicts:

# In slurm-factory-spack-repo/packages/slurm/package.py
class Slurm(CMakePackage):
    """Slurm package with relocatability enhancements"""
    
# In slurm-factory-spack-repo/packages/curl/package.py
class Curl(AutotoolsPackage):
    """cURL with additional protocol support"""

Benefits:

• ✅ Clear separation from upstream packages
• ✅ Easy to override specific packages
• ✅ Access to all upstream packages
• ✅ Simpler maintenance and updates

Key Differences from Upstream

The custom repository enhances standard Spack packages:

Aspect	Upstream Spack	slurm-factory-spack-repo
Relocatability	Basic RPATH	Enhanced with padded paths and RUNPATH
Variants	Standard options	Optimized defaults for production
Dependencies	Flexible versions	Pinned for reproducibility
GPU Support	Optional	Tested with CUDA 11.8+ and ROCm 5.7+
OpenMPI	Basic PMIx support	Enhanced with UCX and hwloc integration
REST API	Basic curl	Full LDAP/SSH/TLS support via enhanced curl
Compiler Support	Standard	Tested with GCC 7.5.0 through 15.2.0
Module Generation	Basic	Enhanced Lmod modules with autoloading
Build Optimizations	Generic	CPU-specific (x86_64_v3) by default

Custom Packages

slurm_factory.slurm

Enhancements over upstream:

# Additional variants
variant('rest', default=True, description='Build REST API support')
variant('pmix', default=True, description='Build with PMIx support')
variant('hwloc', default=True, description='Build with hwloc support')
variant('ucx', default=True, description='Build with UCX support')

# Relocatability patches
patch('fix-rpath-relocatable.patch')
patch('remove-hardcoded-paths.patch')

# Enhanced dependencies
depends_on('curl+ldap+ssh+ssl', when='+rest')
depends_on('pmix@5:', when='+pmix')
depends_on('ucx+rdma', when='+ucx')

Benefits:

• ✅ True relocatability via RPATH fixes
• ✅ Enhanced REST API with full protocol support
• ✅ Better MPI integration with UCX
• ✅ Improved hardware locality with hwloc

slurm_factory.curl

Enhancements over upstream:

# Additional protocols
variant('ldap', default=True, description='LDAP support')
variant('rtmp', default=True, description='RTMP support')
variant('ssh', default=True, description='SSH/SCP support')

# Security enhancements
depends_on('openssl@3:', type='link')
depends_on('libssh2', when='+ssh')
depends_on('openldap', when='+ldap')

Benefits:

• ✅ Full LDAP support for Slurm REST API
• ✅ SSH/SCP for remote operations
• ✅ Consistent OpenSSL 3.x usage
• ✅ RTMP for streaming protocols

Repository Structure

slurm-factory-spack-repo/
├── packages/
│   ├── slurm/
│   │   ├── package.py                     # Custom Slurm package
│   │   ├── fix-rpath-relocatable.patch    # RPATH fixes
│   │   └── remove-hardcoded-paths.patch   # Path fixes
│   └── curl/
│       ├── package.py                     # Custom cURL package
│       └── enable-all-protocols.patch     # Protocol enhancements
├── repo.yaml                              # Repository metadata
└── README.md                              # Documentation

Package Maintenance

The custom Spack repository is maintained separately to:

• Track Slurm releases independently and quickly
• Test patches thoroughly before production use
• Contribute improvements back to upstream Spack when appropriate
• Maintain stability across Slurm Factory versions
• Support multiple Slurm versions simultaneously

Update Process

Version Compatibility

Slurm Factory	Spack Repo	Spack Version	Slurm Versions
1.0.x	main	v1.0.0	25.11, 24.11, 23.11
0.9.x	v0.9	v0.22.0	24.11, 23.11

Contributing

If you encounter issues or have improvements:

1. Check existing issues in the slurm-factory-spack-repo
2. Review package definitions in packages/
3. Submit pull requests with:
   • Clear description of the change
   • Test results showing it works
   • Backward compatibility considerations
4. Coordinate releases with Slurm Factory maintainers

Example Contribution

Adding support for a new Slurm version:

# 1. Fork and clone the repo
git clone https://github.com/yourusername/slurm-factory-spack-repo.git
cd slurm-factory-spack-repo

# 2. Update packages/slurm/package.py
# Add new version, checksums, and any needed patches

# 3. Test locally
cd /path/to/slurm-factory
slurm-factory build-slurm --slurm-version NEW_VERSION

# 4. Submit PR with test results

Using Custom Packages Manually

You can use the custom repository outside of Slurm Factory:

# 1. Clone Spack
git clone --depth 1 --branch v1.0.0 https://github.com/spack/spack.git
source spack/share/spack/setup-env.sh

# 2. Add custom repository
git clone https://github.com/vantagecompute/slurm-factory-spack-repo.git
spack repo add slurm-factory-spack-repo

# 3. Install Slurm with custom package
spack install slurm@25.11 +rest +pmix +hwloc

Related Documentation

• Architecture - How Slurm Factory integrates components
• Build Artifacts - Output package structure
• Slurm Factory Spack Build Cache - Binary cache usage
• Contributing - How to contribute improvements