particle-os-tools/docs/apt-layer/rpm-ostree/experimental/ex-replace.md

# override replace --experimental

## Overview

The experimental `override replace --experimental` feature provides advanced package replacement capabilities with additional options and features beyond the standard `override replace` command. This feature is designed for complex deployment scenarios and advanced system management.

## Experimental Status

### Current State
- **Status**: Experimental/Beta
- **Stability**: Unstable, may change
- **Production Use**: Use with caution
- **API**: Subject to change

### Feature Flags
```bash
# Enable experimental features
export RPMOSTREE_EXPERIMENTAL=1

# Use experimental override replace
rpm-ostree override replace --experimental package-name
```

## Basic Usage

### Simple Package Replacement
```bash
# Replace package with experimental features
rpm-ostree override replace --experimental kernel

# Replace with specific version
rpm-ostree override replace --experimental kernel:5.15.0

# Replace with custom package
rpm-ostree override replace --experimental kernel:custom-kernel-5.15.0
```

### Advanced Options
```bash
# Replace with additional options
rpm-ostree override replace --experimental \
    --force \
    --allow-downgrade \
    --no-deps \
    kernel:custom-kernel

# Replace with repository specification
rpm-ostree override replace --experimental \
    --repo=custom-repo \
    --repo=backup-repo \
    package-name:custom-version
```

## Advanced Features

### Dependency Handling

#### Automatic Dependency Resolution
```bash
# Replace package with automatic dependency resolution
rpm-ostree override replace --experimental \
    --resolve-deps \
    --auto-deps \
    complex-package

# Replace with dependency analysis
rpm-ostree override replace --experimental \
    --analyze-deps \
    --show-deps \
    package-name
```

#### Manual Dependency Control
```bash
# Replace with specific dependencies
rpm-ostree override replace --experimental \
    --deps="dep1,dep2,dep3" \
    --exclude-deps="unwanted-dep" \
    package-name

# Replace with dependency version constraints
rpm-ostree override replace --experimental \
    --dep-version="dep1>=1.0.0" \
    --dep-version="dep2=2.1.0" \
    package-name
```

### Conflict Resolution

#### Automatic Conflict Resolution
```bash
# Replace with automatic conflict resolution
rpm-ostree override replace --experimental \
    --resolve-conflicts \
    --auto-resolve \
    conflicting-package

# Replace with conflict analysis
rpm-ostree override replace --experimental \
    --analyze-conflicts \
    --show-conflicts \
    package-name
```

#### Manual Conflict Handling
```bash
# Replace with specific conflict resolution
rpm-ostree override replace --experimental \
    --conflict-resolution="remove-old" \
    --conflict-resolution="keep-new" \
    package-name

# Replace with conflict options
rpm-ostree override replace --experimental \
    --conflict-options="--force" \
    --conflict-options="--nodeps" \
    package-name
```

### Repository Management

#### Multiple Repository Support
```bash
# Replace using multiple repositories
rpm-ostree override replace --experimental \
    --repo=primary-repo \
    --repo=backup-repo \
    --repo=testing-repo \
    package-name

# Replace with repository priority
rpm-ostree override replace --experimental \
    --repo-priority=primary-repo:1 \
    --repo-priority=backup-repo:2 \
    package-name
```

#### Repository Validation
```bash
# Replace with repository validation
rpm-ostree override replace --experimental \
    --validate-repos \
    --check-repo-signatures \
    package-name

# Replace with repository options
rpm-ostree override replace --experimental \
    --repo-options="--gpgcheck=1" \
    --repo-options="--repo_gpgcheck=1" \
    package-name
```

## Configuration Options

### Package Selection

#### Version Specification
```bash
# Replace with exact version
rpm-ostree override replace --experimental \
    --version="1.2.3" \
    package-name

# Replace with version range
rpm-ostree override replace --experimental \
    --version-range=">=1.0.0,<2.0.0" \
    package-name

# Replace with latest version
rpm-ostree override replace --experimental \
    --latest \
    package-name
```

#### Architecture Specification
```bash
# Replace with specific architecture
rpm-ostree override replace --experimental \
    --arch=x86_64 \
    package-name

# Replace with architecture compatibility
rpm-ostree override replace --experimental \
    --arch-compat \
    --multi-arch \
    package-name
```

### Build Options

#### Custom Build Configuration
```bash
# Replace with custom build options
rpm-ostree override replace --experimental \
    --build-options="--with-debug" \
    --build-options="--without-docs" \
    package-name

# Replace with build environment
rpm-ostree override replace --experimental \
    --build-env="CC=gcc" \
    --build-env="CFLAGS=-O2" \
    package-name
```

#### Source Package Handling
```bash
# Replace with source package
rpm-ostree override replace --experimental \
    --source \
    --build-from-source \
    package-name

# Replace with custom source
rpm-ostree override replace --experimental \
    --source-url="https://example.com/source.tar.gz" \
    --source-version="1.2.3" \
    package-name
```

## Advanced Scenarios

### Multi-Package Replacement
```bash
# Replace multiple packages
rpm-ostree override replace --experimental \
    kernel:custom-kernel \
    systemd:custom-systemd \
    glibc:custom-glibc

# Replace with package groups
rpm-ostree override replace --experimental \
    --group="security-packages" \
    --group="monitoring-packages" \
    package-name
```

### Conditional Replacement
```bash
# Replace based on conditions
rpm-ostree override replace --experimental \
    --condition="arch=x86_64" \
    --condition="version>=1.0.0" \
    package-name

# Replace with fallback
rpm-ostree override replace --experimental \
    --primary="package-name:version1" \
    --fallback="package-name:version2" \
    package-name
```

### Rollback and Recovery
```bash
# Replace with rollback capability
rpm-ostree override replace --experimental \
    --rollback \
    --rollback-point="before-replace" \
    package-name

# Replace with recovery options
rpm-ostree override replace --experimental \
    --recovery-mode \
    --safe-mode \
    package-name
```

## Error Handling

### Validation and Checks
```bash
# Replace with comprehensive validation
rpm-ostree override replace --experimental \
    --validate \
    --check-integrity \
    --verify-signatures \
    package-name

# Replace with dry-run
rpm-ostree override replace --experimental \
    --dry-run \
    --simulate \
    package-name
```

### Error Recovery
```bash
# Replace with error recovery
rpm-ostree override replace --experimental \
    --error-recovery \
    --continue-on-error \
    package-name

# Replace with rollback on error
rpm-ostree override replace --experimental \
    --rollback-on-error \
    --auto-rollback \
    package-name
```

## Performance Optimization

### Parallel Processing
```bash
# Replace with parallel processing
rpm-ostree override replace --experimental \
    --parallel \
    --jobs=4 \
    package-name

# Replace with optimized processing
rpm-ostree override replace --experimental \
    --optimize \
    --cache \
    package-name
```

### Resource Management
```bash
# Replace with resource limits
rpm-ostree override replace --experimental \
    --memory-limit="2G" \
    --cpu-limit="50%" \
    package-name

# Replace with resource monitoring
rpm-ostree override replace --experimental \
    --monitor-resources \
    --resource-log="/var/log/rpm-ostree/resources.log" \
    package-name
```

## Monitoring and Logging

### Detailed Logging
```bash
# Replace with detailed logging
rpm-ostree override replace --experimental \
    --verbose \
    --debug \
    --log-level=debug \
    package-name

# Replace with log file
rpm-ostree override replace --experimental \
    --log-file="/var/log/rpm-ostree/replace.log" \
    --log-format=json \
    package-name
```

### Progress Monitoring
```bash
# Replace with progress monitoring
rpm-ostree override replace --experimental \
    --progress \
    --show-progress \
    package-name

# Replace with status updates
rpm-ostree override replace --experimental \
    --status-interval=5 \
    --status-file="/tmp/replace-status.json" \
    package-name
```

## Integration Examples

### CI/CD Integration
```bash
#!/bin/bash
# ci-replace.sh
rpm-ostree override replace --experimental \
    --dry-run \
    --validate \
    --log-file="/tmp/replace.log" \
    "$PACKAGE_NAME"

if [ $? -eq 0 ]; then
    rpm-ostree override replace --experimental \
        --rollback \
        --log-file="/tmp/replace.log" \
        "$PACKAGE_NAME"
else
    echo "Validation failed, not applying changes"
    exit 1
fi
```

### Configuration Management
```yaml
# replace-config.yaml
replacements:
  - package: kernel
    version: "5.15.0"
    options:
      - "--experimental"
      - "--rollback"
      - "--validate"
    repositories:
      - "custom-repo"
    dependencies:
      - "kernel-modules"
    conflicts:
      - "old-kernel"
```

### Ansible Integration
```yaml
# ansible task
- name: Replace package with experimental features
  command: >
    rpm-ostree override replace --experimental
    --dry-run
    --validate
    --log-file=/tmp/replace.log
    {{ package_name }}
  register: replace_result
  changed_when: replace_result.rc == 0
```

## Troubleshooting

### Common Issues

#### Dependency Conflicts
```bash
# Check for dependency conflicts
rpm-ostree override replace --experimental \
    --analyze-deps \
    --show-conflicts \
    package-name

# Resolve conflicts manually
rpm-ostree override replace --experimental \
    --resolve-conflicts \
    --manual-resolve \
    package-name
```

#### Repository Issues
```bash
# Check repository status
rpm-ostree override replace --experimental \
    --check-repos \
    --validate-repos \
    package-name

# Use alternative repositories
rpm-ostree override replace --experimental \
    --repo=backup-repo \
    --repo=mirror-repo \
    package-name
```

#### Build Failures
```bash
# Debug build issues
rpm-ostree override replace --experimental \
    --debug-build \
    --build-log="/tmp/build.log" \
    package-name

# Use pre-built package
rpm-ostree override replace --experimental \
    --pre-built \
    --no-build \
    package-name
```

### Debug Commands
```bash
# Enable debug mode
export RPMOSTREE_DEBUG=1
export G_MESSAGES_DEBUG=all

# Run with debug output
rpm-ostree override replace --experimental \
    --debug \
    --verbose \
    package-name
```

## Best Practices

### Safety Measures
1. **Always use dry-run first**: Test changes before applying
2. **Enable rollback**: Use rollback options for safety
3. **Validate thoroughly**: Validate packages and dependencies
4. **Monitor closely**: Watch for issues during replacement

### Performance Optimization
1. **Use parallel processing**: Enable parallel operations
2. **Optimize resources**: Set appropriate resource limits
3. **Use caching**: Enable caching for faster operations
4. **Monitor performance**: Track resource usage

### Error Handling
1. **Plan for failures**: Have recovery procedures ready
2. **Use error recovery**: Enable automatic error recovery
3. **Log everything**: Maintain comprehensive logs
4. **Test recovery**: Test rollback and recovery procedures

---

*The experimental override replace feature provides advanced package replacement capabilities, but it should be used with caution. Always test thoroughly and have rollback procedures ready.*