Hugo Module Mounts

Overview

Hugo's module mounts map arbitrary directories into Hugo's content tree using the [[module.mounts]] configuration. This creates a union file system — multiple source directories appear as a single content tree without symlinks or build-time copying. This is Hugo's official mechanism for multi-directory content aggregation.

Use module mounts when a repository has documentation scattered across multiple subdirectories (per-plugin, per-service, per-tool) and needs a unified Hugo site.

Prerequisites

Hugo modules require Go and module initialization:

# Initialize Hugo modules (required once per project)
hugo mod init github.com/username/repo

This creates go.mod and go.sum files. Commit both to the repository.

Basic Mount Configuration

In hugo.toml, mounts map a source directory to a target location in Hugo's virtual filesystem:

[[module.mounts]]
source = 'content'
target = 'content'

[[module.mounts]]
source = 'static'
target = 'static'

[[module.mounts]]
source = 'layouts'
target = 'layouts'

[[module.mounts]]
source = 'data'
target = 'data'

[[module.mounts]]
source = 'assets'
target = 'assets'

[[module.mounts]]
source = 'i18n'
target = 'i18n'

[[module.mounts]]
source = 'archetypes'
target = 'archetypes'

When you define any mount, Hugo's default mounts are replaced. Always include the standard mounts above when adding custom mounts, or the default directories will stop working.

Multi-Directory Content Aggregation

The core pattern: mount each subdirectory's docs/ folder into the content tree.

Example: Plugin Marketplace

Repository structure:

repo/
├── hugo.toml
├── content/           # Root site content (home page, about, etc.)
├── plugin-a/
│   ├── docs/          # Plugin A documentation
│   │   ├── _index.md
│   │   └── usage.md
│   └── src/
├── plugin-b/
│   ├── docs/
│   │   ├── _index.md
│   │   └── api.md
│   └── src/
└── plugin-c/
    ├── docs/
    └── src/

Mount configuration:

# Standard mounts (required when defining any custom mounts)
[[module.mounts]]
source = 'content'
target = 'content'

[[module.mounts]]
source = 'static'
target = 'static'

[[module.mounts]]
source = 'layouts'
target = 'layouts'

[[module.mounts]]
source = 'data'
target = 'data'

[[module.mounts]]
source = 'assets'
target = 'assets'

# Plugin documentation mounts
[[module.mounts]]
source = 'plugin-a/docs'
target = 'content/plugins/plugin-a'

[[module.mounts]]
source = 'plugin-b/docs'
target = 'content/plugins/plugin-b'

[[module.mounts]]
source = 'plugin-c/docs'
target = 'content/plugins/plugin-c'

Result: Hugo sees a unified content tree:

content/
├── _index.md                    # From content/
├── plugins/
│   ├── plugin-a/
│   │   ├── _index.md           # From plugin-a/docs/
│   │   └── usage.md
│   ├── plugin-b/
│   │   ├── _index.md           # From plugin-b/docs/
│   │   └── api.md
│   └── plugin-c/
│       └── ...

Example: Monorepo Services

# Service documentation mounts
[[module.mounts]]
source = 'services/api-gateway/docs'
target = 'content/services/api-gateway'

[[module.mounts]]
source = 'services/auth-service/docs'
target = 'content/services/auth-service'

[[module.mounts]]
source = 'services/worker/docs'
target = 'content/services/worker'

Example: CLI Tool Collection

# Tool documentation mounts
[[module.mounts]]
source = 'tools/migrate/docs'
target = 'content/tools/migrate'

[[module.mounts]]
source = 'tools/validate/docs'
target = 'content/tools/validate'

[[module.mounts]]
source = 'tools/generate/docs'
target = 'content/tools/generate'

Section Index Pages

Each mounted directory needs an _index.md to appear as a proper section. The parent directory also needs one.

Create content/plugins/_index.md (or content/services/_index.md):

---
title: "Plugins"
description: "Documentation for all plugins"
weight: 10
---

Browse documentation for individual plugins below.

Each mounted directory needs its own _index.md (inside the source docs/ folder):

---
title: "Plugin A"
description: "Plugin A documentation"
weight: 1
---

Plugin A overview content.

Mount Precedence

When files conflict (same path from multiple mounts), the first mount wins:

# This mount takes precedence for any conflicting paths
[[module.mounts]]
source = 'content'
target = 'content'

# This mount's files are used only when they don't conflict with above
[[module.mounts]]
source = 'shared-content'
target = 'content'

Order mounts from highest to lowest priority.

Mounting Non-Content Directories

Mounts work for any Hugo component directory, not just content:

# Mount shared layouts
[[module.mounts]]
source = 'layouts'
target = 'layouts'

[[module.mounts]]
source = 'shared/layouts'
target = 'layouts'

# Mount data files from a subdirectory
[[module.mounts]]
source = 'data'
target = 'data'

[[module.mounts]]
source = 'plugin-a/data'
target = 'data/plugins/plugin-a'

Valid mount targets: archetypes, assets, content, data, i18n, layouts, static.

Adding a New Mount

When adding documentation for a new subdirectory:

1. Create the docs/ directory with _index.md
2. Add the mount entry to hugo.toml
3. Ensure the parent section has _index.md
4. Run hugo server to verify

Common Mistakes

Mistake	Fix
Defining custom mounts without standard mounts	Always include mounts for content, static, layouts, data, assets when adding any custom mount
Missing _index.md in mounted directories	Every mounted directory needs _index.md to be a proper Hugo section
Missing parent section _index.md	If mounting to content/plugins/foo, ensure content/plugins/_index.md exists
Forgetting hugo mod init	Module mounts require module initialization
Absolute paths in source	Use paths relative to the repository root
Not committing go.mod and go.sum	These are required for reproducible builds

Debugging Mounts

# Verify Hugo sees all mounted content
hugo list all

# Check which files Hugo resolves
hugo config mounts

# Verbose build output to see mount resolution
hugo --verbose