Include directive for modular config in Nginx - Commands & Configuration

Introduction

Managing large configuration files can be hard. The include directive lets you split your nginx settings into smaller files. This makes it easier to organize and update parts without touching the whole file.

When you want to separate your server settings from your main nginx configuration for easier updates.

When you have multiple websites and want each site’s config in its own file.

When you want to reuse common settings like security rules across different configs.

When you want to keep your main config clean and simple by moving complex parts to separate files.

When you want to quickly enable or disable parts of your config by adding or removing include lines.

Config File - nginx.conf

nginx.conf

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;

events {
    worker_connections 1024;
}

http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    keepalive_timeout  65;

    include /etc/nginx/conf.d/*.conf;
}

This is the main nginx configuration file.

The include /etc/nginx/conf.d/*.conf; line tells nginx to load all configuration files ending with .conf from the /etc/nginx/conf.d/ directory.

This allows you to keep site-specific or modular configs separate from the main file.

Commands

Check the nginx configuration syntax to make sure the include directive and all configs are valid before restarting.

Terminal

sudo nginx -t

Expected Output

nginx: the configuration file /etc/nginx/nginx.conf syntax is ok

nginx: configuration file /etc/nginx/nginx.conf test is successful

Reload nginx to apply the new configuration without stopping the server.

Terminal

sudo systemctl reload nginx

Expected Output

No output (command runs silently)

List the files in the conf.d directory to see which modular config files are included.

Terminal

ls /etc/nginx/conf.d/

Expected Output

example-site.conf

security.conf

Key Concept

If you remember nothing else from this pattern, remember: the include directive lets nginx load extra config files so you can organize settings in smaller, manageable pieces.

Common Mistakes

Forgetting to test the config with 'nginx -t' after adding include files.

Nginx will fail to reload if there are syntax errors in any included file, causing downtime.

Always run 'sudo nginx -t' to check syntax before reloading nginx.

Using incorrect file paths or wildcards in the include directive.

Nginx won't find the files and will ignore them or throw errors.

Use absolute paths and correct wildcards like '*.conf' to include the right files.

Placing include directives inside wrong blocks like 'events' instead of 'http'.

Nginx expects certain directives only in specific blocks; wrong placement causes errors.

Put include directives for site configs inside the 'http' block.

Summary

Use the include directive in nginx.conf to load extra config files from a directory.

Test your configuration with 'nginx -t' before reloading to avoid errors.

Reload nginx to apply changes without downtime.

Practice

1. What is the main purpose of the include directive in nginx configuration?

easy

A. To define a new server block

B. To start the nginx server

C. To insert the contents of another configuration file into the current file

D. To reload the nginx configuration without downtime

Solution

1. Step 1: Understand the role of include directive

   The include directive is used to insert the contents of one file into another configuration file.

2. Step 2: Compare with other options

   Starting the server, defining server blocks, or reloading configs are done by other commands or directives, not include.

3. Final Answer:

   To insert the contents of another configuration file into the current file -> Option C

4. Quick Check:

   Include directive = insert config file [OK]

Hint: Include means 'add file content here' in config [OK]

Common Mistakes:

• Confusing include with server start commands
• Thinking include defines servers or reloads configs
• Assuming include runs commands instead of inserting files

2. Which of the following is the correct syntax to include all configuration files ending with .conf from the /etc/nginx/conf.d/ directory?

easy

A. include /etc/nginx/conf.d/*.conf;

B. include /etc/nginx/conf.d/*.conf

C. include /etc/nginx/conf.d/*.conf();

D. include /etc/nginx/conf.d/*.conf{};

Solution

1. Step 1: Recall nginx include syntax

   The correct syntax requires the path with wildcard and ends with a semicolon: include path/*.conf;.

2. Step 2: Compare options to correct syntax

   The valid syntax is include /etc/nginx/conf.d/*.conf;. Syntax with parentheses, missing semicolon, or extra braces causes parsing errors.

3. Final Answer:

   include /etc/nginx/conf.d/*.conf; -> Option A

4. Quick Check:

   Include syntax ends with semicolon [OK]

Hint: Include paths always end with a semicolon in nginx [OK]

Common Mistakes:

• Omitting the semicolon at the end
• Adding parentheses or braces incorrectly
• Using wrong wildcard syntax

3. Given this nginx config snippet:

http {
    include /etc/nginx/mime.types;
    include /etc/nginx/conf.d/*.conf;
}

What happens when nginx loads this configuration?

medium

A. It inserts the contents of mime.types and all .conf files from conf.d into the http block

B. It ignores the include directives because they are inside http

C. It only loads mime.types but not the files in conf.d

D. It throws a syntax error because multiple includes are not allowed

Solution

1. Step 1: Understand include behavior inside blocks

   Include inserts file contents exactly where placed, even inside blocks like http.

2. Step 2: Analyze the given includes

   Both mime.types and all .conf files in conf.d are included inside http, so their contents become part of http.

3. Final Answer:

   It inserts the contents of mime.types and all .conf files from conf.d into the http block -> Option A

4. Quick Check:

   Include inserts files where placed [OK]

Hint: Include works anywhere in config blocks [OK]

Common Mistakes:

• Thinking include only works at top level
• Assuming include causes syntax errors with multiple files
• Believing include ignores wildcards inside blocks

4. You wrote this in your nginx config:

include /etc/nginx/conf.d/*.conf

But nginx fails to start with a syntax error. What is the most likely cause?

medium

A. The wildcard *.conf is not supported in include

B. Missing semicolon at the end of the include directive

C. The path must be relative, not absolute

D. Include directive cannot be used inside http block

Solution

1. Step 1: Check syntax rules for include

   Every nginx directive must end with a semicolon; missing it causes syntax errors.

2. Step 2: Validate other options

   Wildcards are supported, absolute paths are allowed, and include works inside http.

3. Final Answer:

   Missing semicolon at the end of the include directive -> Option B

4. Quick Check:

   Every directive ends with semicolon [OK]

Hint: Always end include lines with semicolon [OK]

Common Mistakes:

• Forgetting the semicolon at line end
• Thinking wildcards are invalid
• Assuming include only works outside blocks

5. You want to organize your nginx config by splitting server blocks into separate files inside /etc/nginx/sites-enabled/. Which is the best way to include all these files in your main nginx.conf?

hard

A. Add include /etc/nginx/sites-enabled/*.conf; inside the server block

B. Add include /etc/nginx/sites-enabled/*.conf; outside any block at the top of nginx.conf

C. Add include /etc/nginx/sites-enabled/*.conf; inside the events block

D. Add include /etc/nginx/sites-enabled/*.conf; inside the http block

Solution

1. Step 1: Understand where server blocks belong

   Server blocks must be inside the http block in nginx configuration.

2. Step 2: Determine correct include placement

   Including all server config files inside http ensures they are loaded properly. Including outside blocks or inside events or server blocks is invalid.

3. Final Answer:

   Add include /etc/nginx/sites-enabled/*.conf; inside the http block -> Option D

4. Quick Check:

   Server blocks go inside http block [OK]

Hint: Include server configs inside http block [OK]

Common Mistakes:

• Placing include outside http block
• Including inside events block
• Trying to include inside a server block