Nested location blocks in Nginx - Step-by-Step Execution

Process Flow - Nested location blocks

Request comes in

↓

Match outer location block

Yes↓

Check nested location blocks

Yes↓

Match most specific nested location

↓

Serve content or proxy

↓

End

When a request arrives, nginx first matches the outer location block, then checks nested locations inside it to find the most specific match before serving content.

Execution Sample

Nginx

server {
  location /app/ {
    root /var/www/html;
    location /app/images/ {
      root /var/www/images;
    }
  }
}

This config shows a nested location where /app/images/ overrides the root for image files inside /app.

Process Table

Step	Request URI	Outer Location Match	Nested Location Check	Nested Location Match	Action Taken
1	/app/index.html	/app/ matches	Check nested locations	No nested match	Serve /var/www/html/app/index.html
2	/app/images/logo.png	/app/ matches	Check nested locations	/app/images/ matches	Serve /var/www/images/app/images/logo.png
3	/app/css/style.css	/app/ matches	Check nested locations	No nested match	Serve /var/www/html/app/css/style.css
4	/other/page.html	No outer match	No nested check	No nested match	No match, default server action

💡 Execution stops after serving matched content or default action if no location matches.

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4
Request URI		/app/index.html	/app/images/logo.png	/app/css/style.css	/other/page.html
Outer Location	none	/app/	/app/	/app/	none
Nested Location	none	none	/app/images/	none	none
Root Used	none	/var/www/html	/var/www/images	/var/www/html	default

Key Moments - 2 Insights

Why does /app/images/logo.png use a different root than /app/index.html?

Because /app/images/ is a nested location inside /app/ with its own root directive, nginx uses the nested location's root for more specific matches as shown in step 2 of the execution_table.

What happens if a request does not match the outer location block?

Nginx skips nested location checks and uses the default server action, as shown in step 4 where /other/page.html does not match any location.

Visual Quiz - 3 Questions

Look at the execution table, what root is used for the request /app/css/style.css?

A /var/www/images

B /var/www/html

C default root

D No root used

💡 Hint

Check step 3 in the execution_table under 'Root Used' column.

At which step does nginx find a nested location match?

A Step 3

B Step 1

C Step 2

D Step 4

💡 Hint

Look at the 'Nested Location Match' column in the execution_table.

If the nested location /app/images/ was removed, what would happen to requests for /app/images/logo.png?

A They would use /var/www/html root

B They would use /var/www/images root

C They would not match any location

D They would cause an error

💡 Hint

Refer to the variable_tracker and execution_table for how nested locations override outer roots.

Concept Snapshot

Nested location blocks in nginx allow more specific matching inside a broader location.
Nginx first matches the outer location, then checks nested locations.
The most specific nested location's settings override outer ones.
If no nested match, outer location settings apply.
Requests not matching outer location skip nested checks.
Use nested locations to organize and override config cleanly.

Full Transcript

When nginx receives a request, it first tries to match the outer location block. If it finds one, it then checks if any nested location blocks inside it match the request more specifically. If a nested location matches, nginx uses its configuration, such as root or proxy settings, to serve the request. If no nested location matches, nginx uses the outer location's settings. If the request does not match the outer location at all, nginx skips nested checks and uses the default server behavior. For example, a request to /app/images/logo.png matches the outer /app/ location and the nested /app/images/ location, so nginx uses the nested root /var/www/images. A request to /app/index.html matches only the outer location, so it uses /var/www/html. This layered matching helps organize configurations clearly and apply specific rules where needed.