Use IIS with URL Rewrite as a reverse proxy

Use IIS with URL Rewrite as a Reverse Proxy

If you want Grafana to be a subpath or subfolder under a website in IIS then the URL Rewrite module for ISS can be used to support this.

Example:

Parent site: http://localhost:8080
Grafana: http://localhost:3000

Grafana as a subpath: http://localhost:8080/grafana

Setup

If you have not already done it, then a requirement is to install URL Rewrite module for IIS.

Download and install the URL Rewrite module for IIS: https://www.iis.net/downloads/microsoft/url-rewrite

You will also need the Application Request Routing (ARR) module for IIS for proxy forwarding

Download and install ARR module for IIS: https://www.iis.net/downloads/microsoft/application-request-routing

Grafana Config

The Grafana config can be set by creating a file named custom.ini in the conf subdirectory of your Grafana installation. See the installation instructions for more details.

Given that the subpath should be grafana and the parent site is localhost:8080 then add this to the custom.ini config file:

[server]
domain = localhost:8080
root_url = %(protocol)s://%(domain)s/grafana/

Restart the Grafana server after changing the config file.

IIS Config

Forward Proxy

Open the IIS Manager and click on the server
In the admin console for the server, double click on the Application Request Routing option:
Click the Server Proxy Settings action on the right-hand pane
Select the Enable proxy checkbox so that it is enabled
Click Apply and proceed with the URL Rewriting configuration

Note: If you don’t enable the Forward Proxy, you will most likely get 404 Not Found if you only apply the URL Rewrite rule

URL Rewriting

Open the IIS Manager and click on the parent website
In the admin console for this website, double click on the URL Rewrite option:

Click on the Add Rule(s)... action
Choose the Blank Rule template for an Inbound Rule

Create an Inbound Rule for the parent website (localhost:8080 in this example) with the following settings:

pattern: grafana(/)?(.*)
check the Ignore case checkbox
rewrite URL set to http://localhost:3000/{R:2}
check the Append query string checkbox
check the Stop processing of subsequent rules checkbox

Finally, navigate to http://localhost:8080/grafana (replace http://localhost:8080 with your parent domain) and you should come to the Grafana login page.

Troubleshooting

404 error

When navigating to the Grafana URL (http://localhost:8080/grafana in the example above) and a HTTP Error 404.0 - Not Found error is returned then either:

the pattern for the Inbound Rule is incorrect. Edit the rule, click on the Test pattern... button, test the part of the URL after http://localhost:8080/ and make sure it matches. For grafana/login the test should return 3 capture groups: {R:0}: grafana {R:1}: / and {R:2}: login.
The root_url setting in the Grafana config file does not match the parent URL with subpath.

Grafana Website only shows text with no images or css

The root_url setting in the Grafana config file does not match the parent URL with subpath. This could happen if the root_url is commented out by mistake (; is used for commenting out a line in .ini files):

; root_url = %(protocol)s://%(domain)s/grafana/
or if the subpath in the root_url setting does not match the subpath used in the pattern in the Inbound Rule in IIS:

root_url = %(protocol)s://%(domain)s/grafana/

pattern in Inbound Rule: wrongsubpath(/)?(.*)
or if the Rewrite URL in the Inbound Rule is incorrect.

The Rewrite URL should not include the subpath.

The Rewrite URL should contain the capture group from the pattern matching that returns the part of the URL after the subpath. The pattern used above returns 3 capture groups and the third one {R:2} returns the part of the URL after http://localhost:8080/grafana/.