HTTP API

Cumulus Linux implements an HTTP application programming interface to NCLU. Instead of accessing Cumulus Linux using SSH, you can interact with the switch using an HTTP client, such as cURL, HTTPie or web browser.

HTTP API Basics

Cumulus Linux includes the supporting software for the API. To use the REST API, you must enable nginx on the switch:

cumulus@switch:~$ sudo systemctl enable nginx; systemctl restart nginx

To enable the HTTP API service, run the following command:

cumulus@switch:~$ sudo systemctl enable restserver

To start or stop the service, run the following commands:

cumulus@switch:~$ sudo systemctl start restserver
cumulus@switch:~$ sudo systemctl stop restserver

To disable the service from running at startup, run the following command:

cumulus@switch:~$ sudo systemctl disable restserver

Each service runs as a background daemon.

Configure API Services

To configure the HTTP API services, edit the /etc/nginx/sites-available/nginx-restapi.conf configuration file, enter the IP address on which the REST API listens, then run the sudo systemctl restart nginx command.

IP and Port Settings

You can modify the IP and port combinations on which services listen by changing the parameters of the listen directives. By default, nginx-restapi.conf has only one listen parameter.

All URLs must use HTTPS instead of HTTP.

For more information on the listen directive, refer to the NGINX documentation.

Configure Security

Authentication

The default configuration requires all HTTP requests from external sources (not internal switch traffic) to set the HTTP Basic Authentication header.

The user and password must correspond to a user on the host switch.

Transport Layer Security

You secure all traffic in transport using TLSv1.2 by default. Cumulus Linux contains a self-signed certificate and private key used server-side in this application so that it works out of the box; however, NVIDIA recommends you use your own certificates and keys. Certificates must be in PEM format.

For step by step documentation on generating self-signed certificates and keys, and installing them to the switch, refer to the Ubuntu Certificates and Security documentation.

Do not copy the cumulus.pem or cumulus.key files. After installation, edit the ssl_certificate and ssl_certificate_key values in the configuration file for your hardware.

cURL Examples

This section includes several example cURL commands you can use to send HTTP requests to a host. The examples use the following settings:

  • Username: user
  • Password: pw
  • IP: 192.168.0.32
  • Port: 8080

For NCLU requests, set the Content-Type request header to application/json.

The cURL -k flag is necessary when the server uses a self-signed certificate. This is the default configuration (see the Security section). To display the response headers, include the -D flag in the command.

To retrieve a list of all available HTTP endpoints:

cumulus@switch:~$ curl -X GET -k -u user:pw https://192.168.0.32:8080

To run net show counters on the host as a remote procedure call:

cumulus@switch:~$ curl -X POST -k -u user:pw -H "Content-Type: application/json" -d '{"cmd": "show counters"}' https://192.168.0.32:8080/nclu/v1/rpc

To add a bridge using ML2:

cumulus@switch:~$ curl -X PUT -k -u user:pw https://192.168.0.32:8080/ml2/v1/bridge/"br1"/200

Considerations

The net show configuration files command output does not list the /etc/restapi.conf file.