Pinger

This simple module monitors websites by making https requests (via drupal_http_request), to provided URLs, and logs the duration, timestamp, and response code. It leverages Drupal's Queue API and cron to schedule and make the actual requests.

All information is exposed to views.

The module makes use of entities for both the site record and responses, so you can use hook_entity_insert/update to do things like send notifications for response codes other then 200 OK.

Site add form is located at admin/config/services/pinger.

Use Case:
Say you are a developer and host a couple of client websites. This module will allow you to monitor your clients sites and be notified if they are unreachable, or if the response time is over a certain threshold.