About Checker

Checker is a service that monitors HAProxy, NGINX, Apache and Keepalived services as well as HAProxy backends. Checker sends a notification via Telegram, Slack, email, PagerDuty and/or Mattermost when a backend or service is down. It also supports real-time alerting via the Roxy-WI panel and stores the history of incidents.

If you installed services manually, read how to configure them here.

The checker service consists of the following components:

Master checker
Worker checker for HAProxy
Worker checker for NGINX
Worker checker for Apache
Worker checker for Keepalived

The Master checker must always be running because it runs the Worker checkers.

The Master checker also launches the local worker for HAProxy, NGINX, Apache, and Keepalived services so you can monitor them.

Checker Features

The Worker checker for HAProxy performs the following operations:

checks the HAProxy service status;
check the backends status;
checks if the number of connections is about to reach the limit;
sends notifications via Telegram, Slack, email, PagerDuty and Mattermost.

The Worker checker for NGINX performs the following operations:

checks the NGINX service status;
sends notifications via Telegram, Slack, email, PagerDuty and Mattermost.

The Worker checker for Apache performs the following operations:

checks the Apache service status;
sends notifications via Telegram, Slack, email, PagerDuty and Mattermost.

The Worker checker for Keepalived performs the following operations:

checks the Keepalived service status;
sends notifications via Telegram, Slack, email, PagerDuty and Mattermost.

Installation

To install the Checker, run the following command:

Here you can find all information about RPM packages.

Telegram parameters

Since version 6.1.0, Checker can send notifications to Telegram for NGINX, HAProxy, Apache, and Keepalived server events. To set up notifications via Telegram, go to the Monitoring => Сhecker: Settings section. Then, in the section for the desired server, select the Telegram channel from the drop-down list where you want to receive notifications.

To add a new channel, go to the Monitoring => Channels section and click Add.

Specify the following parameters in the pop-up window:

Parameter:	Description:
Token	Token received from @father_bot.
Channel	Name of your channel. The channel must be public.
Group	You can specify one of the existing groups. A group is equivalent to a namespace. Members of one group cannot see the servers of the other groups.

Slack parameters

Slack notifications are available for each server starting with version 6.1.0. Setting up notifications for Slack is quite the same as for Telegram.

To add a new Slack channel, go to the Monitoring => Channels section and click Add.

Specify the following parameters in the pop-up window:

Parameter:	Description:
Token	Token received via the Slack API.
Channel	Name of your channel. The channel must be public.
Group	You can specify one of the existing groups. A group is equivalent to a namespace. Members of one group cannot see the servers of the other groups.

Notification settings

Use the Monitoring => Checker settings section to manage notifications for all your NGINX, HAProxy, Apache, and Keepalived servers.

Select a channel from the drop-down list to enable notifications, or select Disabled to stop sending notifications. If you want to send email notifications to all group members, check the Email checkbox.

Email notifications are not sent to users in the Guest role.

If necessary, check the other checkboxes to be notified of the following information:

Service availability (the Service checkbox)
Changes in the server status (the Status checkbox)
HAProxy backend servers availability (the Backend checkbox)
The Maxconn parameter value for HAProxy; e.g. when the value is about to reach the specified threshold, а notification is sent (the Maxconn checkbox)

Logs

You can find the Master checker and the Worker checker logs in the Admin area => Internal logs section.

To view logs:

Select the desired log from the drop-down list
(Optional) Select the number of rows to display
(Optional) Specify the information you want to find in the logs (regular expressions are supported)
(Optional) Specify the information you want to exclude from the logs (regular expressions are supported)
Select the time period for viewing logs by moving the slider
Click Show

For more information about Internal logs, click here.

Updating

To update the Checker, run the following command:

You can also update it via the Roxy-WI interface. To do this, go to the Admin area => Update section and click Update next to the service:

Checker service description