Email alerts

Email alerts can be a crucial part of your monitoring and alerting strategy, enabling you to stay informed about the health of your servers.

You can configure email alerts to get notifications about load balancer events. When an event is generated, it is categorized under a specific level of importance. These levels range from debug (the least serious) to emergency (the most serious). You will set the level for which you want to receive alerts.

Alerts will be sent when:

• An active server is marked as down and the configured alert level is alert or lower.
• A disabled server is marked as down and the configured alert level is notice or lower.
• A server is marked as up or enters the drain state and the configured alert level is notice or lower.
• The option log-health-checks directive is enabled with the configured alert level as info or lower, and a health check status update occurs.

Configure mail servers Jump to heading #

You must first configure a mailers section where you list Message Transfer Agent (MTA) servers. These servers deliver your messages to recipients using the SMTP protocol. The load balancer sends an email to each mail server in the list. You can define multiple mailer sections.

1. Create a new mailers section in your configuration file with a label of your choice, such as smtp_servers. In the example below, we list two MTA servers:

   haproxy
   mailers smtp_servers
     mailer smtp1 192.168.1.10:587
     mailer smtp2 192.168.1.11:587

   haproxy
   mailers smtp_servers
     mailer smtp1 192.168.1.10:587
     mailer smtp2 192.168.1.11:587

   A mailer line has these arguments:

   • A label, such as smtp1
   • An IP address and port

2. Add email-alert directives to a frontend or defaults section:

   haproxy
   defaults
     mode http
     log global
     option httplog
     timeout connect 10s
     timeout client 1m
     timeout server 1m
     
     # email settings
     email-alert mailers smtp_servers
     email-alert from alerts@mycompany.com
     email-alert to helpdesk@mycompany.com
     email-alert level info
     email-alert myhostname LoadBalancer1

   haproxy
   defaults
     mode http
     log global
     option httplog
     timeout connect 10s
     timeout client 1m
     timeout server 1m
     
     # email settings
     email-alert mailers smtp_servers
     email-alert from alerts@mycompany.com
     email-alert to helpdesk@mycompany.com
     email-alert level info
     email-alert myhostname LoadBalancer1

   In this example:

   • email-alert mailers [mailersectionname] sets the mailers section to use to send emails.
   • email-alert from [emailaddr] sets the email sender’s address, also known as the From field.
   • email-alert to [emailaddr] sets the recipient’s address, also known as the To field.
   • email-alert level [level] sets the maximum log level of messages for which email alerts will go out; The <level> can be any of these syslog levels: emerg alert, crit, err, warning, notice, info, debug.
   • email-alert myhostname [hostname] sets the hostname to use when communicating with mailers; by default, it is the system’s hostname.

Enable the Lua implementation Jump to heading #

The alerts feature is compiled into the software, making it impossible to customize. If, however, you wish to make changes to the email template, start by enabling the Lua implementation. It is a drop-in replacement for the compiled-in implementation, but allows you to edit the code.

1. Add the lua-load directive to your global section. For HAProxy Enterprise:

   haproxy
   global
     lua-load /opt/hapee-3.0/doc/lua/mailers.lua

   haproxy
   global
     lua-load /opt/hapee-3.0/doc/lua/mailers.lua

   For HAProxy, download mailers.lua from GitHub:

   • http://git.haproxy.org/?p=haproxy-2.8.git;a=blob_plain;f=examples/lua/mailers.lua

2. Make changes to the Lua file to suit your needs.

3. Reload the load balancer configuration.

See also Jump to heading #

• Mailers reference