The Health Monitor tab explains the health monitor settings for the pool.

Incorporate a Health Monitor to verify the health of server instances within the pool. There are two kinds of health monitors:

  • Passive Health Monitor: A passive health monitor listens only to client-to-server communication. If servers are replying with errors (such 500 busy or TCP connection errors), then the passive health monitor will reduce the amount of connections or requests sent to that server. The reduction percentage depends on the number of servers available within the pool. When the server responds satisfactorily to the throttled requests directed to it, the passive health monitor will restore the server to full traffic volume. You may use this monitor with any other health monitors. Errors are defined in the analytics profile assigned to the virtual service. Best practice is to ensure that a passive health monitor is enabled in addition to any synthetic check that may also be configured.

  • Active Health Monitor: In addition to normal client-to-server traffic, NSX Advanced Load Balancer can generate synthetic connections or requests to servers to ensure the integrity of the server’s health. Add one or more health monitors to the pool by clicking Add button and either selecting a health monitor or clicking to create a new one. You may disassociate a health monitor from the pool by clicking the trash can icon to the right of the monitor name.

In Create Pool window, click Health Monitor tab.

Health Monitors: Click ADD to select the required health monitors from the drop-down menu. The following are the options available in the drop-down menu:

  • System-HTTP

  • System-HTTPS

  • System-Ping

  • System-TCP

  • System-UDP

  • System-SCTP

  • System-DNS

  • System-Xternal_Perl

  • System-Xternal-Shell

  • System-Xternal-Python

  • Horizon_l4_monitor

  • Horizon-HTTPS

Enable Passive Health Monitor: Check this box to monitor client to server connections and requests and adjust traffic load to servers based on successful responses. This may alter the expected behavior of the LB method, such as 'Round Robin' method.

Health Monitors to be considered "Up": Specify the minimum number of health monitors in UP state to mark server UP.