F5 Health Monitors: Best Practices
Apply the default monitor icmp on bigip-1 to all nodes
Bigip-1: Apply the node-specific monitor to node
Bigip-1: Use the default monitor gateay_icmp for pool http.
Create a ssh-custom monitor and apply to pool http and member server01.
Bigip-1: Use the member-specific monitor http to member server02 or ssh to server03
Monitors monitor the performance and availability of devices, links and services within a network. The availability of health monitors is checked. Performance monitors monitor the load and performance. BIG-IP can redirect traffic to other resources if a monitored device or link does not respond within a set timeout period. Monitors collect information about your network. Monitors can display the information they gather. This information can be used to troubleshoot issues and determine which resources in your network need maintenance or reconfiguration.
Address monitoring
An address monitor is a simple way to verify an address on a network. This monitor sends a request for information to a virtual server. The test is considered successful when it receives a response. An address check monitor associates with a node to determine the availability of all services associated to that node’s address. If the monitor fails to determine if a node exists, the monitor marks that node and pool members at that IP address Offline.eg.icmp
Application check monitors
An application monitor communicates with servers via multiple commands and processes multiple responses. Eg. FTP
Service check monitors
A service check monitor checks whether a service is available. This monitor opens a connection with an IP address and port and then closes it. The test is complete when the TCP connection has been established. The following is the description and the list of status indicators

Apply the default monitor icmp to node on bigip-1. Type the HTTPS:// address on the browser. You will see the next page of bigip

Click on the local traffic menu to expand it and click on node. As shown below

Click on node to open the page. The following page will display the node list. To apply default monitor, click the tab marked red as shown below.

Click on the default Monitor to open the following page. In the configuration section, there is a list of available monitors. Click on the arrow to move the monitor into the Active section.

Click on the left arrow to bring it under the section. In this example, we are applying the icmp monitoring and click on the update button to apply it.

After you have applied it, you can go to the node listing by clicking on node in the local traffic section or clicking on node list

Click node list to open the page. The status green circle indicates that all nodes are available. This is in response to the icmp echo message sent by bigip-1 according the applied icmp monitor.

To apply the node-specific monitor to a particular node, select the node. In this example, we are selecting node server01. Click on it as shown below

Click on server 01 to open the next page. Here you can see the properties of node_server01. You will notice that this node has inherited our default monitor which we applied earlier

Now, change the monitor specific node