Network fencing with a Cisco switch via SNMP

As we have mentioned before, we cannot enable the HA function if we don't have fencing devices on our cluster. When we check the HA service status, it gives an empty result, which means that the HA function is not enabled:

The HA-enabled VM creation process will be introduced in the next chapter. Let's take a look at what will happen if we try to enable HA on a VM at this point:

This error message simply tells us that when we try to enable HA on a VM, the HA service is not available, which causes error. The main reason for this is leaking fencing devices. In the next section, we are going to configure a fencing device with our Cisco switches. To make it easier, I will introduce the graphical tools for you to perform this task. If you are using a Linux platform as your workstation, you can simply execute the screen command, shown as follows:

root@workstation# screen /dev/ttyS0 9600

Assuming that we are using the Windows environment, we make use of...