⁠6.9.2. Demonstrating high-availability when host connections are disrupted

  1. On the Tree pane, click Hosts. On the Hosts tab, select the Pacific host, and click the Network Interfaces subtab on the details pane. Check the physical interface name of the rhevm network; in this example it is the eth0 network.
  2. As before, connect to the Pacific host via SSH. Disable the management network by running: 
    # ifdown rhevm
    You have now shut down the network connecting the Pacific host to the Red Hat Enterprise Virtualization Manager. The next time that the Manager attempts to transmit signals to the host, it triggers the automatic fencing operation.
  3. From the Tree pane, click VMs to display the Virtual Machines tab. The highly available virtual machines, RHEL6RioGrande and RHEL6Thames, have restarted on the Atlantic host. Conversely, RHEL6Erie did not restart because it was not configured to be highly available.
  4. Finally, go to the Tree pane and click Hosts to examine the status of the hosts. After a short period, the Pacific host will be rebooted, assuming that power management was successfully configured on this host.
You have just run a demonstration where a non-responsive host was automatically fenced and rebooted. As you had simulated a non-persistent network failure, the host will recover from the fault following its reboot. In the interim period while it is being restarted, the highly available virtual machines originally running on it are restarted on another available host in the cluster. Conversely, non-highly available virtual machines need to be manually restarted.
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