What happens as a result of the failure?

A network administrator has discovered a failure that has affected accessibility to the management network As a result, none clusters are able to communicate on this network. The cluster was configured with default settings.

What happens as a result of the failure?

The VMs will be powered off on slave hosts in the cluster.

All VMs on all hosts in the cluster are unaffected.

The VMs will be powered off on slave hosts that cannot communicate with the master on the affected network.

The VMs will be powered down on all hosts in the cluster



9 Comments on “What happens as a result of the failure?

    1. admin says:

      Thanks. Please view this ref: http://www.vmware.com/pdf/vsphere4/r40/vsp_40_availability.pdf

      “Failure Detection and Host Network Isolation

      Agents communicate with each other and monitor the liveness of the hosts in the cluster. This is done through the exchange of heartbeats, by default, every second. If a 15-second period elapses without the receipt of heartbeats from a host, and the host cannot be pinged, it is declared as failed. In the event of a host failure, the virtual machines running on that host are failed over, that is, restarted on the alternate hosts with the most available unreserved capacity (CPU and memory.)

      NOTE : In the event of a host failure, VMware HA does not fail over any virtual machines to a host that is in maintenance mode, because such a host is not considered when VMware HA computes the current failover level. When a host exits maintenance mode, the VMware HA service is reenabled on that host, so it becomes available for failover again.

      Host network isolation occurs when a host is still running, but it can no longer communicate with other hosts in the cluster. With default settings, if a host stops receiving heartbeats from all other hosts in the cluster for more than 12 seconds, it attempts to ping its isolation addresses. If this also fails, the host declares itself as isolated from the network.

      When the isolated host’s network connection is not restored for 15 seconds or longer, the other hosts in the cluster treat it as failed and attempt to fail over its virtual machines. However, when an isolated host retains access to the shared storage it also retains the disk lock on virtual machine files. To avoid potential data corruption, VMFS disk locking prevents simultaneous write operations to the virtual machine disk files and attempts to fail over the isolated host’s virtual machines fail. By default, the isolated host shuts down its virtual machines, but you can change the host isolation response to Leave powered on or Power off. See “Virtual Machine Options,” on page 23.

      NOTE If you ensure that your network infrastructure is sufficiently redundant and that at least one network path is available at all times, host network isolation should be a rare occurrence. ”

          1. 2bthebest4u says:

            From where are you see in the “vsphere-esxi-vcenter-server-50-availability-guide.pdf” that the correct answer is ““All VMs on all hosts in the cluster are unaffected” is correct”

  1. firebird says:

    Even though on page 28 of the Availability Guide says that “leave power on” is the default for host isolation I have tested in my Lab environment with ESXi5.0 and the default configuration that appears when I create the cluster is “shutdown”.
    So we have a discrepancy between the teory and practice.

  2. bob says:

    The default action seems to change with every revision and edition of VMware. So always check and make a decision based on the environment.
    (doesn’t help on the exam though!)

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