Lab 6 - High Availability Scenarios
The Red Hat Enterprise Virtualization Manager offers various high availability features which can be applied in a granular manner, from the level of a single virtual machine up to protection against multiple host failure scenarios. In addition, you can protect your virtual machines against various failures by combining virtual machine high availability with out of band power management, Red Hat Enterprise Virtualization Manager's failure detection and failure recovery solutions.
This lab enables you to configure virtual machine high availability, and demonstrates its use in several common enterprise scenarios. It is assumed that you have successfully completed the basic labs of
Section 1, “Track A: Standard Setup”, meaning that you have correctly installed and configured Red Hat Enterprise Virtualization, and have several running virtual machines.
In addition, to successfully complete this lab you must have a power management card for each of your hosts. This lab uses the Intelligent Power Management Interface (IPMI) device as an example. If you have a different device see the Red Hat Enterprise Virtualization Administration Guide.
This lab takes you through the best practices of configuring and testing a reliable Red Hat Enterprise Virtualization environment where virtual machines running critical workloads are not easily interrupted. This lab should take you about 30 minutes.
1. Configure Power Management
At this point, you should have two hosts and at least two virtual machines, however this lab uses six virtual machines. You can use as many virtual machines as you want, but for optimal demonstration of high availability features, it is recommended that you add four new virtual machines to your environment.
Highly available virtual machine settings will only be effective if power management is enabled on the hosts. However before configuring power management, recall that you have previously defined a power saving cluster policy in
Lab 3 - Live Migration Scenarios. Cluster policies and high availability can be used concurrently; however to best demonstrate Red Hat Enterprise Virtualization's high availability features for this lab, reset the cluster policy. This ensures that the virtual machines remain where they are staged before each demonstration, so the migration is triggered by high availability rather than the cluster's load balancing policies.
To disable cluster policy
On the administration portal, navigate to the Tree pane, click the Expand All button, and click the Default cluster. The Cluster tab displays, select the Default cluster to display its details pane.
On the General subtab, you can see that the policy is set to Power Saving. Click Edit Policy.
The Edit Policy dialog displays. Select the None button to remove the previously configured policy. Click OK.
Now, you can configure power management on your hosts. Power management enables the system to fence a troublesome host using an additional interface such as an Intelligent Platform Management Interface (IPMI) device. Perform this procedure for each host.
You have now configured power management for your hosts, meaning that your hosts' power status can be verified and controlled by the Red Hat Enterprise Virtualization Manager. Power management checks that a host is properly powered down, then restarts its virtual machines on another host in the same cluster. However, if the host's status cannot be verified, the virtual machines that were originally running on it will not be restarted.
Next, configure high availability for several virtual machines in the system.