By: Matt Rabe

Software Engineer - Power Systems Enablement - PowerVC

Overview

It is common for production environments to deploy redundant HMC pairs and with the 1.2.3 release, PowerVC has the capability to utilize this fault-tolerant design. This feature allows users to specify and manually switch to a secondary HMC for a set of hosts. In the event of an HMC failure, you can still manage hosts and VMs by switching over to a redundant HMC. This also enables the user to update and make changes to an HMC that would otherwise impede host or VM management.

What is New

In older versions of PowerVC, the administrator would need to remove the host and add it back with the new HMC connection and manually manage the VMs in that host. In PowerVC 1.2.3 the process is now much simpler. There is a new “Change HMC” button In the Hosts pane of PowerVC V1.2.3 that enables the user to edit the HMC connection for hosts. The operation allows for the multi-selection of hosts so that the administrator can switch multiple hosts to a new HMC:

Only HMCs that are managing the selected host can be candidates for the change. PowerVC will filter out the HMCs under the HMC Connections tab that do not meet this criterion. The option to add a new HMC connection is also available when the user clicks the Change button. After clicking “Change HMC”, the Change HMC Connection window opens:

In the image above, HMC_1 is the existing connection for the selected hosts. Because HMC_2 is another connection within PowerVC that manages the selected hosts, it shows up as a change candidate. If the user selects a new connection and the HMC does not manage all of the selected hosts, then a message will indicate that the operation cannot be performed.

It is important that no VM operations such as deploy, migrate, resize, etc. are running in PowerVC for the selected hosts when their HMC connection is changed. This is because the compute services for the hosts need to be restarted in order to pick up the configuration change. If the host is leveraging a shared storage pool, then users should avoid storage operations prior to and during the change HMC operation.

When the action is validated and submitted, a message will be shown saying that the HMC change request is processing for each host. A success message indicates that the operation was completed without errors.

Any new and existing HMC connections can be managed under the HMC Connections tab in the Hosts pane on the UI: