Planning for PowerVM hosts

PowerVM hosts can be managed by PowerVM NovaLink or HMC. Plan appropriately, depending on how you are managing your systems. Starting PowerVC 2.2.0, you can register or add a NovaLink or an HMC host directly into the standby mode.

Note: It is important that your virtual machines can access the necessary storage. Additionally, when a virtual server is deployed, you can only deploy to a host system that can connect to the storage on which the deployment image resides.

Planning for host management - NovaLink

NovaLink enables highly scalable cloud management and deployment for critical enterprise workloads. In your PowerVC environment, there can be hosts that are managed by NovaLink and hosts that are managed by HMC. If NovaLink is installed on a host, even if an HMC is connected to it, PowerVC must manage that host through the NovaLink partition. However, an HMC is still required for NovaLink to be able to use Capacity on Demand through co-management mode.

Managing a host through NovaLink gives you access to several functions that are not supported through HMC. For example, NovaLink is required for software-defined infrastructure. For details, see Feature support of PowerVC for Private Cloud edition.

If you have a host that was added to PowerVC as HMC managed and change it to be NovaLink managed, follow the instructions in Changing a host from HMC managed to NovaLink managed to ensure that PowerVC recognizes the change and can continue communicating with it.

Planning for host management - HMC only

If you typically use redundant HMCs to manage your hosts, you can continue the practice with PowerVC. Each host can be managed by multiple HMCs. The HMC through which the host is registered first will be the primary HMC for the host. If the host is also being managed by a second HMC and that HMC is later added to PowerVC, then that HMC is set as secondary HMC for the host in PowerVC. If the primary HMC fails, PowerVC automatically fails over the host connection to the secondary HMC.

For example, assume you have a Host A, and it is being managed by HMC1 and HMC2. If you add HMC1 to PowerVC and then add Host A, HMC1 is set as the primary HMC for Host A. If you later add HMC2 to PowerVC, it is automatically set as the secondary HMC for Host A.

PowerVC also allows you to change the HMC that is managing a host or group of hosts. In that case, the HMC that is now managing the host will be set as the secondary HMC and the selected HMC will be set as the primary HMC. The HMC must already be managing the hosts before you can change to that HMC in PowerVC. To change the HMC that is managing a host or group of hosts, go to the Hosts page, select a host or group of hosts, and click Edit Host Connection.

For the above example, you could select the Host A, click Edit Host Connection and change HMC2 to be managing Host A. It is now the primary HMC for Host A and HMC1 is set as the secondary HMC.

You can add additional HMC connections on the Host page on the PowerVC user interface, or on the Edit Host Connection wizard when you edit the host or host group details.
  • PowerVC does not support management of OpenPOWER systems through HMC.
  • For redundant or dual HMC configuration, you must register both HMCs based on the configuration requirements. The primary and secondary HMCs must be at the same level.
  • Although you can register multiple secondary HMCs for a host, failover is supported to only one HMC, based on the registration order.
  • Multinode controller configuration does not support co-management mode.

Planning for I/O management - multiple Virtual I/O Servers

In PowerVC, a host can have multiple dual VIOS pairs. A dual VIOS setup promotes redundancy, accessibility, and serviceability. It can enhance virtual I/O client partition performance and lets you easily expand hardware or add new functions. It also offers load balancing capabilities for Multipath I/O (MPIO) and multiple shared Ethernet adapter configurations.

For more information about using multiple Virtual I/O Servers, see the IBM Redpaper publication IBM System p Advanced POWER® Virtualization (PowerVM) Best Practices.