Patterns in the multisystem environment
Patterns are managed in a multisystem environment in much the same way as a single system environment, along with the added benefit of continuous availability for key applications by deploying across multiple systems.
You can deploy virtual system patterns, virtual application patterns, and shared services to a multisystem environment.
- Classic virtual system patterns and promoted classic virtual system patterns can be deployed only to a single system.
- You must use a multi-cloud environment profile when deploying a multisystem deployment. To deploy patterns to a multi-cloud environment profile, all of the components in your pattern must use IBM® Foundation Pattern version 2.1.0.0 or later whether for single-system or multisystem deployment, and must not contain a Hypervisor Edition virtual image. You can use single-cloud or multi-cloud environment profiles for single-system deployment.
When you deploy a pattern in a multisystem environment, the system uses a placement algorithm to determine where to place the virtual machines for the deployment. You can use the suggested placement for the deployment, or you can move the virtual machines to different cloud groups as you want. If you move the virtual machines, the new placement is validated to ensure that the necessary resources and artifacts are available on the selected systems to support the deployment.
After the pattern is deployed, you can manage it from the Instances page. If you want to know which cloud groups an instance is deployed to, you can check the In cloud group field on the Instances page. This field lists all cloud groups where the deployment has a virtual machine. To determine the cloud group for a specific virtual machine, look at the In cloud group field for the virtual machine in the Virtual machine perspective section of the Instances page.
Scaling is supported for multisystem deployments. Horizontal scaling operations work in the same way as they do for deployments on a single system, except that the same placement algorithm that is used for deployment is also used to determine where to place the virtual machines for scaling operations. Horizontal scaling can deploy to additional cloud groups and systems that were not previously in the environment profile at the time of your original deployment, provided those cloud groups and systems have sufficient capacity and have all necessary artifacts to support the deployment. If you perform a manual horizontal scale-out operation on a virtual machine in a multisystem deployment, scale out one virtual machine at a time. If more than one virtual machine is specified for a horizontal scale-out, but only one virtual machine is provisioned, perform another horizontal scale-out.
Updates to instances also work in the same way as they do for deployments on a single system. The only difference is that in a multisystem environment, regardless of which system you are logged in to when you check for updates, the check for available updates is always made based on the available plug-ins on the system where the instance was deployed. Before an upgrade is carried out, the system validates that the plug-ins that are needed for the update are available on all systems where virtual machines for the instance have been deployed. The update fails if the remote locations cannot be contacted, are missing the plug-ins that are required for the update, or if the signatures for the plug-ins do not match.