Resizing an instance (OpenStack)

You can modify the amount of resources that are used by the virtual machines.

About this task

Complete the following steps to resize a virtual machine.

Procedure

  1. Stop the virtual machine that you want to resize.
  2. Click the virtual machine that you want to resize.
  3. Click the arrow next to the Create Snapshot button.
  4. Click Resize Instance.
  5. Select a new flavor for the virtual machine.
    Notes:
    • The flavor details change depending on the size flavor that you select.
    • When you update the flavor, the processor, memory, and storage size fields accept integers only. Any fractional data is omitted.
    • If approvals are enabled, then the approval must be completed before the instance is resized. To verify that the instance was resized, check the virtual machine flavor ID property of the instance.
    • If the instance is running, OpenStack stops, resizes, and restarts the instance after the hypervisors are resized (except PowerVM® instance).
    • Active resize is supported for PowerVC instances. The instances stay active during the resizing progress. The active resize action is limited by instance resource ranges (maximum and minimum values of processor, memory, and processor units), and unsupported flavors are filtered. In addition, the active resize action is not allowed unless the health status of the instance is OK. For more information about resource ranges, see Extra specifications.
    • (PowerVM and Hyper-V) If you are changing the storage size, you can update to a larger disk size only.
    • IBM® Power® Virtualization Center Standard Edition 1.3 does not synchronize the disk size to IBM Cloud Manager with OpenStack. PowerVC causes the disk attribute of the flavor to be set to ZERO, which impacts the instance Resize functionality of IBM Cloud Manager with OpenStack.
    • With IBM Power Virtualization Center Standard Edition version 1.3, resizing a PowerVC instance from IBM Cloud Manager with OpenStack does not work as expected. To resize a PowerVC 1.3 instance, use the PowerVC API or the PowerVC graphical user interface. The size of a volume attached to a virtual machine can be extended by using a PowerVC API extension or PowerVC graphical user interface. For more information, see Extend volume size.
    • (KVM, KVM for IBM z Systems®, and PowerKVM only) If you choose a flavor with a smaller storage size, KVM skips storage resize if it cannot be completed. The other resources are resized accordingly.
    • (KVM, KVM for IBM z Systems, and PowerKVM) You might encounter the following error ssh ...Permission denied. As a Nova user, ensure the hypervisors can ssh to each other by public key. For more information, see SSH permissions error when resizing or migrating an instance (OpenStack).
    • (KVM and PowerKVM only) Resizing an instance only supports local storage.
    • (z/VM® only) You can change only the CPU and memory resources assigned to the virtual machine.
    If you are resizing an instance on the Hyper-V hypervisor, the IBMComputeNodeService service that is deployed with the Hyper-V agent installer must run with domain credentials and configure Kerberos constrained delegation. You can set the service credentials by using the following command: 
    C:\sc config "IBM SmartCloud Entry Compute Service" obj="DOMAIN\username" password="password"

    To configure the Kerberos constrained delegation setting, see step 1 in the following guide: Configure constrained delegation.