9.18. VM disks
9.18.1. Hot-plug virtual disks to running VMs 링크 복사링크가 클립보드에 복사되었습니다!
You can hot-plug or hot-unplug virtual disks from running VMs to dynamically adjust storage without downtime.
Only data volumes and persistent volume claims (PVCs) can be hot plugged and hot-unplugged. You cannot hot plug or hot-unplug container disks.
A hot plugged disk remains attached to the VM even after reboot. You must unplug the disk to remove it from the VM.
Each VM has a virtio-scsi controller so that hot plugged disks can use the SCSI bus. The virtio-scsi controller overcomes the limitations of VirtIO while retaining its performance advantages. It is highly scalable and supports hot plugging over 4 million disks.
When you hot plug disks to the VirtIO (virtio-blk) bus, each disk uses a PCI Express (PCIe) slot in the VM. The number of PCIe slots is limited and pre-set automatically at the VM creation as specified in the "Available VirtIO Ports" table. Therefore, you can use virtio-blk for a small number of disks that does not exceed the number of available slots.
9.18.1.1. Hot plugging and hot unplugging a disk by using the web console 링크 복사링크가 클립보드에 복사되었습니다!
You can hot plug a disk by attaching it to a virtual machine (VM) while the VM is running by using the OpenShift Container Platform web console.
The hot plugged disk remains attached to the VM until you unplug it.
Prerequisites
- You must have a data volume or persistent volume claim (PVC) available for hot plugging.
Procedure
-
Navigate to Virtualization
VirtualMachines in the web console. - Select a running VM to view its details.
-
On the VirtualMachine details page, click Configuration
Storage. Add a hot plugged disk:
- Click Add.
- In the Add disk (hot plugged) window, select the disk from the Source list and click Save.
- Optional: Select the type of the interface bus. The options are VirtIO and SCSI. The default bus type is VirtIO.
Optional: Change the type of the interface bus of an existing hot plugged disk:
-
Click the Options menu
beside the disk and select the Edit option.
- In the Interface field, select the desired option.
-
Click the Options menu
Optional: Unplug a hot plugged disk:
-
Click the Options menu
beside the disk and select Detach.
- Click Detach.
-
Click the Options menu
9.18.1.2. Hot plugging and hot unplugging a disk by using the CLI 링크 복사링크가 클립보드에 복사되었습니다!
You can hot plug and hot unplug a disk while a virtual machine (VM) is running by using the command line.
The hot plugged disk remains attached to the VM until you unplug it.
Prerequisites
- You must have at least one data volume or persistent volume claim (PVC) available for hot plugging.
Procedure
Hot plug a disk by running the following command:
$ virtctl addvolume <virtual-machine|virtual-machine-instance> \ --volume-name=<datavolume|PVC> \ [--bus <bus_type>] [--serial=<label_name>]-
The optional
--busflag allows you to specify the bus type of the added disk. The options arevirtioandscsi. The default bus type isvirtio. -
The optional
--serialflag allows you to add an alphanumeric string label of your choice. This helps you to identify the hot plugged disk in a guest virtual machine. If you do not specify this option, the label defaults to the name of the hot plugged data volume or PVC.
-
The optional
Hot unplug a disk by running the following command:
$ virtctl removevolume <virtual-machine|virtual-machine-instance> \ --volume-name=<datavolume|PVC>