8.21. VM disks
8.21.1. 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.
8.21.1.1. Hot plug and unplug disks 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
8.21.1.2. 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>