Attaching a disk to a VM

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Yandex Cloud

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Updated at October 17, 2024

Attaching a disk
Mounting a disk created from a snapshot or image
Partitioning and mounting an empty disk

You can attach an extra disk to either a running or stopped VM.

On a Linux VM deployed from Cloud Marketplace or custom images with the driver kit installed, the connected extra disk will be available as a new device without rebooting the VM.

For the disk to be successfully connected, the VM operating system must be fully booted or stopped, otherwise the operation will fail. If an error occurs, stop the VM and try again.

On a Windows VM, the connected extra disk will be available as a new device only after the VM reboots.

When you select a disk to attach to a VM, you can specify whether that disk should be deleted when deleting the VM. You can choose this option when creating a VM, updating it, or attaching a new disk to it.

Attaching a disk

Note

You can only attach a local disk to a VM on a dedicated host while creating it. For more information, see this guide.

Management console

CLI

API

In the management console, select the folder the VM belongs to.
Select Compute Cloud.
In the left-hand panel, select Disks.
Select an unattached disk or create a new one.
Next to the disk you want to attach, click and select Attach.
In the window that opens:
- In the VM field, select the virtual machine you want to mount your disk to.
- To attach an encrypted disk, select a service account with the kms.keys.encrypterDecrypter role for the KMS key that was used to encrypt the disk.
- Enter a device name.
- Enable the Delete along with the virtual machine option if needed.
Click Attach.

If you do not have the Yandex Cloud command line interface yet, install and initialize it.

The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.

View a description of the CLI attach disk command:
```
yc compute instance attach-disk --help
```

Get a list of VMs in the default folder:

yc compute instance list

Result:

+----------------------+-----------------+---------------+---------+----------------------+
|          ID          |       NAME      |    ZONE ID    | STATUS  |     DESCRIPTION      |
+----------------------+-----------------+---------------+---------+----------------------+
| fhm0b28lgfp4******** | first-instance  | ru-central1-a | RUNNING | my first vm via CLI  |
| fhm9gk85nj7g******** | second-instance | ru-central1-a | RUNNING | my second vm via CLI |
+----------------------+-----------------+---------------+---------+----------------------+

Select the ID or NAME of the VM, e.g., first-instance.

Get a list of disks in the default folder:

yc compute disk list

Result:

+----------------------+--------------+-------------+-------------------+--------+----------------------+-----------------+-------------+
|          ID          |     NAME     |    SIZE     |       ZONE        | STATUS |     INSTANCE IDS     | PLACEMENT GROUP | DESCRIPTION |
+----------------------+--------------+-------------+-------------------+--------+----------------------+-----------------+-------------+
| a7lqgbt0bb9s******** | first-disk   | 20401094656 |   ru-central1-a   | READY  | a7lcvu28njbh******** |                 |             |
| a7lv5j5hm1p1******** | second-disk  | 21474836480 |   ru-central1-a   | READY  |                      |                 |             |
+----------------------+--------------+-------------+-------------------+--------+----------------------+-----------------+-------------+

Select the ID or NAME of the required disk, e.g., first-disk. To view a list of disks attached to the VM, run the command:
```
yc compute instance get --full first-instance
```
Attach the disk to the VM:
```
yc compute instance attach-disk first-instance \
  --disk-name first-disk \
  --mode rw
```
To automatically delete the disk when deleting the VM, set the --auto-delete flag.

Note

Empty disks do not have a file system. If you attach an empty disk, partition and mount it manually. Alternatively, instead of attaching an empty disk, you can create a snapshot of the boot disk and create a VM based on such a snapshot.

If an error occurs, stop the VM:
```
yc compute instance stop first-instance
```
Then reattach the disk.

If the VM was stopped, restart it:

yc compute instance start first-instance

Use the attachDisk REST API method for the Instance resource or the InstanceService/AttachDisk gRPC API call.

Mounting a disk created from a snapshot or image

Linux

Windows

Attach a disk to a VM instance.
Connect to the VM over SSH.

Run the blkid command and make sure that there are no partitions with duplicate UUIDs:

sudo blkid

Result:

/dev/vda2: UUID="0d6dfef0-542d-47ba-b55b-18ab5f5f9210" TYPE="ext4" PARTUUID="752aa845-94ee-4850-9188-71c2f919ee7b"
/dev/vdb2: UUID="0d6dfef0-542d-47ba-b55b-18ab5f5f9210" TYPE="ext4" PARTUUID="752aa845-94ee-4850-9188-71c2f919ee7b"
...

If there are, generate a new UUID for the duplicates that come last in the blkid command output. In the example from the previous step, you need to generate a UUID for the /dev/vdb2 partition:
```
sudo e2fsck -f /dev/vdb2
sudo tune2fs -U $(uuidgen) /dev/vdb2
```
This method works for partitions with ext2, ext3, and ext4 file systems. The latter is used in the Linux images provided by Yandex Cloud. The file system type is returned by the blkid command in the TYPE parameter.

If you have a different file system, use the appropriate commands. For example, for XFS, execute:
```
sudo xfs_admin -U generate /dev/vdb2
```
To see if the UUID changed, run the blkid command again:
```
sudo blkid
```
Result:
```
/dev/vda2: UUID="0d6dfef0-542d-47ba-b55b-18ab5f5f9210" TYPE="ext4" PARTUUID="752aa845-94ee-4850-9188-71c2f919ee7b"
/dev/vdb2: UUID="ea004485-07fb-4128-b20d-e408db1e8ae8" TYPE="ext4" PARTUUID="752aa845-94ee-4850-9188-71c2f919ee7b"
...
```
When creating a snapshot or image in Linux, the UUID and PARTUUID of disk partitions are saved. Linux uses this data when mounting partitions, including the root one, so the IDs must be unique. For example, if you clone a boot disk and attach it to the same VM, two partitions with the same UUIDs appear on the VM. As a result, after starting the VM, the root partition may not be the one you specified as the boot disk.
Mount disk partitions using the mount utility. For example, mount the vdb2 partition to the /mnt directory:
```
sudo mkdir /mnt
sudo mount /dev/vdb2 /mnt
```
Run the df command to check the state of the file system.

Connect to the VM via RDP.
Run Computer Management (the compmgmt.msc snap-in) as an administrator.
Under Storage, select Disk Management.

Note

When you attach a disk to a running VM, it might not appear in the list. In that case, restart the OS and repeat steps 1 and 2 of this guide.
If the attached disk is Offline, right-click it and select Online.
Assign a letter to the attached disk if needed. For information about how to do this, see the Microsoft documentation.
Open Explorer to check that the attached disk is properly mounted and available.

Partitioning and mounting an empty disk

Linux

Windows

Attach an empty disk to the VM.
Connect to the VM via SSH.
Check whether the disk is attached as a device and get its path in the system:
```
ls -la /dev/disk/by-id
```
Result:
```
total 0
drwxr-xr-x 2 root root 140 Jan 16 12:09 .
drwxr-xr-x 6 root root 120 Jan 13 13:51 ..
lrwxrwxrwx 1 root root   9 Jan 16 12:09 virtio-fhm1dn62tm5d******** -> ../../vdc
lrwxrwxrwx 1 root root   9 Jan 13 13:51 virtio-fhm4ev6dodt9******** -> ../../vdb
lrwxrwxrwx 1 root root  10 Jan 13 13:51 virtio-fhm4ev6dodt9********-part1 -> ../../vdb1
lrwxrwxrwx 1 root root  10 Jan 13 13:51 virtio-fhm4ev6dodt9********-part2 -> ../../vdb2
lrwxrwxrwx 1 root root   9 Jan 13 13:51 virtio-nvme-disk-0 -> ../../vda
```
Where:
- Network disk links have the virtio-<disk_ID> format. For example, virtio-fhm1dn62tm5d******** -> ../../vdc means that an unpartitioned disk with the fhm1dn62tm5d******** ID is labeled vdc.
- Local disks on dedicated hosts have links, such as virtio-nvme-disk-<disk_number> (if you attached the disks to your VM when creating it). Disk numbering starts from zero. For example, virtio-nvme-disk-0 -> ../../vda means that the first local disk (numbered zero) is labeled vda.
Partition your disk. To do this, create partitions using the cfdisk utility, the fdisk utility, or the parted utility.

Run commands as a superuser. To do this, use sudo in each command, or run the sudo su - command initially to switch to the superuser in the terminal. For example, let's create partitions using fdisk:
1. Run the utility:
```
sudo fdisk /dev/<disk_label>
```
  Where <disk_label> is the label of the disk to be partitioned, e.g., vdb or vdc.
  
  You will be taken to the fdisk menu. To get a list of available commands, type m and press Enter.
2. Create a new partition: type n and press Enter.
3. Specify that the partition will be primary: type p and press Enter.
4. You will be prompted to select a partition number. Press Enter to create partition 1.
5. Leave the default values for the numbers of the first and last sectors of the partition: press Enter twice.
6. Make sure the partition has been created. To do this, request a list of disk partitions: type p and press Enter.
  
  Result:
```
Device     Boot Start      End  Sectors Size Id Type
/dev/vdc1        2048 41943039 41940992  20G 83 Linux
```
  Where vdc1 is the partition label consisting of a disk label and a partition number. You will need the partition label for further actions with the partition.
7. To save your changes, type w and press Enter.
Format the partition to the required file system. To do this, you can use the mkfs utility. For example, to format a partition to ext4, run the command, specifying the label of the previously created partition:
```
sudo mkfs.ext4 /dev/<partition_label>
```
Result:
```
Creating filesystem with 261888 4k blocks and 65536 inodes
Filesystem UUID: 584a800c-e1fc-4f66-9228-a444f2d7440d
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376

Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done
```
Where Filesystem UUID is the unique partition ID. You will need the partition ID when setting up automatic mounting of this partition to the system. You can also get the partition ID using the sudo blkid /dev/<partition_label> command.
Mount the disk partition using the mount utility. To mount a partition named /dev/<partition_label> to the /mnt/new_disk directory, run the following command:
```
sudo mkdir /mnt/new_disk && sudo mount /dev/<partition_label> /mnt/new_disk
```
Configure the partition write and read permissions using the chmod utility. For example, to allow all users to write to the partition, run the following command:
```
sudo chmod a+w /mnt/new_disk
```
Configure automatic mounting of the partition to the mnt/new_disk directory when the VM starts:
1. Open the /etc/fstab file using the nano text editor:
```
sudo nano /etc/fstab
```
2. Add the following line to the end of the file, specifying the ID of your partition in the UUID parameter:
```
UUID=<partition_ID> /mnt/new_disk ext4 defaults 0 2
```
  Where UUID is the unique partition ID obtained earlier during formatting, e.g., 584a800c-e1fc-4f66-9228-a444f2d7440d.
3. Save the changes and close the file.

Check the state of your file systems:

df

Result:

Filesystem     1K-blocks    Used Available Use% Mounted on
udev              989424       0    989424   0% /dev
tmpfs             203524     816    202708   1% /run
/dev/vdb2       13354932 2754792  10015688  22% /
tmpfs            1017608       0   1017608   0% /dev/shm
tmpfs               5120       0      5120   0% /run/lock
tmpfs            1017608       0   1017608   0% /sys/fs/cgroup
tmpfs             203520       0    203520   0% /run/user/1000
/dev/vdc1         523260    3080    520180   1% /mnt/vdc1

Connect to the VM via RDP.
Run Computer Management (the compmgmt.msc snap-in) as an administrator.
Under Storage, select Disk Management.

Note

When you attach a disk to a running VM, it might not appear in the list. In that case, restart the OS and repeat steps 1 and 2 of this guide.
If the attached disk is Offline, right-click it and select Online.
Initialize the disk. To do this, right-click it and select Initialize Disk. This opens the Initialize Disk dialog.
Select a partition style and click OK.
Create partitions on the disk. To do this, right-click the empty disk and select New Simple Volume.
Use the New Simple Volume Wizard to set the required partition size, assign a drive letter, and specify the file system type.
Open Explorer to check that the attached disk is properly mounted and available.

Attaching a disk to a VM

Attaching a diskAttaching a disk

Mounting a disk created from a snapshot or imageMounting a disk created from a snapshot or image

Partitioning and mounting an empty diskPartitioning and mounting an empty disk

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Attaching a disk

Mounting a disk created from a snapshot or image

Partitioning and mounting an empty disk