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--- kvm:add_disk_image [2016/07/04 09:47] – created peter
+++ kvm:add_disk_image [2019/11/30 12:45] (current) – removed peter
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-====== KVM - Add Disk Image ======
-This is useful when you for example want to expand the disk space of your virtual machine when it is using LVM, or if you want to add a swap disk to a virtual machine.  Note that you can also create a swap file instead of a disk, however, this is an example for adding the disk.
-===== Requirements =====
-  * Host running KVM and virsh
-  * Virtual Machine to add disk to
-The example VM is named **example-vm** in virsh (domain).
-===== Create and attach the disk image =====
-Execute these steps on the KVM hypervisor host.
-cd to the folder where you store your disk images:
-<code bash>
-cd /var/lib/libvirt/images/
-</code>
-Create the new disk image:
-<code bash>
-qemu-img create -f raw example-vm-swap.img 1G
-</code>
-We use **qemu-img** to **create** a new **raw** disk image with a size of 1 GB.
-Attach the disk to the example virtual machine using virsh:
-<code bash>
-virsh attach-disk example-vm --source /var/lib/libvirt/images/example-vm-swap.img --target vdb --persistent
-</code>
-We use virsh to attach the disk image **/var/lib/libvirt/images/example-vm-swap** as a **virtio** (**/dev/vdb**) disk to the domain (vm) **example-vm**.  The **--persistent** option updates the domain xml file with an element for the newly attached disk.
-Note that if you already have a **/dev/vdb** disk you need to change **vdb** to a free device like **vdc** or **vdd**.
-===== Formatting the disk =====
-Execute these steps in your virtual machine.
-Reboot it so that the kernel sees the new disk:
-<code bash>
-reboot
-</code>
-Partition the drive with **cfdisk**.  For our example we use filesystem type 82 (linux/linux swap):
-<code bash>
-cfdisk /dev/vdb
-</code>
-Format the disk as swap:
-<code bash>
-mkswap /dev/vdb1
-</code>
-Or format it as ext4:
-<code bash>
-mkfs.ext4 /dev/vdb1
-</code>
-Make the swap active:
-<code bash>
-swapon /dev/vdb1
-</code>
-Or mount the partition:
-<code bash>
-mkdir /mnt/new-disk
-mount /dev/vdb1 /mnt/new-disk
-</code>
-Add to /etc/fstab for reboot persistence:
-<file bash /etc/fstab>
-/dev/vdb1   swap            swap    defaults    0 0
-</file>
-Or for the ext4 disk:
-<file bash /etc/fstab>
-/dev/vdb1   /mnt/new-disk   ext4    defaults    0 0
-</file>
-That's it.  You've now created, attached, formatted and mounted a new disk in your VM.
-===== Sources =====
-  * qemu-img man page [http://linux.die.net/man/1/qemu-img]
-  * virsh-attach doc page [http://builder.virt-tools.org/artifacts/libvirt-virshcmdref/html/sect-attach-disk.html]