Sysadmin/Add resources to a VM: Difference between revisions

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   sudo virsh start "name_of_vm"
-=== Extending the disk file of a VM ===
+=== Extending a raw disk image ===
+This procedure applies to full-disk images containing an MBR partition table.
+**NOTE: Any VM using this disk must be shut down beforehand, or you'll corrupt the filesystem!**
+First, append some space at the end of the disk:
+ dd if=/dev/zero bs=1M count=$((1024-256)) >>example-boot.img
+Then extend the partition to fill the entire disk:
+ parted example-boot.img
+ (parted) resizepart 1
+ End?  [267MB]? -1
+ (parted) p
+ Model:  (file)
+ Disk /var/lib/libvirt/images/boot/example-boot.img: 1074MB
+ Sector size (logical/physical): 512B/512B
+ Partition Table: msdos
+ Disk Flags:
+ Number  Start   End     Size    Type     File system  Flags
+      1049kB  1073MB  1072MB  primary  ext4         boot
+ (parted) quit
+Now create device nodes for the new partition table:
+ # kpartx -av lightwave-boot-new.img
+ add map loop7p1 (253:4): 0 2093152 linear 7:7 2048
+Grow the filesystem inside the partition (resize2fs requires an fsck beforehand):
+ # e2fsck -f /dev/mapper/loop7p1
+ # resize2fs /dev/mapper/loop7p1
+Now loopback-mount your grown up filesystem to check if it's healthy:
+ # mount /dev/mapper/loop7p1 /mnt
+ # df -h /mnt
+ Filesystem           Size  Used Avail Use% Mounted on
+ /dev/mapper/loop7p1  986M  112M  820M  12% /mnt
+Don't forget to unmount the filesystem and undefine the loopback devices!
+ umount /mnt
+ kpartx -d lightwave-boot-new.img
+Et voilà!
+=== Extending a QCOW disk file ===
 Create a file containing the amount of space you want to add to the VM