Virtual servers are fantastic when you need to test something and want to make sure that you have a well know environment. A virtual server has no value. You can create it over and over again and it will only cost you some time to start and stop.

VirtualBox and Vagrant is a really easy combination to get started with. However, it may turn ut that the base box you use need to be enhanced. I will show you how you can increase the disk space available on the virtual host. Unfortunately, it isn't as easy as one could hope for. But it is possible and I will show you how. When the disk has been increased, I will repackage the virtual host so it can be reused easily.

I assume that you have VirtualBox and Vagrant installed. If not, stop here and install them. I also assume that you are able to run commands from a shell. I am on a Mac and this has been tested in my terminal. You might want to consider installing Cygwin if you are using a broken os.

I want to make it clear where each command is executed, either in my terminal och the mac or in the virtual host. I will indicate the different environments like this:
The mac terminal: mac$ ls
The virtual host terminal: virtaul$ pwd
This should be interpreted as that I did ls on the mac and pwd on the virtual host.

I would cut and paste each command to the terminal. If you do so, do not include the initial part (mac$ or virtaul$).

The problem

I need to have a test host running CentOS. I will start from a base box created by Puppet Labs. The problem, however, is that the disk is too small for the application I want to test.

This means that the first thing I want to do is to increase the available disk space. This step by step guide has been my inspiration for increasing the disk: https://gist.github.com/christopher-hopper/9755310

As far as I know, I am not doing anything that is CentOS specific. This means that I expect this guide to be usable for any Linux box that uses LVM for managing its disks.

Let's go through a scenario step by step.

Create a home for virtual boxes

My virtual boxes should have a home in ~/virtual-boxes and this CentOS test host should live in ~/virtual-boxes/centos

Get a new box and start it

Get a new Vagrant box for VirtualBox:

mac$ vagrant box add puppetlabs/centos-6.6-64-puppet --provider virtualbox

This will download the needed resources from the Internet. It may take a while, it is a large download.

Change to the home directory for this virtual box:

mac$ cd ~/virtual-boxes/centos

Initiate it:

mac$ vagrant init puppetlabs/centos-6.6-64-puppet

Start it:

mac$ vagrant up

SSH into it:

mac$ vagrant ssh

Verify that we have a LVM system

Check the physical volume:

virtaul$ sudo pvdisplay

The result is: 

  --- Physical volume ---
  PV Name               /dev/sda2
  VG Name               VolGroup
  PV Size               19.51 GiB / not usable 3.00 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              4994
  Free PE               0
  Allocated PE          4994
  PV UUID               wqDj0S-MIE8-RITx-Otf7-WsSe-5pPg-XYPCJw

This gave us something usable back, we have a LVM volume and can increase it.

Exit the host.

virtaul$ exit

Stop it.

mac$ vagrant halt

Locate the disk that should be increased

List all virtual boxes that VirtualBox is aware of:

mac$ VBoxManage list vms

I found "centos_default_1441182442099_63483" {b8bd7884-9c1a-4680-8fd6-52ac5b2d9ff3}

Locating the disk means searching for it using the box name. Let's do

mac$ VBoxManage showvminfo centos_default_1441182442099_63483

This tells me much more than I need. Let me grep for anything with the suffix 'vmdk'.

mac$ VBoxManage showvminfo centos_default_1441182442099_63483 | grep vmdk

The result looked like this: 

IDE Controller (0, 0): /Users/tsu/VirtualBox VMs/centos_default_1441182442099_63483/packer-centos-6.6-x86_64-virtualbox-vagrant-puppet-1437997185-disk1.vmdk (UUID: 21a9238f-1ffe-4c53-8b0c-3168a2026f30)

I notice that the disk is stored in ~/VirtualBox VMs. That is the default location for VirtualBox files.

Clone the disk

VMDK disks can't be extended. I will therefore clone it to a vdi disk that can be extended.

mac$ cd ~/VirtualBox\ VMs/centos_default_1441182442099_63483/

mac$ VBoxManage clonehd packer-centos-6.6-x86_64-virtualbox-vagrant-puppet-1437997185-disk1.vmdk clone-disk1.vdi --format vdi

Find the current disk size

Let's see how large the current disk is

mac$ VBoxManage showhdinfo clone-disk1.vdi

I got: 

UUID:           62bb925f-ea3a-4325-85ac-7bfeaeb97761
Parent UUID:    base
State:          created
Type:           normal (base)
Location:       /Users/tsu/VirtualBox VMs/centos_default_1441182442099_63483/clone-disk1.vdi
Storage format: VDI
Format variant: dynamic default
Capacity:       20480 MBytes
Size on disk:   1854 MBytes
Encryption:     disabled

This tells me that the current size is 20 GBytes, 20480 MBytes. That is too small for stuff I want to test. I will resize it to 40 GBytes.

mac$ VBoxManage modifyhd clone-disk1.vdi --resize 40960

Find the name of the storage controller

Find out the name of the storage controller this resized disk should be attached to.

mac$ VBoxManage showvminfo centos_default_1441182442099_63483 | grep Storage

I got 

Storage Controller Name (0):            IDE Controller
Storage Controller Type (0):            PIIX4
Storage Controller Instance Number (0): 0
Storage Controller Max Port Count (0):  2
Storage Controller Port Count (0):      2
Storage Controller Bootable (0):        on

Attach the disk to the storage controller

mac$ VBoxManage storageattach centos_default_1441182442099_63483 --storagectl "IDE Controller" --port 0 --device 0 --type hdd --medium clone-disk1.vdi

Increase the disk size on the host

Bring the box up again

mac$ cd ~/virtual-boxes/centos/

mac$ vagrant up

Ssh back into it and become root

mac$ vagrant ssh

virtaul$ sudo su -

Find the name of the logical volume for the file system

virtaul$ df

I got 

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/mapper/VolGroup-lv_root
                      19003260   1185320  16845960   7% /
tmpfs                   251080         0    251080   0% /dev/shm
/dev/sda1               487652     28352    433700   7% /boot
vagrant              487358464 263884424 223474040  55% /vagrant

The name I am looking for is

/dev/mapper/VolGroup-lv_root

Find the name of the physical volume using disk.

virtaul$ fdisk -l

This gave me 

Disk /dev/sda: 42.9 GB, 42949672960 bytes
255 heads, 63 sectors/track, 5221 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000906bd

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          64      512000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              64        2611    20458496   8e  Linux LVM

Disk /dev/mapper/VolGroup-lv_root: 19.9 GB, 19906166784 bytes
255 heads, 63 sectors/track, 2420 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000


Disk /dev/mapper/VolGroup-lv_swap: 1040 MB, 1040187392 bytes
255 heads, 63 sectors/track, 126 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

I am interested in /dev/sda

Create a new primary partition

Let's use /dev/sda to create a new primary partition.

virtaul$ fdisk /dev/sda

Follow these steps:

A new partition was created.

Reboot the machine, ssh back into it and become root.

virtaul$ reboot

mac$ vagrant ssh

virtaul$ sudo su -

Create a new physical volume

virtaul$ pvcreate /dev/sda3

Find the name of the logical volume group

virtaul$ vgdisplay

I got 

  --- Volume group ---
  VG Name               VolGroup
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               19.51 GiB
  PE Size               4.00 MiB
  Total PE              4994
  Alloc PE / Size       4994 / 19.51 GiB
  Free  PE / Size       0 / 0
  VG UUID               kolyjB-epDi-uOQt-pp9k-3WOe-twe8-JJb9pz

Extend the volume group to use the new physical volume

virtaul$ vgextend VolGroup /dev/sda3

Find the name of the logical volume

virtaul$ df

I got 

Filesystem           1K-blocks    Used Available Use% Mounted on
/dev/mapper/VolGroup-lv_root
                      19003260 1185428  16845852   7% /
tmpfs                   251080       0    251080   0% /dev/shm
/dev/sda1               487652   28352    433700   7% /boot

Extend the logical volume to use all available space

virtaul$ lvextend -l +100%FREE /dev/mapper/VolGroup-lv_root

Resize the file system

virtaul$ resize2fs /dev/mapper/VolGroup-lv_root

Verify that there are more space available

virtaul$ df -h

I got 

Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root
                       38G  1.2G   35G   4% /
tmpfs                 246M     0  246M   0% /dev/shm
/dev/sda1             477M   28M  424M   7% /boot

The disk is increased! We are almost done.

Now we want to do some cleaning and then repackage this as a new base box.

Clean and repackage

Remove the command history and last login. As root, do this:

virtaul$ cat /dev/null > ~/.bash_history && cat /dev/null > /var/log/lastlog && history -c && exit

and then, as vagrant, do

virtaul$ cat /dev/null > ~/.bash_history && history -c && exit

Now there won't be any history available when you login again.

Time to re-package the new box.

mac$ vagrant package --output centos-6.6-64-puppet-40Gb.box

Move the new box somewhere where we can refer to it when a new box is created from it. Create a home for base boxes.

mac$ mkdir ~/virtual-boxes/base-boxes/

Then, move the newly created box there:

mac$ mv centos-6.6-64-puppet-40Gb.box ~/virtual-boxes/base-boxes/

Add this new box to Vagrant for later usage.

mac$ vagrant box add centos-6.6-64-puppet-40Gb ~/virtual-boxes/base-boxes/centos-6.6-64-puppet-40Gb.box

Destroy the current CentOS box

mac$ vagrant destroy -f

and finally delete the Vagrant file

mac$ rm Vagrantfile

Initiate the new box:

mac$ vagrant init centos-6.6-64-puppet-40Gb

Start it

mac$ vagrant up

Use the new box with the increased disk.

mac$ vagrant ssh

Conclusion

This was a step by step guide that initiated a small CentOS box, increased the disk and created a new base box.

I hope you have use for it.

Acknowledgements

I would like to thank Johan Helmfrid for proof reading.

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