13.3. Directory-based Storage Pools

⁠13.3. Directory-based Storage Pools

This section covers storing guest virtual machines in a directory on the host physical machine.

Directory-based storage pools can be created with virt-manager or the virsh command-line tools.

⁠13.3.1. Creating a Directory-based Storage Pool with virt-manager

Create the local directory
1. Optional: Create a new directory for the storage pool
  Create the directory on the host physical machine for the storage pool. This example uses a directory named /guest_images.
```
# mkdir /guest_images
```
2. Set directory ownership
  Change the user and group ownership of the directory. The directory must be owned by the root user.
```
# chown root:root /guest_images
```
3. Set directory permissions
  Change the file permissions of the directory.
```
# chmod 700 /guest_images
```
4. Verify the changes
  Verify the permissions were modified. The output shows a correctly configured empty directory.
```
# ls -la /guest_images
total 8
drwx------.  2 root root 4096 May 28 13:57 .
dr-xr-xr-x. 26 root root 4096 May 28 13:57 ..
```
Configure SELinux file contexts
Configure the correct SELinux context for the new directory. Note that the name of the pool and the directory do not have to match. However, when you shut down the guest virtual machine, libvirt has to set the context back to a default value. The context of the directory determines what this default value is. It is worth explicitly labeling the directory virt_image_t, so that when the guest virtual machine is shutdown, the images get labeled 'virt_image_t' and are thus isolated from other processes running on the host physical machine.
```
# semanage fcontext -a -t virt_image_t '/guest_images(/.*)?'
# restorecon -R /guest_images
```
Open the storage pool settings
1. In the virt-manager graphical interface, select the host physical machine from the main window.
  Open the Edit menu and select Connection Details
2. click the Storage tab of the Connection Details window.
  ⁠
  Figure 13.5. Storage tab
Create the new storage pool
1. Add a new pool (part 1)
  Press the + button (the add pool button). The Add a New Storage Pool wizard appears.
  Choose a Name for the storage pool. This example uses the name guest_images. Change the Type to dir: Filesystem Directory.
  ⁠
  Figure 13.6. Name the storage pool
  Press the Forward button to continue.
2. Add a new pool (part 2)
  Change the Target Path field. For example, /guest_images.
  ⁠
  Figure 13.7. Selecting a path for the storage pool
  Verify the details and press the Finish button to create the storage pool.
Verify the new storage pool
The new storage pool appears in the storage list on the left after a few seconds. Verify the size is reported as expected, 36.41 GB Free in this example. Verify the State field reports the new storage pool as Active.
Select the storage pool. In the Autostart field, confirm that the On Boot check box is checked. This will make sure the storage pool starts whenever the libvirtd service starts.
⁠
Figure 13.8. Verify the storage pool information
The storage pool is now created, close the Connection Details window.

⁠13.3.2. Deleting a Storage Pool Using virt-manager

This procedure demonstrates how to delete a storage pool.

To avoid any issues with other guest virtual machines using the same pool, it is best to stop the storage pool and release any resources in use by it. To do this, select the storage pool you want to stop and click at the bottom of the Storage window.
Delete the storage pool by clicking . This icon is only enabled if you stop the storage pool first.

⁠13.3.3. Creating a Directory-based Storage Pool with virsh

Create the storage pool definition
Use the virsh pool-define-as command to define a new storage pool. There are two options required for creating directory-based storage pools:
- The name of the storage pool.
  This example uses the name guest_images. All further virsh commands used in this example use this name.
- The path to a file system directory for storing guest image files. If this directory does not exist, virsh will create it.
  This example uses the /guest_images directory.
```
 # virsh pool-define-as guest_images dir - - - - "/guest_images" Pool guest_images defined
```

Verify the storage pool is listed

Verify the storage pool object is created correctly and the state reports it as inactive.

# virsh pool-list --all
Name                 State      Autostart
-----------------------------------------
default              active     yes
guest_images     inactive   no

Create the local directory

Use the virsh pool-build command to build the directory-based storage pool for the directory guest_images (for example), as shown:

# virsh pool-build guest_images
Pool guest_images built
# ls -la /guest_images
total 8
drwx------.  2 root root 4096 May 30 02:44 .
dr-xr-xr-x. 26 root root 4096 May 30 02:44 ..
# virsh pool-list --all
Name                 State      Autostart
-----------------------------------------
default              active     yes
guest_images     inactive   no

Start the storage pool

Use the virsh command pool-start to enable a directory storage pool, thereby allowing volumes of the pool to be used as guest disk images.

# virsh pool-start guest_images
Pool guest_images started
# virsh pool-list --all
Name                 State      Autostart
-----------------------------------------
default             active     yes
guest_images    active     no

Turn on autostart

Turn on autostart for the storage pool. Autostart configures the libvirtd service to start the storage pool when the service starts.

# virsh pool-autostart guest_images
Pool guest_images marked as autostarted
# virsh pool-list --all
Name                 State      Autostart
-----------------------------------------
default              active     yes
guest_images         active     yes

Verify the storage pool configuration
Verify the storage pool was created correctly, the size is reported correctly, and the state is reported as running. If you want the pool to be accessible even if the guest virtual machine is not running, make sure that Persistent is reported as yes. If you want the pool to start automatically when the service starts, make sure that Autostart is reported as yes.
```
# virsh pool-info guest_images
Name:           guest_images
UUID:           779081bf-7a82-107b-2874-a19a9c51d24c
State:          running
Persistent:     yes
Autostart:      yes
Capacity:       49.22 GB
Allocation:     12.80 GB
Available:      36.41 GB

# ls -la /guest_images
total 8
drwx------.  2 root root 4096 May 30 02:44 .
dr-xr-xr-x. 26 root root 4096 May 30 02:44 ..
#
```

A directory-based storage pool is now available.

⁠13.3.4. Deleting a Storage Pool Using virsh

The following demonstrates how to delete a storage pool using virsh:

To avoid any issues with other guest virtual machines using the same pool, it is best to stop the storage pool and release any resources in use by it.
```
# virsh pool-destroy guest_images_disk
```
Optionally, if you want to remove the directory where the storage pool resides use the following command:
```
# virsh pool-delete guest_images_disk
```
Remove the storage pool's definition
```
# virsh pool-undefine guest_images_disk
```