How to use the command 'virsh pool-list' (with examples)

The virsh pool-list command is a component of the virsh utility, which is part of the libvirt toolkit used for interactions with virtual infrastructure on a host. This specific command plays a crucial role in managing and inspecting virtual machine storage pools. Storage pools in virtualization contexts are storage domains representing a particular storage device, file system, or storage backend that can be used to provide storage to virtual machines. Using this command helps administrators gather important information about storage pools’ state, their configuration, and operational statistics.

Use case 1: List the name, state, and whether autostart is enabled or disabled for active storage pools

Code:

virsh pool-list

Motivation: The fundamental motivation for executing virsh pool-list without any additional options is to get a quick overview of all active storage pools currently managed by the virtualization infrastructure. This is particularly useful for system administrators who need to regularly monitor the status of storage resources. By understanding which pools are active and their autostart settings, administrators can ensure that the necessary resources are automatically managed when the host system reboots.

Explanation:

• virsh: A command-line interface to manage virtual machines and storage pools.
• pool-list: A command option that lists storage pool details. By default, it only shows active storage pools.

Example output:

 Name      State    Autostart
-------------------------------
 default   active   yes
 storage1  active   no

Use case 2: List information for active and inactive or just inactive storage pools

Code:

virsh pool-list --all

or

virsh pool-list --inactive

Motivation: As virtual environments evolve, storage pools can transition between active and inactive states depending on their usage or need. Being able to list inactive pools alongside active ones (--all) or isolating only inactive pools (--inactive) is vital for administrators performing audits or troubleshooting. This capability is essential for understanding storage utilization and identifying pools that may require attention or can be decommissioned.

Explanation:

• --all: A flag that directs virsh to display all storage pools, regardless of their active status.
• --inactive: Filters the list to show only inactive storage pools.

Example output (--all):

 Name      State    Autostart
-------------------------------
 default   active   yes
 storage1  inactive no

Example output (--inactive):

 Name      State    Autostart
-------------------------------
 storage1  inactive no

Use case 3: List extended information about persistence, capacity, allocation, and available space for active storage pools

Code:

virsh pool-list --details

Motivation: In complex virtualization environments, just knowing the status of a storage pool might not be enough. Administrators often require detailed information, such as how much storage capacity a pool has and how much is allocated or available. The --details option is integral for capacity planning, ensuring storage is efficiently utilized, and for verifying that persistence configurations align with operational expectations.

Explanation:

• --details: Enhances the list command to provide a more comprehensive output that includes capacity metrics and boolean persistence status for each pool.

Example output:

 Name      State    Autostart  Capacity  Allocation  Available
---------------------------------------------------------------
 default   active   yes        100 GiB   50 GiB      50 GiB
 storage2  active   no         200 GiB   75 GiB      125 GiB

Use case 4: List information for active storage pools with either autostart enabled or disabled

Code:

virsh pool-list --autostart

or

virsh pool-list --no-autostart

Motivation: When configuring a virtual environment, it’s crucial to know which pools are set to automatically start with the host (--autostart) and which are not (--no-autostart). This understanding ensures all necessary resources are readily available when the system is powered on and helps identify any pools that require manual intervention or configuration changes to align startup behavior with deployment strategies.

Explanation:

• --autostart: Filters the listing to show only storage pools configured to start automatically with the host.
• --no-autostart: Lists only pools that do not have autostart configured.

Example output (--autostart):

 Name      State    Autostart
-------------------------------
 default   active   yes

Example output (--no-autostart):

 Name      State    Autostart
-------------------------------
 storage1  active   no

Use case 5: List information for active storage pools that are either persistent or transient

Code:

virsh pool-list --persistent

or

virsh pool-list --transient

Motivation: Persistent storage pools are those defined for continued existence beyond host reboots, while transient pools are temporary. Differentiating between these (--persistent and --transient) aids administrators in understanding the longevity and management needs of their storage resources, which assists strategic planning and risk mitigation associated with data storage and retrieval post-host restart.

Explanation:

• --persistent: Displays only pools that have been defined as permanent.
• --transient: Shows pools intended for temporary use.

Example output (--persistent):

 Name      State    Autostart
-------------------------------
 default   active   yes

Example output (--transient):

 No active transient storage pools found

Use case 6: List the name and UUID of active storage pools

Code:

virsh pool-list --name --uuid

Motivation: When dealing with numerous storage pools, administrators might need to reference pools by their unique identifiers (UUIDs) for scripting, automation, or integration with other systems. The ability to list just the name and UUID streamlines inventory and audit processes, ensuring efficient and precise identification and management of resources.

Explanation:

• --name: Outputs only the names of storage pools, allowing for a concise and focused display.
• --uuid: Adds the UUID to each pool’s output, providing an unambiguous identification alongside the name.

Example output:

 Name      UUID
-------------------------------
 default   2abc81cc-0f1e-4f27-94a1-9c3f29ba6b69
 storage1  3de61c0b-8a23-4d1c-b52e-8f9ea9cd60ee

Conclusion:

The virsh pool-list command is an indispensable tool for administrators overseeing virtual environments. It provides critical insights into storage pool states, configurations, and operational details, accommodating various aspects of resource management, from basic status checks to in-depth capacity assessments and UUID tracking for better identification and integration within broader IT infrastructures.