Content libraries are container objects for VM and vApp templates and other types of files, such as ISO images, text files, and so on. vSphere administrators can use the templates in the library to deploy virtual machines and vApps in the vSphere inventory. Sharing templates and files across multiple vCenter Server instances in the same or different locations results in consistency, compliance, efficiency, and automation in deploying workloads at scale.

A content library stores and manages content in the form of library items. A single library item can contain one file or multiple files. For example, the OVF template is a set of files (.ovf, .vmdk, and .mf). When you upload an OVF template to the library, you upload the entire set of files, but in the content library UI you only see one library item of the OVF template type.

In previous versions of vSphere, content libraries supported only OVF templates. As a result, VM and vApp templates were both converted to OVF files when you uploaded them to a content library. Starting with vSphere 6.7 Update 1, content libraries also support VM templates. Templates in the content library can either be of the OVF Template type, or the VM Template type. vApp templates are still converted to OVF files when you upload them to a content library.

You create and manage a content library from a single vCenter Server instance, but you can share the library items with other vCenter Server instances if HTTP(S) traffic is allowed between them.

You can create two types of libraries: local or subscribed library.

Local Libraries

You use a local library to store items in a single vCenter Server instance. You can publish the local library so that users from other vCenter Server systems can subscribe to it. When you publish a content library externally, you can configure a password for authentication.

Note:

You cannot publish a local library that contains VM templates.

Subscribed Libraries

You subscribe to a published library by creating a subscribed library. You can create the subscribed library in the same vCenter Server instance where the published library is, or in a different vCenter Server system. In the Create Library wizard you have the option to download all the contents of the published library immediately after the subscribed library is created, or to download only metadata for the items from the published library and to later download the full content of only the items you intend to use.

To ensure the contents of a subscribed library are up-to-date, the subscribed library automatically synchronizes to the source published library on regular intervals. You can also manually synchronize subscribed libraries.

You can use the option to download content from the source published library immediately or only when needed to manage your storage space.

  • When you synchronize a subscribed library that is set with the option to download all the contents of the published library immediately, the process synchronizes both the item metadata and the item contents. During synchronisation, the library items that are new for the subscribed library are fully downloaded to the storage location of the subscribed library.

  • When you synchronize a subscribed library that is set with the option to download contents only when needed, the process synchronizes only the metadata for the library items from the published library, and does not download the contents of the items. This saves storage space. If you need to use a library item, you need to synchronize that item. When you no longer need the item, you can delete the item contents to free space on the storage. For subscribed libraries that are set with the option to download contents only when needed, synchronizing the subscribed library downloads only the metadata of all the items in the source published library, while synchronizing a library item downloads the full content of that item to your storage.

You can take advantage of optimized transfer speed for synchronization between a published and a subscribed library under certain circumstances.

  • If a published and a subscribed library belong to vCenter Server systems that are in the same vCenter Single Sign-On domain, and both libraries use datastores as backing storage, transfer speed for synchronization is faster. The transfer speed optimization is made possible if the libraries can store their contents to datastores managed by ESXi hosts that are directly connected to each other. Therefore, the synchronization between the libraries is handled by a direct ESXi host to ESXi host transfer.

  • If the datastores have VMware vSphere Storage APIs - Array Integration (VAAI) enabled, the library content synchronization between the published and the subscribed library is further optimized. In this case, the contents are synchronized by a direct datastore to datastore transfer.

If you use a subscribed library, you can only utilize the content, but cannot contribute content to the library. Only the administrator of the published library can manage the templates and files.

Table 1. Source Objects to Which You Can Subscribe by Creating a Subscribed Library in the vSphere Client.

Source Object

Download library content immediately

Download library content when needed

A library running in a vCenter Server 6.x instance.

Supported

Supported

A catalog running in a vCloud Director 5.5 and later instance.

Supported

Not supported

A third-party library.

Supported for third-party libraries that require authentication, if the username of the third-party library is vcsp. If the username of the source third-party library is different than vcsp, you can subscribe to it by using VMware vCloud Suite API.

Supported for third-party libraries that require authentication, if the username of the third-party library is vcsp. If the username of the source third-party library is different than vcsp, you can subscribe to it by using VMware vCloud Suite API.

Libraries store content on a file system or a datastore. To ensure optimal performance, use file systems for libraries that are published, and use datastores for local and subscribed libraries.