External sessions

This feature is in private preview. To enroll, request access from Posit support.

Posit Workbench normally runs each user session inside the Workbench service, called local sessions. When configured to run external sessions, each user session runs as a separate Snowflake job service, using a Snowflake filesystem to store user home directories.

Local vs. external sessions

	Local sessions	External sessions
Where a session runs	Inside the Workbench service	As its own Snowflake job service, on a dedicated session compute pool
Session startup	Seconds	Minutes
Isolation	Sessions share the Workbench service’s resources	Each session is isolated in its own job service
Storage	Block storage volume	Snowflake shared filesystem
Backup and restore	Supported	Not supported

Choose external sessions when session isolation matters more than startup latency, for example to prevent one user’s session from affecting the resource availability of another. You cannot switch between local and external sessions after activating Workbench. This choice is permanent for a given installation.

Learn more about the technical differences between local sessions and external sessions on the architecture page.

Prerequisites

External sessions require two private preview features that are not available by default:

Posit Team private preview access. Request access from Posit support.
Snowflake shared filesystem private preview access. Open a support case with Snowflake to request access for your account.

Complete both requests before continuing.

Set up external sessions

Install Posit Team for external sessions

The Posit Team Native App lets you install multiple instances of Posit Team in your Snowflake account. Test Workbench external sessions in a separate Posit Team installation, not your primary one.

In Snowsight, go to Apps > App gallery, find the Posit Team entry, and select the Add instance menu item to create a second installation (Snowflake documentation). Use a unique name for the new installation, such as POSIT_TEAM_PREVIEW, and configure the application.

This guide assumes that you used the application name POSIT_TEAM_PREVIEW.

Create a filesystem

If your account does not already have a Snowflake filesystem, create one. For example, you might create a 1024 GiB filesystem named MY_FILESYSTEM with the following SQL:

Snowsight UI

CREATE FILESYSTEM IF NOT EXISTS MY_FILESYSTEM TYPE=PREMIUM SIZE=1024;

Filesystem provisioning is not immediate. Check its state and wait until it reads AVAILABLE:

Snowsight UI

DESCRIBE FILESYSTEM MY_FILESYSTEM;

Grant filesystem access to the application

Grant the application permission to create filesystem volumes. Run the following SQL as ACCOUNTADMIN in a Snowflake Worksheet:

Snowsight UI

GRANT CREATE VOLUME ON FILESYSTEM MY_FILESYSTEM TO APPLICATION POSIT_TEAM_PREVIEW;

Configure Workbench

Begin Workbench setup as usual, starting with the license.

In the Settings card, choose the smallest compute pool instance family for the primary Workbench compute pool. With external sessions, this pool only runs the Workbench service itself. Workbench sessions run on the session compute pools you configure below, not on this pool.

The Sessions control defaults to Local sessions.

The Workbench activate page Settings card showing the Sessions control with Local sessions selected. — Local sessions selected

Select External sessions.

The Workbench activate page Settings card showing the Sessions control with External sessions selected. — External sessions selected

Selecting external sessions adds two controls: Session Compute Pools and Filesystem.

Configure one or more compute pools to host sessions. A session runs on the smallest compute pool that fits its requested CPU and memory. See session placement for an example. Save the session compute pools.

The Workbench activate page Settings card with the Session Compute Pools control highlighted, showing an instance family, capacity, and a button to save. — Session compute pools

Enter the name of the filesystem you created and granted access to above, then save it.

The Workbench activate page Settings card with the Filesystem control highlighted, showing an input for the filesystem name and a button to save. — Filesystem configuration

Important

Selecting external sessions disables Launch from Backup. Backup and restore are not supported with external sessions.

The Workbench activate page Launch from Backup card showing it is unavailable because external sessions are selected. — Launch from Backup disabled

Continue through the rest of setup (Snowflake managed credentials) as described in the setup guide.

Launching sessions

Users launch sessions from Workbench as usual, for example by clicking New Session. Each session launches as a separate Snowflake job service on one of the configured session compute pools rather than inside the Workbench service.

The Workbench New Session dialog showing available editors including Positron Pro, RStudio Pro, JupyterLab, VS Code, and Jupyter Notebook. — New Session dialog

Sessions can take several minutes to start.

Management

The Workbench management page shows you the configured filesystem and lets you modify the Workbench compute pool and its session compute pools.

Change the instance family of the Workbench compute pool, or add, remove, or resize session compute pools. Perform an upgrade after making changes to apply them. You set the filesystem name during activation and cannot change it here.

The Backups panel is disabled. Backup and restore are not supported with external sessions.

The Workbench management page Backups panel showing it is disabled. — Backups disabled

Troubleshooting

The diagnostics bundle includes the session compute pool configuration and logs for every session job service.