Creating a shared analysis services datasource in SSRS

Here are the steps:

• Open report manager
• Click on New datasource
• Type in the name
• Type in the Description
• Set Data source type to SQL Server Analysis Services
• Paste in the connection string
• In connect using: Credentials stored securely in the report server. Type in the username with access to SSAS (no need to give fully qualified username if user is on localhost).
• Be SURE to check use windows credentials when connecting to the datasource.

All set. Enjoy!