SAML for Atlassian Data Center release notes
Seamless single-sign on with using a SAML Identity Provider
Using the add-on you can easily integrate your existing JIRA Software Data Center, JIRA Service Desk Data Center and Bitbucket Data Center instances with a SAML 2.0 Identity Provider, to allow seamless single sign-on for your users.
Easy to install and configure
The add-on can be installed in an existing instance running a supported product version. After installation, SAML authentication can be configured in the 'SAML Authentication' administration screen.
Please see the user documentation for a full list of supported platforms, and detailed instructions on configuring SAML single sign-on on your instance, best practices and troubleshooting information.