For detailed SDN Controller Vendor and Open Source SDN Controller comparisons, checkout the 2017 Future of Network Virtualization and SDN Controllers Report also available as PDF Download
In addition to the commercial Contrail Controller, Juniper also offers OpenContrail, an open source version. It is available under an Apache 2.0 license, and allows for easy integration with OpenStack, the open source cloud architecture software.
Juniper is a member of the OpenDaylight Project, but despite its commitment to open standards, has made limited contributions until last spring, when the company floated the OpenContrail plug-in proposal. Juniper pulled out of OpenDaylight in 2015 after making no contributions.