I know this is an old thread, but check out this funny bit:
From (https://www.juniper.net/documentation/en_US/release-independent/junos/topics/reference/requirements/virtual-chassis-ex2300-hardware-planning.html, emphasis mine):
- License requirements—You must have license keys for all the devices. See Understanding Software Licenses for EX Series Switches.
But from that very article they link to (https://www.juniper.net/documentation/en_US/junos/topics/concept/ex-series-software-licenses-overview.html, emphasis mine):
For a Virtual Chassis deployment, two license keys are recommended for redundancy—one for the device in the master role and the other for the device in the backup role:
[...]
You do not need additional license keys for Virtual Chassis member switches that are in the linecard role or for the redundant Routing Engine (RE) modules or the redundant Switch Fabric and Routing Engine (SRE) modules in an EX8200 member switch.
Cool, so, depending on how you read all that, for a 4-switch EX2300 VC, you need 1, 2, or 4 VC license keys.