When you upgrade or deploy the new Next Generation Routing Engines (NG-RE). You may add the following management interface configuration templates to the "em0", or the "em1" interface. Depending to the MX model, it may be using this interface for internal communication between the Junos VM and the Hypervisor (or VMHost see the link above). 

set interfaces em0 unit 0 family inet
set interfaces em0 unit 0 description "..."

If this knob is implemented, the system will detect a conflict during the configuration validation and will not assign the IP address to em0.32768, which is used for internal communication between Junos and VMhost. Upon executing this command, IFL identifies the conflict, and as a result, the JunOS VM fails to allocate the internal address to em0.32768, causing the system to crash within 5-15 minutes.

The em0 interface is used as the communication channel between Junos and VMHOST. When you put configure the em0 interface, it removed the "hidden" default configuration and disrupts the comunication.
RE reboots by itself every 5-15 minutes, it will report a Non-Maskable-Interrupt (NMI) and could generate core dumps after each crash.
 

user@hostname# set interfaces em0.0 description "test" 
[edit]
user@hostname# commit 
commit complete
[edit]
user@hostname# May  1 15:33:53.980  hostname-re0 last message repeated 11 times

May  1 15:34:04.080  hostname dcd[13322]: DCD_CONFIG_WRITE_FAILED: IFL em0.0 configuration write failed for an IFL ADD: File exists

user@hostname-re0> show interfaces terse em0 

Interface               Admin Link Proto    Local                 Remote

em0                     up    up                                                   
em0.0                   up    up 

Customer should remove the config from the router (both RE0 and RE1) and configured commit synchronize to delete that configuration line.

 

username@hostname# delete groups re0 interfaces em0 
username@hostname# delete interfaces em0 


username@hostname# set system commit synchronize

username@hostname# commit synchronize
username@hostname# exit

After this, customer should restart the VMhost.

>request vmhost reboot

After restart, the system will have the correct IP address assigned to the em0.32768 interface
 

username@hostname> show configuration interfaces em0 

username@hostname> show interfaces terse em0 

Interface               Admin Link Proto    Local                 Remote

em0                     up    up
em0.32768               up    up   inet     192.168.1.1/24  >>>>> IP assigned that will be used for VMhost Internal communication