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Deployment and Feature Restrictions of vJunos-switch VM

Before you begin, you must:

The Release Notes states that “Due to its nested architecture, the vJunos-switch cannot be used in any deployments that launch the instances from within a VM.” This means that only a BMS-based deployment is supported. This is because the vJunos-switch VM launches additional VMs internally and connects them to as an easily manageable and deployable single VM externally. But the launched additional VMs are archived in this single VM. This means:

  • This document covers the instructions that you need to pass a special CPU flag to the VM to allow this nested operation even on a regular deployment on a supported BMS Platform.
  • You cannot deploy or use vJunos-switch in another VM as double-nesting is not supported.

A diagram of a server Description automatically generated

Note:

Avoid double-nesting deployment. The start time for these systems might exceed an hour than the usual ~three minutes. They might not find their FCP or create any virtual ge-0/0/x revenue interfaces, and crash frequently.

Also, in the current version, an ungraceful shutdown of a launched vJunos-switch has a high chance to corrupt the internal disk. After a restart, the VM fails to reboot correctly and is unusable. To avoid this situation, we recommend using:

  • BMS KVM server—Use virsh shutdown <VM> to shut down the VM gracefully. This might take less than 20 seconds. Avoid using virsh destroy <VM> to encounter the ungraceful shutdown issue.
  • BMS EVE-NG server—EVE-NG does not support a graceful shutdown option. You must connect to the VM console and run the command request system power-off before you instruct EVE-NG to stop the VM.

The following are few other known vJunos-switch feature limitations that are asked frequently, and are not explicitly mentioned in the vJunos-switch Release Notes:

  • vJunos-switch does not support building Virtual Chassis.
  • vJunos-switch does not support VXLAN group-based policy (GBP). You can assign and view GBP-Tags, but the enforcement functions and the traffic blocking does not work.
  • When testing DHCP relay in campus fabric, you might see duplicates of the original client requests on the DHCP server. This is because no-dhcp-flood option is not enforced on the irb configuration. But the client can still get its lease as the DHCP protocol is robust against these duplicated messages.

You can use physical Juniper switches to evaluate the Junos OS features. You can also build hybrid labs using both physical and virtual switches in a single campus fabric lab, but this is not in the scope of this document.

Note:

We do not officially support deployment on AMD CPUs. You can try the unofficial tweaks mentioned in chapter AMD-CPU Unofficial Tweaks but we cannot guarantee success.