Skip to content

Juniper vJunos-router#

Juniper vJunos-router is a virtualized MX router, a single-VM version of the vMX that requires no feature licenses and is meant for lab/testing use. It is identified with juniper_vjunosrouter kind in the topology file. It is built using vrnetlab project and essentially is a Qemu VM packaged in a docker container format.

Juniper vJunos-router nodes launched with containerlab come up pre-provisioned with SSH, SNMP, NETCONF and gNMI services enabled.

How to obtain the image#

The qcow2 image can be freely downloaded from the Juniper support portal without a Juniper account and built with vrnetlab.

Managing Juniper vJunos-router nodes#


Containers with vJunos-router inside can take up to ~5-10min to fully boot.
You can monitor the progress with docker logs -f <container-name>.

Juniper vJunos-router node launched with containerlab can be managed via the following interfaces:

to connect to a bash shell of a running Juniper vJunos-router container:

docker exec -it <container-name/id> bash

to connect to the vJunos-router CLI

ssh admin@<container-name/id>

NETCONF server is running over port 830

ssh admin@<container-name> -p 830 -s netconf


Default user credentials: admin:admin@123

Interfaces mapping#

Juniper vJunos-router container can have up to 11 interfaces and uses the following mapping rules:

  • eth0 - management interface connected to the containerlab management network
  • eth1 - first data interface, mapped to a first data port of vJunos-router VM
  • eth2+ - second and subsequent data interface

When containerlab launches Juniper vJunos-router node, it will assign IPv4/6 address to the eth0 interface. These addresses can be used to reach the management plane of the router.

Data interfaces eth1+ need to be configured with IP addressing manually using CLI/management protocols or via a startup-config text file.

Features and options#

Node configuration#

Juniper vJunos-router nodes come up with a basic configuration supplied by a mountable configuration disk to the main VM image. Users, management interfaces, and protocols such as SSH and NETCONF are configured.

Startup configuration#

It is possible to make vJunos-router nodes boot up with a user-defined startup-config instead of a built-in one. With a startup-config property of the node/kind user sets the path to the config file that will be mounted to a container and used as a startup-config:

      kind: juniper_vjunosrouter
      startup-config: myconfig.txt

With this knob containerlab is instructed to take a file myconfig.txt from the directory that hosts the topology file, and copy it to the lab directory for that specific node under the /config/startup-config.cfg name. Then the directory that hosts the startup-config dir is mounted to the container. This will result in this config being applied at startup by the node.

Configuration is applied after the node is started, thus it can contain partial configuration snippets that you desire to add on top of the default config that a node boots up with.

Known issues and limitations#

  • vJunos-router requires Linux kernel 4.17+
  • To check the boot log, use docker logs -f <node-name>.