Adding a New Switch to an Existing QFX Series Virtual Chassis
Use this procedure to add a new switch to a QFX Series Virtual Chassis.
To add a switch to a Virtual Chassis Fabric (VCF), see Adding a Device to a Virtual Chassis Fabric.
Adding a New Switch to a QFX Series Virtual Chassis
You can use this procedure to add a switch in a supported combination to an existing Virtual Chassis. A QFX Series Virtual Chassis can be a non-mixed or mixed Virtual Chassis consisting of a supported combination of switches interconnected using Virtual Chassis ports (VCPs). QFX series switches that can be members of a Virtual Chassis include QFX3500, QFX3600, QFX5100, QFX5110, or QFX5200 switches. EX4300 switches can also be members of a mixed QFX Series Virtual Chassis with QFX 3500, QFX3600, or QFX5100 switches. See Understanding Mixed EX Series and QFX Series Virtual Chassis for details on the types and combinations of switches that can make up a mixed QFX Series Virtual Chassis.
EX4300 multigigabit model (EX4300-48MP) switches are not supported in a mixed Virtual Chassis with QFX Series switches.
Before you begin, make sure you have:
Mounted the new switch in a rack.
Enabled automatic software updates on the Virtual Chassis. See Configuring Automatic Software Update on Virtual Chassis Member Switches.
When adding a QFX5100 switch installed with a “-qfx-5-” Junos OS image to a QFX5110 Virtual Chassis, you must first upgrade the QFX5100 switch to run a “-qfx-5e-” Junos OS image.before this step in the procedure. The automatic software update feature cannot automatically update a QFX5100 switch running a “-qfx-5-” Junos OS image to a “-qfx-5e-” image. See Upgrading a QFX5100 Switch with a USB Device to Join a QFX5110 Virtual Chassis or Virtual Chassis Fabric
Determined which ports you will use as Virtual Chassis ports on the new switch, and the member ports in the existing Virtual Chassis to which you will interconnect the new switch.
If you are expanding a preprovisioned configuration:
Made a note of the serial number (the number is on the back of the switch). You’ll need to edit the Virtual Chassis configuration to include the serial number of the new member switch.
Serial number values are case-sensitive.
Edited the existing Virtual Chassis configuration to include the serial number of the new member switch. The Virtual Chassis applies the parameters in the master’s configuration file to the new switch after it has been interconnected with an existing member switch.
(If you are using the autoprovisioning feature to add a member switch to an existing preprovisioned Virtual Chassis) Confirmed that the member ports in the Virtual Chassis to which you will interconnect the new switch are not already configured as VCPs. One condition for automatic VCP conversion is that the ports on both sides of the new link must not already be configured as VCPs. See Automatic Virtual Chassis Port (VCP) Conversion for details.
(Optional) Configured Ethernet interfaces on different member switches into the same LAG. See Configuring Link Aggregation.
An active member switch might temporarily go down before coming back up as part of this procedure. If you configure the Virtual Chassis members so that traffic is load-balanced across member switches using a LAG, you can alleviate traffic loss during this procedure.
To add a new member switch to an existing Virtual Chassis configuration:
- If you previously configured the new member switch, revert that switch’s configuration to the factory defaults before interconnecting it into the Virtual Chassis. See Reverting to the Default Factory Configuration.
- (Recommended for a QFX5100 Virtual Chassis under certain
conditions) When you add or replace a QFX5100-24Q switch that is configured
in the Routing Engine role in a QFX5100 Virtual Chassis, if the new
switch has two EX4600-EM-8F expansion modules, we recommend that you
set the mastership priorities on the routing engine members and the
new switch to prevent a mastership switchover to the new switch until
after the new switch is completely initialized in the Virtual Chassis.
Before interconnecting the new switch into the Virtual Chassis in this case, see Adding a New QFX5100-24Q Switch with Two Expansion Modules in a QFX5100 Virtual Chassis for details on why, when, and how you should do this step..
You might need to do this even if the new switch has the default factory configuration.
- (Required for a mixed Virtual Chassis only) Set the new
switch into mixed mode and reboot the switch to complete the configuration:
You do not need to configure your Virtual Chassis into mixed mode if the Virtual Chassis is composed of only QFX3500 and QFX3600 switches or only QFX5110 and QFX5100 switches (which are considered non-mixed Virtual Chassis).
user@device> request virtual-chassis mode mixed reboot
If you are adding a switch that converts a non-mixed Virtual Chassis into a mixed Virtual Chassis, you must also log onto the Virtual Chassis and enter the request virtual-chassis mode mixed all-members reboot command either before or after interconnecting the new switch into your Virtual Chassis. This step makes sure all switches in the Virtual Chassis can communicate with the new mixed-mode member switch.
- Interconnect the new switch to one member of the existing
Virtual Chassis using an interface that can be configured into a VCP.
See Understanding Virtual Chassis Components for details on ports you can use as VCPs.
Connect only one interface on the new switch to a VCP on a member switch in the existing Virtual Chassis at this point of the procedure.
- Set the interconnecting interfaces for the new member
switch as Virtual Chassis Ports (VCPs) if needed:
user@switch> request virtual-chassis vc-port set pic-slot slot-number port port-number
You do not need to perform this step in a preprovisioned Virtual Chassis if you set up the right conditions to use the autoprovisioning feature. (See Automatic Virtual Chassis Port (VCP) Conversion.) After the new switch is provisioned and cabled into the Virtual Chassis, the interconnecting links automatically convert into VCP links. You do not need to manually set the ports on either side of the links as VCPs.
- Confirm that the new member switch is now included within the Virtual Chassis configuration by entering the show virtual-chassis command on a Virtual Chassis console or management port. You should see the new member switch listed in the output with Status displayed as Prsnt.
- Cable the next port into the Virtual Chassis, using Steps
2 through 5.
If you immediately cable both VCPs on the new switch into the existing Virtual Chassis at the same time, a member switch that was already part of the Virtual Chassis might become non-operational for several seconds. The Virtual Chassis drops network traffic to this switch during the downtime.
The member switch returns to the normal operational state with no user intervention, and normal operation of the Virtual Chassis resumes after this downtime.
- If you need to customize your Virtual Chassis configuration further, see Configuring a QFX Series Virtual Chassis.
Adding a New QFX5100-24Q Switch with Two Expansion Modules in a QFX5100 Virtual Chassis
A QFX5100-24Q switch installed with two EX4600-EM-8F expansion modules needs more time to check and initialize all its interfaces than a switch with one or no expansion modules. If you add a new switch or replace a member switch in an QFX5100 Virtual Chassis, when you connect and power on the new switch, the Virtual Chassis detects the new switch and reconfigures the Virtual Chassis to include it.
If the new switch is a QFX5100 switch with two expansion modules and:
Is configured in the Routing Engine role
Has a system MAC address lower than the other member switches in the Routing Engine role
Has the same mastership priority as the other member switches in the Routing Engine role
then the Virtual Chassis might reassign mastership to this new switch before it is fully initialized and ready to take the master Routing Engine role. (See Understanding How the Master in a Virtual Chassis Is Elected.) The Virtual Chassis takes significantly longer to re-stabilize across a mastership switchover during Virtual Chassis reconfiguration, which causes traffic loss.
To avoid a mastership switchover in this case, before cabling the new switch into the Virtual Chassis, you can reassign the new switch’s mastership priority to be lower than the other Virtual Chassis member switches configured in the Routing Engine role.
For example, you have a QFX5100 Virtual Chassis with member 0 as the master routing engine and member 1 as the backup routing engine. Both members have mastership priority 255 in the current Virtual Chassis configuration, and you want to replace member 0 with a QFX5100-24Q switch that has two expansion modules.
- Remove member 0 according to the procedure in Remove a Member Switch and Make Its Member ID Available for Reassignment to a Different Switch.
Member 1 assumes mastership of the Virtual Chassis.
- Reconfigure the mastership priority of member 0 on the
Virtual Chassis to a lower number than member 1 to make sure member
1 retains mastership while you replace member 0:
user@switch> set virtual-chassis member 0 mastership-priority 128
user@switch> set virtual-chassis member 1 mastership-priority 255
user@switch> commit synchronize
- Add the new member 0 into the Virtual Chassis using the procedure in Adding a New Switch to a QFX Series Virtual Chassis.
- After the new member switch is fully initialized and established
as a member of the Virtual Chassis, you can restore the mastership
priorities on member 0 so the Virtual Chassis switches mastership
back to the new member 0:
user@switch> set virtual-chassis member 0 mastership-priority 255
user@switch> commit synchronize
See Configuring Mastership of a Virtual Chassis for more details on changing mastership priorities.