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Manage a Virtual Chassis Using Mist

Follow these steps to manage the members of a Virtual Chassis.

You can use the Modify Virtual Chassis option on the switch details page to manage your Virtual Chassis. The operations you can perform include renumbering and replacing the Virtual Chassis members and adding new members to a Virtual Chassis.

The Modify Virtual Chassis workflow leverages the Junos preprovisioning method which configures the role and serial number of all members in a Virtual Chassis.

Note: The Modify Virtual Chassis option is available for switches that have the configuration management enabled in Mist.

The preprovisioned configuration specifies the chassis serial number, member ID, and role for both member switches in the Virtual Chassis. When a new member router joins the Virtual Chassis, Junos compares its serial number against the values specified in the preprovisioned configuration. Preprovisioning prevents any accidental role assignment to a Routing Engine, or any accidental addition of a new member to the Virtual Chassis. Role assignments, member ID assignments, and additions or deletions of members in Virtual Chassis are under the control of a preprovisioned configuration.

Note:

  • The Modify Virtual Chassis option is available:

    • To Super Users or Network Admins.

    • For switches that have their configuration managed by Mist.

  • This workflow applies to all the EX Series and QFX Series platforms that support Virtual Chassis.

  • To delete a member whose MAC address is used as the Virtual Chassis device ID, trash and replace it with an existing member in the Virtual Chassis. To verify if any Virtual Chassis member is used as the device identifier, look for the device ID on the switch details page (Virtual Chassis page) or on the switch list.
  • The Add Switch dropdown only shows the switches that:
    • Are part of the same site. Models with dedicated Virtual Chassis ports can be in connected or disconnected state. However, to modify the EX2300, EX4650, or QFX5120 Virtual Chassis, the members should be in the connected state as these switches don’t have dedicated Virtual Chassis ports.
    • Have configuration management enabled in Mist.
    • Are not currently part of the same or another Virtual Chassis.
    • Are of the same model family. For example, an EX4100-F switch can be part of a Virtual Chassis with an EX4100-48MP switch.
  • The Modify Virtual Chassis button is disabled when the Configuration Management option is disabled for the switch.
  • When a Virtual Chassis configuration is in progress, you cannot make any changes inside the Modify Virtual Chassis page.

Prerequisites

Before your perform any modification to a Virtual Chassis, you must remove all the additional CLI commands specific to Virtual Chassis (the virtual-chassis commands) from the associated device or site template. The additional CLI commands take precedence over other types of configurations. If a Virtual Chassis configuration is detected under the Additional CLI Commands section, you cannot make any changes using the Modify Virtual Chassis option. When you attempt to modify a Virtual Chassis, the Mist dashboard displays a message to indicate that the Additional CLI commands (if present) need to be removed and saved.

Before you modify an existing Virtual Chassis that uses a member MAC address as its device ID, we recommend converting it to use a virtual device ID. This makes managing the Virtual Chassis easier. For more information, refer to Convert a Virtual Chassis to Use a Virtual Device ID.

Convert a Virtual Chassis to Use a Virtual Device ID

When a Virtual Chassis device is represented in Mist by the MAC address of one of its member switches, managing it can become challenging. Especially, replacing or removing a member switch may cause inconsistencies in how the Virtual Chassis is represented, potentially disrupting connectivity.

Therefore, we recommend converting any existing Virtual Chassis device that uses the member 0 MAC address as its device ID to use a virtual device ID instead. Moving to a virtual device ID provides a consistent and centralized way to represent and manage a Virtual Chassis as a single logical entity, making future operations cleaner and more reliable.

A virtual device ID starts with the value 0200. A device ID that starts with any other value is assumed to be based on a member MAC address.

You can convert a Virtual Chassis using the Mist portal or via API.

To convert a virtual chassis using the Mist portal:

  1. Click Switches to go to the list of switches.

  2. From the list of switches, identify the Virtual Chassis device which you want to convert.

  3. Click the Virtual Chassis device to open it.

    The Virtual Chassis details page (switch details page) appears.

  4. Click the Modify Virtual Chassis button on the upper right of the page.

    For a Virtual Chassis device that is using a MAC address-based device ID, the Modify Virtual Chassis page displays a banner message recommending that you convert the Virtual Chassis to use a virtual device ID instead.

  5. Click the How do I convert? button on the right of the banner message.

  6. Click Convert to initiate the conversion.

After conversion, you will be redirected to the switch list page. Following conversion, the existing Virtual Chassis device (represented by a member MAC) is disconnected from the Mist cloud, and a new device along with a virtual device ID is created and displayed. A virtual device ID typically starts with '0200'.

To convert a virtual chassis via API:

  1. Locate the site where the Virtual Chassis is deployed and identify the site ID. To do that, use the steps below:
    1. Navigate to Organization > Site Configuration.
    2. Select the site to open it. You can find the site ID on the Information tile on this page.
  2. Identify the current device ID of the Virtual Chassis that is represented using a member MAC address. To do that, use the steps below:
    1. Click Switches to navigate to the switches page and locate the Virtual Chassis that needs to be converted.
    2. Click the Virtual Chassis device to open the Virtual Chassis (switch) details page. Look for the device ID in the URL. A MAC address-based device ID typically starts with a value other than '0200'.
  3. Perform the conversion by issuing a POST request to the API endpoint below using your Site ID and Device ID.

    Endpoint:

    Example:

Following conversion, the existing Virtual Chassis device (represented by a member MAC) is disconnected from the Mist cloud, and a new device along with a virtual device ID is created and displayed. A virtual device ID typically starts with '0200'.

Note:

  • Converting a Virtual Chassis device to use a virtual device ID will permanently erase all the events and stats previously stored for this device in the Mist cloud.

  • The newly created Virtual Chassis may initially show as disconnected on the switch list page. However, within a few minutes, it will automatically reconnect and appear on the switch list as connected.

  • The conversion does not impact the data plane—switching functionality continues uninterrupted.

Replace a Virtual Chassis Member

Note:

Instructions in this topic apply to any Virtual Chassis device that uses a virtual device ID, represented by a device ID starting with '0200', as shown in the image below. If the Virtual Chassis uses a member MAC address as its device identifier, you must follow the instructions in Replace a Member Whose MAC Address is Used as Virtual Chassis Device ID to avoid any connectivity disruptions during the process. You can find the device ID on the switch details page (Virtual Chassis page).

Replacing a Virtual Chassis member switch involves deleting the old member and adding a new member. Before replacing a member switch, you must ensure that:

  • The new switch is of the same model family as the other members in the Virtual Chassis.
  • The new switch is connected to the Virtual Chassis.
  • The new switch is assigned to the same site as the other members in the Virtual Chassis.

To replace a Virtual Chassis member that has a device ID starting with '0200':

  1. Onboard the replacement switch to the Mist cloud and assign it to the same site as the other members in the Virtual Chassis. To onboard the switch, use the Claim Switch or Adopt Switch option on the Inventory page (Organization > Inventory). You can also use the Mist AI mobile app to claim a switch.

    During the switch onboarding, remember to enable the configuration management for the switch by selecting the Manage configuration with Mist option.

    Note: Before your replace a switch, you must ensure that the new switch is in connected state.

    For the Adopt Switch workflow, the Manage configuration with Mist option is available during the site assignment step. For more information on the Adopt Switch workflow, see Onboard a Brownfield Switch.

    For the Claim Switch workflow, the Manage configuration with Mist option is available on the Claim Switches and Activate Subscription page. For more information about the Claim Switch workflow, see Onboard Switches to Mist Cloud.

  2. If you are replacing the primary member, i.e. Routing Engine of the Virtual Chassis, perform a graceful switchover from the primary role to the backup role.

    For more information, refer to Initiate Routing Engine Switchover.

  3. When the backup becomes the new primary, power off the original primary member (the member to be replaced). Or remove the Virtual Chassis port (VCP) cables from this member.
  4. Connect the Virtual Chassis cables from the existing Virtual Chassis members to the new replacement switch.
  5. On the Mist portal, navigate to the switch (Virtual Chassis) details page by clicking Switches > Switch Name.
  6. Wait for the switch details page to display the member switch to be replaced as offline, as shown below:
  7. Click Modify Virtual Chassis.

    Because you removed the VCP connection from the member switch being replaced, the Modify Virtual Chassis window displays a broken link for this member switch along with a delete (trash) icon.

  8. Delete the member to be replaced by clicking the trash icon.
  9. Click Add Switch to add the new replacement member.
  10. Renumber the new switch by dragging and dropping it into the appropriate slot.
  11. Edit the MAC address of the primary or backup switch if you are replacing one of them.
  12. Click Update.
  13. Ensure that the replacement switch, which is onboarded, is powered on.
  14. Wait for Virtual Chassis formation to be complete.

    The Switch Events page displays all the Virtual Chassis update events.

    The switch details page displays the updated Virtual Chassis information.

Replace a Member Whose MAC Address is Used as Virtual Chassis Device ID

Note:

Before you attempt the steps in this section, we recommend converting any existing Virtual Chassis device that uses a member MAC address as its device ID to use a virtual device ID (for more information, refer to Convert a Virtual Chassis to Use a Virtual Device ID). This makes managing the Virtual Chassis device easier. To replace a member in a Virtual Chassis that is converted to use a virtual device ID, you must follow the steps in Replace a Virtual Chassis Member.

Instructions in this topic apply to any Virtual Chassis device that uses a member MAC address as its device identifier, as shown in the image below. If the Virtual Chassis that has a device ID starting with 0200, you must follow the instructions in Replace a Virtual Chassis Member to replace its members. You can find the device ID on the switch details page (Virtual Chassis page).

If a Virtual Chassis uses the MAC address of a member (typically the FPC0) as the device identifier, you cannot replace that member in a single operation as it is used to communicate to the Mist cloud. You need to carry out the replacement in a 2-step process that includes adding the new replacement switch and then removing the switch to be replaced. In such cases, you should carry out the member replacement operation in a maintenance window as this operation can impact the traffic to the clients connected.

Note: Replacing an FPC member that is used as the device identifier will freshly assign the Virtual Chassis with a new device ID that is no longer tied to any FPC member.

Before replacing a member switch, you must ensure that:

  • The new switch is of the same model family as the other members in the Virtual Chassis.
  • The new switch is connected to the Virtual Chassis.
  • The new switch is assigned to the same site as the other members in the Virtual Chassis.

  • The Virtual Chassis is pre-provisioned. For a 2-member VC, the split and merge feature is disabled by default (no-split-detection) if the Virtual Chassis is provisioned by the cloud.

To replace a member (FPC0, for example) whose MAC address is used as the Virtual Chassis device ID:

  1. Remove the uplink connection (in-band or OOB) from the FPC0 member (if an uplink is present). Ensure the connectivity to the Mist cloud is maintained after the removal of the uplink. If this is the only uplink, connect it to another member that can provide the uplink connectivity.
  2. If the FPC0 is a primary member, i.e. Routing Engine of the Virtual Chassis, perform a graceful switchover from the primary role to the backup role.

    For more information, refer to Initiate Routing Engine Switchover.

  3. Power off the FPC0 member to be replaced. Or remove the VCP cable from it.
  4. Claim the new member switch, assign it to the same site, and enable configuration management on the switch.

    If this member switch belongs to a model (such as the EX2300, EX4000-8P, EX4650, or QFX5120) that does not have a dedicated VC port, you should connect it to the Mist cloud.

    For information on how to claim a switch, refer to Cloud-Ready EX and QFX Switches with Mist.

  5. Connect the VCP cable to the new member in the same ports.

    The new member is added to the Virtual Chassis.

    Now, the Virtual Chassis status in Junos will look like the below:

    • fpc0 - Not present

    • fpc1 - Present

    • fpc2 - Non-provisioned because the fpc0 and fpc1 were already pre-provisioned.

      Note: The "Unprvsnd" (Unprovisioned) status will not be displayed for switch models that do not have dedicated VCPs. Mist will automatically push the necessary VCP settings to such switches after you complete the Modify Virtual Chassis steps.
  6. In the Mist portal, click Switches > Switch Name to go to the switch details page of the Virtual Chassis to be modified.
  7. Click Modify Virtual Chassis.
    The Modify Virtual Chassis window appears.
  8. On the Modify Virtual Chassis window, click Add Switch and add the replacement switch to the Virtual Chassis as a new member.
  9. Click Update.
  10. Wait for 5 to 10 minutes for the data to synchronize and appear on the Mist portal.
  11. Click Modify Virtual Chassis again.

    Because you removed the VCP connection from the FPC0 being replaced, the Modify Virtual Chassis window displays a broken link against this member switch along with a delete (trash) icon.

  12. Delete the member to be replaced by clicking the trash icon.
    The Modify Virtual Chassis window displays a message indicating that FPC0 is required.
  13. Move the FPC2 member to slot 0 (the FPC0 slot) by dragging and dropping.
    Note:

    Ensure that no role change is performed.
  14. Click Update.
  15. Update the Routing Engine 2 field with the MAC address of the new switch.
  16. Click Update.

Renumber the Virtual Chassis Members

If you prefer to see the Virtual Chassis members on the Mist portal in the same order as they are physically stacked, you need to reorder the switches (after they are powered on and connected to Virtual Chassis) using the Modify Virtual Chassis option.

You can modify the member switches’ order on the Mist portal by renumbering the members. On the Modify Virtual Chassis window, accessible from the switch details page, you can move around the port panel of a switch to change the order of the member. The order is incremental. The first entry is member 0, the second is member 1, and so on. You are required to specify the FPC0.

To renumber the switches in a preprovisioned Virtual Chassis:

  1. Click the Switches tab on the left to navigate to the Switches page.
  2. Click the Virtual Chassis in which you want to renumber the members.
    The switch details page appears.
  3. On the switch details page, click Modify Virtual Chassis.
    The Modify Virtual Chassis window appears.
  4. On the Modify Virtual Chassis screen, drag and drop the port panel of a switch to different slots to change the switch number. The order is incremental. The first entry is member 0, the second is member 1, and so on. In the example below, the FPC1 has been renumbered as FPC2 and the FPC2 has been renumbered as FPC1.
    Note:

    • Within a Virtual Chassis that uses the MAC address of a member (typically FPC0) as the device identifier, you cannot renumber or move around that member unless it is disconnected.

    • Renumbering the members within a Virtual Chassis does not renumber the port configurations and port profile assignment. When you renumber a VC, Mist displays the following warning (as shown in the picture above): "Renumbering of VC members has been detected. The port configurations defined under Port Configuration > Port Profile Assignment will not be modified. Please verify that port configurations are correct after saving these changes."

      So, ensure that these changes are taken care of before or after renumbering the members in the Virtual Chassis.

  5. After you have made the changes, click Update.
    The members are renumbered.

Reassign Virtual Chassis Member Roles

A Virtual Chassis configuration in a Juniper Mist™ network has two switches in the Routing Engine role - one in the primary Routing Engine role, and the other in the backup Routing Engine role. The remaining member switches operate in the linecard role.

To change the role of Virtual Chassis members:

  1. Click the Switches tab on the left to navigate to the Switches page.
  2. Click the Virtual Chassis in which you want to change the member roles.
    The switch details page appears.
  3. On the switch details page, click Modify Virtual Chassis.
    The Modify Virtual Chassis window appears.
  4. On the Modify Virtual Chassis screen, specify Routing Engine 1 or Routing Engine 2. All the other switches assume a linecard role.
    Network management interface for modifying a virtual chassis configuration, showing two switches (EX4400-48P and EX4400-24MP) with their serial numbers, port IDs, routing engine assignments, a diagram of the physical connection layout, and options to add switches or update settings.
  5. After you have made the changes, click Update.
    The member roles are changed.

You will see the updated status about the role change on the switches page on the Mist portal. The role change will take some time (approximately 15 minutes) to appear on the Mist portal. You can see a banner message at the top after every change that you make, as shown below:

Delete Virtual Chassis Members

You can delete the member switches from the Virtual Chassis, by clicking the delete (trash) icon on the Modify Virtual Chassis window. Before deleting any member switch, you must ensure that the switch to be removed is disconnected from the Virtual Chassis. If the switch is connected, power it off or remove the VCP connection from it.

To delete a member switch from Virtual Chassis:

  1. If you are removing a primary member, i.e. Routing Engine of the Virtual Chassis, perform a graceful switchover from the primary role to the backup role.

    For more information, refer to Initiate Routing Engine Switchover.

  2. Power off the member to be removed. Or remove the VCP cable from it.
  3. On the Mist portal, click the Switches tab on the left to navigate to the Switches page.
  4. Click the Virtual Chassis from which you want to delete a member switch.
    The switch details page appears.
  5. On the switch details page, click Modify Virtual Chassis.
    The Modify Virtual Chassis window appears. Because you have removed the VCP connection from the member switch, the Modify Virtual Chassis window displays a broken link for the member switch along with a delete icon.
  6. Click the delete icon.
  7. Click Update.
    Mist removes the member switch from the Virtual Chassis.

Add a Member Switch to a Virtual Chassis

You can add one or more member switches to a Virtual Chassis from the Modify Virtual Chassis window. Before adding a new member switch to a Virtual Chassis, ensure the following:

  • The new switch is of the same model family as the other members in the Virtual Chassis.
  • The new switch is connected to the network (applicable to EX2300, EX4650, and QFX5120).
  • The new switch is assigned to the same site as the other members in the Virtual Chassis.
Note:

Juniper Mist automatically upgrades a Virtual Chassis linecard member if it is running a Junos version different from that of the primary member. The linecard member will be upgraded to the same version as the primary member if the following conditions are met:

  • The switch must form a Virtual Chassis with three or more members—that is, a primary, a backup, and a linecard member.

  • The Junos version on the linecard member is different from that on the primary member.

  • The linecard member must be in Inactive state.

    Note that a linecard member will be upgraded only if it is inactive and running a clearly different Junos version. Minor differences, such as different spin numbers, will not trigger an upgrade.

  • Only the Junos versions listed on the Mist portal are available for upgrade.

To add a new member switch to the Virtual Chassis:

  1. Onboard the new switch to the Mist cloud and assign it to the same site as the other members in the Virtual Chassis. To onboard the switch, use the Claim Switch or Adopt Switch option on the Inventory page (Organization > Inventory). You can also use the Mist AI mobile app to claim a switch.

    During the switch onboarding, remember to enable the configuration management for the switch by selecting the Manage configuration with Mist option.

    For the Adopt Switch workflow, the Manage configuration with Mist option is available during the site assignment step. For more information on the Adopt Switch workflow, see Onboard a Brownfield Switch.

    For the Claim Switch workflow, the Manage configuration with Mist option is available on the Claim Switches and Activate Subscription page. For more information about the Claim Switch workflow, see Onboard Switches to Mist Cloud.

  2. On the Mist portal, click the Switches tab on the left to navigate to the Switches page.
  3. Click the Virtual Chassis to which you want to add the new member switch.
    The switch details page appears.
  4. On the switch details page, click Modify Virtual Chassis.
    The Modify Virtual Chassis window appears.
  5. On the Modify Virtual Chassis window, click Add Switch.
  6. Specify the VC port ID for the switch, if needed (the port ID configuration applies to the EX2300, EX4650, and QFX5120 switches).
  7. Click Update.
  8. Connect the VCPs as specified on the Modify Virtual Chassis window and wait for 3 to 5 minutes for virtual chassis to be updated.
    While the Virtual Chassis is forming, the switches page displays the status as 'VC Forming'.

    After Mist updates the Virtual Chassis, the switch details page displays the front panel of all the three Virtual Chassis members.

Preprovision a Virtual Chassis

Before modifying any Virtual Chassis, we recommend that you ensure it is preprovisioned.

The preprovisioned configuration specifies the chassis serial number, member ID, and role for the member switches in a Virtual Chassis. When a new member router joins the Virtual Chassis, Junos compares its serial number against the values specified in the preprovisioned configuration. Preprovisioning prevents any accidental role assignments, or the accidental addition of a new member to the Virtual Chassis. Each role, member ID, addition or removal of members, is under the control of the configuration.

To preprovision a Virtual Chassis:

  1. Navigate to the Switches page (switch list) and review the preprovisioning status in the Preprovisioned VC column. The Virtual Chassis devices that are not preprovisioned are highlighted with an 'x' mark in red.
  2. Click to open the Virtual Chassis that has not been preprovisioned.
    The Virtual Chassis (switch) details page appears with a warning message indicating that the device is not yet preprovisioned.
  3. Click the Preprovision button on the right side of the warning message to go to the Modify Virtual Chassis window.
  4. On the Modify Virtual Chassis window, click Preprovision Virtual Chassis.

    This action pushes the preprovisioned Virtual Chassis configuration to the device and overwrites the old autoprovision Virtual Chassis configuration pushed to the device during the ZTP process. This option assumes the current positioning of the members and preprovisions them as is.

Initiate Routing Engine Switchover

You can manually initiate Routing Engine switchover in a Virtual Chassis.

In a Virtual Chassis, one member switch is assigned the primary role and hosts the primary Routing Engine. Another member switch is assigned the backup role and hosts the backup Routing Engine. Routing Engine switchover enables the system to transition control from the primary Routing Engine to the backup Routing Engine.

To perform Routing Engine switchover:

  1. Click the Switches tab on the left to navigate to the Switches page.
  2. Click the Virtual Chassis in which you want to initiate a Routing Engine switchover.
    The switch details page appears.
  3. On the switch details page, click Modify Virtual Chassis.
    The Modify Virtual Chassis window appears.
  4. On the Modify Virtual Chassis screen, click Switchover Routing Engine.

    This option is available only if the following conditions are met:

    • The Virtual Chassis is preprovisioned.

    • The Virtual Chassis has a primary and a backup member.

    Note: Note that the switchover briefly affects the operation of Virtual Chassis.
  5. Click Continue.
    Routing Engine switchover is initiated and you are redirected to the switch details page.

You will see the updated status about the Routing Engine switchover on the switch details page. This operation takes some time (approximately 15 minutes) to complete.