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request chassis routing-engine master

Syntax

Syntax (M Series, MX Series, T Series Routers, ACX7509, ACX1000 Devices)

Syntax (TX Matrix Routers)

Syntax (TX Matrix Plus Routers)

Syntax (MX Series Virtual Chassis)

Syntax (QFX Series)

Syntax

Description

For routers or switches with multiple Routing Engines, control which Routing Engine is the primary.

CAUTION:

(Routing matrix based on the TX Matrix or TX Matrix Plus routers only) Within the routing matrix, we recommend that all Routing Engines run the same Junos OS Release. If you run different releases on the Routing Engines and a change in primary role occurs on any backup Routing Engine in the routing matrix, one or all routers (in a routing matrix based on the TX Matrix router or in a routing matrix based on a TX Matrix Plus router) might become logically disconnected from the TX Matrix router and cause data loss. For more information, see the TX Matrix Router Hardware Guide or the Junos OS High Availability User Guide.
Note:

Successive graceful Routing Engine switchover events must be a minimum of 240 seconds (4 minutes) apart after both Routing Engines have come up.

If the router or switch displays a warning message similar to “Standby Routing Engine is not ready for graceful switchover. Packet Forwarding Engines that are not ready for graceful switchover might be reset,” do not attempt switchover. If you choose to proceed with switchover, only the Packet Forwarding Engines that were not ready for graceful switchover are reset. None of the Flexible PIC concentrators (FPCs) should spontaneously restart. We recommend that you wait until the warning no longer appears and then proceed with the switchover.

You will receive an error message stating “Command terminated. Not ready for primary role switch, try after n seconds” when this command is re-entered before 240 seconds have elapsed on EX Series switches.
Note:

On a QFabric system, to avoid traffic loss on the network Node group, switch primary role of the routing engine to the backup routing engine, and then reboot.

Options

acquire

(Not available for Junos OS Evolved) Attempt to become the primary Routing Engine.
release

(Not available for Junos OS Evolved) Request that the other Routing Engine become the primary.
switch

Toggle primary role between Routing Engines.

Note:

The acquire option should be used with caution because acquiring a Routing Engine may result in a corrupted database. If possible, use the switch option instead.

The acquire, release, and switch options have the following suboptions:

all-chassis

(TX Matrix and TX Matrix Plus routers only) On a routing matrix composed of a TX Matrix router and the attached T640 routers, switch primary role on all the Routing Engines in the routing matrix. Likewise, on a routing matrix composed of a TX Matrix Plus router and the attached T1600 or T4000 routers, switch primary role on all the Routing Engines in the routing matrix.
all-lcc

(TX Matrix Plus routers only) Request to acquire primary role for all line-card chassis (LCC).
all-members

(MX Series routers only) (Optional) Control Routing Engine primary role on the Routing Engines in all member routers of the Virtual Chassis configuration.
check

(ACX7509, MX104, MX480, MX960, MX2010, MX2020, and MX2008 routers, QFabric systems, and PTX5000 routers only) (Optional) Available with the switch, release, and acquire options. Check graceful switchover status of the standby Routing Engine before toggling primary role between Routing Engines (RE). Check if the RE is ready for a switchover.

interconnect-device name

(QFabric systems only) (Optional) Control Routing Engine primary role on the Routing Engines on an Interconnect device.
lcc number

(TX Matrix router and TX Matrix Plus router only) (Optional) Line-card chassis number.

Replace number with the following values depending on the LCC configuration:

  • 0 through 3, when T640 routers are connected to a TX Matrix router in a routing matrix.

  • 0 through 3, when T1600 routers are connected to a TX Matrix Plus router in a routing matrix.

  • 0 through 7, when T1600 routers are connected to a TX Matrix Plus router with 3D SIBs in a routing matrix.

  • 0, 2, 4, or 6, when T4000 routers are connected to a TX Matrix Plus router with 3D SIBs in a routing matrix.
local

(MX Series routers only) (Optional) Control Routing Engine primary role on the Routing Engines in the local Virtual Chassis member.
member member-id

(MX Series routers only) (Optional) Control Routing Engine primary role on the Routing Engines of the specified member in the Virtual Chassis configuration. Replace member-id with a value of 0 or 1.
no-confirm

(Optional) Do not request confirmation for the switch.
node-group name

(QFabric systems only) (Optional) Control Routing Engine primary role on the Routing Engines on a Node group.
scc

(TX Matrix routers only) TX Matrix (switch-card chassis).
sfc

(TX Matrix Plus routers only) TX Matrix Plus router (or switch-fabric chassis).

Additional Information

Always use the show system switchover command on the backup Routing Engine to determine if the backup is ready to take over as the primary Routing Engine.

Because both Routing Engines are always running, the transition from one to the other as the primary Routing Engine is immediate. However, the changeover interrupts communication to the System and Switch Board (SSB). The SSB takes several seconds to reinitialize the Flexible PIC Concentrators (FPCs) and restart the PICs. Interior gateway protocol (IGP) and BGP convergence times depend on the specific network environment.

By default, the Routing Engine in slot 0 (RE0) is the primary and the Routing Engine in slot 1 (RE1) is the backup. To change the default primary Routing Engine, include the routing-engine statement at the [edit chassis redundancy] hierarchy level in the configuration.

To have the backup Routing Engine become the primary Routing Engine, use the request chassis routing-engine master switch command. If you use this command to change the primary and then restart the chassis software for any reason, the primary reverts to the default setting.

Note:

Although the configurations on the two Routing Engines do not have to be the same and are not automatically synchronized, we recommend making both configurations the same.

Required Privilege Level

maintenance

Output Fields

When you enter this command, you are provided feedback on the status of your request.

Sample Output

request chassis routing-engine primary acquire

request chassis routing-engine primary switch

Switch primary role back to the local Routing Engine:

request chassis routing-engine master switch (Junos OS Evolved)

Switching back to primary router:

If you did not switch back and tried to enter configuration mode, you would get the following error message:

request chassis routing-engine primary switch check (ACX7509, M Series, MX Series, and T Series Devices)

Output when system is ready for graceful switchover.

You can similarly check the backup Routing Engine for the switchover readiness.

request chassis routing-engine master switch check (DRAM Size Mismatch Between Primary and Standby)

To check switchover readiness, use the show system switchover command before changing the mastership. Please note that the switchover is denied until 360 seconds have passed from the previous switchover.

Release Information

Command introduced before Junos OS Release 7.4.

all-chassis option added in Junos OS Release 8.0.

sfc option introduced for the TX Matrix Plus router in Junos OS Release 9.6.

Command support added to ACX7509 platform in Junos OS Evo Release 22.1.

Related Documentation