Description

At times, users may want to switch over the primary RE to another one so as to replace it or execute some workaround on an MX Series Virtual-Chassis (VC or MXVC for short). This switchover operation can be executed safely only if the whole VC is ready for a switchover.

In this article, we demonstrate the necessary steps to check a VC's readiness for global switchover on VC-Pp or local switchover on VC-Bp, and particularly in the Broadband Network Gateway (BNG) scenario as well.

Solution

For a normal MXVC scenario, execute the following steps to check if the MXVC is ready for a switchover:

  1. Execute the following command for basic check:

    1.1 Execute the following command on VC-Pp for global switchover

    request virtual-chassis master switch check >> Output must show switchover ready and not show any warning message.
     

    1.2 Execute the following command on VC-Bp for local switchover

    request chassis routing-engine master switch check >> Output must show switchover ready and not show any warning message.
     
  2. Execute the following commands on VC-Pp and VC-Bp:

    • show task replication >> All task synchronization status should be complete.
    • show bgp replication  >> Synchronization state should be complete.
    • show system switchover >> Observe the status (On/Ready/Ready/Ready). 

Note: Sometimes, it is required to collect the output several times until kernel status = ready.

For BNG MXVC scenario

In addition to the above steps, execute the following steps on VC-Pp and VC-Bp:

show system subscriber-management detail 

Note: All subscribers-mgmt daemons should report DONE state (subscribers-mgmt daemons and subscribers-mgmt related daemons such as dcd, dfwd, cosd, rpd, dfcd, jdhcpd, autoconfd, authd, pfed, and bdbrepd).

show database-replication summary -> (Database = Synchronized and Message Queue = Ready)
Example:

For normal MXVC scenario

On VC-Pp

[master:member1-re0]
root@Router1-RE0> request virtual-chassis routing-engine master switch check    
Switchover Ready

[master:member1-re0]
root@Router1-RE0> show system switchover
member0:
--------------------------------------------------------------------------
Graceful switchover: On
Configuration database: Ready
Kernel database: Ready
Switchover Status: Ready

[master:member1-re0]
root@Router1-RE0> show task replication
        Stateful Replication: Enabled
        RE mode: Master
    Protocol                Synchronization Status
    OSPF                    Complete              
    BGP                     Complete              
    MPLS                    Complete              
    RSVP                    Complete              
    LDP                     Complete

[master:member1-re0]
root@Router1-RE0> show bgp replication    
Synchronization master:
  Precision timer registration: NotRegistered
  Session state: Up, Since: 8:26:36
  Flaps: 21, Last flap reason: Socket replication deactivated
  Protocol state: Idle, Since: 8:26:36
  Synchronization state: Complete
  Number of peers waiting: AckWait: 0, SoWait: 0, Scheduled: 0
  Messages sent: Open 1, Establish 1, GrHelper 0, Update 0, GrStaleLabel 0 Error 0, Complete 1
  Messages received: Open 1, Request 1 wildcard 0 targeted, EstablishAck 1, GrHelperAck 0, CompleteAck 1

On VC-Bp

[backup:member0-re1]
root@Router0-re0> request chassis routing-engine master switch check 
Switchover Ready

[backup:member0-re0]
root@Router0-RE0> show task replication
        Stateful Replication: Enabled
        RE mode: Backup

[backup:member0-re0]
root@Router0-RE0> show bgp replication
Synchronization backup:
  State: Established 8:35:45 ago

[backup:member0-re0]
root@Router0-RE0> show system switchover
member0:
--------------------------------------------------------------------------
Graceful switchover: On
Configuration database: Ready
Kernel database: Ready
Switchover Status: Ready
For BNG MXVC scenario

In addition to the above steps, execute the following commands as well on VC-Pp and VC-Bp.

On VC-Pp

[master:member1-re0]
root@Router1-RE0> show system subscriber-management detail
General:
    Graceful Restart     Enabled
    Mastership           Master
    Database             Available
    Standby              Synchronized
    Chassisd ISSU State  IDLE
    ISSU State           IDLE
    ISSU Wait            0
 
Daemon        Pid     Recovery  Issu State          Issu Wait
------        ---     --------  ----------          ---------
cosd          10312   Done      N/A                 N/A      
jl2tpd        6750    Done      IDLE                0        
dfwd          10360   Done      N/A                 N/A      
pppoed        10315   Done      IDLE                0        
repd          10368   N/A       IDLE                0        
rpd           10345   Done      N/A                 N/A      
jdhcpd        6912    Done      IDLE                0        
l2ald         10308   N/A       N/A                 N/A      
rpd           6737    Done      N/A                 N/A      
dfcd          10318   Done      IDLE                0        
pfed          6324    Done      IDLE                0        
bbe-smgd      6757    Done      IDLE                0        
jpppd         6749    Done      IDLE                0        
dcd           10350   Done      N/A                 N/A      
smihelperd    10332   N/A       N/A                 N/A      
bdbrepd       10361   Done      IDLE                0        
bbe-statsd    6763    Done      IDLE                0        
authd         6747    Done      IDLE                0        
Total 18

[master:member1-re0]
root@Router1-RE0> show database-replication summary
General:
    Graceful Restart           Enabled
    Mastership                 Master
    Connection                 Up
    Database                   Synchronized
    Message Queue              Ready

On VC-Bp

[backup:member0-re0]
root@Router0-RE0> show system subscriber-management detail
General:
    Graceful Restart     Enabled
    Mastership           Standby
    Database             Available
    Standby              Synchronized
 
Daemon        Pid     Recovery  Issu State          Issu Wait
------        ---     --------  ----------          ---------
authd         9337    Done      IDLE                0        
bbe-statsd    9357    Done      IDLE                0        
bbe-smgd      9345    Done      IDLE                0        
pfed          6328    Done      IDLE                0        
repd          9363    N/A       N/A                 N/A      
jl2tpd        9340    Done      IDLE                0        
jpppd         9339    Done      IDLE                0        
jdhcpd        9336    Done      IDLE                0        
bdbrepd       9338    N/A       N/A                 N/A      
Total 9

[backup:member0-re0]
root@Router0-RE0> show database-replication summary
General:
    Graceful Restart           Enabled
    Mastership                 Standby
    Connection                 Up
    Database                   Synchronized
    Message Queue              Ready

Modification History

2021-03-25: Updated the article terminology to align with Juniper's Inclusion & Diversity initiatives
2020-07-24: Modified title and added a check for local switchover on VC-Bp