Switching HCM Mastership

When HCM mastership changes because of failure, Routing Engine mastership will change as well.

If the Routing Engines are running JUNOS Release 6.0 or later and are configured for graceful switchover, the standby Routing Engine immediately assumes Routing Engine functions and there is no interruption to packet forwarding. Otherwise, packet forwarding halts while the standby Routing Engine becomes the master and the Packet Forwarding Engine components reset and connect to the new master Routing Engine. For information about configuring graceful switchover, see the section about Routing Engine redundancy in the JUNOS System Basics Configuration Guide.

NOTE: Router performance might change if the standby Routing Engine's configuration differs from the former master's configuration. For the most predictable performance, configure the two Routing Engines identically, except for parameters unique to a Routing Engine, such as the hostname defined at the [edit system] hierarchy level and the management interface (fxp0 or equivalent) defined at the [edit interfaces] hierarchy level. To configure Routing Engine-specific parameters and still use the same configuration on both Routing Engines, include the appropriate configuration statements under the re0 and re1 statements at the [edit groups] hierarchy level and use the apply-groups statement. For instructions, see the JUNOS System Basics Configuration Guide.

Action

To switch HCM mastership to the backup HCM, use the following CLI command:

user@host> request chassis routing-engine master switch

Sample Output

user@host> request chassis routing-engine master switch

warning: Traffic will be interrupted while the PFE is re-initialized

Toggle mastership between routing engines ? [yes,no] yes

Resolving mastership...

Complete. The other routing engine becomes the master.

What It Means

The HCM that was master is now the backup HCM.

Action

To check HCM status and mastership after a switchover, use the following CLI command:

user@host> show chassis environment hcm

Sample Output

user@host> show chassis environment hcm 

HCM 0 status:

  State                           Online Standby

  FPGA Revision                27

HCM 1 status:

  State                           Online Master

  FPGA Revision                27

Action

To switch HCM mastership from the backup to the default master, use the following CLI command

user@host> request chassis routing-engine master switch

warning: Traffic will be interrupted while the PFE is re-initialized

Toggle mastership between routing engines ? [yes,no] (no) yes 

Resolving mastership...

Message from syslogd@host cfeb at Jan 28 15:10:37  ...

argh cfeb RDP: Remote side reset connection: 
rdp.(scb:17408).(serverRouter:chassis) 

Message from syslogd@host cfeb at Jan 28 15:10:37  ...

argh cfeb RDP: Remote side reset connection: rdp.(scb:17409).(serverRouter:pfe) 

Message from syslogd@host cfeb at Jan 28 15:10:37  ...

argh cfeb CM: ALARM SET: (Major) RE chassis socket closed abruptly 

Complete. The local routing engine becomes the master.