Juniper JUNOS - NETWORK OPERATION GUIDE REV1

Switching HCM Mastership ! 627
Chapter 48: Monitoring Redundant HCMs
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.
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
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.