Juniper JUNOS - NETWORK OPERATION GUIDE REV1 User Manual

Determining Why Mastership Switched ! 483
Chapter 36: Host Redundancy Overview
The master Routing Engine gives up control of the system bus and goes into the
backup state. The backup Routing Engine becomes master and restarts the Packet
Forwarding Engine. You can then diagnose the original master Routing Engine for
problems or prepare it for upgrade or reconfiguration. When switchover occurs, the
backup Routing Engine does not run through its full boot cycle (only the packet
forwarding components run through a full boot cycle).
When you enter the
request chassis routing-engine master release command on the
master Routing Engine, the system passes mastership to the backup Routing
Engine. The master Routing Engine gives up control of the system bus and goes into
the backup state. The backup Routing Engine becomes master and restarts the
Packet Forwarding Engine. You can then diagnose the original master Routing
Engine for problems or prepare it for upgrade or reconfiguration.
In all cases, once the switchover occurs, the new master Routing Engine
reestablishes routing adjacencies, populates the routing table, and transfers
forwarding table information to the Packet Forwarding Engine. When Routing
Engine mastership changes, the Packet Forwarding Engine components are
rebooted to reestablish communication links and download the microkernel to each
component. When this occurs, forwarding is interrupted and packet buffers are
flushed.
Determining Why Mastership Switched
Mastership can switch between the master Routing Engine and the backup Routing
Engine for the following reasons:
! Hardware problems.
! The master Routing Engine is pulled.
! Software issues, such as a Routing Engine kernel crash.
Action View the log file /var/log/mastership for redundancy logging. This file contains
hardware and software transitions to help debug auto-redundancy issues.
user@host> show log mastership
Table 107 lists the event codes that can be displayed in the mastership log.
Table 107: Logging Events
Event Code Description
E_NULL = 0 The event is a null event.
E_CFG_M The Routing Engine is configured as master.
E_CFG_B The Routing Engine is configured as backup.
E_CFG_D The Routing Engine is configured as disabled.
E_MAXTRY The maximum number of tries to acquire or release mastership was
exceeded.
E_REQ_C A claim mastership request was sent.
E_ACK_C A claim mastership acknowledgement was received.

Juniper JUNOS - NETWORK OPERATION GUIDE REV1 Specifications

General

Brand	Juniper
Model	JUNOS - NETWORK OPERATION GUIDE REV1
Category	Software
Language	English