In Junos Evolved, the backup Routing Engine (RE) does not have anything written to the log file called /var/log/messages . The backup RE logs messages file is not being updated. It gets updated only when it becomes the primary RE.

This specification is different from other platforms running Junos OS.

This article provides more details.

The primary RE messages are written in the primary RE messages file.

Primary RE

{MASTER}

labroot@ptx10008-re0> start shell user root
Password:
[vrf:none] root@ptx10008-re0:~# logger "I am master"

[vrf:none] root@ptx10008-re0:~# cat /var/log/messages |grep "I am master"    >>>> On primary host
Jun 18 07:04:45  ptx10008-re0 labroot[32090]: %USER-5: I am master

[vrf:none] root@ptx10008-re0:~# ps -auxw |grep master-eventd
root      1558  0.0  0.0   6744   824 pts/2    S+   07:05   0:00 grep master-eventd
root     26507  0.0  0.2 6467096 133544 ?      Ssl  Jun17   0:27 /usr/sbin/eventd -N -r -s --app-name master-eventd -I object_select --shared-objects-mode 3

{MASTER}
labroot@ptx10008-re0> file show /var/log/messages
Jun 18 07:04:45  ptx10008-re0 labroot[32090]: %USER-5: I am master
Jun 18 07:04:45  ptx10008-fpc0 evo-cda-bt[17920]: %USER-7: Read value in 0 attempts, Time Taken: 0 ms

Backup RE messages are written in the primary RE messages file.

Backup RE

{BACKUP}

labroot@ptx10008-re1> start shell user root
Password:
[vrf:none] root@ptx10008-re1:~# logger "I am backup"

[vrf:none] root@ptx10008-re0:~# cat /var/log/messages | grep "I am backup"  >>>> Recorded on primary host
Jun 18 07:06:32  ptx10008-re1 labroot[29334]: %USER-5: I am backup

[vrf:none] root@ptx10008-re1:~# ps -auxw |grep master-eventd
root     31582  0.0  0.0   6744   728 pts/0    S+   07:07   0:00 grep master-eventd

{MASTER}
labroot@ptx10008-re0> file show /var/log/messages
Jun 18 07:06:12  ptx10008-fpc0 evo-cda-bt[17920]: %USER-7: Read value in 0 attempts, Time Taken: 0 ms
Jun 18 07:06:32  ptx10008-re1 labroot[29334]: %USER-5: I am backup    <<<<< Backup RE messages are written in primary RE messages file.
Jun 18 07:06:32  ptx10008-fpc0 evo-cda-bt[17920]: %USER-7: Read value in 0 attempts, Time Taken: 0 ms

{MASTER}
labroot@ptx10008-re0> show chassis hardware
Hardware inventory:
Item             Version  Part number  Serial number     Description
Chassis                                EP901             JNP10008 [PTX10008]
Midplane 0       REV 16   750-086802   BCBS5053          Midplane 8
FPM 0            REV 02   711-086964   BCBS5564          Front Panel Display
PSM 0            Rev 03   740-069994   1F21A340356       JNP10K 5500W AC/HVDC Power Supply Unit
PSM 1            Rev 03   740-069994   1F21A340288       JNP10K 5500W AC/HVDC Power Supply Unit
PSM 2            Rev 03   740-069994   1F21A340300       JNP10K 5500W AC/HVDC Power Supply Unit
PSM 3            Rev 03   740-069994   1F21A340301       JNP10K 5500W AC/HVDC Power Supply Unit
PSM 4            Rev 03   740-069994   1F21A340359       JNP10K 5500W AC/HVDC Power Supply Unit
PSM 5            Rev 03   740-069994   1F21A340371       JNP10K 5500W AC/HVDC Power Supply Unit
Routing Engine 0          BUILTIN      BUILTIN           JNP10K-RE1-E
Routing Engine 1          BUILTIN      BUILTIN           JNP10K-RE1-E
CB 0             REV 06   750-101345   BCBR7151          Control Board
CB 1             REV 06   750-101345   BCBR7244          Control Board

The master-eventd process, which dumps messages in the syslog file, runs only in the primary RE and not in the backup RE. This is the reason you see messages on the primary node. This is the Day-1 design behavior in Junos Evolved.

You can find the backup RE messages in the primary RE messages file. 

• Displaying System Log Files