3troubleshootingjunos

The following are configuration options for tracing:

•

file filename: Specifies the name of the file in which to store

information.

•

size size: Specifies the maximum size of each trace file, in kilobytes

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(KB), megabytes (MB), or gigabytes (GB). When a trace file named

trace-file reaches this maximum size, it receives compression a d

is renamed trace-file.0.gz. When the trace file again reaches its

maximum size, trace-file.0.gz is renamed trace-file.1.gz,

and trace-file is compressed and renamed trace-f le.0.gz.

This renaming scheme continues until it reaches the max mum number

of allowable trace files. The software then overwrites he

ldest race file.

If you do not specify a maximum number of tra e files w

h he f les

option, the default number of files to keep is ten. If you spe ify a

maximum file size, you also must specify a maximum number of trace

files with the files option. You can se xk, xm, or xg to specify

kilobytes, megabytes, or gigabytes, respectively. The default range is

128 KB.

•

flag flag: Specifies a tracing operation to perform. You can specify

multiple flags.

•

files number: Specifies the maximum number of trace files. When a

trace file named trace-file eaches its maximum size, JUNOS

Software renames it ace-file.0, then trace-file.1, and so

forth, until it reaches the maximum number of trace files. The software

then ov rwrit s the old st trace file. The default is ten files.

Including the traceoptions stat m

nt at the [edit interfaces

interface-name] hi rarchy l v

l allows you to trace the operations of individual

router interfaces. You can also trace the operations of the interface process, which is

the device control process.

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When t acing a specific interface, the software does not support the specification of a

trace file. The JUNOS Software kernel does the logging in this case, so the software

places the t acing information in the system’s messages file. In contrast, global

inte face t acing supports an archive file; by default it uses /var/log/dcd for global

inter ace tracing.

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Jan 7

18:22:40 Parsing c nfigReproductionfile

Viewing Logs and Trac

s

By default, log and trace fil

s are stored in /var/log. To view stored log files, use

the command show log.

call that the CLI automatically pauses when it has more

than one screen’s worth of information, and that at this more prompt, you can enter a

Display hisforwahelp text:

h

d slash (/) character to conduct a forward search. As a hint, enter h when at a

mo e p ompt for a context help screen of available commands:

---(Help for CLI aut m

e)---

c or C

Clear all match and except strings:

Display all line matching a regexp:

m or M <string>

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e or E <string>

Display all lines except those matching a regexp:

D n't h ld in automore at bottom of output:

N

H ld in au

more at bottom of output:

H

M ve d wn half display:

TAB, d, or ^D

M ve d wn

ne line:

Enter, j, ^N, ^X, ^Z, or Down-Arrow

Being able to cascade multiple instances of the CLI’s pipe functionality is a real

benefit when you must search a long file for associated entries. In the example, the

match function cascades so that only lines containing the words packet ignored

and virtual are displayed; this cascading creates a logical AND type matching

function. Being able to search for multiple criteria in a logical OR fashion is extremely

handy, especially when you are not quite sure what it is that you are seeking. The slide

provides two examples of a logical OR search. The basis for the former is

human-readable keywords while the latter makes use of explicit message priority

codes to display all messages ranging from level 0 (emergency) to level 4 (war i g).

Note that searching by messag priority requires enabling sysl g pr r ty with the

explicit-priority keyword.

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Monitoring Logs and Trace Fil s

Use the monitor CLI command to view real-time log information. You can monitor

several log files at one time. You can identify the messages from each log by

filename, where filename is the name of the file that displays entries. This line

displays initially and when the CLI switches between log files.

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Using Esc+q enables and disables syslog output to screen; using monitor stop

ceases all m nito ing. Note that you can us the CLI’s match functionality to monitor a

ile in

eal time, while displaying only entries that match your search criteria. To make

use

the functionality, use a command in the following form:

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start messages | match fail

lab@San Jose> m ni

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Troubleshooting Tools: Int ractive UNIX Shell

The slide highlights the topic we discuss next.

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