Comparison of Unix and Linux Log File Management Tools by Dusan Baljevic

© 2008 Dusan Baljevic The information contained herein is subject to change without notice

Unity and Disunity of Unix Log File Management Tools

Dusan BaljevicSydney, Australia

April 8, 2023 Webinar - Dusan Baljevic 2

Unix Log Files and Their Management Tools - Present

• Most of the time, admins rely on Shell or Perl scripts

• As well, find command is commonly used for cleanups


Unix Log Files and Their Management Tools

Solaris logadm

Linux logrotate

AIX (built-in log file rotation and compression)

HP-UX (various tools)


AIX syslog• AIX has built-in log file rotation and compression. They are optional fields

• Formatmsg_src_list destination [rotate [size sizek|m] [files files] [time timeh|d|w|m|y] [compress] [archive archive]]

msg_src_list is a semicolon separated list of facility.priorityfacility all (except mark) mark - time marks kern,user,mail,daemon, auth,...

priority is one of (from high to low): emerg/panic,alert,crit,err(or),warn(ing),notice,info,debug(meaning all messages of this priority or higher)

destination is: /filename - log to this file username[,username2...] - write to user(s) @hostname - send to syslogd on this machine * - send to all logged in users


AIX syslog Features (part 1/2)

• If destination is a regular file and the word rotate is specified, then the destination is limited by either size or time, or both. The backup filenames are created by appending a period and a number to destination, starting with .0. The time value causes the destination to be rotated after time. If both time and size are specified, then logfiles will be rotated once the logfile size exceeds size or the after time, whichever is earlier

• If the compress option is specified then the logfile names will be generated with a .Z extension. The files keyword will be applicable to the logfiles which are currently under rotation. For example, if we specify the compress option, then only file with .Z extension will be under rotation and the number of such files will be limited byfiles files. Any logfiles with an extension other than .Z will not be under the rotation scheme and thus will not be under the restriction of files files. Similarly if the compress option is removed then the files which have been generated with .Z extension will no longer be the part of rotation scheme and will not be limited by the files files


AIX syslog Features (part 2/2)

• The minimum size that can be specified is 10k. The minimum number of files that can be specified is 2. The default size is 1MB and the default for files is unlimited. Therefore, if only rotate is specified, the log will be rotated with size = 1m. The compress option means that rotated log files that are not in use will be compressed. The archive option will save rotated log files that are not in use to archive. The default is not to rotate log files

• The letter indicating the unit must immediately follow the number in the syntax. For example, to specify the log rotation of every two days, the phrase time “2d” is correct, but “2 d” is not


AIX /etc/syslog.conf

• Example /etc/syslog.conf

*.info /var/adm/syslog/syslog.log*.alert /var/adm/syslog/syslog.log*.notice /var/adm/syslog/syslog.log*.warning /var/adm/syslog/syslog.log*.err /var/adm/syslog/syslog.log*.crit /var/adm/syslog/syslog.log rotate time 1d files 9daemon.debug /var/adm/ftpd.log rotate size 1024k files 5


Linux logrotate• It allows automatic rotation, compression, removal, and mailing of log files. Each log file may be handled daily, weekly, monthly, or when it grows too large.

Normally, logrotate is run as a daily cron job. It will not modify a log multiple times in one day unless the formula for that log is based on the logs size and logrotate is being run multiple times each day, or unless the “-f” or “-force” option is used.

• Cron job /etc/cron.daily/logrotate

#!/bin/sh /usr/sbin/logrotate /etc/logrotate.confEXITVALUE=$?if [ $EXITVALUE != 0 ]; then /usr/bin/logger -t logrotate "ALERT exited abnormally with [$EXITVALUE]"fiexit 0


Linux /etc/logrotate.confweeklyrotate 4createdateextinclude /etc/logrotate.d

/var/log/wtmp { monthly create 0664 root utmp rotate 1}

/var/log/btmp { missingok monthly create 0600 root utmp rotate 1}


Linux logrotate Command Usage

Usage: logrotate [OPTION...] <configfile> -d, --debug Don't do anything, just test (implies -v) -f, --force Force file rotation -m, --mail=command Command to send mail (instead of `/bin/mail') -s, --state=statefile Path of state file -v, --verbose Display messages during rotation

Help options: -?, --help Show this help message --usage Display brief usage message


Linux /etc/logrotate.d Directory

# ls /etc/logrotate.d

bittorrent fail2ban munin-node rpm squid yum clamav-update httpd nagios samba squidGuard zabbixcollectl mgetty named sa-updatesyslog cups mimedefang pppsetroubleshoot tux dirmngr munin psacct snmpd wpa_supplicant


Linux /etc/logrotate.d Example

# cat /etc/logrotate.d/httpd

/var/log/httpd/*log { missingok notifempty sharedscripts postrotate kill -HUP `cat /var/run/httpd.pid 2>/dev/null` 2> /dev/null \ || true endscript}


Solaris logadm

• Starting from Solaris 9, there is a standard tool, called logadm, to rotate logs • logadm is an independent utility (unlike integrated in syslog daemon capability that can be found in AIX). The logadm command is a preconfigured entry in the default crontab file supplied starting with Solaris 9

•/usr/lib/newsyslog script is no longer used

• Before Solaris 9 there was FreeBSD-style tool newsyslog located in /usr/lib and Perl script rotatelog. It was run from cron. For Solaris 8 and earlier download the tar.gz file, untar it, go in the new directory, and execute make install. It will install /usr/local/sbin/rotatelog and /usr/local/etc/rotatelog.conf


Solaris /etc/logadm.conf (part 1/2)

logadm.conf specifies the schedule for log rotation and options with which rotation will be performed. The default configuration:

/var/log/syslog -C 8 -P 'Sun Sep 14 17:10:00 2008' -a 'kill -HUP `cat /var/run/syslog.pid`‘

/var/adm/messages -C 4 -P 'Fri Sep 12 17:10:00 2008' -a 'kill -HUP `cat /var/run/syslog.pid`'

/var/cron/log -P 'Fri Aug 22 17:10:00 2008' -c -s 512k -t /var/cron/olog

/var/lp/logs/lpsched -C 2 -N -t '$file.$N'


Solaris /etc/logadm.conf (part 2/2)

/var/fm/fmd/errlog -M '/usr/sbin/fmadm -q rotate errlog && mv /var/fm/fmd/errlog.0- $nfile' -N -s 2m

smf_logs -C 8 -s 1m /var/svc/log/*.log

/var/adm/pacct -C 0 -N -a '/usr/lib/acct/accton pacct' -g adm -m 664 -o adm -p never

/var/log/pool/poold -N -a 'pkill -HUP poold; true' -s 512k

/var/fm/fmd/fltlog -A 6m -M '/usr/sbin/fmadm -q rotate fltlog && mv /var/fm/fmd/fltlog.0- $nfile' -N -s 10m


Solaris logadm Command Usage (part 1/3)

Usage: logadm [options] (processes all entries in /etc/logadm.conf or conffile given by -f) or: logadm [options] logname... (processes the given lognames)

General options: -e mailaddr mail errors to given address -f conffile use conffile instead of /etc/logadm.conf -h display help -N not an error if log file nonexistent -n show actions, don't perform them -r remove logname entry from conffile -V ensure conffile entries exist, correct -v print info about actions happening -w entryname write entry to config file


Solaris logadm Command Usage (part 2/3)Options which control when a logfile is rotated:(default is: -s1b -p1w if no -s or -p) -p period only rotate if period passed since last rotate -P timestamp used to store rotation date in conffile -s size only rotate if given size or greater

Options which control how a logfile is rotated:(default is: -t '$file.$n', owner/group/mode taken from log file) -a cmd execute cmd after taking actions -b cmd execute cmd before taking actions -c copy & truncate logfile, don't rename -g group new empty log file group -l rotate log file with local time rather than UTC -m mode new empty log file mode -M cmd execute cmd to rotate the log file -o owner new empty log file owner -R cmd run cmd on file after rotate -t template template for naming old logs -z count gzip old logs except most recent count


Solaris logadm Command Usage (part 3/3)

Options which control the expiration of old logfiles:(default is: -C10 if no -A, -C, or -S) -A age expire logs older than age -C count expire old logs until count remain -E cmd run cmd on file to expire -S size expire until space used is below size -T pattern pattern for finding old logs


Solaris logadm and Timezone

• By default, logadm works in GMT. All entries written to the /etc/logadm.conf file will have a GMT timestamp

• Use the “-l” option to set logadm to local time


Solaris logadm – Example for wtmpx• Add into /etc/logadm.conf

/var/adm/utmpx -C 12 -P ‘Mon Oct 13 17:00:00 2008' -s 100m -z 0

"-C 12" means it will preserve 12 versions of the log file"-P .." means when to first start processing the log file"-s 100m" defines the maximum size of the log file before it is rotated"-z 0" sets the gzip compression

• Run command:

# logadm

• Check it:

# logadm -V


HP-UX 11i syslogd

• HP-UX 11i v1 and earlier do not have log file automation • HP-UX 11.23 and later syslogd logs messages into a set of files. Once the size of a log file reaches 2 GB, syslogd stops logging to that file. Configure the maximum size of syslogd log files by setting the variable LOG_SIZE in /etc/default/syslogd

The value of LOG_SIZE can be any positive integer greater than 2, representing the maximum size of the file in GB. When LOG_SIZE=NOLIMIT, syslogd uses the limit imposed by the file system on file size


HP-UX 11i syslogd Simple Rotation

# /sbin/init.d/syslogd stop

# /sbin/init.d/syslogd start

It will rename syslog.log to OLDsyslog.log in /var/adm/syslog directory.


HP-UX 11i Other RC Cleanups• /etc/rc.config.d/clean_tmp for /tmp cleanup at boot

CLEAR_TMP=1

• /etc/rc.config.d/clean

CLEAN_ADM=1CLEAN_UUCP=1

/var/adm/sulog /var/adm/diaglog /var/adm/messages renamed to OLD*

• /etc/rc.config.d/clean_uucp uuclean(1m) at boot

CLEAN_UUCP=1


HP-UX 11i Examples of Log Directories and Files• Examples of log files that can grow out of bounds:

/var/spool/lp/var/adm/lp/var/opt/perf/datafileslost+found directories in top-level of each file system/var/adm/diag/var/opt/ignite/var/stm/logs/sys */var/adm/wtmp/var/adm/wtmps/var/adm/btmp/var/adm/sw(others truncated for the sake of brevity)


HP-UX 11i auto_parms.log

• /etc/auto_parms.log is updated by auto_parms(1m) command that handles first-boot configuration (setting of unique system “initial identity parameters”), and ongoing management of DHCP leases

• auto_parms(1m) saves old copy into /etc/auto_parms.log.old


HP-UX 11i rc.log

• Run Command (RC) scripts update /etc/rc.log at boot time

• At reboot, previous version of /etc/rc.log is renamed to /etc/rc.log.old


HP-UX 11i EMS Logs

• The EMS log files in /etc/opt/resmon/log are limited to 500 KB in size and are then moved to <logfile>.old. The previous *.old gets lost

• The limit of 500 KB per logfile can be removed by creating the file /etc/opt/resmon/unlimited_log

• Be careful with creating the unlimited_log. Growing EMS log files can easily fill up root file system


HP-UX 11i Glance and MeasureWare Logs

• /var/opt/perf/parm is read by both the GlancePlus product and the MeasureWare products. Glance uses only the Application definitions

size global=10, application=10, process=20, device=10, transaction=10

The sizes are in MB

• The logfiles are stored in /var/opt/perf/datafiles directory


HP-UX 11i Integrity VM Driver Log File • /var/opt/hpvm/common/hpvm_mon_log is limited to 1024 KB by default. When the log file grows larger than this, it is copied to a new file (hpvm_mon_log.$time) and an empty one is created for the new log

• To allow this log file to grow larger than 1024 KB, include the following line in /etc/rc.config.d/hpvmconf

VMMLOGSIZE=10420 # In KB

Then, restart the daemon:

# kill –HUP `cat /var/run/hpvmmonlogd.pid`


HP-UX 11i Integrity VM Guest Log File

• /var/opt/hpvm/guests/guest_name/log file records guest start and stop information. These log files can grown very large

To close the current log file, rename it, and open a new one:

# hpvmconsole rec -rotate


HP-UX 11i SMH * # cat /opt/hpsmh/conf.common/smhpd.xml<?xml version="1.0" encoding="UTF-8"?><system-management-homepage><admin-group></admin-group><operator-group></operator-group><user-group></user-group><allow-default-os-admin>True</allow-default-os-admin><anonymous-access>False</anonymous-access><localaccess-enabled>False</localaccess-enabled><localaccess-type>Anonymous</localaccess-type><trustmode>TrustByCert</trustmode><xenamelist></xenamelist><ip-restricted-logins>False</ip-restricted-logins><ip-restricted-include></ip-restricted-include><ip-restricted-exclude></ip-restricted-exclude><ip-binding>False</ip-binding><ip-binding-list></ip-binding-list><rotate-logs-size>N</rotate-logs-size></system-management-homepage>


HP-UX 11i TCB Auditing • It records instances of access by subjects to objects and allows detection of any (repeated) attempts to bypass the protection mechanism and any misuses of privileges

• audsys allows the user to start or halt the auditing system, to specify the auditing system "current" and "next" audit files (and their switch sizes), or to display auditing system status information. The "current" audit file is the file to which the auditing system writes audit records. When the "current" file grows to either its Audit File Switch (AFS) size or its File Space Switch (FSS) size (see audomon), the auditing system switches to write to the "next“ audit file

# audsysAuditing system is currently oncurrent file: /var/adm/audit/audfile1next file: /var/adm/audit/audfile2statistics- afs Kb used Kb avail % fs Kb used Kb avail %current file: 10000 0 100 4825088 963704 80next file: 10000 0 100 4825088 963704 80


HP-UX 11i HIDS HIDS log files increase rapidly. However, the Configuration Change Console agent keeps log files truncated to save disk space. To ensure that the log files do not increase in file size while the agent is not running, run a script to periodically truncate the HIDS log files.

A sample script to manage HIDS log files is provided. This script should be runfrom the crontab:

#!/bin/shfilesize=`/bin/ls -l /var/opt/ids/alert.log | /bin/awk '{print $5}'`if [ "$filesize" -gt "5000000" ]then mv /var/opt/ids/alert.log /var/opt/ids/alert.log_Dec_2008 firm /var/opt/ids/ids_1*

Sample entry to configure the crontab to run every hour where the bold letters are replaced by the actual path of the trunclog.sh file:

0 * * * * /<location of script>/trunclog.sh 2>/dev/null 2>&1


HP-UX 11i ServiceGuard Package Log File

SCRIPT_LOG_FILE (SG 11.17+) A new package attribute that allows a name to be assigned to a package log file

Necessary for support of multiple packages sharing a common package control script

Legacy Package ConfigurationSCRIPT_LOG_FILE /etc/cmcluster/pkga/pkga.log

Modular Package Configurationscript_log_file $SGRUN/log/$SG_PACKAGE.log


HP-UX 11i ulimit

# ulimit -a

time(seconds) unlimitedfile(blocks) unlimiteddata(kbytes) 1048576stack(kbytes) 8192memory(kbytes) unlimitedcoredump(blocks) 4194303nofiles(descriptors) 2048


HP-UX 11i v3 coreadm *

# coreadm

global core file pattern: init(1M) core file pattern: global core dumps: disabledper-process core dumps: enabledglobal setid core dumps: disabledper-process setid core dumps: disabled


HP-UX cleanup - HP-UX patch cleanup utility

# cleanup –c 1

The cleanup command provides functions useful when dealing with HP-UX patches.

The cleanup command logs all information to /var/adm/cleanup.log.


HP-UX savecrash utility

/etc/rc.config.d/savecrash

CHUNK_SIZE Size of single crash image file (how big you want each of image.n.x, image.n.x+1, etc. to be). If not specified, savecrash will choose one based on the physical memory size of the system. Can be specified in bytes (b), kilobytes (k), megabytes (m), or gigabytes (g). The default unit is KB. See savecrash(1M) “–s” option for size constraints.

COMPRESS: Whether you want the kernel and crash image files to be compressed.


HP-UX Alternative Log File Tools(part 1/3)

• Old but maybe still applicable bundle (needs to be tested):

http://hpux.cs.utah.edu/hppd/hpux/Sysadmin/logrotate-2.5/

• Shell script logrotate:

http://iain.cx/src/logrotate/

• Scripts based on Perl modules like Logfile-Rotate

•Perl-Logrotate:

http://freshmeat.net/projects/perl-logrotate


HP-UX Alternative Log File Tools(part 2/3)

• newsyslog project (old and possibly obsolete):

http://www.weird.com/~woods/projects/newsyslog.html

• logtrim by Bill Hassell (released in HP ITRC forum several years ago):

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1053445&admit=109447626+1221799837763+28353475

• Replace standard syslog daemon with Syslog-NG and SQL database:

http://www.balabit.com/network-security/syslog-ng/features/detailed


HP-UX Alternative Log File Tools(part 3/3)• smartlog (very old bundles for HP-UX 10.20 and 11.00 only):

http://gatekeep.cs.utah.edu/hppd/hpux/Sysadmin/smartlog-3.5/

• Many other Shell scripts, for example:

http://www.zazzybob.com/bin/logrevolver.sh.html

• LogWatch:

http://www2.logwatch.org:81/


HP-UX Syslog-NG

• Syslog-NG and SQL database (MySQL, Microsoft SQL (MSSQL), Oracle, PostgreSQL, SQLite)

• Log rotation based on output filenames - Log output filenames can be based on templates names which support macro expansion. For example, if the output filename template contains the month macro, a new filename will created each month

• Often, syslog-ng is used for log file consolidation (centralized management)


Conclusion

• Log file management is mostly managed reactively

• Majority of Unix admins I meet are not aware of OS-native tools that are designed for log file administration

© 2008 Dusan Baljevic The information contained herein is subject to change without notice

Thank You!

Dusan BaljevicSydney, Australia

Technology

Comparison of Unix and Linux Log File Management Tools by Dusan Baljevic