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Logrotate 2.- Configure logrotate for AIX

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NOTE:  This is a follow-up, from the previous post: AIX 6L+ , AIX 7DevOps and Logrotate on AIX

Logrotate is a utility from RHEL, and therefore it comes preconfigured for RHEL & fedora, so after installing it using yum, we need to adapt it to work in our AIX system.

2.1- Fix logrotate.conf invalid entries

By default, logrotate’s main config file treats logs of wtmp & btmp, but since we can treat wtmp separately, and btmp is not implemented in AIX, we can just comment out or better still, delete those lines from /etc/logrotate.conf:

[root@aix72:/etc/logrotate.d]vi /etc/logrotate.conf
 # see "man logrotate" for details
 # rotate log files weekly
 weekly

# keep 4 weeks worth of backlogs
 rotate 4

# create new (empty) log files after rotating old ones
 create

# use date as a suffix of the rotated file
 dateext

# uncomment this if you want your log files compressed
 #compress

# RPM packages drop log rotation information into this directory
 include /etc/logrotate.d

# no packages own wtmp and btmp -- we'll rotate them here      
/var/log/wtmp {
 monthly
 create 0664 root utmp
 minsize 1M
 rotate 1
 }

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

NOTE: There is also a good idea to put a line like the following to the bottom of /etc/logrotate.conf to sepparate the default system config from future additions:

# Installed by Carlos Ijalba, 2017. Put new generic logconfigs below this line: ##########

 

2.2- Fix the log rotation for yum

By default, logrotate comes configured to treat yum logs, but we need to change the owner group of the yum logs in RHEL (root) for AIX default system group (system), so we edit the file /etc/logrotate.d/yum, and change line 6 last root entry for system:

[root@aix72:/etc/logrotate.d]cat /etc/logrotate.d/yum
 /var/log/yum.log {
 missingok
 notifempty
 size 30k
 yearly
 create 0600 root system
 }

2.3- Setup logrotate schedule in crontab

And the last step, will be to configure the contab entry for logrotate execution, by default it is planned daily, but we can configure it more often, and even set up customized logrotates for specific applications, by defining new logrotate config files in different directories and invoking them specifically.

In this example we will just configure daily rotation at day’s change ( 00:00 hours ) so we edit crontab ( crontab -e ) and add the following line after skulker (it makes sense, as skulker does system’s cleanup by deleting old files and logs, so it might save logrotate some extra work):

0 0 * * * /etc/logrotate

Done, so now we can go to the step 3, to check that logrotate works OK.

 

2.4- Add logrotate controls for our logs

Logrotate has loads of options, and even supports mini-scripting previous,during, and post-rotation, etc. Full documentation and examples can be found here:

https://linux.die.net/man/8/logrotate

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/s2-log_rotation.html

If we want to add some simple logrotation configuration, we can add for example the following 3 files to /etc/logrotate.d directory to deal with supposed logs from some of our administration scripts (called check_all.ksh, start_all.ksh & stop_all.ksh):

[root@aix72:/etc/logrotate.d]vi /etc/logrotate.d/check_all
 # log rotation for check_all.ksh sysadmin script:
 /home/admin/log/check_all.log {
 missingok
 daily
 rotate 2
 size 2M
 }
[root@aix72:/etc/logrotate.d]vi /etc/logrotate.d/start_all
 # log rotation for start_all.ksh sysadmin script:
 /home/admin/log/start_all.log {
 missingok
 rotate 1
 size 1M
 }
[root@aix72:/etc/logrotate.d]vi /etc/logrotate.d/stop_all
 # log rotation for stop_all.ksh sysadmin script:
 /home/admin/log/stop_all.log {
 rotate 1
 compress
 size 1M
 }

And the options are quite self-explanatory: in this case missingok will not report an error when the log file does not exist, daily rotates the log everyday (can be daily, weekly, monthly, annual), rotate X keeps X additional versions of the log, so rotate 2 will keep the original log, plus a log.1 and a log.2 copies (ex: rotate 2 == keep 2 additional copies), size 1M rotates the log when this one becomes bigger than 1MB (can be 10k, 10M, etc).

But since the above scripts are all part of a set of administration scripts all kept in /home/admin, in this case, it will be a better idea to just add the three stanzas all in the same config file, say sysadmin, as follows :

[root@aix72:/etc/logrotate.d]vi /etc/logrotate.d/sysadmin
 # log rotation for sysadmin scripts located in /home/admin
 #

# log rotation for check_all.ksh sysadmin script:
 /home/admin/log/check_all.log {
 missingok
 daily
 rotate 2
 size 1M
 }

# log rotation for start_all.ksh sysadmin script:
 /home/admin/log/start_all.log {
 missingok
 rotate 1
 weekly
 size 10k
 }

# log rotation for stop_all.ksh sysadmin script:
 /home/admin/log/stop_all.log {
 rotate 1
 compress
 size 10k
 }

Done, so now we can go to the step 3.1, to check that logrotate works OK with our new config file.

But of course, step 3 and successive, will be food for the next post…

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One thought on “Logrotate 2.- Configure logrotate for AIX

  1. Pingback: Logrotate 3.- Logrotate checks | Sysadmin's Shouts!

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