Amit's Blog

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Rsyslog V 5 supports TLS / SSL for sending and receiving logs. Download the source from here :http://www.rsyslog.com/rsyslog-5-8-4-v5-stable/ Steps : Do this on both client and server 1. cd /usr/src 2. wget http://www.rsyslog.com/rsyslog-5-8-4-v5-stable/ 3. tar -zxvf  rsyslog-5-8-4-v5-stable 4. cd rsyslog-5-8-4 5. yum install

A new slave can be added to an existing replication without stopping the master. Setup the new slave by making a copy of existing slave. Dont forget to change the server-id value . To copy an existing slave : 1. Stop the slave : >mysqladmin shutdown 2. Copy the data directory from

The following steps are to be followed to setup replication of an existing MySQL Database : 1. Login To the Existing mysql database and issue the following command : > reset master; > FLUSH TABLES WITH READ LOCK; > Master Show Status; Note the Binary Log Position and the Binary Log name

It is good idea to turn of MySQL server at start. So that if the master goes down it does not start by itself when it comes back up. Follow these steps on the slave : Note: The Slave also has to be setup with binary logging enabled. In order to

> !/bin/sh # # Startup script for the Apache Web Server # # chkconfig: 345 85 15 # description: Apache is a World Wide Web server. It is used to serve \ # HTML files and CGI. # processname: httpd # pidfile: /var/run/httpd.pid # config: /etc/httpd/conf/httpd.conf # Source function library. . /etc/rc.d/

apxs -i -a -c modules/filters/mod_deflate.c http://httpd.apache.org/docs/current/dso.html

The following script can help uninstall perl module > !/usr/bin/perl -w use ExtUtils::Packlist; use ExtUtils::Installed; $ARGV[0] or die “Usage: $0 Module::Name\n”; my $module = $ARGV[0]; my $inst = ExtUtils::Installed->new(); foreach my $item (sort($inst->files($module))) { print “Removing $item\n”

To view what packages are installed from which repo : rpm -qa --qf '%{NAME} %{VENDOR}\n' Display RPM Architecture Just one line in ~/.rpmmacros will save all sorts of trouble later. echo "%_query_all_fmt %%{name}-%%{version}-%%{release}.%%{arch}" >> ~/.rpmmacros

This command will show you the list of last failed login attempts : last -f /var/log/btmp This file can get huge, so you might want to rotate this file : > /var/log/btmp { monthly minsize 1M create 0600 root utmp rotate 1 } You can put this in logrotate.conf

Force Log Rotation : logrotate /etc/logrotate.d/file_to_be_rotated or `logrotate -v -f /etc/logrotate.d/firewall           (v = verbose, f = force even if not required) ``` In order to rotate a log file you can add an entry to #/etc/logrotate.conf or you can create a custom separate

cannot find lltdl : libtool-ltdl-devel

Create an alias email from postfixadmin and set go to to be  pipe_handler@hostname eg. set support@xyz.com to go to supporthandler@hostname.com Edit aliases file : vi /etc/postfix/aliases Add the following line at the end: supporthandler: “| php -q /path/to/handler.php” save the file

You can have your server log files sent to an email address. Edit the logwatch configuration file : vi /etc/logwatch/conf/logwatch.conf ( if this file is empty , edit the following file) vi /usr/share/logwatch/default.conf/logwatch.conf find mailto and put the email address there. Or you

> for instance in *;do /usr/bin/du -hs $instance;done

This script finds, logs and deletes files and folders older than x days. #/bin/bash DIRS="/dir1/,/path/to/dir2/,/dir3/" LOG_FILE="path to log file" TIMESTAMP=date +%Y:%m:%d DAYS_OLD="10" # This will find and delete folders and files older

The health of hard drive can be checked in linux using the command : smartctl -H /dev/sda

Try the following command to forcefully unmount a busy or non existing mounted drive or partition. umount -l /mnt/path or if this doesnot work, issue: fuser -km /cdrom

rm -f /var/lib/rpm/__db*<br></br> rpm --rebuilddb ```

export LANG=’EN us’ Use pstree -A instead of pstree -p, the result would be like this:

Export Putty Sessions : 1. Run > regedit /ea putty.reg  HKEY_CURREN_USER\Software\SimonTatham\PuTTY 2. Copy putty.reg on to the new computer 3. On the new computer, open up a command prompt : > regedit /s putty.reg Delete All Putty sessions : c:>putty -cleanup >

/sbin/ip address add IP_ADDR/32 dev /sbin/ip address del IP_ADDR/32 dev

It’s a good idea to set email notification on login on your servers. You can set it by adding a script to your /etc/profile file. vi /etc/profile At the bottom add /path/to/your/script Now put the script in that path : > !/bin/bash #Author : Amit

To fix the jabber load issue : > echo “/usr/local/lib” > /etc/ld.so.conf.d/iksemel.conf This fixes the path issue

There are times, when replication stop working between mysql servers because of the invalid queries. First of all find out whether mysql replication is running and if not what caused it to stop. Usually the logs are located at /var/log/mysql In order to make sure.. log in to