Zabbix auto install script

few weeks ago I've noticed that Zabbix team actively developed version 2 of their nice monitoring tool. I decided to install beta version with Postgresql 9.1. Unfortunately Zabbix 1.9.6 does not support Psql 9.1, but with my help :) they fixed that issue. meanwhile I've prepared script which install zabbix from source on clean Centos with Psql 8.4 support.

there is download link to that script https://www.dropbox.com/s/e205kh9vnwyppp8/zabbix_install_centos.sh

this script will be good for testers, sys admins who want to check new features of zabbix :)


reboot hung server

The "magic SysRq key" provides a way to send commands directly to the kernel through the /proc filesystem. It is enabled via a kernel compile time option, CONFIG_MAGIC_SYSRQ, which seems to be standard on most distributions. First you must activate the magic SysRq option:
    echo 1 > /proc/sys/kernel/sysrq
When you are ready to reboot the machine simply run the following:
    echo b > /proc/sysrq-trigger
This does not attempt to unmount or sync filesystems, so it should only be used when absolutely necessary, but if your drive is already failing then that may not be a concern.


How to upgrade Postgres 8.4.x to 9.0.x

I've found a couple of manuals where this procedure is described, but I faced with the problem with postgres-libs which were required for my SVN.

so there is my way how to perfom upgrade

1. service postgresql stop
2. rsync -a -v --progress /var/lib/pgsql/ /var/lib/pgsql.old/ #this will backup everything
3. wget http://yum.pgrpms.org/reporpms/9.0/pgdg-centos-9.0-2.noarch.rpm
4. rpm -i pgdg-centos-9.0-2.noarch.rpm
5. /etc/yum.repos.d/CentOS-Base.repo and add 'exclude=postgresql*' to the [base] and [updates] sections
6. yum remove postgresql84*
7. rpm -e postgresql-libs --nodeps
8. yum install postgresql90 postgresql90-server postgresql90-libs postgresql90-contrib postgresql90-devel
9. service postgresql-9.0 initdb
10. export PATH=/usr/pgsql-9.0/bin:$PATH
11. su - postgres ; export PATH=/usr/pgsql-9.0/bin:$PATH ; pg_upgrade --old-datadir "/var/lib/pgsql.old/data" --new-datadir "/var/lib/pgsql/9.0/data" --old-bindir "/usr/bin" --new-bindir "/usr/pgsql-9.0/bin"
12. cp /var/lib/pgsql.old/data/pg_hba.conf /var/lib/pgsql/9.0/data/pg_hba.conf
13. service postgresql-9.0 start
14. vacuumdb --all --analyze-only

Have fun with new Psql version :)


hackmysql mirror

I've created mirror of hackmysql for personal usage

replace mysql-server with percona server

what is percona-server:

Percona Server is an enhanced drop-in replacement for MySQL. With Percona Server,

Your queries will run faster and more consistently.
You will consolidate servers on powerful hardware.
You will delay sharding, or avoid it entirely.
You will save money on hosting fees and power.
You will spend less time tuning and administering.
You will achieve higher uptime.
You will troubleshoot without guesswork.

Does this sound too good to be true? It's not. Percona Server offers breakthrough performance, scalability, features, and instrumentation. Its self-tuning algorithms and support for extremely high-performance hardware make it the clear choice for companies who demand the utmost performance and reliability from their database server

now if you want to have such miracle on your cpanel server you need to do this steps for replacing mysql-server with percona-server:

1. backup VPS.
2. dump all dbs.
3. stop all services on the vps
/etc/init.d/httpd stop ; /etc/init.d/exim stop ; /etc/init.d/pure-ftpd stop ; /etc/init.d/dovecot stop ; /etc/init.d/cpanel stop ; /etc/init.d/lfd stop ; /etc/init.d/munin-node stop ; /etc/init.d/crond stop ; /etc/init.d/mysql stop ; /etc/init.d/exim stop ;

4. make sure that everything is stopped
5. check what mysql packages are installed

rpm -qa | grep -i mysql

in my case it was MySQL-client MySQL-devel MySQL-test MySQL-bench MySQL-shared MySQL-server
so I run this command to completely remove mysql from vps
yum remove MySQL-client MySQL-devel MySQL-test MySQL-bench MySQL-shared MySQL-server

6. add percona repo

rpm -Uhv http://www.percona.com/downloads/percona-release/percona-release-0.0-1.x86_64.rpm

7. check what packages are available in percona repo

yum list | grep percona

should be something like

# yum list | grep percona
percona-release.x86_64                    0.0-1                        installed
Percona-SQL-50-debuginfo.x86_64           5.0.92-b23.85.rhel5          percona
Percona-SQL-client-50.x86_64              5.0.92-b23.85.rhel5          percona
Percona-SQL-devel-50.x86_64               5.0.92-b23.85.rhel5          percona
Percona-SQL-server-50.x86_64              5.0.92-b23.85.rhel5          percona
Percona-SQL-shared-50.x86_64              5.0.92-b23.85.rhel5          percona
Percona-SQL-shared-compat.x86_64          5.1.43-2                     percona
Percona-SQL-test-50.x86_64                5.0.92-b23.85.rhel5          percona
Percona-Server-51-debuginfo.x86_64        5.1.56-rel12.7.224.rhel5     percona
Percona-Server-55-debuginfo.x86_64        5.5.11-rel20.2.115.rhel5     percona
Percona-Server-client-51.x86_64           5.1.56-rel12.7.224.rhel5     percona
Percona-Server-devel-51.x86_64            5.1.56-rel12.7.224.rhel5     percona
Percona-Server-server-51.x86_64           5.1.56-rel12.7.224.rhel5     percona
Percona-Server-shared-51.x86_64           5.1.56-rel12.7.224.rhel5     percona
Percona-Server-test-51.x86_64             5.1.56-rel12.7.224.rhel5     percona
gnuplot.x86_64                            4.2.6-14                     percona
gnuplot-emacs.x86_64                      4.2.6-14                     percona
maatkit.noarch                            7284-1                       percona
xtrabackup.x86_64                         1.6-245.rhel5                percona
xtrabackup-debuginfo.x86_64               1.6-245.rhel5                percona

8. decide what version you need 5.1 or 5.5
in my case I've installed percona 5.5

# rpm -qa | grep Percona

9. after Percona-server installation it is necessary to check if it started correctly as some variables in my.cnf are not supported.
10. after successful start it is necessary to run mysql_upgrade.
11. for finishing installation run easyapache and recompile apache/php/etc
12. Go to Server Configuration -> Update Config and set MySQL to "never", save, double check it has been done
13. Test new Apache to be sure server is working


add json support into Flex4

Adobe itself made a JSON library that you can find at https://github.com/mikechambers/as3corelib Follow these steps to add your JSON library to your Flex project:
  1. Download the .zip archive and extract it. What you need is the .swc file in the lib folder.
  2. In Flex Builder / Flash Builder, go to your project’s properties, and then to the Flex Build Path panel.
  3. Click on Add SWC, and select the as3corelib.swc file
  4. In your project, add the following line: import com.adobe.serialization.json.JSON;
You should be able now to use JSON functionalities in your Flex project :)