xen image on CentOS 5

yum install xen
vi /boot/grub/menu.lst change default=0
reboot

Install Hudson

yum install java
java -version
cd /usr/share/
mkdir hudson
cd hudson/
http://hudson-ci.org/latest/hudson.war
java -jar hudson.war
http://localhost:8080

Install Sun Java on Ubuntu 11.04

1. sudo add-apt-repository "deb http://archive.canonical.com/ lucid partner"

2. sudo apt-get update

3. sudo apt-get install sun-java6-bin sun-java6-jre sun-java6-jdk

4. set JAVA_HOME=/usr/lib/jvm/java-6-sun

5. set PATH=$JAVA_HOME/bin:$PATH

6. java -version

Mount NTFS disk to CentOS 5.5

1. Find out the hardware platform:
uname -i

2. Download the rpmforge-release package.

i386 - http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.i386.rpm
x86_64 - http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.x86_64.rpm

3. Install GPG key:
rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt

4. Install the package.
rpm -i rpmforge-release-0.5.2-2.el5.rf.*.rpm

5. Install fuse-ntfs-3g packages.
yum install fuse fuse-ntfs-3g

6. Check the NTFS partition.
fdisk -l

7. Create the mount point.
mkdir /mnt/windows

8. Mount the NTFS disk.
mount /dev/sdb1 /mnt/windows

Use At to run repeated task

Following is an example, schedule.sh, to run check_process.sh script at /home/pwong every 3 minutes within 12 hours period.


WorkDir=/home/pwong

if [ ! -f off_time ]; then
date --date="+12 hours" +"%k" > off_time
fi

if [ `date +%k` -eq `cat off_time` ]; then
rm off_time
exit 1
fi

sleep 60

cd $WorkDir

at -f schedule.sh +3 minutes

check_process.sh

exit 0

Install and Test SNMP on CentOS 5.5

1. Install net-net-snmp and net-snmp-utils
# yum install net-snmp-utils

2. Create /etc/snmp/snmpd.conf. Following is a very simple example for the testing.

rocommunity public
syslocation "ABC, ABC Inc."
syscontact me@abc.com

3. Startup snmpd server
# /etc/init.c/snmpd start

4. Ues snmpwalk to test SNMP setup.
# snmpwalk -v 1 -c public -O e 127.0.0

Or
# snmpwalk -v 1 -c public localhost system

If something similar to the following show up on the screen, the SNMP is working.

SNMPv2-MIB::sysDescr.0 = STRING: Linux localhost.localdomain 2.6.18-194.el5 #1 SMP Fri Apr 2 14:58:35 EDT 2010 i686
SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (977) 0:00:09.77
SNMPv2-MIB::sysContact.0 = STRING: me@abc.com
SNMPv2-MIB::sysName.0 = STRING: localhost.localdomain
SNMPv2-MIB::sysLocation.0 = STRING: "ABC, ABC Inc."
...

5. If someting is wrong, check /etc/snmpd/snmpd.conf for error. Following commands can be used for troubleshooting as well. If everything is fine, then firewall settings should be checked.
# /etc/init.d/snmpd status
# snmpd -f -Le

6. Enable the snmpd starts up when the system reboot.
# chkconfig snmpd on

Mysqldump Performance Issue

When dumping really big tables, mysqldump was using up large amounts of memory, so it may cause no-response problem. To overcome this, --quick and --single-transaction options can used. Following are the sections for these options in the mysqldump man page.

--quick, -q
This option is useful for dumping large tables. It forces mysqldump to retrieve rows for a table from the server a row at a time rather than retrieving the entire row set and buffering it in memory before writing it out.

--single-transaction
To dump big tables, you should combine this option with --quick.

Use Remote Variables with Rsh or Ssh

Followng are the difference between local and remote variables. $PWD is the local variable passed to remote system, but \$PWD is the variable defined in the remote system.

/home/patrickw/tools $ sudo ssh host "echo $PWD"
/home/patrickw/tools

/home/patrickw/tools $ sudo ssh host "echo \$PWD"
/root

Therefore, backslashes in the following example is necessary. Without the backslashes, awk will complain syntax error since the variables are blank.

sudo ssh host "top -b -n 1 | egrep sudo\|ssh\|xinet | awk '{print \$1, \$9, \$10, \$12}'"

Xen on CentOS

yum install xen yum install xen

yum install xen

reboot

Install OpenNMS with postgreSQL 9 on CentOS 5.5

1. yum install yum-fastestmirror
2. rpm -Uvh http://yum.opennms.org/repofiles/opennms-repo-stable-rhel5.noarch.rpm
3. wget http://www.pgrpms.org/9.0/redhat/rhel-5-x86_64/pgdg-centos-9.0-2.noarch.rpm
4. rpm -i pgdg-centos-9.0-2.noarch.rpm
5. yum install postgresql90-server postgresql90-devel
6. /etc/init.d/postgresql-9.0 initdb
7. vi /var/lib/pgsql/9.0/data/pg_hba.conf, to change ident to trust for all local, IPv4, and IPv6.
   
8. vi /var/lib/pgsql/9.0/data/postgresql.conf to modify work_mem, vacuum_cost_delay, wal_buffer, checkpoint_segment, etc to meet your need.
   
9. /etc/init.d/postgresql-9.0 restart
10. createdb -U postgres opennms
11. wget http://sourceforge.net/projects/opennms/files/IPLIKE/stable-2.0/iplike-2.0.0.tar.gz
12. tar xfz iplike-2.0.0.tar.gz
13. cd iplike-2.0.0
14. ./configure --with-pgsql=/usr/pgsql-9.0/bin/pg_config
15. make
16. make install
17. /usr/local/sbin/install_iplike.sh
18. psql -U postgres -h localhost -d opennms -c '\df+ iplike|head'
19. yum install opennms --nogpgcheck
20. /opt/opennms/bin/runjava -s
21. /opt/opennms/bin/install -dis
22. /etc/init.d/opennms start

The OpenNMS page is at http://localhost:8980/opennms/login.jsp. Both initial user name and password are admin.

Add local disk to Xenserver 5.5 running under VMware

1. Find the new disk name.

fdisk -l

2. Create physical volume.

pvcreate /dev/hdb

3. Find out the name of the disk.

ll /dev/disk/by-id/

...

lrwxrwxrwx 1 root root 9 Jan 28 22:18 ata-VMware_Virtual_IDE_Hard_Drive_01000000000000000001 -> ../../hdb

4. Create SR.

xe sr-create type=lvm content-type=user device-config:device=/dev/disk/by-id/ata-VMware_Virtual_IDE_Hard_Drive_01000000000000000001 name-label=”LOCAL DISK”

After the running above command, the LOCAL DISK will be in Xenserver's Storage Repositories.

Note: You can name your own name-label.

Install Lighttpd With PHP5/MySQL on Ubuntu 10.10

The following link has detailed instructions:

http://www.howtoforge.com/installing-lighttpd-with-php5-and-mysql-support-on-ubuntu-10.10

Fix vSphere problem on Windows 7

Following link has a detailed explanation:

http://www.techhead.co.uk/running-vmware-vsphere-client-on-windows-7

Subversion on Red Hat Enterprise 5