Somehow in an unlucky moment(s) you’ll find that your yum command stop working, I have experienced it a couple of time, never find out how it happen.

It is quite simple to re install yum in an rpm base linux distros, specifically CentOS in my case. What you need to do first is to download the source file (rpm) from CentOS repo.

Check your current kernel, make sure you download the correct package later;

uname -a
Linux xxx.yyy.com 2.6.18-128.7.1.el5 #1 SMP Mon Aug 24 08:21:56 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

Go to the correct repo url, and search for yum rpm link url. For x86_64 Kernel, go to http://mirror.centos.org/centos-5/5.3/os/x86_64/CentOS/ (assuming that you are using the latest version of CentOS), copy the link of yum package, and download them into your server, you must at this point have wget installed.

cd /usr/local/src/
wget http://mirror.centos.org/centos-5/5.3/os/x86_64/CentOS/yum-3.2.19-18.el5.centos.noarch.rpm

Check yor current version of installed yum

rpm -qa | grep yum
yum-metadata-parser-1.1.2-2.el5
yum-updatesd-0.9-2.el5
yum-utils-1.1.16-13.el5.centos
yum-3.2.19-18.el5.centos
yum-fastestmirror-1.1.16-13.el5.centos

The result confirmed that you have yum-3.2.19-18, erase it using rpm and no dependencies check option.

rpm -e --nodeps yum-3.2.19-18.el5.centos

Reinstall with rpm from yum rpm you just downloaded;

rpm -ivh yum-3.2.19-18.el5.centos.noarch.rpm

Occasionally I have to leave my XP workstation and use Linux or Mac Desktop, both don’t have putty like in XP, most probably because they have built in SSH client installed :).

But I need somehow make it easier to connect from those desktop to servers with Key Authentication, instead of running this from the terminal;

ssh -p xxxx -l root 117.103.xx.xx -i ~/ssh-keys/me\@tajidyakub.net.ppk

While in Putty, I could simply use Connection Sessions preferences load a particular private key for specific connection and utilize Putty PageAnt to Authorize the pass phrase automatically. It is as simple as it gets since I only have to double click, and logged in instantly.

But turns out I can do the task event simpler in Linux or Mac. I create a folder in My Desktop to store my connection;

mkdir ~/Desktop/SSH/

And create a file with .sh extension. doesn’t have to be .sh extension, just wanted to name it that way :).

cd ~/Desktop/SSH/
vi myserver.sh

And insert the content;

ssh -p xxxx -l root 117.103.xx.xx -i ~/path/to/yourprivatekey.ppk

yourprivatekey.ppk is a private key, in my case, I exported it using Putty Gen from my XP machine so it is going to look like this;

tjdykb$ cat me\@tajidyakub.net.ppk
-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CBC,...
nYMNS/d7RJSx1qswncyw2cd7NiCXfwZkQ6m+OMzcCtXMj8vCBDhTSyhkwxQ0lByY
tgp0zA3HkKKYI5ACl5+Q7MEZwwi+Dpz8wHY2E5adjqAbWm5M/Li9e1EBJgWM15EQ
.......
8OfpeNjO85IGBPpNYct56Z1VFCpadkph0WPE1vdrLmjhQOBu2ftamY8hJ9kFaNRH
At/j4dC4HI3kwmuM7onZIb2vZIfxmW2sUceY2NhBLEbT+kOd3Tu2/EYkKNlfmW43
3gfOqCOzUqnGON7hopzQbMK/PfvOvT+bPIE14RZG8IFhiNUu10yrd+FkF6HFlNIi
ljJTuFKDgCm/3OezeV/bzWcVMkBqoaMwxN/hI7OHe1HYb0QpZbIU/ePwt6cVGYSh
zfkIFTJl61WWTvB81oRhS5JZ6nf3OUkuFxCjJ4PseFw=
-----END RSA PRIVATE KEY-----

And to load the connection from a terminal, simply execute the file (don’t forget to chmod so it becomes executable – like 755);

./yourserver.sh

In a desktop environment, a pop up will appear asking for the pass phrases, you could add the pass phrase to your key chain or saved password avoid this the next time you load the connection.

Build the Image

Build the image using dd command, give the size according to your needs. This example shows a 512MB image file.

dd if=/dev/zero of=/path/to/directory/swap.image oflag=direct bs=1M count=512

Format the Image

Format the image to SWAP file type.

mkswap  /direktori/swap.image

Activate Your Newly Created SWAP Image

mkswap  /path/to/directory/swap.image

Configure fstab

If you want the SWAP survive reboot.

vi /etc/fstab

### add the line similar to

/path/to/directory/swap.image swap                    swap    defaults        0 0

cat /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0
BOOTPROTO=static
BROADCAST=xxx.xxx.xxx.255
IPADDR=xxx.xxx.xxx.12
NETMASK=255.255.255.0
NETWORK=xxx.xxx.xxx.0
ONBOOT=yes
TYPE=Ethernet
USERCTL=no
IPV6INIT=no
PEERDNS=yes

cat /etc/sysconfig/network

NETWORKING=yes
HOSTNAME=xxx.magnet-id.com
GATEWAY=xxx.xxx.xxx.1

Put the resolver DNS IP Address on your /etc/resolv.conf (get them from your ISP or Data Center)

cat /etc/resolv.conf

nameserver 117.103.57.4
nameserver 117.103.56.5

If you want to make an alias IP Address, do this step;

Copy the ifcfg startup script

cp /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth0:0

Edit the newly created ifcfg script, customize to your other IP Address (aliased to the same network interface). Change the Device and IP Address Informations.
Restart Network Service

service network restart

cp /usr/share/zoneinfo/Asia/Jakarta /etc/localtime

That is if your box ran CentOS and you want the Time Zone in WIT (GMT+7)