check backup server

==== client side ====
we will make a script in each server to pump date into a file. so when we check at backup server, we will check if this file was backup to backup server since it will update the date everyday.\\

below is the script contain (/root/record)
----------------- Start ---------------------------
#! /bin/sh

echo `date` > /root/assessment

then use crontab -e to run this script everyday
0 12 * * * /root/record > /dev/null 2>&1

----------------- End ---------------------------

==== backup server side ====
at the server side, i had make a folder name assessment and put the script inside.\\
below is the script contain (check_assessment)

------------------- Start -------------------------------
#! /bin/sh

echo "assessment done on `date`" > /mnt/backup/assessment/assessment_result.txt -> this is to pump the date it run the script
echo " " >> /mnt/backup/assessment/assessment_result.txt -> give an empty space

for host in `cat /mnt/backup/assessment/list`    # -> this is to loop the server list
do
echo $host >> /mnt/backup/assessment/assessment_result.txt -> this is to pump the server name before it start check so we know the result is belong to which server

for n in {1..9} -> loop to check folder 01-09
do
FILE="/mnt/backup/$host/0$n/root/assessment"


if [ -f $FILE ];
then
cat $FILE >> /mnt/backup/assessment/assessment_result.txt -> if the file exist, copy the date to assessment_result.txt
else
echo "day $n didnt backup" >> /mnt/backup/assessment/assessment_result.txt -> if the file not exist, echo what day it didnt backup
fi

done


for n in {10..31} -> loop day 10-31
do
FILE="/mnt/backup/$HOST/$n/root/assessment"

if [ -f $FILE ];
then
cat $FILE >> /mnt/backup/assessment/assessment_result.txt
else
echo "day $n didnt backup" >> /mnt/backup/assessment/assessment_result.txt
fi

done

echo " " >> /mnt/backup/assessment/assessment_result.txt

done

uuencode /mnt/backup/assessment/assessment_result.txt /mnt/backup/assessment/assessment_result.txt | mail -s "[My-Backup] monthly check result" sat.support@my.offgamers.com -> this is to email the result to us as attachment

--------------------------- End -----------------------------------------

then put the server name you want this script to check into a file name list
example:-
my-domain
my-proxy
my-dns1
my-dns2

then use crontab -e to run this script every first day of the month

Nagios Alert using Gammu

Nagios Alert Notification Using Gammu

Install Epel repo

• Download the latest EPEL repository

#wget http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-3.noarch.rpm

• Run the rpm install command

#rpm -Uvh epel-release-5*.rpm

Install Gammu

There are 3 package need to be install

1. gammu
2. gammu-devel
3. gammu-libs

After install, Open gammu config file and edit it
#vi /etc/gammurc
[gammu]
port = /dev/ttyS0
connection = at19200

for the connection type, please refer to the mobile model at http://wammu.eu/phones/
plug the mobile to the server and test if it can detect the mobile by using this command
#gammu –identify
#gammu –monitor 1

# ls -l /dev/ttyS0 crw-rw—- 1 root dialout 4, 64 jan 5 16:14 /dev/ttyS0
Nagios is usually running as user “nagios”, so any notification command would be executed as “nagios”. We can see user nagios wouldn’t have permissions to access devices connected to /dev/ttyS0.
We’ll apply the SUID bit (set-UID) on the command in charge of sending SMS notifications, this will execute gammu on behalf of user root.
# chmod 4755 /usr/bin/gammu
Now we test to send out a sms testing by
# echo “test” | gammu –sendsms TEXT 0128157399
If you want break, press Ctrl+C…
Sending SMS 1/1….waiting for network answer..OK, message reference=181

This proof it is success

Edit Nagios

We will start to edit nagios to allow send out command to trigger sms notification.
#vi /etc/nagios/objects/commands.cfg
then add this part into it

this will ask nagios to execute a script and pass the parameter to script

define command{
      command_name    host-notify-by-sms
      command_line    /bin/bash /etc/nagios/nagios-test "$HOSTNAME$" "$HOSTSTATES$" "$HOSTOUTPUT$" "$SHORTDATETIME$"
      }

define command{
      command_name    notify-by-sms
      command_line    /bin/bash /etc/nagios/nagios-test "$HOSTALIAS$" "$SERVICESTATE$" "$SERVICEOUTPUT$" "$SHORTDATETIME$"
      }

then we edit the contact part
#vi /etc/nagios/objects/contacts.cfg
then add this part into it

define contact{
      contact_name                    sms
      alias                           sms
      service_notification_period     24x7
      host_notification_period        24x7
      service_notification_options    c,r
      host_notification_options       d,r
      service_notification_commands   notify-by-sms
      host_notification_commands      host-notify-by-sms
      }

define contactgroup{
      contactgroup_name       admins
      alias                   Nagios Administrators
      members                 nagiosadmin, sms
      }

Script

hostname=$1
 hoststates=$2
 hostoutput=$3
 shortdatetime=$4
 
 echo "Host: $hostname / state: $hoststates / Info: $hostoutput / Date: $shortdatetime" | ssh root@172.30.10.98 'gammu --sendsms TEXT 012345678'
 echo "Host: $hostname / state: $hoststates / Info: $hostoutput / Date: $shortdatetime" | ssh root@172.30.10.98 'gammu --sendsms TEXT 0123338888'

The script will accept the parameter and form a message using echo and pass it to another server which was install with Gammu to send out the sms
So in order to allow Nagios to use ssh, below section need to be perform

Nagios SSH

We will using Nagios to setup ssh keygen so that it can no need input password when ssh to gammu server

• login to Nagios server as root
• change to nagios user using

#su nagios

• then we create the keygen for nagios

#ssh-keygen

• then scp the id_rsa.pub to the gammu server and add into authorized keys

#cat id_rsa.pub » /root/.ssh/authorized_keys
Done, now nagios allow to use SSH and able to enter the gammu server

Nagios timeout

Nagios default timeout for notification was 30 second and was not enough if we need to send out sms alert more than 3 number.
Therefor we will need to increase the timeout #vi /etc/nagios/nagios.cfg
Original was

notification_timeout=30

then edit

notification_timeout=60

Linux smallest partition

VM partition for non-heavy usage Standard 4GB storage

partition	mount point	filesystem	size (MB)	type
/dev/sda1	/boot	ext3	100	primary
/dev/sda2	/	ext3	2,000	primary
/dev/sda3	swap	swap	300	primary
/dev/sda4	-	-	-	extended
/dev/sda5	/home	ext3	200	logical
/dev/hda6	/tmp	ext3	500	logical
/dev/hda7	/var	ext3	remaining	logical

When doing yum update, the package was download to /var partition before proceed to installation part.
So make sure /var partition is enough for the yum update

log rotate

this is to add function to rotate specific log

create a new file at /etc/logroate.d/
and write this into it for rotate log function

/var/log/SAT-backup/*.log {
     monthly
     rotate 4
     missingok
     compress
}

Centos change resolution

you can change the console resolution at
/boot/grub/grub.conf

add vga=775 at the end of kernal line

Centos - basic knowledge

change DNS setting
/etc/resolve.conf

change host IP
/etc/sysconfig/network-script/ifcfg-eth0

change hostname
/etc/sysconfig/network

The easiest way to do it is
# system-config-network

Adding Swap Space

To add a swap file:

1. Determine the size of the new swap file in megabytes and multiply by 1024 to determine the number of blocks. For example, the block size of a 64 MB swap file is 65536.
   
2. At a shell prompt as root, type the following command with count being equal to the desired block size:
   

   dd if=/dev/zero of=/swapfile bs=1024 count=65536

3. Setup the swap file with the command:
   

   mkswap /swapfile

4. To enable the swap file immediately but not automatically at boot time:
   

   swapon /swapfile

5. To enable it at boot time, edit /etc/fstab to include the following entry:
   

   /swapfile          swap            swap    defaults        0 0

   The next time the system boots, it enables the new swap file.
   
6. After adding the new swap file and enabling it, verify it is enabled by viewing the output of the command cat /proc/swaps or free.

To remove the swap file:

1. First must stop the swap file created by:
   swapoff  /swapfile
2. Then delete the:
   rm -rf   /swapfile