Tuesday, October 30, 2018
Wednesday, October 24, 2018
How to use SAR to troubleshoot linux box and generate reports.
SAR stands for System Activity Report, as its name suggest sar command is used to collect, report & save CPU, Memory, I/O usage in Unix like operating system. SAR command produce the reports on the fly and can also save the reports in the log files as well.
Now a days sar includes in general Linux installation. You can check if sar is installed by executing following command.
rpm -qa | grep sysstat
Incase if sar is not installed you can use following command or RPM package to install it.
yum install sysstat
Sysstat data collection is doing by sadc (system activity data collector). It saves the reports in log file “/var/log/sa/saDD” where DD represents Current day and already existing files will be archived.
[root@localhost ~]# systemctl start sysstat
[root@localhost ~]# systemctl enable sysstat
It collects the data every 10 minutes and generate its report daily. Below crontab file is responsible for collecting and generating reports.
Generating CPU Report on the Fly 5 times every 2 seconds.
[root@localhost ~]# sar 2 5
Linux 3.10.0-123.el7.x86_64 (localhost.localdomain) Monday 26 October 2015 _x86_64_ (2 CPU) 01:43:55 EDT CPU %user %nice %system %iowait %steal %idle 01:43:57 EDT all 0.00 0.00 0.25 0.00 0.00 99.75 01:43:59 EDT all 0.00 0.00 0.00 0.00 0.00 100.00 01:44:01 EDT all 0.00 0.00 0.25 0.00 0.00 99.75 01:44:03 EDT all 0.00 0.00 0.25 0.25 0.00 99.50 01:44:05 EDT all 0.00 0.00 0.00 0.00 0.00 100.00 Average: all 0.00 0.00 0.15 0.05 0.00 99.80 [root@localhost ~]#
Reading SAR log file using -f
[root@localhost ~]# sar -r -f /var/log/sa/sa26
You need download KSAR tool to create graphs using /var/log/sa/sar* files
https://sourceforge.net/projects/ksar/
You need to convert time format in sar file before loading to sar you can do it by using following commands
cd /var/log/sa
LC_TIME="POSIX" sar -A -f sa08 > /tmp/sar.data.txt
now download sar.data.txt file and load it in to KSAR
Now a days sar includes in general Linux installation. You can check if sar is installed by executing following command.
rpm -qa | grep sysstat
Incase if sar is not installed you can use following command or RPM package to install it.
yum install sysstat
Sysstat data collection is doing by sadc (system activity data collector). It saves the reports in log file “/var/log/sa/saDD” where DD represents Current day and already existing files will be archived.
[root@localhost ~]# systemctl start sysstat
[root@localhost ~]# systemctl enable sysstat
It collects the data every 10 minutes and generate its report daily. Below crontab file is responsible for collecting and generating reports.
Generating CPU Report on the Fly 5 times every 2 seconds.
[root@localhost ~]# sar 2 5
Linux 3.10.0-123.el7.x86_64 (localhost.localdomain) Monday 26 October 2015 _x86_64_ (2 CPU) 01:43:55 EDT CPU %user %nice %system %iowait %steal %idle 01:43:57 EDT all 0.00 0.00 0.25 0.00 0.00 99.75 01:43:59 EDT all 0.00 0.00 0.00 0.00 0.00 100.00 01:44:01 EDT all 0.00 0.00 0.25 0.00 0.00 99.75 01:44:03 EDT all 0.00 0.00 0.25 0.25 0.00 99.50 01:44:05 EDT all 0.00 0.00 0.00 0.00 0.00 100.00 Average: all 0.00 0.00 0.15 0.05 0.00 99.80 [root@localhost ~]#
Generating Memory Usage report using -r
Reading SAR log file using -f
[root@localhost ~]# sar -r -f /var/log/sa/sa26
Create Graphs using KSAR tool
You need download KSAR tool to create graphs using /var/log/sa/sar* files
https://sourceforge.net/projects/ksar/
You need to convert time format in sar file before loading to sar you can do it by using following commands
cd /var/log/sa
LC_TIME="POSIX" sar -A -f sa08 > /tmp/sar.data.txt
now download sar.data.txt file and load it in to KSAR
Tuesday, October 23, 2018
How Reset Root Password in RHEL 7 from 9 Simple st...
cyber-techno-lk: How Reset Root Password in RHEL 7 from 9 Simple st...:
How Reset Root Password in RHEL 7 from 9 Simple steps =================================================
How Reset Root Password in RHEL 7 from 9 Simple steps =================================================
How to install Apache from source
Download and copy Apache source to local Linux machine
cd /opt/software/httpd-2.4.33
./configure --prefix=/usr/local/apache LD_LIBRARY_PATH=/usr/local/ssl/lib/ LIBS=-L/usr/local/ssl/lib --with-included-apr --enable-ssl --enable-so --enable-http --enable-info --enable-cgi --enable-vhost-alias --enable-rewrite --with-mpm=prefork --enable-mods-shared --enable-deflate --enable-headers --enable-security --enable-reqtimeout --enable-so
make
make install
cp /usr/local/apache/bin/apachectl /etc/init.d/web.system chmod 777 /etc/init.d/web.system
change http.conf according to your settings.
Go to browser and open http://x.x.x.x/index.html
cd /opt/software/httpd-2.4.33
./configure --prefix=/usr/local/apache LD_LIBRARY_PATH=/usr/local/ssl/lib/ LIBS=-L/usr/local/ssl/lib --with-included-apr --enable-ssl --enable-so --enable-http --enable-info --enable-cgi --enable-vhost-alias --enable-rewrite --with-mpm=prefork --enable-mods-shared --enable-deflate --enable-headers --enable-security --enable-reqtimeout --enable-so
make
make install
cp /usr/local/apache/bin/apachectl /etc/init.d/web.system chmod 777 /etc/init.d/web.system
change http.conf according to your settings.
Go to browser and open http://x.x.x.x/index.html
How to install PHP 7
Download and extract php source to /opt/software folder
cd /opt/software/php-7.2.7
yum install libjpeg-devel libpng-devel
./configure --prefix=/usr/local/apache/php --with-config-file-path=/usr/local/apache/php --with-apxs2=/usr/local/apache/bin/apxs --disable-cgi --with-zlib --with-gettext --with-sqlite3 --enable-mbstring --enable-calendar --with-curl=/usr/lib64 --with-gd --with-jpeg-dir=/usr/lib64/libjpeg.so --with-png-dir=/usr/lib64/libpng.so --enable-soap --with-libdir=/lib64 --enable-zip --with-mysqli --with-pdo-mysql --with-openssl-dir
make
make install
Add following lines in httpd.conf to enable php
LoadModule php7_module modules/libphp7.so
AddType application/x-httpd-php .php
<IfModule dir_module>
DirectoryIndex index.html index.php
</IfModule>
Restart httpd
/etc/init.d/web.system restart
cd /opt/software/php-7.2.7
yum install libjpeg-devel libpng-devel
./configure --prefix=/usr/local/apache/php --with-config-file-path=/usr/local/apache/php --with-apxs2=/usr/local/apache/bin/apxs --disable-cgi --with-zlib --with-gettext --with-sqlite3 --enable-mbstring --enable-calendar --with-curl=/usr/lib64 --with-gd --with-jpeg-dir=/usr/lib64/libjpeg.so --with-png-dir=/usr/lib64/libpng.so --enable-soap --with-libdir=/lib64 --enable-zip --with-mysqli --with-pdo-mysql --with-openssl-dir
make
make install
Add following lines in httpd.conf to enable php
LoadModule php7_module modules/libphp7.so
AddType application/x-httpd-php .php
<IfModule dir_module>
DirectoryIndex index.html index.php
</IfModule>
Restart httpd
/etc/init.d/web.system restart
Monday, October 22, 2018
Installing nagios NRPE on AWS EC2
yum install nagios-plugins-all nagios-plugins-nrpe nrpe
chkconfig nrpe on
update the config by checking allowed_hosts and
vi /etc/nagios/nrpe.cfg
sudo /etc/init.d/nrpe start
How to install Nagios on AWS
Prerequisites
=========
* Apache
* PHP
* GCC compiler
* GD development libraries
Steps
====
sudo yum install httpd php
sudo yum install gcc glibc glibc-common
sudo yum install gd gd-devel
Create Users
=========
sudo adduser -m nagios
sudo passwd nagios
sudo groupadd nagcmd
sudo usermod -a -G nagcmd nagios
sudo usermod -a -G nagcmd apache
Download Nagios Core
=================
mkdir ~/downloads
cd ~/downloads
wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-4.0.8.tar.gz
wget http://nagios-plugins.org/download/nagios-plugins-2.0.3.tar.gz
Compile and Install Nagios
====================
tar zxvf nagios-4.0.8.tar.gz
cd nagios-4.0.8
./configure --with-command-group=nagcmd
make all
sudo make install
sudo make install-init
sudo make install-config
sudo make install-commandmode
Customize Configuration
==================
Sample configuration files have now been installed in the /usr/local/nagios/etc directory. These sample files should work fine for getting started with Nagios. You'll need to make just one change before you proceed...
Edit the /usr/local/nagios/etc/objects/contacts.cfg config file with your favorite editor and change the email address associated with the nagiosadmin contact definition to the address you'd like to use for receiving alerts.
sudo vim /usr/local/nagios/etc/objects/contacts.cfg
Configure the Web Interface
====================
Install the Nagios web config file in the Apache conf.d directory.
sudo make install-webconf
Create a nagiosadmin account for logging into the Nagios web interface. Remember the password you assign to this account - you'll need it later.
sudo htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
Type the new password twice. Restart Apache to make the new settings take effect.
sudo service httpd restart
Compile and Install the Nagios Plugins
============================
cd ~/downloads
tar zxvf nagios-plugins-2.0.3.tar.gz
cd nagios-plugins-2.0.3
Compile and install the plugins.
./configure --with-nagios-user=nagios --with-nagios-group=nagios
make
sudo make install
Start Nagios
=========
sudo chkconfig --add nagios
sudo chkconfig nagios on
Verify the sample Nagios configuration files.
sudo /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
If there are no errors, start Nagios.
sudo service nagios start
Enable 80 port in AWS
=================
* From the EC2 console select Security Groups from the left navigation pane.
* Select the Security Group applicable for the instance that Nagios was installed on and open the Inbound tab
* If there is no rule to allow HTTP traffic on port 80 then click edit in the Inbound tab to add a new rule
* Click on New Rule button
* Scroll down to select HTTP from the list under Type
* If you want to be able to access nagios from anywhere then select Save, otherwise enter the IP address or range of IP address you want to be able to access it from then select Save.
Access Nagios
===========
http://ec2-xx-xxx-xxx-xx.ap-southeast-2.compute.amazonaws.com/nagios/
=========
* Apache
* PHP
* GCC compiler
* GD development libraries
Steps
====
sudo yum install httpd php
sudo yum install gcc glibc glibc-common
sudo yum install gd gd-devel
Create Users
=========
sudo adduser -m nagios
sudo passwd nagios
sudo groupadd nagcmd
sudo usermod -a -G nagcmd nagios
sudo usermod -a -G nagcmd apache
Download Nagios Core
=================
mkdir ~/downloads
cd ~/downloads
wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-4.0.8.tar.gz
wget http://nagios-plugins.org/download/nagios-plugins-2.0.3.tar.gz
Compile and Install Nagios
====================
tar zxvf nagios-4.0.8.tar.gz
cd nagios-4.0.8
./configure --with-command-group=nagcmd
make all
sudo make install
sudo make install-init
sudo make install-config
sudo make install-commandmode
Customize Configuration
==================
Sample configuration files have now been installed in the /usr/local/nagios/etc directory. These sample files should work fine for getting started with Nagios. You'll need to make just one change before you proceed...
Edit the /usr/local/nagios/etc/objects/contacts.cfg config file with your favorite editor and change the email address associated with the nagiosadmin contact definition to the address you'd like to use for receiving alerts.
sudo vim /usr/local/nagios/etc/objects/contacts.cfg
Configure the Web Interface
====================
Install the Nagios web config file in the Apache conf.d directory.
sudo make install-webconf
Create a nagiosadmin account for logging into the Nagios web interface. Remember the password you assign to this account - you'll need it later.
sudo htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
Type the new password twice. Restart Apache to make the new settings take effect.
sudo service httpd restart
Compile and Install the Nagios Plugins
============================
cd ~/downloads
tar zxvf nagios-plugins-2.0.3.tar.gz
cd nagios-plugins-2.0.3
Compile and install the plugins.
./configure --with-nagios-user=nagios --with-nagios-group=nagios
make
sudo make install
Start Nagios
=========
sudo chkconfig --add nagios
sudo chkconfig nagios on
Verify the sample Nagios configuration files.
sudo /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
If there are no errors, start Nagios.
sudo service nagios start
Enable 80 port in AWS
=================
* From the EC2 console select Security Groups from the left navigation pane.
* Select the Security Group applicable for the instance that Nagios was installed on and open the Inbound tab
* If there is no rule to allow HTTP traffic on port 80 then click edit in the Inbound tab to add a new rule
* Click on New Rule button
* Scroll down to select HTTP from the list under Type
* If you want to be able to access nagios from anywhere then select Save, otherwise enter the IP address or range of IP address you want to be able to access it from then select Save.
Access Nagios
===========
http://ec2-xx-xxx-xxx-xx.ap-southeast-2.compute.amazonaws.com/nagios/
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