Soft link creation in linux

We are going to create soft link for test folder in new directory under disk2

#cd /root/test
#mv -v test /disk2/
#ln -s /cvs2/test/  test

Rsync command

From local system to remote system:

# rsync -avzpe ssh modules/ root@10.10.2.42:/usr/local/jboss-as/modules/



--delete : delete files that don't exist on sender (system)
-v : Verbose (try -vv for more detailed information) 
-e "ssh options" : specify the ssh as remote shell 
-a : archive mode 
-r : recurse into directories 
-z : compress file data


                          ****************************************

Errcode: 28 in Mysql in linux

Error :

[root@ghrmsdb dbbackup]# mysql -p DBNAME < DBNAME_14122012-0700.sql
Enter password:
ERROR 3 (HY000) at line 33: Error writing file './GHRMS/B2B_Exception_Dtls.frm'


Answer :

If you get error like this, you need to check all filesystems where MySQL installed..  
It will happen only if no space left on hard disk...


    ************************************************************************8

Jboss 7 Installation on RHEL 6.3

Check the server hostname correctly assigned:

# vim /etc/hosts
# vim /etc/sysconfig/network

Check http service running or not:

#/etc/init.d/httpd status.
It should running....

Create jboss user :

#useradd jboss

Download latest  jdk 7 to /user/local and install it:

# rpm -ivh jdk-7u7-linux-x64.rpm
 
To check java installed or not:
# java --version  

Set java variable path:

#JAVA_HOME=/usr/java/latest
#export JAVA_HOME
#PATH=$JAVA_HOME/bin:$PATH:$HOME/bin

Also add the above 3 lines  in vim /etc/bash_profile save and close it.

Download jboss7 to /usr/local/ and unzip it.

#unzip jboss-as-7.1.1.Final.zip  (It will unzip as jboss-as-7.1.1 )
#mv jboss-as-7.1.1 jboss-as

Assign the owner permission to jboss for /usr/local/jboss-as directory.
 
#chown -R jboss:jboss /usr/local/jboss-as


To create service user /etc/init.d do as follow:

#cp /usr/local/jboss-as/bin/init.d/jboss-as-standalone.sh /etc/init.d/jboss
#mkdir /etc/jboss-as
#cp /usr/local/jboss-as/bin/init.d/jboss-as.conf /etc/jboss-as/
#chmod 755 /etc/ini.d/jboss

Edit and add the below entries in /etc/init.d/jboss:

#vim /etc/init.d/jboss

# chkconfig: - 234 80 20  to run jboss in 234 run level
 
# Set defaults.

JBOSS_USER=jboss
export JBOSS_USER

if [ -z "$JBOSS_HOME" ]; then
  JBOSS_HOME=/usr/local/jboss-as
Save and close text editor...


To access jboss console through browser from remote system:

change 0.0.0.0 instead of 127.0.0.0. only in the below lines.

# vim /usr/local/jboss-as/standalone/configuration/standalone.xml 

 <interface name="management">
            <inet-address value="${jboss.bind.address.management:0.0.0.0}"/>
        </interface>
        <interface name="public">
            <inet-address value="${jboss.bind.address:0.0.0.0}"/>


save and close text editor.

#chkconfig --add jboss
#chkconfig jboss on

Now we can start the jboss as system service:

#/etc/init.d/jboss start

and 

We can access it through browser.
10.0.0.1:8080




     *************************************************************

To add jboss mnagement user:
Go to /usr/local/jboss-as/bin/
#./add-user.sh
You should see the following message on the console after executing the command:
What type of user do you wish to add?
a) Management User (mgmt-users.properties)
b) Application User (application-users.properties)
(a): a
We select “a”, next you should see the following message:
Enter the details of the new user to add.
Realm (ManagementRealm) :
Username : jboss
Password :
Re-enter Password :
* hit enter for Realm to use default, then provide a username and password
We select the default value for the Realm (ManagementRealm), by hitting enter, and select “jboss” as our username and password.

 

 






Acl in linux

1.To set acl for a folder :

# setfacl -m u:username:rwx foldername

2.To set acl for solder and their sub folder.

.#setfacl -R -m u:username:rwx foldername 

3.To view acl for a folder :
#getfacl foldername

4.To remove acl for a folder :
setfacl -b u:username:rwx foldername

 
 
 

How to import store proceedure in mysql

To fix this.

Export store procedure from existing database with below command;

#mysqldump -p --no-create-db --no-create-info --no-data --routines DBNAME > DBNAME_23Oct2012.sql   And imoprt .sql file to running db.   #mysql -u root -p DBNAME < DBNAME_23Oct2012.sql       Restart Mysql DB   To check Store procedure in Mysql   #Login into mysql DB and type the below command   SHOW PROCEDURE STATUS; SHOW FUNCTION STATUS;   Thats it!!!!

Starting MySQL.Manager of pid-file quit without updating fi[FAILED]

Am getting below eror on of my mysql server while starting mysql service"Starting MySQL.Manager of pid-file quit without updating fi[FAILED] "

 To resolve this issue i tried the below

# ps -ef | grep -i mysql

kill the all running process 

Try to start mysql

#services mysqld start

It worked for me..

How to import and Export Mysql db

To export mysqlDB:


1.Type the below command to export mysql db:

# mysqldump -u root -p dbname> dbname11092012.sql

To import mysql DB:

1.Go to file location where you saved  backup db and type following command.

 2.login into mysql and create new database.

> create databases newdb

3.exit from sql and type as following

# mysql -u root -p  newdb < db_04102012-0700.sql

[where newdb is newly created db and db_04102012-0700.sql is going to restore newly created db.]

How to Allow MySQL Client to Connect to Remote MySQL server

If you try to connect to a remote MySQL database from your client system, you will get “ERROR 1130: Host is not allowed to connect to this MySQL server” message as shown below.

# mysql -h 10.10.28.8 -u root -p
Enter password:
ERROR 1130: Host '10.10.28.8' is not allowed to connect to this MySQL server

1.Try to telnet server from client machie

# telnet 192.168.1.8 3306
host 10.10.28.8 is not allowed to connect to this mysql server

2.To allow a specific client ip-address (10.10.28.8) to access the mysql database running on a server,

# mysql -u root -p
Enter password:

mysql> use mysql

mysql> GRANT ALL ON *.* to root@'10.10.28.8' IDENTIFIED BY '$dfg!23'; 

mysql> FLUSH PRIVILEGES;

That's it.....It should work!!!!

  

To resolve!! Starting jboss-as: chown: missing operand after `/var/run/jboss-as' Try `chown --help' for more information.in Jboss 7

While starting Jboss service i am getting following error meesage in jboss7.

 "Starting jboss-as: chown: missing operand after `/var/run/jboss-as'Try `chown --help' for more information."

To over come this ,

#vim /usr/local/jboss-as/standalone/configuration/standalone.xml

 and add the below line into standalone.xml file

# Set defaults.
JBOSS_USER=jboss
export JBOSS_USER








Now we can start the jboss server as usual without any error message.
#/etc/init.d/jboss start

Enjoy!!!!...

Enabling php-imap module in php(Cent OS)

1.Install php-imap with following command.

#yum --enablerepo=webtatic install php54w-imap* 


2.Restart HTTP service

#. service httpd restart 

3.Check imap module install in php
# php -i | grep -i imap

How to determine given OS in 32 bit or 64 bit in Linux

Type the following simple command in your linux boxes:

# uname-m

If it 32 bit os the output would  be  follow:

i686   ==> 32-bit kernel

If it 64 bit os the output would be follow:

x86_64 ==> 64-bit kernel

Or

 can use following command to check the OS versions:

# uname -a

# getconf LONG_BIT

# cat /proc/cpuinfo

How to fix Could not complete SSL handshake error.in rhel5

In this case, you need to check on the /etc/xinetd.d/nrpe as following.

# default: on
# description: NRPE (Nagios Remote Plugin Executor)
service nrpe
{
        flags           = REUSE
        socket_type     = stream   
 port  = 5666   
        wait            = no
        user            = nagios
 group  = nagios
        server          = /usr/local/nagios/bin/nrpe
        server_args     = -c /usr/local/nagios/etc/nrpe.cfg --inetd
        log_on_failure  += USERID
        disable               = no
 only_from                = 10.1.2.2
}

You need to make sure the only_from ip is the IP for nagios monitoring server.
If the only_from IP is not correct, rectify it and then restart xinetd.d by using the following command.
[admin@remotehost ~]$ sudo /etc/init.d/xinetd restart
Stopping xinetd:                                           [  OK  ]
Starting xinetd:                                           [  OK  ]
If the nrpe setting is already correct, then you need to check in /var/log/messages in the remote host. You might see the following error.
Jul 29 13:36:56 remotehost xinetd[7336]: FAIL: nrpe address from=10.1.2.2
Jul 29 13:36:56 remotehost xinetd[6595]: START: nrpe pid=7336 from=10.1.2.2
Jul 29 13:36:56 remotehost xinetd[6595]: EXIT: nrpe status=0 pid=7336 duration=0(sec)
Try to restart xinetd daemon using the command above and then check on /var/log/messages again. If you see the following error, it might mean that xinetd had problem to start up nrpe becuase of its bug to release the address.
Jul 29 13:35:54 remotehost xinetd[6595]: bind failed (Address already in use (errno = 98)). service = nrpe
Jul 29 13:35:54 remotehost xinetd[6595]: Service nrpe failed to start and is deactivated.
Jul 29 13:35:54 remotehost xinetd[6595]: xinetd Version 2.3.14 started with libwrap loadavg labeled-networking options compiled in.

In this case, you cannot start nrpe as embeded service in xinetd since this is a bug in xinetd. To fix this, you can start nrpe as standalone daemon. Before you started nrpe as standalone daemon, you need to verify the configuration in /usr/local/nagios/etc/nrpe.cfg. The following are two parameters that you need to take care of. The value for allowed_hosts should be the ip of nagios monitoring host and the server_port is 5666.

allowed_hosts=10.1.8.2

server_port=5666

Besides, you need to make sure xinetd is not running or you need to remove /etc/xinetd.d/nrpe and restart xinetd daemon.

Then, you can issue the following command to start nrpe as standalone daemon.

[admin@remotehost]$ /usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -d

You should see the following log in /var/log/messages.

Jul 29 14:18:31 remotehost nrpe[5947]: Starting up daemon
Jul 29 14:18:31 remotehost nrpe[5947]: Listening for connections on port 5666
Jul 29 14:18:31 remotehost nrpe[5947]: Allowing connections from: 10.1.2.2

In this case, you can now verify the nrpe connection by running check_nrpe from nagios monitoring host as following.

[admin@monitoringhost ~]$ /usr/local/nagios/libexec/check_nrpe -H 10.1.2.12
NRPE v2.12

No more error 'CHECK_NRPE: Error - Could not complete SSL handshake.' now.

Locations of Apache conf files, binary files,Apache Module files

ServerRoot              ::      /etc/httpd
Primary Config Fle      ::      /etc/httpd/conf/httpd.conf
Other Config Files      ::      /etc/httpd/conf.d
Module Locations        ::      /usr/lib/httpd/modules
DocumentRoot            ::      /var/www/html
ErrorLog                ::      /var/log/httpd/error_log
AccessLog               ::      /var/log/httpd/access_log
cgi-bin                 ::      /var/www/cgi-bin (empty and disabled by default)
binary name and path    ::      /usr/sbin/httpd
runtime directory       ::      /etc/httpd/run

Recover MySQL root password

step1: stop mysql

root@bilal# service mysqld stop

root@bilal# /usr/sbin/mysqld --skip-grant-tables &  

step2: Login in to your mysql shell

root@bilal:/# mysql -u root

mysql> UPDATE mysql.user SET Password=PASSWORD('Newpassword') WHERE User='root';
mysql> FLUSH PRIVILEGES; 

Adding banner to ssh l;ogins

Edit

# vi /etc/ssh/sshd_config and uncomment out the line

# Banner /etc/banner (you can use any path you want)

# root@server [/]# /etc/init.d/sshd restart

#  ssh localhost