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2. Cloud Computing Details

Cloud Computing means accessing the hosted services over the Internet. That means, we can access our documents or interact with our application or develop applications that are stored at the service provider from any place.

Cloud Computing Provides Various Services:

•   SaaS:

Software-as-a-service products provide complete hardware infrastructure and software applications. User has to interact with it using front-end tool no matter where he is, e.g. salesforce.com

•   PaaS:

Platform-as-a-service products provide some softwares and development tools also. Users can create their application in provider's infrastructure at any place, e.g. GoogleApps.

•   IaaS:

Infrastructure-as-a-service products provide virtual server and memory. Users have to use providers API to start stop access and configure their virtual server.

e.g. Amazon web services, EMC Atmos

•    DaaS:

Desktop-as-a-service enables us to use our desktop virtually from anywhere.

The pros:

•    Lower computer costs: Not necessary to have high-powered computers to access web applications. Even with cheaper computer also can give efficient results because data is stored in the web not with us.

•    Improved performance: Everything is run in cloud so our computer doesn’t have to take much effort to run applications. As a result, performance will be improved automatically.

•    Unlimited storage capacity: Storage is also one kind of service provided by the Cloud, so there is no limit to store data (based on the service provider).

•    Device independence: The actual documents are in the Cloud, so you can access it wherever you are.

The cons:

•    Requires a constant High speed Internet connection: To get benefit from this we need to have always a high speed Internet connection. 

•    Stored data might not be secure: There is no guarantee that your data stored is in cloud is securely protected. Intruders may access to your vital data at any time.

Deployment Models:

 

Public cloud

A public cloud is one based on the standard cloud computing model, in which a service provider makes resources, such as applications and storage, available to the general public over the Internet. Public cloud services may be free or offered on a pay-per-usage model.

Community cloud

Community cloud shares infrastructure between several organizations from a specific community with common concerns (security, compliance, jurisdiction, etc.). The costs are spread over fewer users than a public cloud (but more than a private cloud), so only some of the benefits of cloud computing are realized.

Hybrid cloud

Hybrid cloud is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together, offering the benefits of multiple deployment models. It can also be defined as multiple cloud systems that are connected in a way that allows programs and data to be moved easily from one deployment system to another.

1. Shell Scripting for LINUX Admin

BASH Shell Script for Multiple Usage ......................

Bash shell script which perform following tasks:

1. Ping_Status: This option ping all the hosts and verify the results
2. Host_Identification: To identify host Operating System
3. SSH_Login: To Remote login into host
4. Login_Failure: It provides information about unauthorized login attempts or any other problems
5. Service_Status: Check various service status and START/STOP them as per your requirement
6. Memory_Status: It can display system summary information as well as list of tasks currently being managed by the Linux kernel.
7. Local_Backup: Backup of Local Host
8. Remote_Backup: Backup to Remote Host
9. Local_Restore: Restore backup file of local host
10. Remote_Restore: Restore of backup file to Remote Host
11. Package_Verification: Verify packages installed/uninstalled
12. Multiple_Package_Installation: Install multiple packages on host
13. Single_Package_Installation: Install packages one by one on host
14. Package_Uninstallation: Uninstall packages
15. Quit: Exit the script.

 

Entire code is as follows:

#!/bin/bash

#Author: Trupti

#Date: 29.11.2011

#Purpose: Illustrate usage of select

PS3='Please select a choice: '

LIST="Ping_Status Host_Identification SSH_Login Login_Failure Service_Status Memory_Status Local_Backup Remote_Backup Local_Restore Remote_Restore

Package_Verification Multiple_Package_Installation Single_Package_Installation Package_Uninstallation Quit"

function pingstatus () {

        echo -en "Enter the machine: "; read machine

        ping -c 2 $machine > /dev/null

        if [ $? = 0 ]

        then

                echo "$machine is REACHABLE via ping"

        else

                echo "$machine is NOT REACHABLE via ping"

        fi

}

function hostidentification () {

        echo -en "Enter the MACHINE: "; read MACHINE

        ping -c 2 $MACHINE > /dev/null

        if [ $? = 0 ]

        then

                echo "$MACHINE is REACHABLE via ping"

                nmap -O $MACHINE > nmap.txt

                HOSTNMAP=`cat nmap.txt | grep OS`

                echo "Host Identification is as follows: "

                echo "$HOSTNMAP"

        else

                echo "$MACHINE is NOT REACHABLE via ping"

        fi

}

function sshsession () {

        echo -en "Enter the server: "; read server

        ping -c 2 $server > /dev/null

        if [ "$?" = 0 ]

        then

                echo "$server is UP and RUNNING"

                echo -en "Do you want to connect this server through SSH session(yes/no): "; read check

                if [ "$check" = "yes" ] || [ "$check" = "YES" ]

                then

                        echo -en "Please provide the username for the server: "; read username

                        ssh $server -l $username

                else

                        exit

                fi

        elif [ "$?" = 1 ]

        then

                echo "$server is UNREACHABLE"

        fi

}

function loginfailure () {

        NUMBER=`cat /var/log/secure | grep -i Failed | wc -l`

        LIST=`cat /var/log/secure | grep -i Failed`

        echo "Unauthorized logins are: $LIST"

        echo "Number of unauthorized users are: $NUMBER"

}

function servicestatus () {

        echo -en "Enter the Service name: "; read perservice

        service $perservice status > /dev/null

        if [ "$?" = "0" ]

        then

                echo "$perservice service is Running"   

                echo -en "Do you want to STOP the service(yes/no): "; read check

                if [ "$check" = "yes" ] || [ "$check" = "YES" ]

                then

                        echo "Stopping..............."

                        service $perservice stop

                else

                        exit

                fi

        else

                echo "$perservice service is NOT Running"

                echo -en "Do you want to START the service(yes/no): "; read check

                if [ "$check" = "yes" ] || [ "$check" = "YES" ]

                then

                        echo "Starting..............."

                        service $perservice start

                else

                        exit

                fi

        fi

}

function memorystatus () {

        echo "Check the Memory status"

        top -d10

}

function localbackup () {

        function backupdirpath() {

        if [ ! -e $BACKUPDIRPATH ]

        then

                echo "No such file or directory. Please give the correct path"

                echo -en "Enter the path for backup directory: "; read BACKUPDIRPATH

                backupdirpath

        fi

        }

        echo -en "Enter the BACKUP Directory Name: "; read BACKUPDIRNAME

        echo -en "Enter the BACKUP Directory Path: "; read BACKUPDIRPATH

        backupdirpath

        BACKUPFILE=scripts.backup.`date +%F`.tgz

        if [ ! -e $BACKUPDIRPATH/$BACKUPDIRNAME ]

        then

                echo "Creating backup directory because it does not exist!"

                mkdir $BACKUPDIRPATH/$BACKUPDIRNAME

                cd $BACKUPDIRPATH/$BACKUPDIRNAME

                echo -en "Enter the entire path of directory which you want to backup: "; read TOBEBACKUP

                tar -czvf $BACKUPFILE $TOBEBACKUP

        else

                echo "File is already exists"

                cd $BACKUPDIRPATH/$BACKUPDIRNAME

                echo -en "Enter the entire path of directory which you want to backup: "; read TOBEBACKUP

                tar -czvf $BACKUPFILE $TOBEBACKUP

        fi

}

function remotebackup () {

        function backupdirpath() {

        if [ ! -e $BACKUPDIRPATH ]

        then

                echo "No such file or directory. Please give the correct path"

                echo -en "Enter the path for backup directory: "; read BACKUPDIRPATH

                backupdirpath

        fi

        }

        echo -en "Enter the BACKUP Directory Name: "; read BACKUPDIRNAME

        echo -en "Enter the BACKUP Directory Path: "; read BACKUPDIRPATH

        backupdirpath

        BACKUPFILE=scripts.backup.`date +%F`.tgz

        if [ ! -e $BACKUPDIRPATH/$BACKUPDIRNAME ]

        then

                echo "Creating backup directory because it does not exist!"

                mkdir $BACKUPDIRPATH/$BACKUPDIRNAME

                cd $BACKUPDIRPATH/$BACKUPDIRNAME

                echo -en "Enter the entire path of directory which you want to backup: "; read TOBEBACKUP

                tar -czvf $BACKUPFILE $TOBEBACKUP

                cd $BACKUPDIRPATH/$BACKUPDIRNAME

                echo -en "Enter the Remote Backup Host: "; read REMOTEBACKUPHOST

                scp $BACKUPFILE $REMOTEBACKUPHOST:

        else

                echo "File is already exists"

                cd $BACKUPDIRPATH/$BACKUPDIRNAME

                echo -en "Enter the entire path of directory which you want to backup: "; read TOBEBACKUP

                tar -czvf $BACKUPFILE $TOBEBACKUP

                cd $BACKUPDIRPATH/$BACKUPDIRNAME

                echo -en "Enter the Remote Backup Host: "; read REMOTEBACKUPHOST

                scp $BACKUPFILE $REMOTEBACKUPHOST:

                if [ $? != 0 ]

                then

                        echo "Problems Coping Backup File To Backup Host"

                fi

        fi

}

function localrestore () {

        function backuppath () {

        if [ ! -e $BACKUPPATH ]

        then

                echo "No such file or directory. Please give the correct PATH"

                echo -en "Provide the BACKUP Path: "; read BACKUPPATH

                backuppath

        fi

        }

        echo -en "Provide the BACKUP Path: "; read BACKUPPATH

        backuppath

        cd $BACKUPPATH

        function restorepath () {

        if [ ! -e $BACKUPPATH/$RESTOREFILE ]

        then

                echo "No such file. Pleave provide the correct FILE: "

                echo -en "Provide the BACKUP File which you want to Restore: "; read RESTOREFILE

                restorepath

        fi

        }

        echo -en "Provide the BACKUP File which you want to Restore: "; read RESTOREFILE

        restorepath

        tar -xzvf $RESTOREFILE

        echo "Restore files are in $BACKUPPATH "

}

function remoterestore () {

        function backuppath () {

        if [ ! -e $BACKUPPATH ]

        then

                echo "No such file or directory. Please give the correct PATH"

                echo -en "Provide the BACKUP Path: "; read BACKUPPATH

                backuppath

        fi

        }

        echo -en "Provide the BACKUP Path: "; read BACKUPPATH

        backuppath

        cd $BACKUPPATH

        function restorepath () {

        if [ ! -e $BACKUPPATH/$RESTOREFILE ]

        then

                echo "No such file. Pleave provide the correct FILE: "

                echo -en "Provide the BACKUP File which you want to Restore: "; read RESTOREFILE

                restorepath

        fi

        }

        BACKUPFILE=scripts.backup.`date +%F`.tgz

        echo -en "Enter the Remote Backup Host: "; read REMOTEBACKUPHOST

        scp $BACKUPPATH $REMOTEBACKUPHOST:

        echo -en "Provide the BACKUP File which you want to Restore: "; read RESTOREFILE

        restorepath

        tar -xzvf $RESTOREFILE

        echo "Restore files are in $BACKUPPATH "

}

function packageverification () {

        echo -en "Enter the Package: "; read Package

        rpm -qa | grep -i $Package

        if [ $? = 0 ]

        then

                echo "Package is Installed"

        else

                echo "Package is NOT Installed"

        fi

}

function packageinstallation () {

        echo -en "Enter the Package: "; read Package

        rpm -qa | grep -i $Package

        PACKAGEPATH2=`rpm -qa | grep -i $Package`

        if [ $? = 0 ]

        then

                echo "Package is Installed"

        else

                echo "Package is NOT Installed"

                echo -en "Do you want to INSTALL this package(yes/no): "; read check

                if [ "$check" = "yes" ] || [ "$check" = "YES" ]

                then

                        echo -en "Please Enter the Package Path: "; read Package_path

                        if [ -e $Package_path ]

                        then

                                echo "File exists"

                                echo "Installing.............."

                                rpm -ivh $Package_path/$Package*

                                echo "Package has been INSTALLED Successfully"

                        else

                                echo "File does not exist. Please Enter the correct path"

                        fi

                elif [ "$check" = "no" ] || [ "$check" = "NO" ]

                then

                        exit 

                fi

        fi

}

function packageinstallation1 () {

        echo -en "Enter the Package: "; read Package

        rpm -qa | grep -i $Package

        PACKAGEPATH2=`rpm -qa | grep -i $Package`

        if [ $? = 0 ]

        then

                echo "Package is Installed"

                echo -en "Provide the path of the package or type Quit to exit: "; read pathpackage1

                if [ $pathpackage1 = "Quit" ]

                then

                        exit

                else

                        echo "Files from path cd `$pathpackage | ls -ltr`"

                fi

        echo -en "If you want to install another package then please give entire name or type Quit to exit: "; read anotherpackage

        if [ $anotherpackage = "Quit" ]

        then

                exit

        else

                rpm -ivh $pathpackage1/$anotherpackage

        fi

else

        echo "Package is NOT Installed"

        echo -en "Do you want to INSTALL this package(yes/no): "; read check

        if [ "$check" = "yes" ] || [ "$check" = "YES" ]

        then

                echo -en "Please Enter the Package Path: "; read Package_path

                if [ -e $Package_path ]

                then

                        echo "File exists"

                        ls -la | grep -i $Package > tmp.txt

                        echo "Files found in the path are: `cat tmp.txt`"

                        LINES=`cat tmp.txt | wc -l`

                        if [ $LINES > 1 ]

                        then

                                echo -en "Please provide the package which you want to Install: "

                                read newpackage

                                rpm -ivh $Package_path/$newpackage

                                exit

                        fi

                        echo "Package has been INSTALLED Successfully"

                else

                        echo "File does not exist. Please Enter the correct path"

                fi

        elif [ "$check" = "no" ] || [ "$check" = "NO" ]

        then

                exit 

        fi

fi

}

function packageuninstallation () {

        echo -en "Enter the Package: "; read Package

        PKRM=`rpm -qa | grep -i $Package`

        if [ -e $PKRM ]

        then

                echo "Package is not available"

        else

                echo -en "Do you want to UNINSTALL this package(yes/no): "; read check

                if [ "$check" = "yes" ] || [ "$check" = "YES" ]

                then

                        rpm -e $PKRM

                        echo "Uninstalling........"

                        echo "Package has been Uninstalled"

                else

                        exit

                fi

        fi

}

select var in $LIST

do

        if [ $var = "Ping_Status" ]

        then

                pingstatus

        elif [ $var = "Host_Identification" ]

        then

                hostidentification

        elif [ $var = "SSH_Login" ]

        then

                sshsession

        elif [ $var = "Login_Failure" ]

        then

                loginfailure

        elif [ $var = "Service_Status" ]

        then

                servicestatus

        elif [ $var = "Memory_Status" ]

        then

                memorystatus

        elif [ $var = "Local_Backup" ]

        then

                localbackup

        elif [ $var = "Remote_Backup" ]

        then

                remotebackup

        elif [ $var = "Local_Restore" ]

        then

                localrestore

        elif [ $var = "Remote_Restore" ]

        then

                remoterestore

        elif [ $var = "Package_Verification" ]

        then

                packageverification

        elif [ $var = "Multiple_Package_Installation" ]

        then

                packageinstallation

        elif [ $var = "Single_Package_Installation" ]

        then

                packageinstallation1

        elif [ $var = "Package_Uninstallation" ]

        then

                packageuninstallation

        elif [ $var = "Quit" ]

        then

                exit

        else

                exit

        fi

done

#END