davopslab

............>ansible....... cd /etc/yum.repos.d/ ll vi amzn2-core.repo %s/enabled=0/enabled=1/g

enabling epel for amazon linux sudo yum install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm ansible and press tab to see cd /etc/ansible/ ll -rw-r--r-- 1 root root 20277 Jan 18 01:34 ansible.cfg -rw-r--r-- 1 root root 1016 Jan 18 01:34 hosts drwxr-xr-x 2 root root 6 Jan 18 01:34 roles

creating ec2 instance

https://www.bogotobogo.com/DevOps/Ansible/Ansible-aws-creating-ec2-instance.php

TOmcat Playbook 1.http://myblogmchopker.blogspot.com/2017/08/ansible-tomcat-installation-deployment.html

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----------- Docker--------------------

cd /etc/yum.repos.d/ ls -ltr vi redhat-rhui.repo :set nu %s/enabled=0/enabled=1/g (small s only) then wq! yum update -y yum install docker -y systemctl start docker ps -ef | grep -i docker cd mkdir -p /opt/devops/docker cd /opt/devops/docker/ mkdir lab1 cd lab1/ echo "This is test docker" >> index.html vi dockerfile FROM nginx:alpine COPY . /usr/share/nginx/html cat dockerfile ls -ltr docker build -t nginxlab:1 .

creating one new imaage and pulling that image to docker hub docker pull ubuntu docker images docker run -it -d ubuntu docker ps -a docker exec -it ddc39c83fc24 bash ls mkdir test-directorry exit docker ps -a docker commit c718a1c0ccca msreddy621/srinivasreddy:7 docker push msreddy621/srinivasreddy:6

A problem rectified to push image from locl to central repo by this https://bugzilla.redhat.com/show_bug.cgi?id=1434897

to build job with docker https://www.upnxtblog.com/index.php/2018/02/02/build-docker-images-using-jenkins/

docker login docker.io

more /etc/sysconfig/docker 164 cd /etc/docker/ 165 ls -lt 166 grep -i redhat * 167 grep -iR redhat * 168 more /etc/containers/registries.conf 169 vi /etc/containers/registries.conf

cd /tmp/ yum install wget unzip -y wget -c --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u131-b11/d54c1d3a095b4ff2b6607d096fa80163/jdk-8u131-linux-x64.rpm rpm -ivh jdk-8u131-linux-x64.rpm wget http://mirrors.estointernet.in/apache/tomcat/tomcat-8/v8.5.37/bin/apache-tomcat-8.5.37-windows-x64.zip unzip apache-tomcat-8.5.37-windows-x64.zip mv apache-tomcat-8.5.37 /opt/tomcat chmod -R 755 /opt/tomcat/ rm -rf /opt/tomcat/webapps/* /opt/tomcat/bin/startup.sh ps -ef | grep tomcat wget https://updates.jenkins-ci.org/download/war/2.156/jenkins.war cp jenkins.war /opt/tomcat/webapps/ wget http://mirrors.estointernet.in/apache/maven/maven-3/3.6.0/binaries/apache-maven-3.6.0-bin.zip unzip apache-maven-3.6.0-bin.zip mv apache-maven-3.6.0 maven yum install git -y

==========K8============

1. first install the instance (take rhel7.5)

2. enable the EPEL for kubernetes

cat < /etc/yum.repos.d/kubernetes.repo [kubernetes] name=Kubernetes baseurl=http://yum.kubernetes.io/repos/kubernetes-el7-x86_64 enabled=1 gpgcheck=1 repo_gpgcheck=1 gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg EOF

3. yum update -y

4. install the kubernetes

yum install kubelet kubeadm kubectl kubernetes-cni -y --nogpgcheck

5. start and enable the kubernet systemctl enable kubelet systemctl start kubelet

6. disable the selinux

vi /etc/selinux/config

go to 7th line and edit (permanently diable) SELINUX=disabled

7)-----------no need to do this step----- stop and disable th firewall ( there is no firewalld package in rhel7 no need to disable and stop the firewalld)

systemctl disable firewalld systemctl stop firewalld

8)enable the EPEL for docker

vi /etc/yum.repos.d/redhat-rhui.repo esc :%s/enabled=0/enabled=1/g

9. install the docker

yum install docker -y

systemctl start docker

systemctl enable docker

10. use below commands to run

sysctl -w net.bridge.bridge-nf-call-iptables=1

echo "net.bridge.bridge-nf-call-iptables=1" > /etc/sysctl.d/k8s.conf

11. from instance reboot the server

12. take the 0wn ami for master

13. run the command kubeadm init

kubeadm join 172.31.22.170:6443 --token ne8lk6.pgf5tng78tna3sc4 --discovery-token-ca-cert-hash sha256:a023ae74566113a008b9c2f7ea87f3fc253198909aa70ca94765f85cc5830068

mkdir -p $HOME/.kube cp -i /etc/kubernetes/admin.conf $HOME/.kube/config chown $(id -u):$(id -g) $HOME/.kube/config

and launch 3 slave nodes

16)Deploy pod network to the cluster

kubectl get nodes kubectl get pods --all-namespaces

15)Run the beneath command to deploy network.

export kubever=$(kubectl version | base64 | tr -d '\n') kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$kubever"

---

1. How to pass argument to a script ? ./script argument

Example : Script will show filename

./show.sh file1.txt

cat show.sh #!/bin/bash cat $1

2. How to use argument in a script ? First argument: $1, Second argument : $2

Example : Script will copy file (arg1) to destination (arg2)

./copy.sh file1.txt /tmp/

cat copy.sh #!/bin/bash cp $1 $2

3. How to calculate number of passed arguments ? $#

4. How to get script name inside a script ? $0

5. How to check if previous command run successful ? $?

6. How to get last line from a file ? tail -1

7. How to get first line from a file ? head -1

8. How to get 3rd element from each line from a file ? awk '{print $3}'

9. How to get 2nd element from each line from a file, if first equal FIND awk '{ if ($1 == "FIND") print $2}'

10. How to debug bash script Add -xv to #!/bin/bash

Example

#!/bin/bash –xv

11. Give an example how to write function ? function example { echo "Hello world!" }

12. How to add string to string ? V1="Hello" V2="World" let V3=$V1+$V2 echo $V3

Output

Hello+World

13. How to add two integers ? V1=1 V2=2 V3=$V1+$V2 echo $V3

Output 3

Remember you need to add "let" to line V3=$V1+$V2 then echo $V3 will give 3

if without let , then it will be

echo $V3 will give 1+2

14. How to check if file exist on filesystem ? if [ -f /var/log/messages ] then echo "File exists" fi

15. Write down syntax for all loops in shell scripting ? for loop :

for i in $( ls ); do echo item: $i done

while loop :

#!/bin/bash COUNTER=0 while [ $COUNTER -lt 10 ]; do echo The counter is $COUNTER let COUNTER=COUNTER+1 done

until loop :

#!/bin/bash COUNTER=20 until [ $COUNTER -lt 10 ]; do echo COUNTER $COUNTER let COUNTER-=1 done

16. What it means by #!/bin/sh or #!/bin/bash at beginning of every script ? That line tells which shell to use. #!/bin/bash script to execute using /bin/bash. In case of python script there there will be #!/usr/bin/python

17. How to get 10th line from the text file ? head -10 file|tail -1

18. What is the first symbol in the bash script file

19. What would be the output of command: [ -z "" ] && echo 0 || echo 1 0

20. What command "export" do ? Makes variable public in subshells

21. How to run script in background ? add "&" to the end of script

22. What "chmod 500 script" do ? Makes script executable for script owner

23. What ">" do ? Redirects output stream to file or another stream.

24. What difference between & and && & - we using it when want to put script to background && - when we wand to execute command/script if first script was finished successfully

25. When we need "if" before [ condition ] ? When we need to run several commands if condition meets.

26. What would be the output of the command: name=John && echo 'My name is $name' My name is $name

27. Which is the symbol used for comments in bash shell scripting ?

28. What would be the output of command: echo ${new:-variable} variable

29. What difference between ' and " quotes ? ' - we use it when do not want to evaluate variables to the values " - all variables will be evaluated and its values will be assigned instead.

30. How to redirect stdout and stderr streams to log.txt file from script inside ? Add "exec >log.txt 2>&1" as the first command in the script

31. How to get part of string variable with echo command only ? echo ${variable:x:y} x - start position y - length example: variable="My name is Petras, and I am developer." echo ${variable:11:6} # will display Petras

32. How to get home_dir with echo command only if string variable="User:123:321:/home/dir" is given ? echo ${variable#:::} or echo ${variable##:}

33. How to get “User” from the string above ? echo ${variable%:::} or echo ${variable%%:}

34. How to list users which UID less that 100 (awk) ? awk -F: '$3<100' /etc/passwd

35. Write the program which counts unique primary groups for users and displays count and group name only cat /etc/passwd|cut -d: -f4|sort|uniq -c|while read c g do { echo $c; grep :$g: /etc/group|cut -d: -f1;}|xargs -n 2 done

36. How to change standard field separator to ":" in bash shell ? IFS=":"

37. How to get variable length ? ${#variable}

38. How to print last 5 characters of variable ? echo ${variable: -5}

39. What difference between ${variable:-10} and ${variable: -10} ? ${variable:-10} - gives 10 if variable was not assigned before ${variable: -10} - gives last 10 symbols of variable

40. How to substitute part of string with echo command only ? echo ${variable//pattern/replacement}

41. Which command replaces string to uppercase ? tr '[:lower:]' '[:upper:]'

42. How to count local accounts ? wc -l /etc/passwd|cut -d" " -f1 or cat /etc/passwd|wc -l

43. How to count words in a string without wc command ? set ${string} echo $#

44. Which one is correct "export $variable" or "export variable" ? export variable

45. How to list files where second letter is a or b ? ls -d ?[ab]*

46. How to add integers a to b and assign to c ? c=$((a+b)) or c=expr $a + $b or c=echo "$a+$b"|bc

47. How to remove all spaces from the string ? echo $string|tr -d " "

48. Rewrite the command to print the sentence and converting variable to plural: item="car"; echo "I like $item" ? item="car"; echo "I like ${item}s"

49. Write the command which will print numbers from 0 to 100 and display every third (0 3 6 9 …) ? for i in {0..100..3}; do echo $i; done or for (( i=0; i<=100; i=i+3 )); do echo "Welcome $i times"; done

50. How to print all arguments provided to the script ? echo $* or echo $@

51. What difference between [ $a == $b ] and [ $a -eq $b ] [ $a == $b ] - should be used for string comparison [ $a -eq $b ] - should be used for number tests

52. What difference between = and == = - we using to assign value to variable == - we using for string comparison

53. Write the command to test if $a greater than 12 ? [ $a -gt 12 ]

54. Write the command to test if $b les or equal 12 ? [ $b -le 12 ]

55. How to check if string begins with "abc" letters ? [[ $string == abc* ]]

56. What difference between [[ $string == abc* ]] and [[ $string == "abc*" ]] [[ $string == abc* ]] - will check if string begins with abc letters [[ $string == "abc*" ]] - will check if string is equal exactly to abc*

57. How to list usernames which starts with ab or xy ? egrep "^ab|^xy" /etc/passwd|cut -d: -f1

58. What $! means in bash ? Most recent background command PID

59. What $? means ? Most recent foreground exit status.

60. How to print PID of the current shell ? echo $$

61. How to get number of passed arguments to the script ? echo $#

62. What difference between $* and $@ $* - gives all passed arguments to the script as a single string $@ - gives all passed arguments to the script as delimited list. Delimiter $IFS

63. How to define array in bash ? array=("Hi" "my" "name" "is")

64. How to print the first array element ? echo ${array[0]}

65. How to print all array elements ? echo ${array[@]}

66. How to print all array indexes ? echo ${!array[@]}

67. How to remove array element with id 2 ? unset array[2]

68. How to add new array element with id 333 ? array[333]="New_element"

69. How shell script get input values ? a) via parameters

./script param1 param2

b) via read command

read -p "Destination backup Server : " desthost

70. How can we use "expect" command in a script ? /usr/bin/expect << EOD spawn rsync -ar ${line} ${desthost}:${destpath} expect "?assword:" send "${password}\r" expect eof EOD

Good luck !! Please comment below if you have any new query or need answers for your questions. Let us know how well this helped for your interview :-)

---

1)to sum ((sum=25+35)) echo $sum

2)diff ((diff=35-10)) echo $diff

3)multi ((mult=35*10)) echo $mult

4)div ((div=40/10)) echo $div

5)The value of count variable will increment by 1 in each step. When the value of count variable will 5 then the while loop will terminate.

valid=true count=1 while [ $valid ] do echo $count if [ $count -eq 5 ]; then break fi ((count++)) done

6)area ((area=5*5)) echo $area

7.for------- loop #!/bin/bash for (( counter=10; counter>0; counter-- )) do echo -n "$counter " done printf "\n"

8.Finding odd and even number using three expressions for (( n=1; n<=5; n++ )) do if (( $n%2==0 )) then echo "$n is even" else echo "$n is odd" fi done

9.Reading static values

for color in Blue Green Pink White Red do echo "Color = $color" done

10.http://www.freeos.com/guides/lsst/ch08.html#q4

11.#!/bin/bash

declare integers

NUM1=2 NUM2=1 if [ $NUM1 -eq $NUM2 ]; then echo "Both Values are equal" elif [ $NUM1 -gt $NUM2 ]; then echo "NUM1 is greater then NUM2" else echo "NUM2 is greater then NUM1" fi

12.Problem: I have a file called 'mypaper.txt' or 'mypaper.tex' or some such somewhere, but I don't remember where I put it. How do I find it?

Solution:

$ find ~ -name "mypaper*"

13.Problem: I have a file containing a list of words. I want to sort it in reverse order and print it.

Solution:

$ cat myfile.txt | sort -r | lpr

14.Problem: my data file has some repeated lines! How do I get rid of them?

Solution:

$ sort datafile.dat | uniq > newfile.dat

15.Problem: I have a text file containing the word 'entropy' in this directory, is there anything like SEARCH?

Solution: yes, try

$ grep -l 'entropy' *

---

how to create ec2 instance with terraform

vi instance.tf change access key and secret key and save it then terraform init then terraform apply then terraform show cd .. cd demo-1 it will show provider.tf instance.tf vars.tf we need to create a file so for that we open cat vars.tf we need to edit (vi terraform.tfvars)

AWS_ACCESS_KEY="AKIAJ4EZGWG2HDVC3KHQ" AWS_SECRET_KEY="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" AWS_REGION="us-east-1"

then cat terraform.tfvars(to see)

--->cat provider.tf ----->cat vars.tf ---->terraform init ---->terraform apply

------->open cd demo-2 in this cp ../demo-1/terraform.tfvars . cat vars.tf cat provider.tf cat script.sh vi script.sh------> change this sleep time 5 cat instance.t terraform init then we need to generate key ssh-keygen.exe -f mykey cp mykey mykey.pem terraform.exe apply to login instance do this chmod 400 mykey.pem ssh -i mykey.pem ubuntu@172.31.82.116

-------->packer......... cd packer-demo ls-ltr cat build-and-launch.sh cat packer-example.json ls -ltrh cat key.tf cp ../demo-2/mykey* . ls -ltrh cp ../demo-2/terraform.tfvars . ./build-and-launch.sh vi packer-example.json enter access and secret keys ./build-and-launch.sh

---------------vedios----------------------------

https://s3.amazonaws.com/aws-videos1/spinnaker_setup.wrf https://s3.amazonaws.com/aws-videos1/log_analysis.wrf https://s3.amazonaws.com/aws-videos1/pkr_tf.wrf

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