How to set up SSH keys in Azure Repos | Setup SSH keys and Java Web App in Repos in Azure DevOps

How to set up SSH keys in Azure Repos and Setup WebApp in Azure Repo

Go to your visual studio home page. You should be able to go by clicking on the below URL.
https://dev.azure.com/

Create a new project by clicking on New project and enter project details like below. This will create a project dashboard.

Once project is created, Click on Repos.

 Click on initialize link to add README.

Click on clone link on the top right hand side.
Click on SSH link
Click Manage SSH keys

Click Add

Go to any virtual machine you had setup that has both Java and Maven installed. If you would like to know how to create a Virtual Machine in Azure Cloud, click here to do so.

Create the SSH keys by executing the below command:
(If you already have keys generated, you can overwrite it or skip to next step to copy keys)
ssh-keygen

execute the below command to copy the keys:

cat ~/.ssh/id_rsa.pub

Add the public keys.
Once keys added into Azure DevOps, go to Repos, copy the SSH clone url

Go to your machine where you have installed Java, Maven, preferably your EC2. Execute this command:
git clone <ssh_url>

This should download the empty repo from Azure DevOps to local machine(or ec2).
now after cloning, it will create a folder with repo name..

type 

ls -al to see the folder name after you cloned.

go inside that folder by
cd reponame

Now create the maven project executing the below command:
mvn archetype:generate -DgroupId=com.cf -DartifactId=MyAwesomeApp -DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false

type git status --> to see the newly created project
git add *
git status

git commit -m "my first project check-in to Azure Repos"
git push

Now go to Azure DevOps, Select the Repos —> Files —> you should see the project uploaded here.

Region does not seem to be available error for AWS module boto.ec2

When you have this error, there is a good chance that your boto version is outdated. You will have to update the boto version by executing the below command:

pip install boto

This will install latest version of Boto framework which is 2.48.0. 

you can confirm by executing the below command:

pip list boto | grep boto

boto (2.48.0)

boto3 (1.5.22)

botocore (1.8.36) 

Git Workflow and commands | Git popular commands

git init

This command turns a directory into an empty Git repository. This is the first step in creating a repository. After running git init, adding and committing files/directories is possible.

git add

Adds files in the to the staging area for Git. Before a file is available to commit to a repository, the file needs to be added to the Git index (staging area). There are a few different ways to use git add, by adding entire directories, specific files, or all unstaged files.

git commit

Record the changes made to the files to a local repository. For easy reference, each commit has a unique ID.
It’s best practice to include a message with each commit explaining the changes made in a commit. Adding a commit message helps to find a particular change or understanding the changes.

git status

This command returns the current state of the repository.

git clone

To create a local working copy of an existing remote repository, use git clone to copy and download the repository to a computer.

git fork
A fork is a copy of a repository. Forking a repository allows you to freely experiment with changes without affecting the original project.

git pull
To get the latest version of a repository run git pull. This pulls the changes from the remote repository to the local computer.

git push

Sends local commits to the remote repository. git push requires two parameters: the remote repository and the branch that the push is for.

git checkout

To start working in a different branch, use git checkout to switch branches.

git merge

Integrate branches together. git merge combines the changes from one branch to another branch. For example, merge the changes made in a staging branch into the stable branch.

git commit --amend

You can also re-write history of your most recent commit in your local git repository by using git commit --amend command.

git commit --amend

sudo: no tty present and no askpass program specified - How to fix no tty present and no askpass program specified error?

You may get this error during deployment to Tomcat from Jenkins. 

The fix for deployment to Tomcat from Jenkins is:

type --> sudo visudo

look for root and make the changes highlighted in red and save the file and re-do the deployment in Jenkins.

# User privilege specification 

root ALL=(ALL:ALL) ALL 
jenkins ALL=(ALL) NOPASSWD: ALL

How to resize memory in EC2 instance in AWS?

Please find steps below to increase or decrease memory for the EC2 instances. For example, if your t2.micro instance is too small for its workload, you can change it to an m3.medium instance.

1. Go to AWS console, choose the instance, instance state, click on stop the instance.
2. once stopped, go to Instance settings, change Instance type to desired type
3. Start the instance again.

That's it. You don't have to create a new instance. This is how you do it!

How to install Puppet on Ubuntu 16.0.4 | How to configure Puppet Master and manage nodes on Ubuntu 16.0.4 on Amazon EC2?

Puppet uses Client/Server model. The server does all the automation of tasks on nodes/servers that have a client(agent) installed. The work of the Puppet agent is to send facts to the puppet master and request a catalog based on certain interval level(default time 30 mins). Once it receives a catalog, Puppet agent applies it to the node by checking each resource the catalog describes. It makes relevant changes to attain the desired state. The work of the Puppet master is to control configuration information.  Each managed agent node requests its own configuration catalog from the master.

Please find the steps needed for Integrating Puppet master and agent on Ubuntu 16.0.4:

Pre-requisites:

a) One Ubuntu instance for Puppet Master - this instance should have 4 GB RAM. so instance type should be at least medium. Master ubuntu EC2 should have a security group to ensure that below ports are open in security firewall
        * TCP 8140 - Agents will talk to the master on this port(puppet enterprise)
        * TCP 22 - To login to the server/instance using SSH

b) one Ubuntu instance as node which will have agent installed - This can be micro instance.

1. Steps for Puppet Master
:

curl -O https://apt.puppetlabs.com/puppetlabs-release-pc1-xenial.deb
sudo dpkg -i puppetlabs-release-pc1-xenial.deb
sudo apt-get update
sudo apt-get install puppetserver

sudo ufw allow 8140
sudo systemctl enable puppetserver
          (the above command is to start the service during starting the Ubuntu instance)

sudo systemctl start puppetserver
          (The above command is for starting the server and this may take some time)
sudo systemctl status puppetserver
       you should see a message like
       puppet systemd[1]: Started puppetserver Service.
    That's it puppet master is up and running.

Now press q to come out of window.

2. Steps for Puppet Agent

Step 2.1 First edit the hosts file on the puppet agent by modifying /etc/hosts
sudo nano /etc/hosts
# Please add Puppet Master server IP address and space and enter puppet
puppet_master_ip_address   puppet

(please do not use public DNS name, use only private IP address)  

Press Ctrl O for saving and then enter
Press Ctrl X for exit after saving.

Step 2.2 — Installing Puppet Agent on server node that Puppet master will manage
wget https://apt.puppetlabs.com/puppetlabs-release-pc1-xenial.deb 

sudo dpkg -i puppetlabs-release-pc1-xenial.deb

sudo apt-get update

sudo apt-get install puppet-agent -y

sudo systemctl enable puppet

sudo systemctl restart puppet

sudo systemctl status puppet

 




Now press q to come out of window.

Step 3 - Signing certificates on Puppet Master
The first time you run the Puppet agent, it generates an SSL certificate and sends a signing request to the Puppet master. After the Puppet master signs the agent's certificate, it will be able to communicate with and control the agent node.

First list the unsigned certificates on puppet master EC2 instance

sudo /opt/puppetlabs/bin/puppetserver ca list

The above command will list agent ip address.
  "your_puppet_Agent_Ec2_private_dns_name"  (SHA256) 46:19:79:3F:70:19:0A:FB:DA:3D:C8:74:47:EF:C8:B0:05:8A:06:50:2B:40:B3:B9:26:35:F6:96:17:85:5E:7C

Now sign the Puppet agent IP address.
sudo /opt/puppetlabs/bin/puppetserver ca sign --certname "your_puppet_Agent_Ec2_private_dns_name"
 
Note: (this is NOT required)
To sign the certificates all, execute the below command.
sudo /opt/puppetlabs/bin/puppetserver ca sign —all

Revoke Certificates (NOT required)
sudo /opt/puppetlabs/bin/puppetserver ca clean hostname

Step 4 - Verifying installation by creating Manifests in Puppet Master

The puppet manifest file is the actual file which contains the configuration details for the agents. This file is centrally stored at Puppet Master.

sudo nano /etc/puppetlabs/code/environments/production/manifests/site.pp
#copy the below yellow lines in the above file
    file {'/tmp/puppet_test.txt':                        # resource type file and filename
    ensure  => present,                             # make sure it exists
    mode    => '0644',                              # file permissions
  content => "Hello from Puppet master to agent on ${ipaddress_eth0}!\n",  # Print the eth0 IP fact
    }

Press Ctrl O for saving and then enter
Press Ctrl X for exit after saving.

Step 5 - Apply Manifests in Puppet Agent
apply the changes in puppet agent by executing below command:
sudo /opt/puppetlabs/bin/puppet agent --test

 


You should see a file being modified in /tmp/puppet_works.txt in agent(node).
You can confirm by typing this command on puppet node 

sudo cat /tmp/puppet_test.txt
Hello from Puppet master to agent on IP_address!!

That's it! you have set up Puppet Master and configured agent on the target node successfully!