Achieve SSO in Privately Hosted Jenkins

Introduction

Providing OAuth 2.0 user authentication directly or using Google+ Sign-in reduces your CI overhead. It also provides a trusted and secure login system that’s familiar to users, consistent across devices, and removes the burden of users having to remember another username and password. One of the hurdles in implementing a Gmail authentication is that Google developer console and your Jenkins server should be in the same network or in simple terms they can talk to each other.

Resources Used

Privately Hosted Jenkins
Google developer console
Ngrok

In this blog, I’m trying to explain how to integrate Gmail authentication feature in your privately hosted Jenkins server so that you get free of filling the form by the time of creating a new user.

Setup 1: Setup Ngrok

NGROK

Ngrok is multiplatform tunneling, reverse proxy software that establishes secure tunnels from a public endpoint such as the internet to a locally running network service while capturing all traffic for detailed inspection and replay.

We are using Ngrok to host our Jenkins service (running on port 8080) to public IP.

Go to google and search for Download Ngrok.

Either Login with google account or do Ngrok own signup.

After Logged in Ngrok Download it.

After Download Ngrok, Go to the console and unzip the downloaded zip file and then move it to /usr/local/bin.

Note: Moving part is optional, we do so for accessing ngrok from anywhere.

Go to ngrok UI page , copy the authentication key and paste it.

Note: Remove ” . / ” sign because we moved ngrok file to /usr/local/bin

Major configuration for Ngrok is done. Now type the command:

ngrok http 8080

Assuming that Jenkins is running on port 8080.

Now Ngrok Host our Jenkins Service to public IP.

Copy this IP, we will use it in the google developer console.

Note: Make this terminal up and running.(don’t do ctrl+c)

Step 2: Setup Google Developer Console

Go to google and search for google developer console.

After sign in into google developer console, we will redirect to Google developer console UI screen.

Go to Select a project → New Project

Give Project Name, here I will use “JenkinsGmailAuthentication” and create a project. Creating a project takes 1 or 2 minutes.

After Project created, we will be redirected to the UI page as shown below. Now click on on the “Credentials” Tab on the left slide bar.

After Go to the OAuth consent screen tab and give the below entries. Here I will give Application name to “JenkinsGmailAuthentication”.

The important part of the Google developer console is Public IP we created using Ngrok. Copy Public IP in Authorized domains and note to remove ” http:// ” in Authorized domains.

After Setting OAuth consent screen, Go to “Credentials Tab”→ Create Credentials→OAuthClientID

Select Application type as Web Application, give the name “JenkinsGmailAuthentication”.

Major Part of Create Credential has Authorized JavaScript origins and Authorized redirect URIs.

Copy Client ID and Client Secret because we are going to use these in Jenkins.

Step 3: Setup Jenkins

I am assuming that Jenkins is already installed in your system.

Go to Manage Jenkins → Manage Plugins→ Available

Search for “Google Login Plugin” and add it.

Go to Manage Jenkins → Configure Global Security

The major part of Jenkins Setup is to Configure Global Security.

Check the Enable security → Login with Google and Paste the Client ID and Client secret generated in Create Credential Step and Save.

Up to here, we are done with the Setup part.

Now Click on login button on Jenkins UI, you will redirect to Gmail for login.

Select the account from which you want to log in.

After selecting Account you will redirect to Jenkins and you are logged in as selected user.

You may be facing a problem when you log in again.

Logout from the current user and login again.

After redirected to Gmail select another user.

After selecting user you will be redirected to Error Page showing: HTTP ERROR 404.

Don’t worry, you have to just remove “securityRealm/” or enter again “localhost:8080”.

You are logged in with the selected user.

So now you know how to do Gmail Authentication between Google developer console and Jenkins when they are not directly reachable to each other.

Here the main bridge between both is Ngrok which host our Privately hosted Jenkins to outer internet.

Unix File Tree Part-2

For those who have surfed straight to this blog, please check out the previous part of this series Unix File Tree Part-1 and those who have stayed tuned for this part, welcome back.In the previous part, we discussed the philosophy and the need for file tree. In this part, we will dive deep into the significance of each directory.

Image result for horizontal file tree linux

Dayum!! that’s a lot of stuff to gulp at once, we’ll kick out things one after the other.

Major directories

Let’s talk about the crucial directories which play a major role.

/bin: When we started crawling on Linux this helped us to get on our feet yes, you read it right whether you want to copy any file, move it somewhere, create a directory, find out date, size of a file, all sorts of basic operations without which the OS won’t even listen to you (Linux yawning meanwhile) happens because of the executables present in this directory. Most of the programs in /bin are in binary format, having been created by a C compiler, but some are shell scripts in modern systems.

/etc: When you want things to behave the way you want, you go to /etc and put all your desired configuration there (Imagine if your girlfriend has an /etc life would have been easier). whether it is about various services or daemons running on your OS it will make sure things are working the way you want them to.

/var: He is the guy who has kept an eye over everything since the time you have booted the system (consider him like Heimdall from Thor). It contains files to which the system writes data during the course of its operation. Among the various sub-directories within /var are /var/cache (contains cached data from application programs), /var/games(contains variable data relating to games in /usr), /var/lib (contains dynamic data libraries and files), /var/lock (contains lock files created by programs to indicate that they are using a particular file or device), /var/log (contains log files), /var/run (contains PIDs and other system information that is valid until the system is booted again) and /var/spool (contains mail, news and printer queues).

/proc: You can think of /proc just like thoughts in your brain which are illusions and virtual. Being an illusionary file system it does not exist on disk instead, the kernel creates it in memory. It is used to provide information about the system (originally about processes, hence the name). If you navigate to /proc The first thing that you will notice is that there are some familiar-sounding files, and then a whole bunch of numbered directories. The numbered directories represent processes, better known as PIDs, and within them, a command that occupies them. The files contain system information such as memory (meminfo), CPU information (cpuinfo), and available filesystems.

/opt: It is like a guest room in your house where the guest stayed for prolong period and became part of your home. This directory is reserved for all the software and add-on packages that are not part of the default installation.

/usr: In the original Unix implementations, /usr was where the home directories of the users were placed (that is to say, /usr/someone was then the directory now known as /home/someone). In current Unixes, /usr is where user-land programs and data (as opposed to ‘system land’ programs and data) are. The name hasn’t changed, but its meaning has narrowed and lengthened from “everything user related” to “user usable programs and data”. As such, some people may now refer to this directory as meaning ‘User System Resources’ and not ‘user’ as was originally intended.

Potato or Potaaato what is the difference?

We’ll be discussing those directories which confuse us always, which have almost a similar purpose but still are in separate locations and when asked about them we go like ummmm…….

/bin vs /usr/bin vs /sbin vs /usr/local/bin

This might get almost clear out when I explained the significance of /usr in the above paragraph. Since Unix designers planned /usr to be the local directories of individual users so it contained all of the sub-directories like /usr/bin, /usr/sbin, /usr/local/bin. But the question remains the same how the content is different?

/usr/bin:

/usr/bin is a standard directory on Unix-like operating systems that contains most of the executable files that are not needed for booting or repairing the system.
A few of the most commonly used are awk, clear, diff, du, env, file, find, free, gzip, less, locate, man, sudo, tail, telnet, time, top, vim, wc, which, and zip.

/usr/sbin:

The /usr/sbin directory contains non-vital system utilities that are used after booting.
This is in contrast to the /sbin directory, whose contents include vital system utilities that are necessary before the /usr directory has been mounted (i.e., attached logically to the main filesystem).
A few of the more familiar programs in /usr/sbin are adduser, chroot, groupadd, and userdel.
It also contains some daemons, which are programs that run silently in the background, rather than under the direct control of a user, waiting until they are activated by a particular event or condition such as crond and sshd.

I hope I have covered most of the directories which you might come across frequently and your questions must have been answered.
Now that we know about the significance of each UNIX directory, It’s time to use them wisely the way they are supposed to be.
Please feel free to reach me out for any suggestions.
Goodbye till next time!

Jenkins Pipeline Global Shared Libraries

When we say CI/CD as code, it should have modularity and reusability which results in Reducing integration problems and allowing you to deliver software more rapidly.

Jenkins Shared library is the concept of having a common pipeline code in the version control system that can be used by any number of pipelines just by referencing it. In fact, multiple teams can use the same library for their pipelines.

Our thought is putting all pipeline functions in vars is much more practical approach, while there is no other good way to do inheritance, we wanted to use Jenkins Pipelines the right way but it has turned out to be far more practical to use vars for global functions.

Practical Strategy
As we know Jenkins Pipeline’s shared library support allows us to define and develop a set of shared pipeline helpers in this repository and provides a straightforward way of using those functions in a Jenkinsfile.This simple example will just illustrate how you can provide input to a pipeline with a simple YAML file so you can centralize all of your pipelines into one library. The Jenkins shared library example:And the example app that uses it:

Directory Structure

You would have the following folder structure in a git repo:

└── vars
    ├── opstreePipeline.groovy
    ├── opstreeStatefulPipeline.groovy
    ├── opstreeStubsPipeline.groovy
    └── pipelineConfig.groovy

Setting up Library in Jenkins Console.

This repo would be configured in under Manage Jenkins > Configure System in the Global Pipeline Libraries section. In that section Jenkins requires you give this library a Name. Example opstree-library

Pipeline.yaml

Let’s assume that project repository would have a pipeline.yaml file in the project root that would provide input to the pipeline:Pipeline.yaml

ENVIRONMENT_NAME: test
SERVICE_NAME: opstree-service
DB_PORT: 3079
REDIS_PORT: 6079

Jenkinsfile

Then, to utilize the shared pipeline library, the Jenkinsfile in the root of the project repo would look like:

@Library ('opstree-library@master') _
opstreePipeline()

PipelineConfig.groovy

So how does it all work? First, the following function is called to get all of the configuration data from the pipeline.yaml file:

def call() {
  Map pipelineConfig = readYaml(file: "${WORKSPACE}/pipeline.yaml")
  return pipelineConfig
}

opstreePipeline.groovy

You can see the call to this function in opstreePipeline(), which is called by the Jenkinsfile.

def call() {
    node('Slave1') {

        stage('Checkout') {
            checkout scm
        }

         def p = pipelineConfig()

        stage('Prerequistes'){
            serviceName = sh (
                    script: "echo ${p.SERVICE_NAME}|cut -d '-' -f 1",
                    returnStdout: true
                ).trim()
        }

        stage('Build & Test') {
                sh "mvn --version"
                sh "mvn -Ddb_port=${p.DB_PORT} -Dredis_port=${p.REDIS_PORT} clean install"
        }

        stage ('Push Docker Image') {
            docker.withRegistry('https://registry-opstree.com', 'dockerhub') {
                sh "docker build -t opstree/${p.SERVICE_NAME}:${BUILD_NUMBER} ."
                sh "docker push opstree/${p.SERVICE_NAME}:${BUILD_NUMBER}"
            }
        }

        stage ('Deploy') {
            echo "We are going to deploy ${p.SERVICE_NAME}"
            sh "kubectl set image deployment/${p.SERVICE_NAME} ${p.SERVICE_NAME}=opstree/${p.SERVICE_NAME}:${BUILD_NUMBER} "
            sh "kubectl rollout status deployment/${p.SERVICE_NAME} -n ${p.ENVIRONMENT_NAME} "

    }
}

You can see the logic easily here. The pipeline is checking if the developer wants to deploy on which environment what db_port needs to be there.

Benefits

The benefits of this approach are many, some of them are as mentioned below:

How to write groovy code is now none of the developer’s perspective.
Structure of the Pipeline.yaml is really flexible, where entire data structures can be passed as input to the pipeline.
Code redundancy saved to a large extent.

Jenkinsfiles could actually just look more commonly, like this:

@Library ('opstree-library@master') _
opstreePipeline()

and opstreePipeline() would just read the the project type from pipeline.yaml and dynamically run the exact function, like opstreeStatefulPipeline(), opstreeStubsPipeline.groovy() . since pipeline are not exactly groovy, this isn’t possible. So one of the drawback is that each project would have to have a different-looking Jenkinsfile. The solution is in progress!So, what do you think?

Reference links:
Image: Google image search (jenkins.io)

AWS RDS cross account snapshot restoration

Many a times you may have faced problem where your production infra is on different AWS account and non prod on different account and you are required to restore the RDS snapshot to non prod account for testing.

Recently I got a task to restore my prod account RDS snapshot to a different account for testing purpose. It was a very interesting and new task for me. and I was in an awe, how AWS thinks about what all challenges we may face in real life and provides a solution to it.

For those who are not aware about RDS, I can brief RDS as a relational database service by Amazon Web Services (AWS), it is a managed service so we don’t have to worry about the underlying Operating System and Database software installation, we just have to use it.

Amazon RDS creates a storage volume snapshot of your DB instance backing up the entire DB instance and not just individual database. As I told you, we have to copy and restore an RDS snapshot to a different aws account. There is a catch!, you can directly copy an aws snapshot to a different region in same aws account, but to copy to a different aws account you need to share the snapshot to aws account and then restore from there, so lets begin.

To share an automated DB snapshot, create a manual DB snapshot by copying the automated snapshot, and then share that copy.

Step 1: Find the snapshot that you want to copy, and select it by clicking the checkbox next to it’s name. You can select a “Manual” snapshot, or one of the “Automatic” snapshots that are prefixed by “rds:”.

Step 2: From the “Snapshot Actions” menu, select “Copy Snapshot”.

Step 3: On the page that appears: Select the target region. In this case, since we have to share this snapshot with another aws account we can select existing region.

Specify your new snapshot name in the “New DB Snapshot Identifier” field. This identifier must not already be used by a snapshot in the target region.
Check the “Copy Tags” checkbox if you want the tags on the source snapshot to be copied to the new snapshot.
Under “Encryption”, leave “Disable Encryption” selected.
Click the “Copy Snapshot” button.

Step 4: Once you click on “Copy Snapshot”, you can see the snapshot being created.

Step 5: Once the manual snapshot is created, select the created snapshot, and from the “Snapshot Actions” menu, select “Share Snapshot”.

Step 6: Define the “DB snapshot visibility” as private and add the “AWS account ID” to which we want to share the snapshot and click on save.

Till this point we have shared our db snapshot to the aws account where we need to restore the db.
Now login to the other aws account and go to RDS console and check for snapshot that was shared just recently.

Step 7: Select the snapshot and from the “Snapshot Actions” menu select “Restore Snapshot”.

Step 8: From here we just need to restore the db as we do normally. Fill out the required details like “DB Instance class”, “Multi-AZ-Deployment”, “Storage Type”, “VPC ID”, “Subnet group”, “Availability Zone”, “Database Port”, “DB parameter group”, as per the need and requirement.

Step 9: Finally click on “Restore DB instance” and voila !!, you are done.

Step 10: You can see the db creation in process. Finally, you have restored the DB to a different AWS account !!

Conclusion:

So there you go. Everything you need to know to restore a production AWS RDS into a different AWS account. That’s cool !! Isn’t it ?, but I haven’t covered everything. There is a lot more to explore. We will walk through RDS best practices in our next blog, till then keep exploring our other tech blogs !!.

Image source: https://unsplash.com/photos/lRoX0shwjUQ

Why I love pods in Kubernetes? Part – 1

When I began my journey of learning Kubernetes, I always thought why Kubernetes has made the pod its smallest entity, why not the container. But when I started diving deep in it I realized, there is a big rationale behind it and now I thank Kubernetes for making the Pod as an only object, not containers.

After being inspired by the working of a Pod, I would like to share my experience and knowledge with you guys.

What exactly Pod means?

The literal meaning of pod means the peel of pea which holds the beans and following the same analogy in Kubernetes pod means a logical object which holds a container or more than one container.
The bookish definition could be – a pod represents a request to execute one or more containers on the same node.

Why Pod?

The question that needs to be raised why pod?So let me clear this, pods are considered the fundamental building blocks of Kubernetes, because all the Kubernetes workloads, like Deployments, ReplicaSets or Jobs are eventually expressed in terms of pods.

Pods are the one and only objects in Kubernetes that results in the execution of containers which means No Pod No Containers !!!

Now after the context setting over pod I would like to answer my beloved question:- Why Pod over container??

My answer is why not 🙂

Let’s take an example, suppose you have an application which generates two types of logs one is access log and other logs are error log. Now you have to add log shipper agent, In case of the container, you will install the log shipper in the container image. Now you got another request to add application monitoring in the application. So again you have to recreate the container image with APM agent in it.
Don’t you think this is quite an untidy way to do it? Of course, it is, why I have to add these things in my application image, it makes my image quite bulky and difficult to manage.

What if I tell you that Kubernetes has its own way of dealing situations like this.

Yup the solution is a sidecar. Just like in real life if I have a two sitter bike and I want to take 3 persons on a ride, So I will add a sidecar in my bike to take 2 persons together on the ride.
In a similar fashion, I can do the same thing with Kubernetes as well. To solve the above problem I will just create 3 containers (application, log-shipper and APM agent) in the same pod. Now the question is how they will access the data between them and how the networking magic will happen.
The answer is quite simple containers within the pod can share Pod IP address and can listen on localhost. For volume, we can share volumes also across the containers in a pod.

The architecture would be something like this:-

Now another interesting query arises that when to use sidecar and when not.

Just as shown in the above image we should not keep application and database as a sidecar in the same pod. The reason behind it is Kubernetes does not scale a container it scales a pod. So when autoscaling will happen it scales the application as well as database which could not be required.

Instead of that, we should keep log-shippers, health-check containers and monitoring agent as a sidecar because anyhow application will scale these agents also needs to be scaled with the application.

Now I am assuming you are also madly in love with the pods.

For diving deep in the pod stay tuned for the next part of this blog Why I love pods in Kubernetes? Part – 2. In my next part, I will discuss the different phases and lifecycle of the pod and how pod makes our life really smooth.
Thanks for reading, I’d really appreciate any and all feedback, please leave your comment below if you guys have any feedback.

Cheers till the next time.