What is contract testing

What is contract testing?

Contract testing is famous in microservices world. When we consider less numbers of microservices,  then contract testing is not so necessary.However when you look at the Amazon or Netflix microservices mesh, it is countless. Such cases it is extremely difficult for developer or tester to maintain unit/automation test suite as per the microservices development chnages.
Contract testing is the best possible solution currently offered for this situation. In contract testing, a mocked service is created to represent the provider.  There are commercial or opensource tools available to stimulate this. In short, contract is set of predefined requests and responses created by automation or developer team to do their testing.

How to read pdf content in java for automation project

How to read pdf content in java?

Apache PDFBox and FontBox jar available can be useful here. Add these two libraries to your Maven Pom.xml or build.gradle dependencies.
Then write java code to parse your PDF files to create POJOs.
What is POJO in javaPOJO stands for Plain java object and it has not restrictions or class path dependency.

What is google App Engine

What is Google’s App Engine ?

Google provides platform as service or PaaS via Google’s App Engine.App Engine is a cloud computing platform where development and hosting of applications can be done.Other feature is App engine scales up on demand basis when the requests are more.
App Engine supports almost all development technologies like Go, Java , Python, .NET, ruby.
Python web frameworks like Flask, Django all can run on App Engine.

What is ELK

What is ELK (Elastic search, Logstash, Kibana) ?

ELK stack is a combination of 3 open-source products as below,

  1. Elasticsearch, a search and analytics engine.
  2. Logstash, that index the data to Elasticsearch. Logstash has a config file that has input,filter and output section. Config file looks like json file.
  3. Kibana, a visualization tool which provides a web based GUI for a user. User can design the bar, plot reporting charts.
    In order to make Kibana and Elasticsearch interact, you need to make both server up and running. Then logstash will index the data to Elasticsearch. 
    Then Kibana would read the data from Elasticsearch and visualize it.

DevOps vs DevSecOps vs NetOps

What is DevOps vs DevSecOps vs NetOps ?

DevOps is the practice of using set of tools, processes and practices to get good agility in software implementation to customers. It combines Dev (software development ) and Ops (information operations). DevOps shortens the development lifecycles and provides Continous Integration & Delivery. 
DevSecOps is when security features are included in DevOps CI/CD flow.
NetOps is when network services are packaged to DevOps.

Jenkins job vs pipeline

What is Jenkins jobs and Jenkins pipeline ?

Jenkins jobs and Jenkins pipeline are essentially same, however pipeline is more staged flow of jobs. For Jenkins pipeline, Jenkinsfile is used.
What is Jenkinsfile?Jenkinsfile is a text file placed in the root project directory. The Jenkinsfile has multiple stages like build, unit test, sonar test, functional,  regression, integration,  performance testing, deployment etc.

What is Apache Kafka

Whats is Apache Kafka and Linkedin’s Initial contribution?

Apache Kafka was built by LinkedIn initially and then offered to Apache Foundation. Development was done using Java and Scala.
Why Kafka is able to handle high volume transactions?
Kafka is meant to handle high volume fractions as the way it is architectured. Message key value pairs are called as “procedures” in Kafka. The data are “partition”ed with in Kafka “topics”
Messages are strictly indexed with timestamps.
What is Kafka brokers ?Kafka brokers are clusters of one more servers. Kafka Partitions of topics are distributed across clusters.
Kafka is more effective compared to Java messaging services (JMS) or Advanced message queuing protocol (AMQP).

What is Flagger

What is Flagger and how that is used in cloud ?

Flagger works are controller of the deployment workflow and helps automating the promotion of canary deployments. It utilizes the Istio’s and Prometheus metrics for analyzing application behaviors.
What is Istio ?
Istio is an open source service mesh that allows you to connect, monitor, secure your microservices deployment on premises or in cloud or in Kubernetes orchestration platforms.
What is Prometheus?Prometheus tracks events and helps as an alerting software. 

What is docker daemon

What is Docker Daemon ?

In short, docker daemon acts as a server and exposes APIs to Docker client CLI and other third parties consumers. Altogether docker architectured as a client server based implementation.
Let’s also understand the basics about how docker works 
Docker is a platform which allows DevOps teams to package the applications and run in containers.
These docker containers talks directly to Operating system kernel to perform activities and keeps the applications and dependencies independently from machines. Docker container can even  run on Virtual machines as well. 
What is Kernel ?
Kernel is the core of any Operating system. Kernel has complete control on OS and connects hardware  and softwares.

What is Ansible roles

What is Ansible roles ?

Ansible roles are used to break the Ansible playbooks into multiple files. Usually an Ansible developer may have a tendency to write large single playbooks that adds complexity and that is when Ansible roles would come into real help.
Ansible molecules are used to create the ansible roles. 
How to install Ansible Molecule:pip install molecule 
How to verify the molecule version:$ molecule –version result : molecule, version 2.19.0
What is Ansible galaxy?
Ansible galaxy is site where the ansible developers collaborate to share ansible roles via installing roles, managing roles etc.
How to Initialize a role using Molecule ?Molecule could init a role. The init command can internally access Ansible galaxy. So molecule can generate a directory which has a directory with default as name. Inside that default directory,  test build and run can be performed using docker container.Molecule.yml will have all test scenarios like how to lint and test the roles and playbook.yml is used to test the roles.