Devops Engineer

It is a YAML file consisting of all the details regarding various services, networks, and volumes that are needed for setting up the Docker-based application. So, docker-compose is used for creating multiple containers, host them and establish communication between them. For the purpose of communication amongst the containers, ports are exposed by each and every container.

1) FROM : This is used to set the base image for upcoming instructions. A docker file is considered to be valid if it starts with the FROM instruction.

2) LABEL : This is used for the image organization based on projects, modules, or licensing. It also helps in automation as we specify a key-value pair while defining a label that can be later accessed and handled programmatically.

3) RUN : This command is used to execute instructions following it on the top of the current image in a new layer. Note that with each RUN command execution, we add layers on top of the image and then use that in subsequent steps.

4) CMD : This command is used to provide default values of an executing container. In cases of multiple CMD commands the last instruction would be considered.

The different stages of the docker container from the start of creating it to its end are called the docker container life cycle.The most important stages are:

1) Created: This is the state where the container has just been created new but not started yet.
2) Running: In this state, the container would be running with all its associated processes.
3) Paused: This state happens when the running container has been paused.
4) Stopped: This state happens when the running container has been stopped.
5) Deleted: In this, the container is in a dead state.

This can be done using the docker load command and the syntax is : docker load -i .tar

Prometheus is used for Kubernetes monitoring. The Prometheus ecosystem consists of multiple components.

1) Mainly Prometheus server which scrapes and stores time-series data.
2) Client libraries for instrumenting application code.
3) Push gateway for supporting short-lived jobs.
4) Special-purpose exporters for services like StatsD, HAProxy, Graphite, etc.
5) An alert manager to handle alerts on various support tools.

The main difference between Kubernetes and Docker are :

1) The installation procedure of the K8s is very complicated but if it is once installed then the cluster is robust. On the other hand, the Docker swarm installation process is very simple but the cluster is not at all robust.

2) Kubernetes can process the auto-scaling but the Docker swarm cannot process the auto-scaling of the pods based on incoming load.

3) Kubernetes is a full-fledged Framework. Since it maintains the cluster states more consistently so autoscaling is not as fast as Docker Swarm.

CMD defines default commands and/or parameters for a container. CMD is an instruction that is best to use if you need a default command which users can easily override. If a Dockerfile has multiple CMDs, it only applies the instructions from the last one.

ENTRYPOINT is preferred when you want to define a container with a specific executable.
You cannot override an ENTRYPOINT when starting a container unless you add the --entrypoint flag.

The Namespace in Docker is a technique which offers isolated workspaces called the Container. Namespaces also offer a layer of isolation for the Docker containers.

Continuous Integration : A software development process where the changes made to software are integrated into the main code as and when a patch is ready so that the software will be always ready to be - built, tested, deployed, monitored - continuously.


Continuous Delivery : This is a Software Development Process where the continuously integrated (CI) changes will be tested & deployed continuously into a specific environment, generally through a manual release process, after all the quality checks are successful.


Continuous Deployment : A Software Development practice where the continuously integrated (CI) changes are deployed automatically into the target environment after all the quality checks are successful.

Jenkins being open-source automation can be used for any kind of software-based automation. Some of the common use-cases include but not limited to -

i) Software build jobs
ii) Sanity/Smoke/CI/Regression test jobs
iii) Web/Data Scraping related jobs
iv) Code coverage measurement jobs
v) General-purpose automation
vi) Reverse Engineering jobs
vii) Key Decoding jobs & many other jobs where software automation will be applicable.

Jenkins Pipelines can be either - a Declarative pipeline or a Scripted Pipeline. Declarative pipeline makes use of numerous, generic, predefined build steps/stages (i.e. code snippets) to build our job according to our build/automation needs whereas, with Scripted pipelines, the steps/stages can be custom-defined & used using a groovy syntax which provides better control & fine-tuned execution levels.

Git stash can be used in cases where we need to switch in between branches and at the same time not wanting to lose edits in the current branch. Running the "git stash" command basically pushes the current working directory state and index to the stack for future use and thereby providing a clean working directory for other tasks.

Git usually handles feature merges automatically but sometimes while working in a team environment, there might be cases of conflicts such as:

1) When two separate branches have changes to the same line in a file

2) A file is deleted in one branch but has been modified in the other.

These conflicts have to be solved manually after discussion with the team as git will not be able to predict what and whose changes have to be given precedence.

Conflicts occur whenever there are multiple people working on the same file across multiple branches. In such cases, git won't be able to resolve it automatically as it is not capable of deciding what changes has to get the precedence.

Following are the steps are done in order to resolve git conflicts : 

1) Identify the files that have conflicts.

2) Discuss with members who have worked on the file and ensure that the required changes are done in the file.

3) Add these files to the staged section by using the git add command.

4) Commit these changes using the git commit command.

5) Finally, push the changes to the branch using the git.

git diff : This shows the changes between commits, working trees, etc.

git status : This shows the difference between the working directory and index that is essential in understanding git in depth.

"git diff" works in a similar fashion to "git status" with the only difference of showing the differences between commits and also between the working directory and index.

Tip 1 : Prepare the points that you will speak in your introduction prior to the interview.
Tip 2 : Tell about your current cgpa, achievements and authenticated certification
Tip 3 : I told about my role in current internship and what all I do