Author: continuous learner

Kubernetes (k8s) installation options Broadly k8s installation is of two types single node: This for developer purposes kind minikube multi node: This if for production Multi-node options Here we have two broader options Are the nodes maintained by you: Here we install k8s cluster you can use physical servers or virtual machines Get the nodes… Continue reading DevOps Classroom notes 17/Jun/2026

Google’s History with Containers Google has a history of running containers in their production environments To manage these containers they have orchestration platorms Omega Borg When docker was adopted, Google has created an open-source container orchestration platform called as Kubernetes and donated it to CNCF. This is written in golang Kuberentes in its early versions… Continue reading DevOps Classroom notes 15/Jun/2026

Multi-staged docker image build Java: To build java application i might need JDK Maven/Gradle To run the java application i need JRE Dotnet: To build dotnet application i need dotnet SDK To run the dotnet application i need dotnet Runtime To solve this docker introduced multi staged Docker file i.e in Dockerfile i can have… Continue reading DevOps Classroom notes 12/Jun/2026

Monolith vs Microservices Monolith A monolith is an application where all feature are deployed together as a single unit. Consider ecommerce application: we have user logins Catalog Cart Payments Orders Notification Deployement: Entire application has to be redeployed irrespective of size/volume of change Scaling: Entire application has to be scaled. docker compose for monolith version:… Continue reading DevOps Classroom notes 11/Jun/2026

Writing docker compose files We have dockerfiles where we are supposed to build docker images and bring them up Refer Here for the changes done to add a docker compose file with Docker images to build Dealing with environmental variables Refer Here for the changes.

Docker compose This lets you bring up multiple containers with simple command docker compose up -d docker compose down # bring down and remove volumes docker compose down -v To use docker compose we need to create an yaml file with name docker-compose.yml YAML file is used to represent data in the form of key… Continue reading DevOps Classroom notes 08/Jun/2026

Docker networking docker network subcommand has options to deal with docker network docker has following network drivers host bridge overlay none The default network driver is bridge, i.e. when you create containers the contianer will be part of default docker network The default bridge network allows containers to communicate over ip but name resolution cannot… Continue reading DevOps Classroom notes 05/Jun/2026

Standards in Containers OCI: Refer Here OCI Image spec OCI Runtime spec Network Standard: CNM: Docker follows CNM CNI: kubernetes follows CNI Problems Docker used the linux kernel to create containers: To solve this docker create a project called as libcontainer. Docker networking: This was part of docker daemon, Docker created libnetwork which follows CNM… Continue reading DevOps Classroom notes 04/Jun/2026

Image layers Articles Refer Here Refer Here Refer Here Storage Driver: Deals with layers How to preserve the data that is present in writable layer Identify the location Create a volume for that location Volume is a seperate space which can exist even after container is deleted. When recreating the container reuse the volume A… Continue reading DevOps Classroom notes 29/May/2026

Docker lifecycle Common docker commands A container is running and you want to see the logs docker logs <contaner-id or name> docker logs <contaner-id or name> -f Docker logs shows only stdout and stderr I want to delete all containers in my system docker rm -f $(docker ps -a -q) I want to delete all… Continue reading DevOps Classroom notes 27/May/2026