Kaniko demo

docker build -t devops-toolkit .

1. Steps to Test building a docker image inside a docker container.

minikube start

• Create a docker container: >kubectl apply -f docker.yaml
• command to wait untill pod is ready: >kubectl wait --for condition=containersready pod docker
• Open a shell on the docker container:

  apk add -U git git clone https://github.com/ezzat223/kaniko-demo.git (Don't use SSH) cd kaniko-demo/ docker build -t devops-toolkit . - It will generate this error Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

  • Finally delete the container.

2. Build docker image through Docker Socket (This is what DinD does):

• The Docker socket (/var/run/docker.sock) is a Unix socket file that the Docker daemon listens on. It allows processes to communicate with the Docker daemon to manage containers, images, networks, etc.

Docker Daemon (dockerd):

• is the core service behind Docker.
• It’s a server that runs in the background on the host machine, managing Docker containers, images, networks, and volumes.
• It listens to Docker API requests (either from docker CLI commands or external programs) and handles the lifecycle of containers.

How Docker Daemon Works:

• The Docker Daemon uses a client-server architecture.

1. Client: This is the docker command-line interface (CLI) or a program that sends requests to the daemon.
2. Server: This is the dockerd process, which listens to these API requests and processes them.

Docker Runtime (runc):

• Once the container is ready to start, the Docker Daemon hands off control to the Docker Runtime.
• The runtime interacts directly with the kernel to launch and run the container using cgroups (for resource limits) and namespaces (for isolation).
• The runtime then ensures the container continues running as expected and interacts with the kernel-level container features.

kubectl apply -f docker-socket.yml

• Open a shell on the docker container:

  apk add -U git git clone https://github.com/ezzat223/kaniko-demo.git (Don't use SSH) cd kaniko-demo/ docker build -t devops-toolkit .

  • It worked!
• Finally delete the container.

3. Build using Kaniko

• Make changes to kaniko-git.yaml by adding your GitHub and Dockerhub users instead.

git add . git commit -m "Changed registry info in kaniko-git.yaml" git push origin master