Master

• Api server -> POD -> Container -> Docker image –> Google Registry
  • validates and configures data for API objects, including pods and services. The API Server provides the frontend to the cluster’s shared state, which is where all of the other components interact

• Etcd -> POD -> Container -> Docker image –> Google Registry
  • etcd is a distributed key-value store and the primary datastore of Kubernetes. It stores and replicates the Kubernetes cluster state.

• Controller mgmr -> POD -> Container -> Docker image –> Google Registry
  • Collection of controllers bundled within a single binary and run in a single process.
• Schedular -> POD -> Container -> Docker image –> Google Registry
  •  to assign pods to nodes within your cluster. The scheduler will use information such as compute requests and limits defined within your workload (if any), as well as finding the right node candidate based on its available resources to appropriately assign your workload to a particular node.
• kubelet
  • agent within nodes and is responsible for the runnings of pod cycles within each node. Its functionality is watching for new or changed pod specifications from master nodes and ensuring that pods within the node that it resides in are healthy, and the state of pods matches the pod specification.
• docker
• kube proxy -> POD -> Container -> Docker image –> Google Registry
  •  network proxy that runs on each node. It maintains network rules, which allow for network communication to Pods from network sessions inside or outside of a cluster. 
• kubectl
• kubeadm

Worker

• kubelet
• docker
• kube proxy -> POD -> Container -> Docker image –> Google Registry
• kubectl
• kubeadm

Workstation

• kubectl

1. Docker Image is a collection of file system rootfs (base) + ufs + appfs

2. 1 COPY of image of get mounted to each container.

3. Image name is the same as repo name

4. repo can be stored in registry (dockerhub etc)

5. Docker images contains multiple file system and each file system is referred to as layer.

6. Base layer is always — root file system

7. When we create a container – all layers are merged into 1 layer and that get mounted to container.

8. In case of conflict between a layers – top layer always win. this means that suppose 2 layers have a file with the same name then the file which is in the upper layer will be the one that will appear in the merged layer

9. If we stop the container : merge layer disappears

10. Each layer of a Docker image is viewable under /var/lib/docker

wait: Block until one or more containers stop, then print their exit codes

in other terminal, if we stop the container, then will get the status code 0

update:

 docker update [OPTIONS] CONTAINER [CONTAINER...]

docker inspect

docker update

similarly we can do for other configurations as well

• Install Docker in your assigned VM?
  • Installed the Docker in the VM. — [root@ip-172-31-8-134 centos]
  • Verification:
• Verify docker installation and basic commands?

• Self proov it – What is Container?

• Playing with different Docker commands:-

Container Lifecycle?

create -> start -> stop -> start -> restart -> pause -> unpause -> kill -> remove

Create a container:

Pulling a jenkins image.:

• start a container:

• stop the container

• start and restart

• pause and unpause a container:

• kill a container

• rename

• remove

• What is the diff between docker pause and docker unpause?

unpause container : un-suspends the processes

• What is the diff between docker stop and docker kill?

docker stop will stop the container and docker kill will release the resources.

& publish and share a url in the chat windows.