Improve Utilization of Hardware more efficient than VM
Common Docker Commands
Give Tag
Build Image
Images Command
Run a Container
Push and Pull Commands
(Alternative Rocket is used compared to Docker)
Docker file is the blueprint for an image
Image is an Immutable file that contains everything necessary to run an application
Images are read only , Writeable Layer is placed on top to write files
Layers can be shared between images which can save disk space and network bandwidth
Dockerfile Instructions
From : Define Base Images (OS)
Run : execute code
ENV : set environment variables
ADD and COPY : copy files and directories
CMD : define the default command for the execution of the container , there can be only one command in case there are many only the last one will be executed
Container Registry
Distribution of named container images
PUSH , PULL registry
Image Naming
hostname/repository:tag
tag can be version number of OS version etc
Running Containers
# Check Docker is installed
docker --version
# use docker CLI to list the images :
docker images
# pull Hello World Docker Image
docker pull hello-world
# Run the hello World image
docker run hello-world
# List the containers to see that your container ran and exited successfully.
docker ps -a
# Remove the Docker Container
# container ID optained from above command
docker container rm <container_id>
# Run the Following Image
docker build . -t myimage:v1
#build from $code Dockerfile
docker build -t myfirstship .
#Run Docker Image (Static Port same)
docker run -d -p 80:80 myfirstship
#Run Another Instance of the Same thing (Random port)
docker run -d -p myfirstship
# Run the Image as Container (8888 -> 80)
docker run -p 8888:80 myimage:v1
# In another terminal ping the container
curl localhost:8080
# Stop the Docker Container
docker stop $(docker ps -q)
Deleting Docker
- list all docker downloaded images
$ docker images -a
- Removing all the docker downloaded images
$ docker rmi $(docker images -a -q)
Docker Command Sheet
# Install docker
sudo apt-get get install docker.io
# list Docker version
sudo docker --version
# Download and create a docker image with ubuntu latest version
sudo docker run --name myubuntu ubuntu:latest
# list all the docker images
sudo docker ps -a
# run and -it is to atach the new container terminals
sudo docker run -it --name myubuntu1 ubuntu:latest
# connect to docker terminal
sudo docker attach myubuntu1
# cntl q command to exit
# Display the working directory of the container
sudo docker exec myubuntu1 pwd
# Display the environment variable of the container
sudo docker exec myubuntu echo $PATH
# List all the Running containers
sudo docker ps -a
# List all docker ID
docker ps -aq
# remove all docker container at once
docker rm $(docker ps -aq)
# Delete a container -f is for force remove
sudo docker rm -f myubuntu
# Run Container that runs in background
sudo docker run -d --name myubuntu ubuntu:latest
# Map port
sudo docker run -d -p 8080:80 myubunut
# docker terminal connect
docker exec -it <id> bash
# Rename docker image
docker rename <old_name> <new_name>
********************************************************
# Load project in Docker Volume
docker exec -it new_site bash
- create a folder inside for project
- Load the project
- exit the project using " exit"
# create a folder in local machine and create a folder
# -v is for refering to a volume -p port
docker run -d -p 8081:80 --name website2 -v $(pwd):/website nginx
# For Windows
docker run -d -p 8080:80 --name website2 -v "%cd%":/usr/share/nginx/html nginx
# verify the container
docker exec -it website2 bash
--------------------------------------------------------
# Create docker volume
docker volume create my-vol
#inspect docker volume
docker inspect my-vol
# Attach the docker volume to the contianer
# mapping multiple ports
# adding the volume <vol_name>:path in container to copy volume data
docker run -d --name myimage -p 5000:5000 -p 8087:8000 -v my-vol:/var/jenkins myImage
---------------------------------------------------------------------
# Copy Data from container to Host
# Create the folder
mkdir data
# copying the data from container to host
docker cp myImage:/var/jenkins_home ./data
--------------------------------------------------------------------
# Create Image tar file from docker image in current path
docker save myImage/myapp > webapp.tar
# Load Tar file as docker image
docker load -i webapp.tar
---------------------------------------------------------------------
# Create Image Tar of the system
# create an ubuntu image
docker run -it --name myUbuntu ubuntu
# Create Tar file
docker export myUbuntu > newsystem.tar
# Unzip from Tar file back
sudo docker import - myImnage/ubuntu < newsystem.tar
Troubleshooting and Monitoring Containers
# Stats for the docker
docker stats
docker logs <id>
# Docker Run Python 3.6
docker --rm -ti python:3.6 python
# Docker Run Python 2.7
docker run --rm -ti python:2.7 python
# Run Jupyter Notebook
docker run --rm -p 8888:8888 jupyter/scipy-notebook
Docker CheatSheet
// Destory all
$ docker prune
// run hello world
$ docker run hello-world
Container Orchestration
manage lifecycle of containers ,in dynamic environments
using Kubernetes
Kubernetes Architecture
Labels / Selectors and Namespace in Cluster
Pod in Cluster
Wrapper for a Single Container
Replica set for Horizontal Scaling
specified using YAML file
Imperative Commands
Declarative Commands
Apply Command
Use the kubectl CLI
Create a Kubernetes Pod
Create a Kubernetes Deployment
Create a ReplicaSet that maintains a set number of replicas
Witness Kubernetes load balancing in action
# Verify the kubectl
kubectl version
#kubectl requires configuration so that it targets the appropriate cluster. Get cluster information with the following command:
kubectl config get-clusters
# A kubectl context is a group of access parameters, including a cluster, a user, and a namespace. View your current context with the following command:
kubectl config get-contexts
#List all the Pods in your namespace
kubectl get pods
#describe pods
kubectl describe pod hello-world
# Delete the Pod
kubectl delete pod hello-world
# Imperatively create a Pod using the provided configuration file.
kubectl create -f hello-world-create.yaml
#Use the kubectl apply command to set this configuration as the desired state in Kubernetes
kubectl apply -f hello-world-apply.yaml
#List Services in order to see that this service was created
kubectl get services
#Delete the Deployment and Service
kubectl delete deployment/hello-world service/hello-world
Managing Applications with Kubernetes
# Build an Image
docker build -t us.icr.io/$MY_NAMESPACE/hello-world:1 . && docker push us.icr.io/$MY_NAMESPACE/hello-world:1
# Run Image as Deployment
kubectl apply -f deployment.yaml
# Access the Application
kubectl expose deployment/hello-world --type=NodePort --port=8080 --name=hello-world --target-port=8080
# Scale up deployment
kubectl scale deployment hello-world --replicas=3
#scale down deployment
kubectl scale deployment hello-world --replicas=1
# Getting Rollout Update
kubectl rollout status deployment/hello-world
# Create a ConfigMap that contains a new message
kubectl create configmap app-config --from-literal=MESSAGE="This message came from a ConfigMap!"
# Build and push a new image that contains your new application code
docker build -t us.icr.io/$MY_NAMESPACE/hello-world:3 . && docker push us.icr.io/$MY_NAMESPACE/hello-world:3
# delete the old ConfigMap and create a new one with the same name but a different message
kubectl delete configmap app-config && kubectl create configmap app-config --from-literal=MESSAGE="This message is different, and you didn't have to rebuild the image!"
# Restart the Deployment so that the containers restart
kubectl rollout restart deployment hello-world
# Delete the Deployment
kubectl delete -f deployment-configmap-env-var.yaml
Openshift Architecture
Source to Image
Build Triggers
Istio
Cloud Native computing Foundation
Redhat Openshift (Code snippets)
Use the oc CLI
Use the OpenShift web console
Build and deploy an application using s2i
Inspect a BuildConfig and an ImageStream
# Check OC version
oc version
# List the pods in the Namespace
oc get pods
# In addition to Kubernetes objects, you can get OpenShift specific objects.
oc get buildconfigs
# View the OpenShift project that is currently in use.
