This is a sample application used to demonstrate how to create dockerized apps and deploy them to Kubernetes cluster.
It takes a sample ASP.NET Core MVC app, creates its Dockerfile, then the Kubernetes deployment objects.
The Dockerfile is used to build the app from source code. Then runs the app inside a docker container.
The k8s objects defined in YAML files are used to deploy the app into a Kubernetes cluster. These files are:
- mvc-deployment.yaml: used to create a Deployment and a Service to run the app.
- mssql-deployment.yaml: used to create a Deployment and a Service to run the SQL Server container.
- mssql-config-map.yaml: creates a ConfigMap object to store the database connection string as key-value pair. It is accessed by the app to retrieve the connection string as apass it as environment variable.
- mssql-secret.yaml: creates a Secret to securely save database connection string as key-value pair.
- mssql-pv.azure.yaml: creates PersistentVolume and PersistentVolumeClaim objects in order to provision a storage space to save the database files.
1.1) The vision: Microservices on Docker containers on Kubernetes hosted on the Cloud and powered by DevOps.
1.2) Learn more about Kubernetes architecture:
1.3) Learn more about Kubernetes objects: Deployment, Service, ConfigMap, Secret, PersistentVolume...
Inside the MvcApp folder, we have a sample ASP.NET Core MVC application that displays web pages and connects to a Database. The goal here is to run this application in a Docker container. For that, we need the Dockerfile which describes the instructions to build/compile app from source code and deploy it into a base image that have .NET Core SDK and Runtime.
2.0) Install Docker into your machine Make sure you have Docker installed and running in your machine: Docker Desktop
2.1) Start Docker in your machine and check if it runs successfully by deploying a sample image called hello-world:
$ docker run hello-world
Hello from Docker!
This message shows that your installation appears to be working correctly.
2.2) Create Docker image
$ cd MvcApp
$ docker build . # don't forget the dot at the end to configure thecontext!
$ docker build --rm -f "Dockerfile" -t mvc-app:1.0 .
2.3) List the created image
$ docker images
2.4) Run the created image
$ docker run --rm -d -p 5555:80/tcp mvc-app:1.0
2.5) List the running image
$ docker ps
2.6) Open browser on localhost:5555 and note how the app doesn't connect to database despite it is configured to!!
2.7) Configure and start SQL Server on container
$ docker run -e 'ACCEPT_EULA=Y' -e 'SA_PASSWORD=@Aa123456' -p 1433:1433 -d mcr.microsoft.com/mssql/server:2019-CU4-ubuntu-16.04 When dealing with multiple containers, Docker Compose becomes really useful. It allows to define the configuration in a single file. This file then will be used to build, deploy and stop all the images using docker-compose CLI. Open the docker-compose.yaml file. Note how we are defining 2 services: one to run the web app and a second one to deploy the database.
3.1) Build the Docker Compose file to create the images
$ docker-compose build
3.2) Run the Docker Compose file to run the created images
$ docker-compose up
Starting sqldb-k8s ... done
Starting mvcapp-k8s ... done Now that we have created the docker image in our machine, we want to deploy it into Kubernetes. But, Kubernetes should get that image through a Container Registry. Container Registry is a like a database for all our containers. We can use Azure ACR or Docker Hub... We'll continue with Docker Hub. Make sure you create a an account here hub.docker.com and take note of your Docker Hub ID (Registry name).
4.1) Create a variable to hold our Registry name
$ $registry="REPLACE_WITH_YOUR_DOCKER_HUB_ID"
4.2) Tag the image by appending the registry name
$ docker tag mvc-app:1.0 $registry/mvc-app:1.0
4.3) Login to Docker Hub and enter your login and password
$ docker login
4.4) Push the image into the registry
$ docker push $registry/mvc-app:1.0
4.5) Check your hub.docker.io, you should see the image uploaded into a repository5.1) Start the Dashboard
5.2) $ minikube start
5.3) $ minikube dashboard 6.1) $ Kubectl run …
6.2) $ kubectl get deployments
6.3) $ kubectl get secrets
6.4) $ kubectl get services 7.1) $ kubectl apply -f mssql-secret.yaml
$ kubectl get secrets
7.2) $ kubectl apply -f mssql-pv.azure.yaml
$ kubectl get pv
7.3) $ kubectl apply -f mssql-deployment.yaml
$ kubectl get deployments
7.4 $ kubectl apply -f mvc-deployment.azure.yaml
$ kubectl get deployments
7.5) $ minikube config set memory 4096 # if we need to resize minikube
7.6) $ kubectl delete services,deployments,pvc,secrets --all -n default8.1) $ az group create \
--location westeurope \
--subscription "Microsoft Azure Sponsorship" \
--name aks-k8s-rg
8.2) $ az aks create \
--generate-ssh-keys \
--subscription "Microsoft Azure Sponsorship" \
--node-count 1 \
--resource-group aks-k8s-rg \
--name aks-k8s
8.3) $ az aks get-credentials \
--resource-group aks-k8s-rg \
--name aks-k8s \
--subscription "Microsoft Azure Sponsorship"
Merged "aks-k8s" as current context in /Users/houssem/.kube/config
8.4) $ kubectl create clusterrolebinding kubernetes-dashboard \
--clusterrole=cluster-admin \
--serviceaccount=kube-system:kubernetes-dashboard
8.5) $ az aks browse \
--resource-group aks-k8s-rg \
--name aks-k8s \
--subscription "Microsoft Azure Sponsorship" 
9.1) CI pipeline: builds the container and pushes it to docker hub.
9.2) CD pipeline: deploys the YAML manifest files into Kubernetes cluster.
scalability, health check, mounting volume, resource limits, service discovery, deploy with Helm...
eShopOnContainers: https://github.com/dotnet-architecture/eShopOnContainers
https://www.udemy.com/kubernetes-for-developers/ Please email me if you want a free coupon :)
