Overview

Prerequisites  

• Kubernetes - Kubernetes is an open source platform that automates container operations and Minikube is best for testing Kubernetes.
  
  

• Kubectl - Kubectl is command line interface to manage Kubernetes cluster either remotely or locally. To configure kubectl in your machine follow this link.

• Shared Persistent Storage - Shared Persistent Storage is permanent storage that we can attach to the Kubernetes container so that we don`t lose our data even container died. We will be using GlusterFS as a persistent data store for Kubernetes container applications.

• .NET Application Source Code - Application Source Code is source code that we want to run inside a kubernetes container.

• Dockerfile - Dockerfile contains a bunch of commands to build .NET application.

• Container-Registry - The Container Registry is an online image store for container images.

• Private Docker Hub
• AWS ECR
• Docker Store
• Google Container Registry

Create a Dockerfile

FROM microsoft/dotnet:1.1-sdk
# Setting Home Directory for application 
WORKDIR /app 

# copy csproj and restore as distinct layers
COPY dotnetapp.csproj .
RUN dotnet restore

# copy and build everything else
COPY . .
RUN dotnet publish -c Release -o out

EXPOSE 2223

ENTRYPOINT ["dotnet", "out/main.dll"]

Building .NET Application Image

$ docker build -t <name of your application>:<version of application> .

Publishing Container Image

Creating Deployment Files for Kubernetes

• Deployment File

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: <name of application>
  namespace: <namespace of Kubernetes>
spec:
  replicas: <number of application pods>
  template:
 metadata:
   labels:
    k8s-app: <name of application>
 spec:
   containers:
   - name: <name of application>
     image: <image name >:<version tag>
     imagePullPolicy: "IfNotPresent"
     ports:
      - containerPort: 2223

• Service File

apiVersion: v1
kind: Service
metadata:
  labels:
 k8s-app: <name of application>
  name: <name of application>
  namespace: <namespace of Kubernetes>
spec:
  type: NodePort
  ports:
  - port: 2223
  selector:
 k8s-app: <name of application>

Running .NET Application on Kubernetes

$ kubectl create -f <name of application>.deployment.yml
$ kubectl create -f <name of application>.service.yml

Verification

$ kubectl get po --namespace=<namespace of kubernetes> | grep <application name>

Result of above command

What is PostgreSQL?

• It runs on all major operating systems, including Linux, UNIX (AIX, BSD, HP-UX, SGI IRIX, MacOS, Solaris, Tru64), and Windows.

• It is fully ACID compliant, has full support for foreign keys, joins, views, triggers, and stored procedures (in multiple languages)

• It includes most SQL:2008 data types, including INTEGER, NUMERIC, BOOLEAN, CHAR, VARCHAR, DATE, INTERVAL, and TIMESTAMP.

• It also supports storage of binary large objects, including pictures, sounds, or video.

• It has native programming interfaces for C/C++, Java, .Net, Perl, Python, Ruby, Tcl, ODBC, among others, and exceptional documentation.

Prerequisites

• Kubernetes Cluster

• GlusterFS Cluster

FROM ubuntu:latest
MAINTAINER XenonStack

RUN apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys B97B0AFCAA1A47F044F244A07FCC7D46ACCC4CF8

RUN echo "deb http://apt.postgresql.org/pub/repos/apt/ xenial-pgdg main" > /etc/apt/sources.list.d/pgdg.list

RUN apt-get update && apt-get install -y python-software-properties software-properties-common postgresql-9.6 postgresql-client-9.6 postgresql-contrib-9.6

RUN /etc/init.d/postgresql start &&\
 psql --command "CREATE USER root WITH SUPERUSER PASSWORD 'xenonstack';" &&\
 createdb -O root xenonstack

RUN echo "host all  all 0.0.0.0/0  md5" >> /etc/postgresql/9.6/main/pg_hba.conf

RUN echo "listen_addresses='*'" >> /etc/postgresql/9.6/main/postgresql.conf

# Expose the PostgreSQL port
EXPOSE 5432

# Add VOLUMEs to allow backup of databases
VOLUME  ["/var/lib/postgresql"]

# Set the default command to run when starting the container
CMD ["/usr/lib/postgresql/9.6/bin/postgres", "-D", "/var/lib/postgresql", "-c", "config_file=/etc/postgresql/9.6/main/postgresql.conf"]

$ docker build -t dr.xenonstack.com:5050/postgres:v9.6

$ gluster volume create postgres-disk replica 2 transport tcp k8-master:/mnt/brick1/postgres-disk  k8-1:/mnt/brick1/postgres-disk
$ gluster volume start postgres-disk
$ gluster volume info postgres-disk

• Docker Image: We have created a Docker Image for Postgres in Step 2

• Persistent Shared Storage Volume: We have created a Persistent Shared Storage Volume in Step 3

• Deployment & Service Files: Next, we will create Deployment & Service Files

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: postgres
  namespace: production
spec:
  replicas: 1
  template:
 metadata:
   labels:
    k8s-app: postgres
 spec:
   containers:
   - name: postgres
     image: dr.xenonstack.com:5050/postgres:v9.6
     imagePullPolicy: "IfNotPresent"
     ports:
     - containerPort: 5432
     env:
     - name: POSTGRES_USER
       value: postgres
     - name: POSTGRES_PASSWORD
       value: superpostgres
     - name: PGDATA
       value: /var/lib/postgresql/data/pgdata
     volumeMounts:
        - mountPath: /var/lib/postgresql/data
          name: postgredb
   volumes:
     - name: postgredb
       glusterfs:
         endpoints: glusterfs-cluster
         path: postgres-disk
         readOnly: false