What is Docker? In this article, you will learn to build Docker image from scratch, and deploy and run your application as a Docker container using Dockerfile.Docker allows developers to build, test, and deploy applications quickly and efficiently using isolated and portable containers that run anywhere.   How to Create Docker File In order to build the container image, you’ll need to use a Dockerfile. A Dockerfile is simply a text-based file with no file extension. A Dockerfile contains a script of instructions that Docker uses to create a container image.In a Dockerfile Everything on left is INSTRUCTION, and on right is an ARGUMENT to those instructions. Remember that the file name is "Dockerfile" without any extension. To create Docker file from visual studio - Open project folder in visual studio - Right click on project folder  - Go to add - Go to docker support     - There are two options to build docker file : windows and Linux - Select one of the given option and it will create the docker file     Here we have selected windows operating system, so it will create docker file for windows image but if you select Linux operating system then it will create docker file for Linux image and rest of the docker commands will be same for windows as well as Linux   How to Build Docker Image We will build our image using the Docker command. The below command will build the image using Dockerfile from the same directory. docker build -t demoimage:1.0 . - t is for tagging the image. - demoimage is the name of the image. - 1.0 is the tag name. If you don’t add any tag, it defaults to the tag named latest. - . means, we are referring to the Dockerfile location as the docker build context.   After the image build output will look like below. Now, we can list the images by using this command. docker images   Test the Docker Image Now after building the image we will run the Docker image. The command will be, docker run -d -p 4000:80 --name democontainer2 demoimage:1.0 - d flag is for running the container in detached mode. - p flag flag for the port number, the format is local-port:container-port. - --name for the container name, democontainer2 in our case.   Docker started our container in the background and printed the Container ID on the terminal. We can check the running container by using the below command. docker ps In a web browser, access http://localhost:4000 and we can see the index page which displays the content in the custom HTML page we added to the docker image. After creating Docker image we can see all the local images in Docker windows Desktop. Go to the images tab and we can see all the images. Go to the containers tab and we can see all the containers also. Here we are using docker desktop for windows,so we have selected switch to windows option,if you are using docker desktop for Linux then select switch to Linux option.   Push Docker Image to Docker Hub Docker Hub is a registry service on the cloud that allows you to download Docker images that are built by other communities. You can also upload your own Docker built images to Docker hub.To push our Docker image to the Docker hub, we need to create an account in the Docker hub. After that, execute the below command to log in from the terminal. It will ask for a username and password (if you are login for the first time). Provide the Docker hub credentials. docker login After login, we now need to tag our image with the docker username as shown below. docker tag demoimage:1.0 <username>/<image-name>:tag For example, here hiral1 is the docker hub username. docker tag demoimage:1.0 hiral1/demoimage:1.0 Run docker images command again and check the tagged image will be there. Now we can push our images to the Docker hub using the below command. docker push hiral1/demoimage:1.0 Now we can check this image will be available in our Docker Hub account.   We can inspect a container by following command. docker inspect <container-id>   We can view Docker logs in a Docker container by following command. docker logs <container-id>   And we can stop the running container by following command. docker stop <container-id>   Pull and Run Docker Image from Docker Hub To pull image from docker hub use the following command. docker pull <imagename:tag>   Docker checks if the image already exists or not, if it is then it does not download further.In our case it is already there.So we need to remove existing image. To remove the docker image use the following command. docker rmi <imagename:tag>   Now pull the docker image from docker hub and check for the list of images.   To run the pulled image use the below command docker run -d -p 4000:80 --name windowscontainer  hiral1/demoimage:1.0 - d flag is for running the container in detached mode. - p flag flag for the port number, the format is local-port:container-port. - --name for the container name, windowscontainer  in our case. In a web browser, access http://localhost:4000 and we can see the index page which displays the content in the custom HTML page we added to the docker image. Below is the example of how to pull and run docker image on Linux VM. Here is the output of the docker image on the browser. Rename/Tag Docker Image To rename the docker image tag the image as follows. docker tag <oldimagename:tag> <newimagename:tag> In our case the old image name is hiral1/demoimage , old tag is 1.0 and new image name is newimage/latest.We have not provided a new tag to newimage, so it gives tag - latest by default.   Remove Docker Image To remove the docker image use the following command. docker rmi <imagename:tag>

You may have heard infrastructure as code(IaC), But do you know what infrastructure is? Why do we need infrastructure as code? What are the benefits of infrastructure as code? Is it safe and secure?    What is Infrastructure as Code(IoC)? Infrastructure as code (IaC) means to manage and upgrade your environments as infrastructure using configuration files. Terraform provides infrastructure as code for provisioning, compliance, and management across any public cloud, private data center, and third-party service. Enables teams to write, share, manage, and automate any infrastructure using version control With automated policy enforcement for security, compliance, and operational best practices and Enable developers to provision their desired infrastructure from within their workflows. IOC has a high impact on the Business perspective by providing Increased Productivity, Reduced Risk, Reduced Cost   Why do we use Infrastructure as Code(IoC)? Terraform is a simple human-readable configuration language, to define the desired topology of infrastructure resources VCS Integration Write, version, review, and collaborate on Terraform code using your preferred version control system Workspaces Workspaces decompose monolithic infrastructure into smaller components, or "micro-infrastructures". These workspaces can be aligned to teams for role-based access control. Variables Granular variables allow easy reuse of code and enable dynamic changes to scale resources and deploy new versions. Runs Terraform uses two-phased provisioning a plan (dry run) & apply (execution). Plans can be inspected before execution to ensure expected behavior and safety. Infrastructure State The state file is a record of currently provisioned resources. State files enable a versioned history of the infrastructure and are encrypted at rest. Versions can be inspected to see incremental changes. Policy as Code Sentinel is a policy as a code framework to automate multi-cloud governance.   What are the benefits of Infrastructure as Code(IoC)? Infrastructure as Code enables Infrastructure teams to test the applications in staging environments or development environment early - likely in the development cycle Infrastructure as Code Saves You Time and Money We can have a version history like when the infrastructure is upgraded and who has done it from the code itself. Else we have to ask to check the Infrastructure admin to look into logs and which is very time-consuming. We can check it into version control and I get versioning. Now we can see an incremental history of who changed what Use Infrastructure as Code to build update and manage any cloud, infrastructure, or services Terraform makes it easy to re-use configurations for the environment for similar infrastructure, helping you avoid mistakes and save time. We can use the same configuration code for the different staging Production and development environments. Terraform supports many Providers to be built from just a simple and less line of code. Major providers are as follows AWS Azure GitHub GitLab Google Cloud Platform VMWare Docker  and  200+ more. A Simple example to create an Ec2 Instance with just a few lines of code. resource "aws_instance" "ec2_instance" {   ami = "ami-*******"   instance_type = "t2.micro"   vpc_security_group_ids = ["${aws_security_group.*****.id}"]   key_name = "${aws_key_pair.****.id}"   tags {     Name = "New-EC2-Instance"   } } But First, we have to write code for which provider we are writing our code. To do so  here is the simple basic code to assign a provider provider "aws" {   region = "us-west-2"   ## PROVIDE CREDENTIALS } Now to Create your Ec2 Instance in AWS. We have to run the commands. So terraform has Four commands to check and apply the infrastructure changes, Init Plan Apply Destroy.   1. Init $ terraform init We can understand from the name of the command that is used to initialize something. So here terraform will be initialized in our code which will create some basic backend and tfstate files in folders for internal use. 2. Plan $ terraform plan As we do compile in some code languages, it will check for the compilation errors and plan what is going to happen when we run the script to generate infrastructure code. It will show you what resources are going to be created and what will be the configuration. 3. Apply $ terraform apply It is time to run the script and check what is being generated from the scripts. So the command will execute the script and apply the changes in our infrastructure, which will generate some resources for what we have written in the code.  4. Destroy $ terraform destroy This command is used when we want to remove or destroy the resource. After some time we don't need that resource then we just run the command which will destroy the resource. And your money is saved.