Tutorial: Installing Docker and Cloning A Containerized Web Server

Docker Tutorial

1. Installing Docker ……………………………………………………………….
2. Pulling Repository/Image ……………………………………………………..
3. Running Container …………………………………………………………….
4. Building a Docker Image……………………………………………………..
5. Troubleshooting Problems & Solutions …………………………………….

Installing Docker

Go to https://hub.docker.com and login to your account.

• If you don't already have a Docker account, you will need to create one

• It's free to create, select the free plan ↓

• Verify your email
• Download Docker Desktop Application ↓

- Verify Docker installed by running the command\> docker
  - Should result in a list of docker help commands

• Open the Docker Desktop Application
  • Docker will prompt you to allow privileges, allow it
  • Accept the service agreement
• Sign In on the Docker Desktop Application ↓

Pulling Repository/Image

Go to docker repository:

https://hub.docker.com/repository/docker/jtamwaffle/visual/general

Copy the command ↓

Open a terminal and enter the command> docker pull jtamwaffle/visual

• You should see this when its finished ↓
• To check if the repository pulled, enter the command> docker images You should see the following ↓

Running Container

Now that the image is pulled, you can run it through the terminal or you can run it through the Docker Desktop Application. I will show how to run it through the Docker Desktop Application first:

• In the desktop application, click the Images tab on the left ↓
• Then, click run for the image you want to create a container for ↓ This window should pop up to run a new container, go to Optional Settings ↓
• Go to Ports -> Host Port and enter the port number to run on your local machine. I chose port 8080 for this tutorial ↓
  • This port number is the local host your machine will use to run and view the container
  • The default port the container will use is 8000
• Then, run the container ↓
• You should be taken to the Container tab and see the following ↓
  • You can also validate the container is running in the terminal by using the command> docker ps
    • You should see the following

To run the application through the terminal

• Use the command> docker run -d -p <local port>:8000 <image ID>
  • If you do not know the image ID
    • Go to the Images tab in the desktop application
    • Under the image you need the ID for is the image ID ↓

• To view the container, go to http://localhost:<local port>
  • If you used the port number 8080, go to http://localhost:8080
  • You should see the running container ↓

When you're done using the container, you should stop the container. This can be done either by using the Docker Desktop Application or through the terminal.

• Using the desktop application, under the Container tab, press the stop button at the top of the page for the container you want to stop ↓

• Using the terminal, enter the command> docker stop <container ID>

  • If you do not know the container ID, enter the command> docker ps

• The container ID will be listed in the first column ↓

Building a Docker Image

This will cover two ways to build a docker image, the first method builds a docker image from the git repository. The second method builds the docker image from a pre-existing docker image, like a copy of the docker image.

Building a Docker Image from Git Repository

• Go to the location where you locally stored the git repository

• Within the git repo is an already made Dockerfile that will be used for building the docker image.

• To build the docker image, use the command> docker build -t <tagname> <path>

• For the tagname, I recommend using your username followed by the name for the docker image

  • Ex) anc224/visual:1.0

• Use '.' for the path to indicate that you are building the image from the current directory

• Verify the docker image was created with the command> docker images

Building a Docker Image from a Docker Image

• Create a Docker file

  • Command> touch Dockerfile
    • Note that there are no file extensions

• Open Docker file

  • Command> vim Dockerfile
    • Press 'i' to enter Insert Mode

• Type "FROM <image name>:latest"

  • Save file and exit with ":x!"

• To build the docker image, use the command> docker build -t <tagname> <path>

• For the tagname, I recommend using your username followed by the name for the docker image

  • Ex) anc224/visual:1.0

• Use '.' for the path to indicate that you are building the image from the current directory

• Verify the docker image was created with the command> docker images

Troubleshooting Problems & Solutions

Command> docker images

"Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?"

• Solution: open the docker desktop application

Command> docker build -t <tagname> <path>

"ERROR: [5/7] COPY local_packages ./: failed to compute cache key: "/local_packages" not found: not found"