Docker - Setting Ubuntu

Docker - Setting Ubuntu

Docker is a strong platform. It helps developers to automate how they deploy applications. We can use lightweight and portable containers for this. When we set up Ubuntu in Docker, we can use the benefits of containerization. We also get to run the popular Ubuntu operating system. This mix is very important. It helps us make our development work easier. It also makes sure everything works the same way in different places. Plus, it simplifies how we manage applications.

In this chapter, we will look at the steps for Docker - Setting Ubuntu. We will cover everything from how to install to how to manage containers well. We will also talk about pulling Ubuntu images. We will create containers and use Docker volumes for keeping data safe. By the end, you will understand Docker and what it can do.

Introduction to Docker

Docker is a strong platform. It helps us with the development, deployment, and management of applications. It uses containerization technology. Containers hold an application and everything it needs to run. This gives us the same environment no matter where we run the application. We don’t have to worry about “it works on my machine.” Docker containers run the same on any system that supports Docker.

Here are some key features of Docker:

• Isolation: Each container runs by itself. This helps with security and managing resources.
• Portability: We can easily move containers between different computing environments.
• Scalability: Docker lets us quickly scale applications. We can run many containers at once.
• Version Control: We can version Docker images. This makes it easy to go back to older versions or update.

If we want to deploy different applications, Docker gives us a strong framework. For example, we can look into setting up Nextcloud or Grafana using Docker containers. Learning how Docker works is important for software development and operations today. This skill is very useful in the tech industry.

Installing Docker on Ubuntu

To install Docker on Ubuntu, we first need to update our package index. We also need to make sure we have some important packages installed. Let us open a terminal and run these commands:

sudo apt update
sudo apt install apt-transport-https ca-certificates curl software-properties-common

Next, we will add Docker’s official GPG key. Then we will set up the stable repository:

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"

After we add the repository, we will update the package index again:

sudo apt update

Now, we can install Docker:

sudo apt install docker-ce

Once we install it, Docker should start on its own. We can check if it is running with this command:

sudo systemctl status docker

If we want Docker to start when the system boots, we run:

sudo systemctl enable docker

Now that we have Docker installed, we can check our installation. We can also explore Docker images and containers. This setup helps us use Docker for many applications. For example, we can use it for setting Ubuntu in containers.

Verifying Docker Installation

After we install Docker on Ubuntu, we need to check if it works well. It is important to make sure everything is okay. We can do this by running a simple command that tests Docker.

1. Check Docker Version: First, we check the Docker version. We open a terminal and type:

   docker --version

   This command shows us the version of Docker we have installed.

2. Run the Hello World Image: Next, we can run a test to see if Docker is working. We type the following command:

   docker run hello-world

   This command gets the hello-world image and runs it in a new container. If everything is good, we will see a message that tells us Docker is working.

3. Check Docker Service Status: We can also see if the Docker service is running. We do this by typing:

   sudo systemctl status docker

   This command shows us if Docker is active and running.

By doing these steps, we can check our Docker installation on Ubuntu. If we want to learn more about using Docker, we can look at topics like Docker - Setting Ubuntu and What is Docker.

Understanding Docker Images and Containers

In the topic of Docker - Setting Ubuntu, we need to know the basic ideas of Docker images and containers.

• Docker Image: A Docker image is a small and complete package. It has everything we need to run a software. This includes the code, the runtime, libraries, and environment variables. Images are read-only. We can get them from places like Docker Hub.

• Docker Container: A Docker container is what we use to run a Docker image. It holds the application and everything it needs in a separate space. This helps the application run the same way in different places. Containers can change. We can start them, stop them, or delete them. This makes them great for using applications in a microservices setup.

We can say the relationship between images and containers is simple:

• We create containers from Docker images.
• We can make many containers from the same image. Each one works on its own.

To learn more about Docker images and Docker containers, check the links. This knowledge is very important for us to set up and manage our Docker space on Ubuntu.

Pulling an Ubuntu Image

To use Ubuntu in Docker, we first need to pull an Ubuntu image from Docker Hub. Docker Hub is a public place where we can find many ready-made images, including different versions of Ubuntu.

We can use this command to pull the latest Ubuntu image:

docker pull ubuntu:latest

This command gets the latest official Ubuntu image. If we want a specific version, we can say it like this:

docker pull ubuntu:20.04

After the image downloads, we can check if it is there by running:

docker images

This will show all our downloaded images, including the Ubuntu image. Knowing how to pull an Ubuntu image is important for using Docker well. By pulling the right Ubuntu image, we can make sure our development environment is ready for our applications.

For more examples of using Docker with other applications, we can look at Docker - Setting PostgreSQL or Docker - Setting Node.js.

Creating a Docker Container from Ubuntu Image

We can create a Docker container from an Ubuntu image. First, we need to pull the image from Docker Hub. Then we can use it to start a container. This helps us run Ubuntu in a separate space. It is very helpful for development and testing.

1. Pull the Ubuntu Image: First, we make sure to pull the latest Ubuntu image from Docker Hub. We can do this with the command:

   docker pull ubuntu:latest

2. Create a Docker Container: After we pull the image, we can create a container. We use the docker run command. The basic way to write it is:

   docker run -it ubuntu:latest

   • -it: This flag lets us talk with the container through the terminal. It is the interactive mode.

3. Run a Command in the Container: When we create the container, we go into a shell inside it. Here we can use normal Ubuntu commands. For example, we can run:

   apt-get update

4. Detaching from the Container: If we want to leave the container but keep it running, we can press Ctrl + P and then Ctrl + Q. If we want to stop the container, we can use:

   docker stop <container_id>

Making a Docker container from an Ubuntu image is easy. It is the first step for more changes and app development. For more examples, we can look at resources on Docker networking and Docker volumes.

Running Commands in a Docker Container

Running commands in a Docker container is very important for using Docker well. After we create a Docker container from an Ubuntu image, we can run commands inside that container. This helps us manage applications, settings, or environments.

To run a command in a container that is already running, we use the docker exec command. Here is how we can do it:

docker exec -it <container_id_or_name> <command>

For example, if we want to open a shell (bash) in our running Ubuntu container, we write:

docker exec -it my_ubuntu_container bash

Running Commands on Container Start

We can also run commands when we create a new container. We do this with the docker run command:

docker run -it ubuntu bash

This command starts a new Ubuntu container and gives us a bash shell.

Example Commands

• List files: We can use ls to see files in the current folder.
• Install software: Use apt-get install <package_name> to install new packages.
• Check system info: Run uname -a to get system information.

For more difficult tasks, like setting up services such as databases or web servers, we should use Docker Compose. This tool makes it easier to manage many containers and their settings.

If we want more help about using Docker, we can check these articles: Docker - Setting PostgreSQL and Docker - Setting Node.js.

Managing Docker Containers

Managing Docker containers is very important for good application deployment and resource management. Docker gives us many commands to control the life of containers. We can start, stop, restart, and remove them when we need.

Key Commands for Managing Containers:

• List Containers:

  docker ps          # Shows running containers
  docker ps -a       # Shows all containers, even the stopped ones

• Start a Container:

  docker start <container_id_or_name>

• Stop a Container:

  docker stop <container_id_or_name>

• Remove a Container:

  docker rm <container_id_or_name>

• Restart a Container:

  docker restart <container_id_or_name>

Container Management Best Practices:

• Use good names for your containers so we can find them easily.
• Watch resource usage with commands like docker stats to make performance better.
• Use container orchestration tools like Docker Compose for apps with many containers.

For more examples and setups, check our other guides on Docker networking and Docker volumes. Good management helps our Docker containers to be efficient, reliable, and scalable.

Exposing Ports and Networking in Docker

Exposing ports and managing networking in Docker is very important. It helps containers talk to each other and to the host system. By default, Docker containers work in a private network. This means they are separate from the host and from each other. To let outside users access services in containers, we need to expose ports.

Exposing Ports

To expose a port when we create a container, we use the -p option with the docker run command:

docker run -d -p host_port:container_port ubuntu

For example, if we want to expose port 80 of an Ubuntu container to port 8080 on the host, we run:

docker run -d -p 8080:80 ubuntu

Networking Modes

Docker has many networking modes:

• Bridge: This is the default mode. It makes a private internal network.
• Host: This mode uses the host’s network stack directly.
• None: This mode turns off all networking.
• Container: This mode shares networking between containers.

For example, if we want to run a container in host mode, we can do:

docker run --network host ubuntu

Conclusion

We need to understand how to expose ports and set up networking in Docker. This is key for deploying applications well. If we want to learn more advanced setups, we can check out Docker Networking. This knowledge is also important for services like Docker - Setting PostgreSQL or Docker - Setting Nginx.

Using Docker Volumes for Data Persistence

Docker volumes are very important for keeping data safe in Docker containers. This is especially true for applications that need steady data storage, like databases or file-sharing services. When we use volumes, data stays even after we stop or remove a container. This way, we do not lose our data.

Here are the steps to create and use a Docker volume:

1. Create a Volume:

   docker volume create my_volume

2. Run a Container with the Volume:

   docker run -d -v my_volume:/data ubuntu

3. Accessing Volume Data: We can get to the data in the volume from the container:

   docker exec -it <container_id> /bin/bash
   cd /data

Benefits of Docker Volumes:

• Data Persistence: The data stays safe even if we delete the container.
• Ease of Backup and Restore: It is easy to backup or restore volumes.
• Sharing Data: We can share volumes between different containers.

For more details about advanced setups, we can check Docker Volumes. By using Docker volumes well, we can keep our applications’ important data safe. This makes our Docker setups more reliable.

Docker - Setting Ubuntu - Full Example

We will show how to use Docker to set up an Ubuntu environment. This example includes pulling an Ubuntu image, creating a container, and running a simple app.

1. Pull the Ubuntu Image
   First, we pull the latest Ubuntu image from Docker Hub:

   docker pull ubuntu:latest

2. Create and Start a Container
   Next, we create a new container from the Ubuntu image and run an interactive terminal:

   docker run -it ubuntu:latest /bin/bash

   This command gives us a shell inside the Ubuntu container.

3. Install an Application
   For this example, we will install curl:

   apt update && apt install -y curl

4. Verify Installation
   We can check if curl is installed correctly:

   curl --version

5. Exit the Container
   To exit the container, we can type exit or press Ctrl + D.

6. Managing Containers
   We can list running containers:

   docker ps

   To list all containers, including stopped ones:

   docker ps -a

This example shows the basic steps of Docker - Setting Ubuntu. For more setups like networking and data storage, check guides like Docker Volumes and Docker Networking.

Conclusion

In this article about Docker - Setting Ubuntu, we looked at the basics of Docker. We talked about how to install it and how to manage containers and images.

By learning how to pull an Ubuntu image and create containers, we can use Docker well for development and deployment. This knowledge is a good base for more complex apps. For example, we can set up services like Nextcloud or Grafana.

Let’s start our Docker journey today!