How to install and use Docker
In this blog post, we will provide a comprehensive guide on installing Docker, followed by a detailed walkthrough on its usage on a rocky based operating system. Our setup revolves around a single node with Docker installed, ready to facilitate the execution of Docker containers.
Let's start with a step-by-step process, starting from creating virtual machines on the Alces Cloud platform, followed by installation of docker and how to use docker cli to perform docker operations.
Launch the Instance
All the steps to launch and connection to instance is provided in link.
Setup Docker
The Docker installation package provided in the official Rocky Linux 9 repository might not always be the most up-to-date version. For access to the latest features and updates, it's recommended to install Docker directly from the official Docker repository. Use below command to update package database and add docker repository.
sudo dnf check-update
sudo dnf config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
Now install the Docker using below commands.
sudo dnf update -y
sudo dnf install -y docker-ce docker-ce-cli containerd.io
After the installation of docker, enable and start the docker.
sudo systemctl enable docker
sudo systemctl start docker
Verify Docker
You can check the web server is up and running by using the below command
systemctl status docker
Output
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● docker.service - Docker Application Container Engine
Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; preset: disabled)
Active: active (running) since Wed 2024-03-20 16:18:27 UTC; 40s ago
TriggeredBy: ● docker.socket
Docs: https://docs.docker.com
Main PID: 50100 (dockerd)
Tasks: 10
Memory: 34.7M
CPU: 395ms
CGroup: /system.slice/docker.service
└─50100 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
Execute Docker command without sudo (optional)
By default, the docker command requires root privileges to run, requiring the command to be prefixed with sudo.
To bypass the need for typing sudo each time you use the docker command, include your username in the docker group:
sudo usermod -aG docker $(whoami)
If you wish to add a user to the docker group for a user other than the one you're logged in as, specify the username explicitly:
sudo usermod -aG docker username
Working with Docker command
You can use the following command to display a list of all available subcommands and additional help:
docker --help
For more detailed information about a specific subcommand, you can type:
docker docker-subcommand --help
Working with Docker images
Docker containers operate on Docker images. Images are fetched from Docker Hub, a registry operated by Docker. Docker Hub enables anyone to construct and share their Docker images, making it a central repository for a wide array of applications and Linux distributions necessary for Docker container deployment.
To ensure Docker is functioning correctly, execute the following command:
docker run hello-world
Output
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Hello from Docker.
This message shows that your installation appears to be working correctly.
...
The displayed output confirms Docker's operational status.
To search for an image on Docker Hub, run the following command:
docker search ubuntu
Output
------
NAME DESCRIPTION STARS OFFICIAL
ubuntu Ubuntu is a Debian-based Linux operating sys… 16959 [OK]
ubuntu-debootstrap DEPRECATED; use "ubuntu" instead 52 [OK]
websphere-liberty WebSphere Liberty multi-architecture images … 298 [OK]
open-liberty Open Liberty multi-architecture images based… 64 [OK]
neurodebian NeuroDebian provides neuroscience research s… 107 [OK]
ubuntu-upstart DEPRECATED, as is Upstart (find other proces… 115 [OK]
ubuntu/nginx Nginx, a high-performance reverse proxy & we… 112
ubuntu/squid Squid is a caching proxy for the Web. Long-t… 86
ubuntu/cortex Cortex provides storage for Prometheus. Long… 4
ubuntu/prometheus Prometheus is a systems and service monitori… 58
ubuntu/apache2 Apache, a secure & extensible open-source HT… 71
ubuntu/kafka Apache Kafka, a distributed event streaming … 44
ubuntu/bind9 BIND 9 is a very flexible, full-featured DNS… 80
ubuntu/zookeeper ZooKeeper maintains configuration informatio… 13
ubuntu/mysql MySQL open source fast, stable, multi-thread… 61
ubuntu/jre Distroless Java runtime based on Ubuntu. Lon… 13
ubuntu/postgres PostgreSQL is an open source object-relation… 35
Once we found the image, we can pull the image locally
docker pull ubuntu
To view the images downloaded to your system, use the command:
docker images
Output
------
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu latest ca2b0f26964c 3 weeks ago 77.9MB
hello-world latest d2c94e258dcb 10 months ago 13.3kB
Running a Docker container
In last steps we have successfully downloaded Docker images (hello-world and ubuntu:latest). Now we will be running the Docker container using the latest image of ubuntu However, this time, we will interacting with the container shell by executing the following command:
docker run -it ubuntu
Output
------
[root@59839a1b7de2 /]#
To list all the docker containers in the system, run the below command
docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
f8b4958bcda6 ubuntu "/bin/bash" 10 seconds ago Exited (0) 5 seconds ago competent_nobel
dbcb92c48a44 hello-world "/hello" About a minute ago Exited (0) About a minute ago brave_carver
Note
For more information about Docker, please refer to the official Docker documentation link