How to check if docker is installed successfully

Docker is an open source containerization platform that can help developers build, deploy and run applications more easily. But before using Docker, you first need to confirm whether Docker has been installed correctly.

This article will introduce several methods to check whether Docker has been installed, including using command line tools, viewing system information and checking Docker service status. The steps are as follows:

1. Use the command line tool to check the Docker installation status

Open the terminal or PowerShell and enter the following command:

docker -v

If you have successfully installed Docker, The version number of Docker will be displayed, for example:

Docker version 19.03.13, build 4484c46d9d

If "command not found" or other error messages appear, it means that you have not installed Docker or Docker is not installed correctly.

2. Check the system information to confirm whether Docker is installed

Use the following command to check the system information:

uname -a

This command will return the name, version and kernel information of the current operating system . If your operating system is Linux and Docker has been installed, you will see information containing the word "Docker" in the returned results. For example:

Linux ubuntu 5.4.0-54-generic #60-Ubuntu SMP Fri Nov 6 10:37:59 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

There are corresponding ways to view it for different operating systems. For example, on Mac, you can enter the following command in the terminal:

system_profiler SPSoftwareDataType |grep -i docker

If the system information does not contain the word Docker , it means you haven't installed it yet.

3. Check the Docker service status

In Linux system, you can use the following command to check the status of the Docker service:

sudo systemctl status docker

If the Docker service has been started, return the following Information:

● docker.service - Docker Application Container Engine
     Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset
     Active: active (running) since Tue 2020-11-10 15:15:37 JST; 1 day 7h ago
       Docs: https://docs.docker.com
   Main PID: 2075 (dockerd)
      Tasks: 18
     Memory: 157.3M
     CGroup: /system.slice/docker.service
             ├─2075 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/cont
             └─2380 containerd --config /var/run/containerd/config.toml --log-l

If the following information is returned, it means that the Docker service has not started:

● docker.service - Docker Application Container Engine
     Loaded: loaded (/lib/systemd/system/docker.service; disabled; vendor preset
     Active: inactive (dead)
       Docs: https://docs.docker.com

If you are using a Windows operating system, you can use the following command to check the status of the Docker service:

Get-Service Docker

If the returned status is "Running", it means that the Docker service has been started. If the status is "Stopped", it means the service is not started.

Summary

This article introduces a variety of methods to confirm whether Docker has been installed correctly. You can try entering "docker -v" on the command line to view the version information of Docker, or check the system information to confirm whether Docker related components have been installed, or check the status of the Docker service. If you are installing Docker or encounter problems, it is recommended to consult the official Docker documentation or community forums for more help.

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