How to solve the problem that docker cannot start after installation

Docker is currently the most popular containerization technology, which can help developers quickly deploy applications and manage and monitor multiple applications. Docker is used more and more widely, but sometimes there are some problems, such as being unable to start after the installation is completed. This article describes possible solutions.

1. Check if Docker is installed correctly

First, we need to check if Docker is installed correctly. We can use the following command to check:

$ docker version

If there are client and server version numbers in the output information, it means that Docker has been installed correctly. If there is no output or there is no version number in the output information, it means that Docker is not installed or is installed incorrectly.

2. Check whether Docker is started

If Docker has been installed correctly but cannot be started, you need to check whether the Docker service is started. We can use the following command to check:

$ systemctl status docker

If the status in the output information is "Active: active (running)", it means that the Docker service has been started. If the status is "Active: inactive (dead)" or "Active: failed", it means that the Docker service has not been started.

If the Docker service does not start, we can use the following command to start the Docker service:

$ sudo systemctl start docker

3. Check whether Docker is configured correctly

If we have determined that Docker The service has been started but still cannot be accessed, you need to check whether the Docker configuration is correct. We can view the Docker configuration through the following command:

$ cat /etc/docker/daemon.json

If the output information is empty, it means that the Docker configuration file does not exist. We need to re-create the configuration file, we can use the following command:

$ sudo nano /etc/docker/daemon.json

Then enter the following:

{
  "debug" : true,
  "tls" : false,
  "tlscert" : "/var/docker/server-cert.pem",
  "tlskey" : "/var/docker/server-key.pem",
  "hosts" : ["unix:///var/run/docker.sock", "tcp://0.0.0.0:2375"]
}

Save the configuration file and close the editor. Then restart the Docker service, you can use the following command:

$ sudo systemctl daemon-reload
$ sudo systemctl restart docker

4. Check whether the Docker image and container are correct

We also need to check whether the Docker image and container are correct. We can use the following command to list Docker images:

$ docker images

If the output information is empty, it means that no image can be used. We need to download the image, we can use the following command:

$ docker pull [image-name]

where [image-name] is the name of the Docker image. After the download is complete, you can use the "docker images" command again to view the image list.

In addition, we also need to check whether the Docker container is correct. We can use the following command to list Docker containers:

$ docker ps -a

If the output information is empty, it means that no containers can be used. We need to create a container and can use the following command:

$ docker run [options] [image-name] [command]

where [options] is the option for Docker to start the container, [image-name] is the name of the Docker image, and [command] is the Docker command. After the creation is complete, you can use the "docker ps -a" command again to view the container list.

Summary

In the process of using Docker, sometimes it cannot be started after the installation is completed. The above are possible solutions, including checking whether Docker is installed correctly, checking whether the Docker service is started, checking whether the Docker configuration is correct, and checking whether the Docker image and container are correct. If none of the above methods solve the problem, we can also check the Docker log file to get more information.

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