Docker memorandum

Docker daemon

It is a persistent process that manages containers, and the Docker daemon manages the start, restart, and stop of containers by executing commands from users using Docker commands.

Docker Hub Docker image registry service. You can publish, search, and download Docker images.

Docker image

A file system that collects the files required to execute a container. A special file system such as AUSF is used. The data on the image is composed of layers and is read-only.

List images

% docker images

Command to create a new image

## %docker tag Original image name New image name
% docker tag docker/whalesay my_whalesay

## %docker tag Original image name New image name:tag
% docker tag docker/whalesay my_whalesay:num1

In the case below, the image "my_whalesay" with the tag name "num1" is created.

Command to display detailed information of image

## %docker inspect Target image or image ID
% docker inspect my_whalesay

Command to delete image

## %docker rmi Target image or image ID
% docker rmi docker/whalesay

Command to forcibly delete the image

## docker rmi -f Target image or image ID
% docker rmi -f docker/whalesay

Command to get image

## %docker pull Image you want to get
% docker pull docker/whalesay

The latest may not be a new image, so see the official for details.

Dockerfile Image definition file. Building an image from a Dockerfile is called an image build.

##FROM specifies the original image when creating the image This time docker/whalesay:latest
FROM docker/whalesay:latest
##RUM specifies commands when building images
RUN apt-get -y update && apt-get install -y fortunes
##CMD is an instruction that specifies a command to execute after the container is created
CMD /usr/games/fortune | cowsay

Command to build image from Dockerfile

## % docker build -t image name.
% docker build -t docker-whale .

-t gives the built image a name This time docker -whale. "." Indicates the directory and file range that can be accessed when creating an image in the build context settings. This time it shows the current directory. (Period).

## % docker build --no-cache -t image name.
% docker build --no-cache -t docker-whale .

When the above image is built again with Dockerfile, the cache is applied and it is not updated. A command that prevents new packages from being installed. It can be updated without using the cache.

Log in to Docker Hub

% docker login
Username Docker Hub username
Password:Docker Hub password

If successful, "Login Succeeded" will be displayed.

Tagging rules in Docker Hub

## %docker tag Original image name Repository name:Tag name
% docker tag docker-whale user/docker-whale:num1

Since it pushes to the repository "user / docker-whale" of Docker Hub, it becomes such a description. If no tag name is specified, it will be the latest tag. Note that if you make a mistake in the repository name, you will not be able to push!

Push the image to Docker Hub

## %docker push repository name:Tag name
% docker push user/docker-whale:num1

If you get an error here, check again if the repository name matches. Make sure the image is pushed to the Docker Hub repository.

Pull the image from Docker Hub

## %docker pull image name:Tag name
% docker pull user/docker-whale:num1

Confirm that the image is pulled with the docker images command.

Command to launch nginx container

## % docker run --name container name-d -p Host side port number:Container port number Image name
% docker run --name some-nginx -d -p 8080:80 some-content-nginx

--neme is an option to name the container to start. -d runs the container in the background in detach mode. If there is no input, other operations will not be possible on the executed screen, so it is recommended to enter it. -p is an option to set the container's port outside the container. Here, the port number that 8080 exposes to the outside. If it runs normally, you can see that nginx is running at http: // localhost: 8080 /.

Check docker container

##View running containers
% docker ps
##Displaying containers that are running or stopped
% docker ps -a

Start docker container

##docker start container name or container ID
% docker start static-site

The status of the container changes to running.

Suspend docker container

##docker pause container name or container ID
% docker pause static-site

The status of the container changes to paused.

Unpause docker container

##docker unpause container name or container ID
% docker unpause static-site

The status of the container changes to running.

Restart docker container

##docker restart container name or container ID
% docker restart static-site

The status of the container goes through restarting and becomes running.

Delete docker container

##docker rm container name or container ID
% docker rm static-site

Note that you cannot delete it unless you stop the container!

Force delete docker container

## docker rm -f Container name or container ID
% docker rm -f static-site

Used when the container cannot be deleted.

status of docker container

You can check the status of the container with the docker ps command or the docker inspect command.

created </ b> ・ ・ ・ A container is created by docker create, and it is in the state before start. It changes to running with docker start. running </ b> ・ ・ ・ The container is running. Paused with the docker pause command, exited with the docker stop command, restarting with the docker restart command, and then running. paused </ b> ・ ・ ・ No response even if you connect to a running container in a suspended state or make a request. Return to running state with docker unpause command. restarting </ b> ・ ・ ・ The container is being restarted and will be restarted immediately, so you cannot see much. When the reboot is finished, it will be running. exited </ b> ・ ・ ・ The container has been closed and remains. Basically, you can delete the container from here with the docker rm command. dead </ b> ・ ・ ・ Displayed when the container remains without being terminated normally. If this happens, there is no choice but to delete it.

Create an image from a container

##docker commit container name or container ID image name:Tag name
% docker commit static-site static-site:ver1

You can save the state of the container as an image. However, since the work done in the container is not recorded as a clear record, it is usually described in the Dockerfile and the history is recorded.

Check the history of the image

##docker history image name or image ID
% docker history docker-whale

You can check the history of docker-whale.

Recommended Posts