Core concepts
Docker has three core concepts: image, container and warehouse.
Docker image
The Docker image is similar to the image of a virtual machine. It can be understood as a read-only template. For example, an image can contain a basic operating system environment in which only Apache applications are installed. It can be called an Apache image.
Image is the basis for creating Docker container.
Through version management and incremental file system, Docker provides a very simple mechanism to update the existing image. Users can even download a completed application image from the Internet and use it.
Docker container
Docker container is similar to a lightweight sandbox. Docker uses containers to run and isolate applications.
Containers are application running instances created from the image. They can start and stop deletion. These containers are isolated from each other and invisible to each other.
Think of the container as a simple Linux system environment and a box of applications running in it.
Docker warehouse
The Docker warehouse is similar to the code warehouse. It is the place where Docker stores image files in a centralized manner.
Docker warehouse can be divided into public warehouse and private warehouse according to whether the saved image is public or not.
Install Docker engine
The following example is to install docker under Windows
- Visit the homepage of the official website.
- Click Apply now to select the windows version to download
- Click project to install
- Install
- Verify successful installation
Open powershell and enter docker
In this way, the windows version of docker has been installed
Using Docker mirroring
The docker image is used as follows
Get image
To obtain the docker image, use the following command.
Enter the command to obtain the docker image
docker pull ubuntu
From the download process, we can see that for the docker container, the image file is generally composed of several layers,
Each string is a unique id. when using the pull command of docker, the relevant images will be downloaded layer by layer, and the image from the previous layer will point to the image from the previous layer.
View mirror information
Use the images command of docker to view the image information of docker.
The image information of docker is listed in images above.
Use the tag command to add the label of the image
To facilitate the use of docker images, use the docker tag command to add the docker image label.
docker tag ubuntu:latest myubuntu:laster
The effect is as follows
Use the inspect command to view the docker details
docker image inspect ubuntu
See the following information
PS C:\Users\Administrator\Desktop> docker image inspect ubuntu
[
{
"Id": "sha256:74435f89ab7825e19cf8c92c7b5c5ebd73ae2d0a2be16f49b3fb81c9062ab303",
"RepoTags": [
"myubuntu:laster",
"ubuntu:latest"
],
"RepoDigests": [
"ubuntu@sha256:35c4a2c15539c6c1e4e5fa4e554dac323ad0107d8eb5c582d6ff386b383b7dce"
],
"Parent": "",
"Comment": "",
"Created": "2020-06-17T01:20:56.323568224Z",
"Container": "9477bb1d88721b63e0c6a359eb48a081741a0992480bf34bbcebf4e5734fcf67",
"ContainerConfig": {
"Hostname": "9477bb1d8872",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
],
"Cmd": [
"/bin/sh",
"-c",
"#(nop) ",
"CMD [\"/bin/bash\"]"
],
"ArgsEscaped": true,
"Image": "sha256:5412cfe47ff528df823761788f99a11568e2d25f48a4245a3d67cdc3e564c839",
"Volumes": null,
"WorkingDir": "",
"Entrypoint": null,
"OnBuild": null,
"Labels": {}
},
"DockerVersion": "18.09.7",
"Author": "",
"Config": {
"Hostname": "",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
],
"Cmd": [
"/bin/bash"
],
"ArgsEscaped": true,
"Image": "sha256:5412cfe47ff528df823761788f99a11568e2d25f48a4245a3d67cdc3e564c839",
"Volumes": null,
"WorkingDir": "",
"Entrypoint": null,
"OnBuild": null,
"Labels": null
},
"Architecture": "amd64",
"Os": "linux",
"Size": 73856440,
"VirtualSize": 73856440,
"GraphDriver": {
"Data": {
"LowerDir": "/var/lib/docker/overlay2/63e1c7f313e414bd5465953da0ceb615cc9c5906c9b539ed164560b18020bc85/diff:/var/lib/docker/overlay2/09f0332099bc97d0052e07879f18271f2c7ea879501498a1eca00711065c9e9a/diff:/var/lib/docker/overlay2/8fef100fbab32d7aa7a3cc70740ef97b45cc9dcfce91453dd10cc502a3fa10f7/diff",
"MergedDir": "/var/lib/docker/overlay2/3ec5eeae7aa3781aa605fa1a1dc598c39d7774796600b3c1f86e8190c24d5a47/merged",
"UpperDir": "/var/lib/docker/overlay2/3ec5eeae7aa3781aa605fa1a1dc598c39d7774796600b3c1f86e8190c24d5a47/diff",
"WorkDir": "/var/lib/docker/overlay2/3ec5eeae7aa3781aa605fa1a1dc598c39d7774796600b3c1f86e8190c24d5a47/work"
},
"Name": "overlay2"
},
"RootFS": {
"Type": "layers",
"Layers": [
"sha256:e1c75a5e0bfa094c407e411eb6cc8a159ee8b060cbd0398f1693978b4af9af10",
"sha256:9e97312b63ff63ad98bb1f3f688fdff0721ce5111e7475b02ab652f10a4ff97d",
"sha256:ec1817c93e7c08d27bfee063f0f1349185a558b87b2d806768af0a8fbbf5bc11",
"sha256:05f3b67ed530c5b55f6140dfcdfb9746cdae7b76600de13275197d009086bb3d"
]
},
"Metadata": {
"LastTagTime": "2020-07-06T13:37:35.064486339Z"
}
}
]
Use the history command to view the mirror history
docker history ubuntu
PS C:\Users\Administrator\Desktop> docker history ubuntu IMAGE CREATED CREATED BY SIZE COMMENT 74435f89ab78 2 weeks ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B <missing> 2 weeks ago /bin/sh -c mkdir -p /run/systemd && echo 'do... 7B <missing> 2 weeks ago /bin/sh -c set -xe && echo '#!/bin/sh' > /... 811B <missing> 2 weeks ago /bin/sh -c [ -z "$(apt-get indextargets)" ] 1.01MB <missing> 2 weeks ago /bin/sh -c #(nop) ADD file:b2342c7e6665d5ff3... 72.8MB PS C:\Users\Administrator\Desktop>
Search for related images
Search the image of official keyword with nginx
PS C:\Users\Administrator\Desktop> docker search --filter=is-official=true nginx NAME DESCRIPTION STARS OFFICIAL AUTOMATED nginx Official build of Nginx. 13426 [OK] PS C:\Users\Administrator\Desktop>
Deleting and cleaning up mirrors
Image related deletion
Deleting a mirror using a label
docker rmi ubuntu
PS C:\Users\Administrator\Desktop> docker rmi ubuntu Untagged: ubuntu:latest Untagged: ubuntu@sha256:35c4a2c15539c6c1e4e5fa4e554dac323ad0107d8eb5c582d6ff386b383b7dce PS C:\Users\Administrator\Desktop>
Delete a mirror using the mirror ID
PS C:\Users\Administrator\Desktop> docker images REPOSITORY TAG IMAGE ID CREATED SIZE myubuntu laster 74435f89ab78 2 weeks ago 73.9MB ubuntu latest 74435f89ab78 2 weeks ago 73.9MB PS C:\Users\Administrator\Desktop> docker rmi ubuntu Untagged: ubuntu:latest Untagged: ubuntu@sha256:35c4a2c15539c6c1e4e5fa4e554dac323ad0107d8eb5c582d6ff386b383b7dce PS C:\Users\Administrator\Desktop> docker images REPOSITORY TAG IMAGE ID CREATED SIZE myubuntu laster 74435f89ab78 2 weeks ago 73.9MB PS C:\Users\Administrator\Desktop> docker rmi 74435f89ab78 Untagged: myubuntu:laster Deleted: sha256:74435f89ab7825e19cf8c92c7b5c5ebd73ae2d0a2be16f49b3fb81c9062ab303 Deleted: sha256:8a8d1f0b34041a66f09e49bdc03e75c2190f606b0db7e08b75eb6747f7b49e11 Deleted: sha256:f1b8f74eff975ae600be0345aaac8f0a3d16680c2531ffc72f77c5e17cbfeeee Deleted: sha256:27d46ebb54384edbc8c807984f9eb065321912422b0e6c49d6a9cd8c8b7d8ffc Deleted: sha256:e1c75a5e0bfa094c407e411eb6cc8a159ee8b060cbd0398f1693978b4af9af10 PS C:\Users\Administrator\Desktop> docker images REPOSITORY TAG IMAGE ID CREATED SIZE PS C:\Users\Administrator\Desktop>
Clean up mirror
Clean up using docker images
PS C:\Users\Administrator\Desktop> docker image prune WARNING! This will remove all dangling images. Are you sure you want to continue? [y/N] y Total reclaimed space: 0B PS C:\Users\Administrator\Desktop> docker images REPOSITORY TAG IMAGE ID CREATED SIZE PS C:\Users\Administrator\Desktop>
create mirror
Create a mirror based on an existing container
View the list of running containers
PS C:\Users\Administrator\Desktop> docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES ff7a974b9771 nginx "/docker-entrypoint...." About a minute ago Up About a minute 80/tcp fervent_curie
Create related containers
docker container commit -m "ming" -a "mingming" ff7a974b9771 test:0.1
View again
PS C:\Users\Administrator\Desktop> docker images REPOSITORY TAG IMAGE ID CREATED SIZE test 0.1 54a6eb8d4483 5 seconds ago 132MB ubuntu latest 74435f89ab78 2 weeks ago 73.9MB nginx latest 2622e6cca7eb 3 weeks ago 132MB PS C:\Users\Administrator\Desktop>
The complete process is shown in the following figure
Create using template
https://download.openvz.org/t...
Download related templates
Import related images
cat centos-6-x86-minimal.tar.gz|docker import - centos6
Create using dockerFile
# Construction phase FROM node # assign work directory WORKDIR / # Specify work port EXPOSE 4000 # Installing gitbook RUN npm install gitbook -g; RUN npm install gitbook-cli -g; # Pull file RUN git clone https://github.com/mySoul8012/SE-Basic-knowledge.git # Enter directory WORKDIR /SE-Basic-knowledge # Initialize mirroring RUN gitbook init CMD ["gitbook", "serve"]
Import built image
docker image build -t ming:0.1
Saving and loading images
Save out image
PS C:\Users\Administrator\Desktop> docker save -o ubuntu.tar ubuntu PS C:\Users\Administrator\Desktop>
Load image
PS C:\Users\Administrator\Desktop> docker load -i ubuntu.tar Loaded image: ubuntu:latest PS C:\Users\Administrator\Desktop> docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES ff7a974b9771 nginx "/docker-entrypoint...." 12 minutes ago Up 12 minutes 80/tcp fervent_curie PS C:\Users\Administrator\Desktop> docker images REPOSITORY TAG IMAGE ID CREATED SIZE test 0.1 54a6eb8d4483 10 minutes ago 132MB ubuntu latest 74435f89ab78 2 weeks ago 73.9MB nginx latest 2622e6cca7eb 3 weeks ago 132MB PS C:\Users\Administrator\Desktop>
Upload image
Upload image to docker
PS C:\Users\Administrator\Desktop> docker push test The push refers to repository [docker.io/library/test] 53d99160caf2: Preparing f978b9ed3f26: Preparing 9040af41bb66: Preparing 7c7d7f446182: Preparing d4cf327d8ef5: Preparing 13cb14c2acd3: Waiting denied: requested access to the resource is denied PS C:\Users\Administrator\Desktop>
You can see the rejection. Log in to the account first
docker login Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one. Username: melovemingming Password: Login Succeeded
Then upload the file
docker push melovemingming/nginx
Note that the uploaded image format must be user name / image name
View the docker hub to see the uploading of docker images
You can see that the docker image has been uploaded