Docker Foundation Summary

by do son · Published · Updated

Docker Foundation Summary

Docker introduction

  • Docker client and server (daemon)
  • Docker image
  • registry
  • Docker container

Docker container is built on the mirror above, we can understand the image as a defined class, and the container is an instance, a class can instantiate a lot of examples, the same docker can also run on the mirror multiple containers, each The container can be the same or it can be customized. Docker client and server can run on the same host, can also be different.
The registry is used to store the user’s image, which is divided into public and private. Docker company operating public registry called docker hub, the user can docker hub registered account, share and save their own mirror.

Docker install

Docker can run on Linux, Mac, Windows.

Install docker

Go to the official website to download the installation package.
download after the direct installation, the installation is completed after the run docker run hello-world, if no error, indicating a successful installation.

Install docker on Linux

Install docker:

sudo apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D

sudo apt-add-repository 'deb https://apt.dockerproject.org/repo ubuntu-xenial main'

sudo apt-get update

apt-cache policy docker-engine

sudo apt-get install -y docker-engine

 

Start the docker daemon:

sudo service docker start

sudo /etc/init.d/docker start

 

 

Docker basic command

The docker base command contains the docker operation, the mirror operation, the container operation, and other related operations. Here are some common commands, please refer to the official documentation, or use the -help command.

Docker operation

View the docker information

$docker info

Containers: 1  

 Running: 1   

 Paused: 0

 Stopped: 0

Images: 5  

Server Version: 1.12.3

......

 

View the docker version

$docker -v

Docker version 1.12.3, build 6b644ec

$docker version

Client:

 Version:      1.12.3

 API version:  1.24

 Go version:   go1.6.3

 Git commit:   6b644ec

 Built:        Wed Oct 26 23:26:11 2016

 OS/Arch:      darwin/amd64

Server:

 Version:      1.12.3

 API version:  1.24

 Go version:   go1.6.3

 Git commit:   6b644ec

 Built:        Wed Oct 26 23:26:11 2016

 OS/Arch:      linux/amd64

 

 

Mirror operation

Local images are stored in the /var/lib/docker directory.
View the local mirror list:

docker images -a

 

Other mirroring operations:

docker search (image-name) 

docker history (image-name) 

docker push (image-name) 

docker pull image-name:tag pull

docker rmi  <image id>  

docker rmi $(docker images -q) 

docker tag image-id imagename:tag 

docker load -i test.tar 

docker save image > test.tar

 

Container operation

Create a container:

docker run --rm -ti ubuntu /bin/bash

 

 

  • -rm Once the process exits, the container is deleted
  • -ti Enter interactive mode
  • Ubuntu container based on the mirror name
  • /bin/bash The command to run
docker run -d -p 8000:80 --name test image-name

 

  • -d running in the background
  • -p mapping of the port, the former for the machine, after the container
  • -name custom name

Note: After creating the container, it will return an ID that is generated randomly.

Check container operating status:

docker ps -a

 

View container-specific information:

docker inspect

 

More detailed than the ps-a command, including network information, configuration information, and other content, you can match with -format, such as:

sudo docker inspect --format '{{ .NetworkSettings.IPAddress }}' c18acd6a8a32

 

View the process inside the container:

docker top container_id

 

Into the container interior:

sudo docker attach container_id

 

Or you can use:

docker exec -ti container_name /bin/bash

 

Exec command can be executed inside the container command, the above code that the container to create a new shell.

Exit container:

[rootq3e1]exit

 

Reboot container:

drocker run —restart=always

 

The restart parameter can set the following:

  • The Docker container is restarted regardless of the code program exiting the container
  • On-failure You can specify an exit code

More container operation:

docker attach container 

docker diff  container 

dcoker logs ID

docker stop ID

docker start ID 

docker restart ID  

docker stop ID docker rm ID  

docker kill [options] container 

docker stop $(docker ps -a -q) 

docker rm $(docker ps -a -q)  

docker commit ID new

docker export container > test.tar 

docker cp container:path hostpath

 

Container network management:

  • Host mode, the use of dockerrun use -net = host specified (docker used in the network and the host is actually the same, in the container to see the network card ip is the host ip)
  • Container mode, use-net = container: container_id/container_name (multiple containers using a common network, see ip is the same)
  • None mode, specified with -net = none (in this mode, no network is configured)
  • Bridge mode, specified with -net = bridge
  • The default mode, do not specify the default is this network mode. (This mode assigns a separate Network Namespace to each container, similar to VMware’s nat network mode. All containers on the same host will be able to communicate with each other under the same network segment.)

Other operation

docker import http://example.com/example.tar  

docker login [options][server] 

docker inspect container/image  

docker wait container

 

Dockerfile

Dockerfile can be used to dynamically generate a new image, for example, we pull a basic centos mirror, now need to install some of the software in this mirror, so that we can run the project code we prepared, then you can use the following two options:

Option 1: (manual)

In the centos mirror to create a container, enter the container interactive interface, manually install some of the necessary software, configure the environment. After doing all the changes, use the docker commit container-id newimagename to create a new image. Then use the new image to create the container, run our project code.

Option 2: (automatic)

The so-called automation, that is, do not need to enter the container manually enter the command to configure, everything is automatically handled when the container is running, then it will use the dockerfile. Dockerfile is simply a configuration file, docker container at run time will handle the contents of the file, such as the installation of software, modify the environment variables, run the program. The advantage of using dockerfile is that you can easily modify the contents of the configuration file to achieve the effect of creating dynamic images.

Create a dockerfile

We need to create a directory to store Dockerfile file, the directory name can be arbitrarily taken in the directory to create Dockerfile file. Here I am going to create a base based on centos mirror, the container will automatically open a python webserver (local monitor 8080 port) example.

Write a dockerfile

In the Dockerfile file to write:

# Version 0.1

FROM centos:latest

MAINTAINER https://securityonline.info

RUN apt-get install wget

CMD python -m SimpleHTTPServer 8080

 

The dockerfile syntax is similar to MakeDown, based on the following:

  • FROM based on the base mirror name
  • MAINTAINER maintainer information
  • RUN run command (install software, etc.)
  • CMD command to run the container (can only write one)

Grammar more than these, more content, you can refer to the official documents.

Generate dockerfile image

Into the directory where the Dockerfile file is located, run:

docker build -t centos_test:01 .

docker build -t centos_test:01 git@github:......

 

At this point, run docker images-a view, will find more than one image, named centos_test, tag 01 If dockerfile write a problem, in the build will be given, then you can docker run container id into the final state of the container to debug.

Use dockerfile to mirror

Run the container on this image:

docker run -d -p 80:8080 centos_test:0.1

 

At this point, open the machine 127.0.0.1:80

Dockerfile rules

Each instruction must be in uppercase letters, such as FROM, RUN, and followed by content, docker file will be from the top down the order of the implementation of these content.

WORKDIR

Role: set the working directory, similar to cd

WORKDIR /root/

RUN apt-get install pip

WORKDIR /root/test

......

 

You can override the container working directory with the -w parameter

docker run -w /root/nmasktools ......

 

ENV

Action: Set the environment variable
in the container to be overridden with -e.

USER

Role: Specify what kind of user to run the container

USER ddos

 

You can use the docker-u to cover it.

ADD, COPY

Add and copy are used to add a file to the mirror, the difference is that copy can only copy the file, but no decompression function.

Tags: docker