Docker Practice (ii) Main concepts and commands __docker

The previous section learned and practiced the foundation and installation of Docker, and this section mainly studies the main concepts and commands of Docker

Docker has three core concepts: Mirroring, container, warehouse one, mirroring

Docker mirroring is a precondition for running a container, and if there is no mirror locally, Docker will attempt to download from the default Mirror warehouse (Docker hub), and users can configure their own private warehouses to download mirrors from a private warehouse, which is important so that enterprise applications can use their own warehouses, Solve the security risks.

1. Get Mirror

The command to get the mirror is: Docker pull Ubuntu

Executing this command will take the last version of Ubuntu (Docker) from the official library, both: Pull Registry.hub.docker.com/ubuntu:latest

If you want to get a specific version of tag, the command is: Docker pull ubuntu:14.04

If you want to get from a private library, the command is: Docker pull 192.168.136.177:5000/ubuntu here 192.168.136.177:5000 is its own private warehouse

After downloading, you can perform the run command such as: Docker run-t-I Ubuntu/bin/bash

2. View mirror Information

Using commands: Docker images can view mirrored information in the current Docker environment

[root@dev-177 ~]# Docker images REPOSITORY TAG IMAGE ID CREATED                        SIZE 192.168.136.177:5000/appname ubuntu 710477b8876f hours ago 560MB appname          Ubuntu 710477b8876f hours ago 560MB ssh Dockerfile        319c7aa50a7f 2 days ago 206MB Ubuntu latest 0458A4468CBC 4 days ago 112MB Registry Latest d1fd7d86a825 2 weeks ago 33                3MB Hello-world latest f2a91732366c 2 months ago 1.85kB Sameersbn/redis               Latest d8f7b0e07097 6 months ago 203MB Sameersbn/gitlab 8.4.4        9d1069e2b30c months ago 720MB sameersbn/redmine 3.2.0-4 7eb43870e9c7 2 years ago 636MB Sameersbn/postgresql 9.4-12 a100f2a18ec3 2 years ago 231MB [root@dev-177 ~]#  

Here is the name, the most important of the several fields:

REPOSITORY explains what warehouse the mirrors are from

Tag mirror tag, used to differentiate versions

Unique identification of image_id mirrors

There are two mirrors: 192.168.136.177:5000/appname and appname mirroring, their IDs are the same, the same mirror, the IP address is generated by the Docker tag command, pointing to the same mirror

After this is specified, you can push into your own private warehouse 192.168.136.177:5000.

To view more detailed information, you can use the command: Docker inspect image_id to view a specific mirror information

3, Find, delete

Find command: Docker search keyword

Delete by mirror name: Docker RMI Mirror Name

Delete by Mirror ID: Docker RMI Mirror ID deletes all mirror name references to this ID

If mirroring is used by a container, it cannot be deleted unless the-f parameter is used to Docker rmi-f Mirror ID

To view the mirrors currently used by the container: Docker ps-a

In principle: First remove the container that uses the mirror, and then remove the mirror

4. Create Mirror:

There are 2 ways to create a mirror: Commit or use a Dockerfile file

When we are in the running container, after modifying some content, we can use the commit command to create

Docker commit-m Modify Content-a author container ID mirror name

Using the Dockerfile file, the following commands are involved:

1) from

Must be the first instruction indicating which base version the mirror inherits from

2) Maintainer

Maintenance information, which is the maintenance of this image

3) RUN

You can use the shell terminal or Exec method to perform

4) CMD

After the container starts, execute the command, each dockerfile can only have a cmd command

5) Expose

Exposed port number

6) ENV

environment variable, used by subsequent run instructions

7) ADD

Copy command, ADD src dest, src can be dockfile directory as a relative path to the root directory, can be a URL, or compressed files

8) COPY

Copy copy src dest, src is a directory

9) entrypoint

Entry point of container

The other slightly, below shows an example of a dockfile file

#继承于镜像ubuntu from Ubuntu #维护人员 maintainer Chen weiqun<cwqsolo@163.com> #更新源 run apt-get update #安装ssh run AP T-get install-y openssh-server #安装vim run apt-get install-y vim #创建sshd service run mkdir-p/var/run/sshd run mkdir-p /root/.ssh #取消pam登录限制 run Sed-ri ' s/^permitrootlogin\s+.*/permitrootlogin yes/'/etc/ssh/sshd_config run Sed-ri ' s/  Usepam yes/#UsePAM yes/g '/etc/ssh/sshd_config #添加认证文件和启动脚本 add authorized_keys/root/.ssh/authorized_keys Add run.sh /root/run.sh #修改确保run. SH Execute permissions run chmod u+x/root/run.sh #暴露端口 expose # #install JDK and TOMCAT run Mkdir-p/US R/java RUN mkdir-p/work ADD jdk-7u80-linux-x64.gz/usr/java/add tomcat/work/#设置环境变量 ENV java_home=/usr/java/jdk1.7 .0_80 classpath= $JAVA _home/lib/dt.jar: $JAVA _home/lib/tools.jar path= $PATH: $JAVA _home/bin RUN Echo java_home=/usr/ Java/jdk1.7.0_80\ncalsspath= $JAVA _home/lib/dt.jar: $JAVA _home/lib/tools.jar\npath= $PATH: $JAVA _home/bin ">> /etc/profile #暴露tomcat端口 expose 8080 EXPOSE 8009 expose 8443 #修改tomcat目录中执行的权限 RUN chmod u+x/work/app-tomcat/bin/*.sh #设置默认启动的命令 CMD ["/root/run.sh"]


 

5. Import and export of mirrors

Export to tar file: Docker save-o mirror image. Tar Mirror name: TAG

Import: Docker load--input mirror. Tar

6, Upload image

Docker Push Name[:tag]

Docker push [library]name[:tag]


second, the container

A container is a running instance of a mirror, and a mirror can run multiple containers. Each container is self-contained, containing one or a set of applications for mirroring and the required operating environment.

1) Create a container

Command: Docker create it mirror name: TAG

You can create a mirror, but it doesn't work.

2) Run

Command: Docker start container ID

Start a container

3 can be created and run together

Command: Docker run Ubuntu/bin/echo "Hello"

This command creates a container based on the Ubuntu image and runs the echo command

4) Terminate and delete containers

Terminate command: Docker stop container ID

Delete Container: Docker RM container ID

5 Import and export of containers

Export: Docker export container ID > export file. tar

Import: Cat export file. Tar | Docker Import-Library/Mirror name: TAG

Import of a container differs from the import of a mirror: the import of a container, which is only the current container mirror, does not contain historical information and metadata. After importing, you can see a mirror that just imported in the mirror.

third, the warehouse

1. Official Warehouse

Docker provides the official warehouse, after installing the Docker environment, using the Pull command is to download the mirror from the official warehouse. Because the enterprise application considers the security problem, will request the Enterprise Library and the network storehouse to have the isolation, therefore the following key point next private storehouse

2. Private Warehouse

1) Download and start the private warehouse

A private warehouse consists of a private warehouse stored in a warehouse management container. Docker provides a registry container to manage the warehouse,

Using commands: Docker run-d-P 5000:5000-v/opt/data/registry:/tmp/registry Registry

This command, is in the local 5000 port, create a private library, storage location: The/opt/data/registry of the machine. Registry is the name of the warehouse management container that the website downloads

When it starts, the warehouse starts to work.

2 use of private warehouses

Docker tag Image[:tag] [Registryhost/][username/]name[:tag]

Downloading mirrors from a private library

such as: Docker pull 192.168.136.177:5000/appname:ubuntu

View mirrors of a private library

[root@work-199 ~]# curl-xget  http://192.168.136.177:5000/v2/_catalog
{"repositories": ["AppName"]}

Iv. Other

1, Docker download the image of how to store

[root@dev-177 docker]# pwd
/var/lib/docker
[root@dev-177 docker]# ls-  l
total dosage
drwx------.  2 root root   24 December 15:34 builder
drwx------.  4 root  150 January  19:55 containers
drwx------.  3 root   21 December 15:34 image
drwxr-x---.  3 root   19 December 15:34 network
drwx------.  19:55 overlay
drwx------. 
  
   4 root root   32 December 15:34 plugins
drwx------.  2 root root    6 December 15:34 swarm
drwx------.  2 root    6 January  19:52 tmp
drwx------.  2 root    6 December 15:34 Trust
drwx------. root 4096 January  17:17 volumes