Docker

1. A Docker Image is a read-only template. Images can be used to create Docker containers, and one image can create many containers

A container is an object, and a mirror is a class

Student s1 = new Student() Student s2=new Student() Student s3=new Student()

Student is a template, a mirror image.

The warehouse is where the image is stored

Official summary:

Dokcer uses a Container to run one or a group of applications independently. Containers are running instances created with images.

It can be started, started, stopped, and deleted. Each container is an isolated, secure platform.

Think of the container as a simplified version of the Linux environment.

Why Docker

1. Lighter weight: Container-based virtualization, which only contains the runtime environment required for service running. The CentOS/Ubuntu basic image is only 170M. Hosts can deploy 100-1000 containers

2. More efficient: No OPERATING system virtualization overhead

3. Be more agile and flexible

The container is a simplified version of the Linux virtual machine environment, stripped of some hardware.

You can’t create a container without an image, that’s the basic premise

1. Create and start a container:

docker run [options] image[command][arg...]
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Some have one minus sign, some have two minus signs

– name= “New container name” Specifies a name for the container

-d: Runs the container in the background and returns the container Id, that is, starts the daemon container

-I: Runs the container in interactive mode, usually in conjunction with -t

-t: reassigns a pseudo-input terminal to the container. It is usually used together with -i.

-p: indicates random port mapping

-p: specifies the port mapping. The value can be in the following formats

​ ip:hostPort:containerPort

​ ip::containerPort

​ hostPort:containerPort

​ containerPort

Docker runit Imageid interactively starts the Dockers image to generate container instances. Docker PS lists all running containers to see which containers are loadedCopy the code

docker ps [options]

Docker Ps-N 3 Last 3

-q: displays only container ids in silent mode

– no-trunc: does not truncate the output

Exit the container in two ways

Enter the running container and interact with it on the command line

Docker execit container id ls -l/TMP can be viewed from the outside, while attach can be attached to the inside

Docker exec -it Container ID bashShell

Re-enter the Docker Attach container ID

Attach directly enters the terminal of the container start command and does not start a new process

Exec opens a new terminal in the container and can start a new process

Start the container

Stop container Docker stop force stop docker kill

Delete stopped containers

Delete multiple containers at once

docker rm -f $(docker ps -a -q)

docker ps -a -q|xargs docker rm

Start a container in background mode

docker run -d centos

Problem: Then docker ps-a to check, will find that the container has quit, it is important to clarify a point: Docker container background operation, there must be a foreground process. Commands run by the container that are not always suspended (such as running top,tail) will exit automatically.

The dockers mechanism problem, such as your Web container, let’s take nginx as an example. Normally, we configure to start the service just by starting the responding service. For example, service nginx start. However, if nginx runs in daemon mode, there will be no applications running in the Docker foreground. Such a container will commit suicide immediately after it starts in daemon mode because it feels it has nothing more to do. Run the program as a console process

Viewing container Logs

Docker logs -f -t –tail Container ID

-t is to add the timestamp -f follows the latest log print –tail number shows the last number

Docker logs -f-t –tail 3

Docker Top Container ID of the process running in the container

Docker inspect Container ID

Copy files from container to host docker cp Container ID: path Path

Image: An image is a lightweight, executable, standalone package used to package a software runtime environment and software developed based on the runtime environment. It contains everything needed to run a piece of software, including code, runtime, libraries, environment variables, and configuration files

Docker run it -p 8888:8080 tomcat Starts Tomcat

Docker data volume synchronization Docker run-it -v/Host absolute path directory :/ The image name of the directory in the container is unlimited

Docker data volume synchronization Docker run-it -v/Host absolute path directory :/ Container directory :ro Image name Not limited Yes Protection restrictions

The DockerFile architecture (reserved word directives) must be all uppercase

FORM Base image, which image the current new image is based on

MAINTAINER New name and email address of the image MAINTAINER

RUN Command to RUN when the container is built

EXPOSE The port that the current container object exposes to the public

WORKDIR Specifies the working directory, a landing point, that the terminal logs in to by default after creating the container

ENV is used to set environment variables during image building

ENV MY_PATH /usr/mytest This environment variable can be used in any subsequent RUN directive, just as it was specified before the command; You can also use these environment variables directly in other directives, such as WORKDIR $MY_PATHCopy the code

ADD copies files in the host directory to the image, and the ADD command automatically processes the URL and decompresses the tar package

COPY Is similar to ADD. Copies files and directories to an image. Copy files/directories from the < source path > directory in the build context directory to the < destination path > location within the image in a new layer

VOLUME A VOLUME used for data storage and persistence

CMD specifies the command to run when a container is started. There can be multiple CMD commands in the Dockerfile, but only the last one takes effect, and CMD is replaced by the argument after the docker run

ENTRYPOINT specifies the command to run when a container is started. The purpose of ENTRYPOINT, like CMD, is to specify the container launcher and parameters

ONBUILD When the command is run to build an inherited Dockerfile, the ONBUILD of the parent image is triggered when the quilt inherits the parent image

Base Images (Scratch) 99% of the images in Dokcer Hub are built by installing and configuring the required software in the Base image

FROM centos
MAINTAINER HYF

ENV MYPATH /usr/local
WORKDIR $MYPATH

RUN yum -y install vim
RUN yum -y install net-tools

EXPOSE 80

CMD echo $MYPATH
CMD echo "success--------ok"
CMD /bin/bash 
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The FROM centos MAINTAINER hyf # hosting c.t xt COPY of the current context to the container/usr/local/directory COPY c.t xt/usr/local/cincontainer. TXT # Java with tomcat Usr /local/ ADD apache-tomcat-9.0.8.tar.gz /usr/local/ # install vim editor RUN yum -y Install vim # install vim # install vim # Configure the Java and Tomcat environment variables ENV JAVA_HOME /usr/local/jdk1.8.0_171 ENV CLASSPATH $JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar ENV CATALINA_HOME /usr/local/apache-tomcat-9.0.8 ENV CATALINA_BASE /usr/local/apache-tomcat-9.0.8 ENV PATH $PATH:$JAVA_HOME/bin:$CATALINA_HOME/LIB:$CATALINA_HOME/bin # ENTRYPOINT ["/usr/local/apache-tomcat-9.0.8/bin/startup.sh"] # CMD ["/usr/local/apache-tomcat-9.0.8/bin/catalina.sh","run"] CMD /usr/local/apache-tomcat-9.0.8/bin/startup.sh && tail -f / usr/local/apache tomcat - 9.0.8 / bin/logs/catalina. OutCopy the code

docker run -d -p 9080:8080 --name myt11 -v / zzyyuse/mydockerfile/tomcat9 / test: / usr/local/apache tomcat - 9.0.8 / webapps/test - v / zzyyuse/mydockerfile/tomcat9 tomcat9logs / : / usr/local/apache tomcat - 9.0.8 / logs - ring = true zzyytomcat9Copy the code