docker tutorial

docker deployment scheme

  

1. Engine introduction                                                                                          

         1.1 Difference between docker and virtual machine

              The process in the container runs in the host kernel, which is the same as the host process, except that the user space of the container is different, which is provided by the container image, that is, the image provides rootfs. The docker container is just a process, which uses the rootfs provided by the image to provide the library support of the user space required for the call, so that the process is carried out in a controlled environment.

         1.2 image Mirror image

              An image is a lightweight, executable, stand-alone software package that contains everything needed to run a piece of software, including code, runtime, libraries, environment variables, and configuration files. The image adopts a hierarchical storage structure,

         1.3 container container

                   A container is an instance of an image running. Containers run applications natively on the host kernel. Each container runs in an independent process, taking up no more memory than any other executable.

         1.4 docker swarm

                   Swarm is an officially designated cluster management tool. It can convert a system composed of multiple docker hosts into a single virtual docker host, so that containers can form a subnet network across hosts.

         1.5 docker compose

                   Compose is a tool for orchestrating multi-container distributed deployments, providing a command set to manage the complete development cycle of containerized applications, including service build, start, and stop.

         1.6 docker machine

                   DockerMachine is an official management tool that supports remote management of docker containers.

 

2. Installation and deployment

         2.1 Environment configuration

                   Docker currently mainly has CE Community Edition and EE Enterprise Edition. Currently using the CE version, the old version of docker is called docker or docker-engine. If they are already installed, uninstall their related dependencies first.

        yum remove docker \

                  docker-client \

                  docker-client-latest \

                  docker-common \

                  docker-latest \

                  docker-latest-logrotate \

                  docker-logrotate \

                  docker-selinux \

                  docker-engine-selinux \

                  docker-engine

         Docker-ce officially recommends setting up the docker repository for installation, which is conducive to future upgrades.

         2.2 Repository Installation

                   1. Install the required packages. yum-utils provides the yum-config-manager utility, and device-mapper-persistent-data and lvm2 are required by the devicemapper storage driver.

Excuting an order:

        yum install -y             yum-utils \

             device-mapper-persistent-data \

             lvm2

                   2. Set up a stable repository. The official website installation version adopts the official source. It is recommended to use the domestic source Ali source.

                     Official source: https://download.docker.com/linux/centos/docker-ce.repo

                     Ali source: http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

Excuting an order:

        yum-config-manager \

                --add-repo\

                https://download.docker.com/linux/centos/docker-ce.repo

                   3. The installation requires a version of docker-ce. There are currently multiple versions. Install the corresponding stable version according to the actual needs of your project.

         This deployment installs version 17.09.1.ce-1.e17.centos.

        yum install docker-ce-<VERSION STRING>       

          yum install docker-ce-17.09.1.ce

         4. Set boot up

        systemctl enable docker

5. Start docker and test the hello-world image

        systemctl start docker

If it fails, check /etc/docker/daemon.json and add {"storage-driver":"devicemapper"}

        docker run hello-world

       2.3 Configuring the accelerator

                   1. The dockerpull image requires an accelerator, and currently free and registration-free sources are available.

                            Docker official China image acceleration: https://registry.docker-cn.com

                            Mirror acceleration of the University of Science and Technology of China: https://docker.mirrors.ustc.edu.cn

                   2.centos7 acceleration configuration

                systemctl enable docker

         vi /etc/systemd/system/multi-user.target.wants/docker.service

                   3. Save and exit, restart to load the configuration and start the service

        systemctl daemon-reload

        systemctl restart docker

                   4. The devicemapper is used for storage when centos is deployed. It is not recommended to use the type of loopback storage.

         dockerinfo will generate a warning alert.

         The centos environment adopts loop-lvm mode by default, and direct-lvm is recommended for the production environment.

         For configuration, please refer to: https://blog.csdn.net/bobpen/article/details/68924208

       2.4 Security Configuration

                   1. The docker server needs to configure the TLS security configuration when binding the port.

        使用 -H tcp://... 需要配置--tlsverify权限或者使用docker-machine进行宿主管理，会自动创建证书配置TLS

       2.5 docker-compose installation

                   1. docker-compose is a tool responsible for the rapid installation and deployment of docker container clusters. By configuring the docker-compose.yml file, a group of associated application containers is defined as a project. There are two important concepts in compose: ① Service: An application container can contain several container instances of the same image. ②Project: A complete business unit consisting of a set of associated application containers, defined by the docker-compose.yml file.

                   2. Compose supports python pip installation, you can also download the compiled binary files directly, or you can run them in a docker container. The first two traditional installation methods are suitable for installation and use in the local environment; the docker installation does not damage the system environment and is suitable for cloud computing scenarios.

                   Binary package installation:

        curl -L https://github.com/docker/compose/releases/download/1.17.1/docker-compose-`uname -s`-`uname -m` > /usr/local/bin/docker-compose

        chmod +x /usr/local/bin/docker-compose

                   This deployment download version 1.17.1 with docker-ce-17.09.1

                   pip install:

        pip install -U docker-compose

3. Use the tutorial

         3.1 container container

                   When building a docker application, the container is the lowest level in the docker hierarchy. The next level up is services. The highest level is the stack, which defines the interaction of all services.

         Getting Started Tutorial: https://www.dubby.cn/detail.html?id=8734

         3.2 service service

                   In distributed applications, different parts of the application are called services. In docker, a service is actually a container in an application. "A service runs only one mirror, but it orchestrates how the mirror runs -- using that port, how many replicas (replicas, that is, multiple instances) are needed to meet the needs, etc." Scaling a service is changing the number of containers running for that service. Use docker-compose.ymlk to configure management.

         Getting Started Tutorial: https://www.dubby.cn/detail.html?id=8735

         3.3 swarm cluster

                  dokcer swarm: cluster management, subcommands include init, join, join-token, leave, update

                   dockernode: Node management, subcommands include demo, inspect, ls, promote, rm, ps, update

                   dockerservice: service management, subcommands include create, inspect, ps, ls, rm, scale, update

                   dockerstack: Orchestrate a group of related servers for unified management

                  Getting Started Tutorial: https://www.dubby.cn/detail.html?id=8738

       3.4 stack stack

                   A stack is a combination of related services that can be orchestrated and managed together. Deploy multiple services through a cluster

         Getting Started Tutorial: https://www.dubby.cn/detail.html?id=8739

4. Common commands

         4.1 Container Lifecycle Management

        docker [run|start|stop|restart|kill|rm|pause|unpause]

                  docker run executes a command in a new container

                  docker start starts one or more stopped containers

                  docker stop stops a running container

                  docker restart restarts a running container

                  docker kill kills a running container

                  docker rm removes one or more containers

                  docker pause pauses all processes of a container

                  docker unpaunse restores all processes of a container

        4.2 Container operation and maintenance

        docker [ps|inspect|top|attach|events|logs|wait|export|port]

                   dockerps list containers

                   dockerinspect lists low-level information about a container or image

                   dockertop shows the processes running in a container

                   dockerattach attaches a running container

                   dockerevents get real-time events from services

                   dockerlog Get the log of a container

                   dockerwait blocks until a container stops, then prints its exit code

                   dockerexport exports a container's filesystem as a tar file

                   dockerport lists the ports mapped by the container

        4.3 Container rootfs command

        docker [commit|cp|diff]

                   dockercommit creates a new image from a container

                   dockercp copies a file or directory from a container to a local directory or stdout

                   dockerdiff shows changes to a container's filesystem

        4.4 Mirror warehouse

        docker [login|pull|push|search]

                   dockerlogin to log in to the warehouse

                   dockerpull pull the image

                   dockerpush push image

                   dockersearch searches for images

        4.5 Local image management

        docker [image|rmi|tag|build|history|save|import|load]

                   dockerimages List local images

                   dockerrmi delete the local image

                   dockertag tags local images

                   dockerbuild builds a local image through Dockerfile

                   dockerhistroy lists the history of the image

                   dockersave saves the local image as a tar file

                   dockerimport imports images through tar

                   dockerload loads the tar image

        4.6 Other commands

        docker [info|version]

5. Data summary

         References:

                   1.Docker official documentation:

                            https://docs.docker.com

                  2. Docker17.09 official document Chinese version:

                            https://legacy.gitbook.com/book/octowhale/docker-doc-cn/details

                   3. Dubby's docker introductory six-part series:

                            https://www.dubby.cn/detail.html?id=8733

                   4. Docker Q&A:

                   https://blog.lab99.org/post/docker-2016-07-14-faq.html#an-zhuang-pei-zhi-wen-ti-8