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Prepare the environment:

• VMware17
• Ubuntu18.04(LTS)：https://releases.ubuntu.com/18.04/ubuntu-18.04.6-desktop-amd64.iso

1. Docker Outlook

---

Docker related documents:

• Docker official website address: https://www.docker.com/
• Docker documentation address: https://docs.docker.com/
• Docker image repository: https://hub.docker.com/

1. What is Docker: It is an open source container engine that can easily manage containers, and the containers are isolated from each other using a sandbox mechanism.

2. What problem does docker solve: Solve the problem of software environment migration.

3. The difference between containers and virtual machines:

• Container: It is an abstraction of an application (packaging code and dependencies together), occupies fewer resources, starts quickly, and is lightweight and flexible.
• Virtual machine: It is an abstraction of physical hardware (turning one server into multiple servers), which takes up a lot of resources and is bulky and powerful.

4. Docker storage:

• Mount directory, example: -v /宿主机目录:容器目录
• Data volume mapping, example:数据卷:容器目录

5. Docker network: Create a custom network to access the host name as a stable domain name. (It allows containers on the same network to communicate with each other)

#示例
#自定义网络
docker network create mynet
#主节点
docker run -d -p 6379:6379 
-v /app/rd1:/bitnami/redis/data 
-e REDIS_REPLICATION_MODE=master 
-e REDIS_PASSWORD=123456 
--network mynet --name redis01 
bitnami/redis

#从节点
docker run -d -p 6380:6379 
-v /app/rd2:/bitnami/redis/data 
-e REDIS_REPLICATION_MODE=slave 
-e REDIS_MASTER_HOST=redis01 
-e REDIS_MASTER_PORT_NUMBER=6379 
-e REDIS_MASTER_PASSWORD=123456 
-e REDIS_PASSWORD=123456 
--network mynet --name redis02 
bitnami/redis
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2. Install Docker

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This article is based on the Ubuntu environment installation. If you lack permissions, just add sudo in front.

1. Turn off the firewall (you don’t need to manually expose the port for subsequent external access, which is convenient for testing)

sudo ufw disable

#关闭防火墙：sudo ufw disable
#查看防火墙状态：sudo ufw status
#开启防火墙：sudo ufw enable
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2. Install Docker

#卸载旧版docker
sudo apt-get remove docker docker-engine docker.io containerd runc

#更新软件包
sudo apt-get update

#安装一些工具
sudo apt-get install 
    apt-transport-https 
    ca-certificates 
    curl 
    gnupg-agent 
    software-properties-common

#安装docker
sudo apt install docker.io 

#验证dokcer是否安装成功
docker --version

#启动& 开机启动docker； enable + start 二合一
sudo systemctl enable docker --now

#配置阿里云镜像加速
sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://82m9ar63.mirror.aliyuncs.com"]
}
EOF

#重新加载配置
sudo systemctl daemon-reload
#重启docker服务
sudo systemctl restart docker
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3. Common Docker commands

---

1. Status management of docker service:

• systemctl status docker: View the running status of docker
• systemctl stop docker: shut down docker
• systemctl start docker: Start Docker
• systemcl restart docker: restart docker
• systemctl enable docker: Set Docker to start automatically at boot

2. Docker image management:

• Search for images: docker search image name
• Pull the image: docker pull image name: tag If you do not specify a tag, the lastest will be pulled
• View images: docker images
• Delete the image: docker rmi image name: tag

3. Docker container management:

• Create a container: docker run -di --name=container name image name: tag
• Shut down the container: docker stop container name
• Start the container: docker start container name
• Delete the container: docker rm container name
• View the container:
  • docker ps -a View all containers, including those that are not running
  • docker ps to view the running containers
• Enter the container: docker exec -it container name/bin/bash

4. Docker data volume:

• Data volume: a folder managed by Docker.

• Uses of data volumes: You can bind a data volume to a path in a container to achieve two-way automatic transfer of files between the container and the host.

  Put the file in the host's data volume: Docker will automatically synchronize the file to the container

  If there are changes in the files in the container, Docker will automatically synchronize them to the data volume of the host machine.

• Data volume operation commands:

  List data volumes: docker volume ls

  Create a data volume: docker volume create data volume name

  View data volume details (actual path): docker volume inspect data volume name

  Delete the data volume: docker volume rm volume name

• Create a container and bind the data volume:

  docker run -di --name=container name -v data volume name: path in container image name: tag

  docker run -di --name=container name -v path in the host: path in the container image name: tag

  Note: All paths in the -v parameter must be absolute paths

5. Image backup:

• Export the image: docker save -o file name image name
• Load the image: docker load -i xxx.tar

4. Dockerfile

---

Documentation: https://docs.docker.com/reference/dockerfile/

Dockerfile function: create a custom image.

Dockerfile is based on a basic image and writes a series of docker instructions. Each instruction builds a layer of image, and finally a target image is built through these instructions layer by layer.

Example:

#编写dockerfile文件
vim Dockerfile
FROM openjdk:17
LABEL author=aopmin
COPY app.jar /app.jar   #把jar包复制到容器的根目录下
EXPOSE 8080
ENTRYPOINT ["java","-jar","app.jar"]  #运行命令

# 构建镜像
docker bulid -f Dockerfile -t 镜像名:tag .
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5. Service Orchestration

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Service orchestration or container orchestration: managing containers in batches according to certain business rules.

Docker Compose is an orchestration tool for defining and running multiple Docker containers.

Multiple containers can be started with one command. This mainly solves the problem of how to manage and orchestrate containers.

There are three steps to using Docker Compose:

1. Use Dockerfile to define the operating environment (if you already have an image, you can skip this step)
2. usedocker-compose.ymlDefine the services that make up your application
3. rundocker-compose up -dStart the application

Install docker-compose:

# 下载docker compose
curl -L https://github.com/docker/compose/releases/download/1.22.0/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose

# 设置权限
chmod +x /usr/local/bin/docker-compose

# 查看版本 
docker-compose -version
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If you want to uninstall docker-compose, execute the following command:

# docker compose是二进制包方式安装的，删除二进制文件即可
rm /usr/local/bin/docker-compose
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Common commands for docker-compose:

# ！！！注意：必须先切换到`docker-compose.yaml`文件所在的目录后，才可以执行以下命令！！！

#创建容器并后台启动
docker-compose up -d

#直接启动容器
docker-compose start

#其它命令：
docker-compose help # 查看帮助
docker-compose stop  # 停止容器
docker-compose start # 启动容器
docker-compose restart # 重启容器
docker-compose rm # 删除已停止的容器
docker-compose down # 停止并删除容器
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Example:

1. Create a docker-compose directory

mkdir ~/docker-compose
cd ~/docker-compose
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2. Writedocker-compose.yamldocument

version: "3.0"
services:
  redis:
    container_name: redis 
    image: redis:5.0
    ports:
      - 6379:6379
  nginx:
    container_name: nginx
    image: nginx:1.14.2
    ports:
      - 80:80
    volumes:
      - /root/volumes/nginx/html:/usr/share/nginx/html
  tomcat:
    container_name: tomcat
    image: tomcat:8.5.88
    ports:
      - 8080:8080
    volumes:
      - /root/volumes/tomcat/webapps:/usr/local/tomcat/webapps
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3. Start

# ！！！注意：必须先切换到有`docker-compose.yaml`文件所在的目录后，才可以执行以下命令！！！
cd ~/docker-compose

# docker-compose up -d 以守护进程方式创建并启动容器
docker-compose up -d
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