Actual combat: dockerfile minimal practice - koa as an example

foreword

Minimal practice means opening up the link and looking at the problem at a higher level, the problem becomes clear. In this article, the author will take you to implement a simplest koa service and deploy it to the server.

Prerequisites: Some understanding of docker

Realize ideas

Step 1: Start a koa application first,

Step 2: Generate a dockerfile again and write it

Step 3: Generate an image based on dockerfile (docker build)

Step 4: Generate (run) a container based on this image and check whether it can run on the local machine

Step 5: If it works, export the image

Step 6: xshell connects to the server (assuming docker is installed on the server), import this image, and generate a container from this image

This is the minimal implementation

Here is another way to do it:

In the fifth step, publish it to the remote repository, and in the sixth step, pull it from the remote to the mirror, but the disadvantage is that your mirror needs to be public (only one private quota)

Step 1: Start a koa application first

Create a new dockerfile_koa_demo file and npm init -y to generate package.json. Download the koa package and create a new app.js

 mkdir dockerfile_koa_demo
cd dockerfile_koa_demo
npm init -y
npm i koa --save
touch app.js

Write app.js again

 const Koa = require('koa');

const app = new Koa();

app.use(async (ctx) => {
    ctx.body = 'hello, docker';
});

app.listen(3010, () => {
    console.log('3010端口已启动');
});

Modify the script of package.json

 ...
"scripts": {
    "start": "nodemon app.js"
},
...

startup script

 npm run start

See the picture below:

Browser access is normal

Step 2: Write a Dockerfile

Create a new Dockerfile

 touch Dockerfile

Write Dockerfile

 # base image
# FROM
FROM node

# 复制文件到容器
ADD . /home/www

# 进入工作目录
WORKDIR /home/www

# 安装项目依赖包
RUN npm install --registry=https://registry.npm.taobao.org

# 暴露 端口
EXPOSE 3010

# 开始命令
CMD ["node", "./app.js"]

Finished the second step

Step 3: Generate an image based on dockerfile

In order to speed up the build, we first .dockerignore and write node_modules

 touch .dockerignore

Write ---87f052345f74784c731be7ff407a9c6f .dockerignore in node_modules , which means that when you docker build node_modules to speed up the build speed ---60cdb8ab214723d0a876

Generate an image through the command line and name it johan/koa_server:v1.0.0

 docker build . -t johan/koa_server:v1.0.0
# -t 就是给镜像起名

Results as shown below:

Check if the mirror is available

 docker images

Step 4: Generate a container based on this image

Generate a container from the command line

 docker run -d --name koa_server_container -p 3010:3010 johan/koa_server:v1.0.0
# -d 后台运行
# --name 给容器起名字
# -p 本机端口隐射镜像中的端口

Check if the image is generated

 docker ps -a

Enter http://localhost:3010/ in the browser, bingo

Step 5: Export this image

 docker save johan/koa_server:v1.0.0 > koa_server.tar

Step 6: Run through the server

Here we assume that the docker and lrzsz packages have been installed on the server (this article will not expand)

Connect to the server through xshell and upload the tar package through the command rz

 rz

Unpack this archive (import)

 docker load < koa_server.tar

Build a container based on this container

 docker run -d --name koa_server_container -p 3010:3010 johan/koa_server:v1.0.0

and look at the containers that are running through

 docker ps -a

Enter the domain name in the browser, bingo

The above is a minimal implementation of dockerfile , is it very simple. Of course, you can upload the image to docker hub in the fifth step, and pull the image from dockerfile ae44b0096cb5b8165c2affb82c0b74d8--- in the sixth step, and then generate the container. as follows

Another method Step 5: Upload the image

Log in to dockerhub from the command line (register first)

 docker login

name the image

 docker tag johan/koa_server:v1.0.0 johanbo/koa_server:v1.0.0

Upload the image to docker hub

 docker push johanbo/koa_server:v1.0.0

Another method Step 6: Pull the image

Log in to the server and pull the image

 docker pull johanbo/koa_server:v1.0.0

Note : You need to tag here, otherwise the latest will be pulled by default

start the container

 docker run -d --name koa_server_container -p 3010:3010 johan/koa_server:v1.0.0

Enter the domain name in the browser, bingo

Note: The server development port needs to go to the cloud service provider to develop the corresponding port (security group configuration rules)

follow-up

You can configure the environment variables you need in dockerfile . The container generated by the image is a "mini server", you can do whatever you want, it has nothing to do with the whole server, so your application is not affected by the environment.

Here is a pain point: even if you solve the environment problem, CICD is still a problem, how to integrate more quickly? In the next section, I will introduce the combination of docker and jenkins, generate jenkins through docker, and enable CICD with jenkins