用docker弹性部署自己的服务

小灰灰 2022-05-06 15:57 181阅读 0赞

很久不看docker的东西了，之前了解的一些基本命令都忘得差不多了，适逢工作需要，再来复习巩固下。今天想完成的是：借助docker不部署下自己的服务。

## 环境准备 ##

都说“巧妇难为无米之炊”，所以还是需要先准备下的。

OS：Ubuntu 16.04， 2G内存  
docker：1.13.2  
coding language: golang (gin web framework)

## 编码 ##

将服务跑起来，是我们要完成的第一个步骤，而且是最重要的一个步骤。所以这一步需要仔细调试，为了方便，我就写的简单点。

1.  app.go

package main
    
    import (
    	"os"
    	"log"
    		"github.com/gin-gonic/gin"
    	"net/http"
    	"time"
    )
    
    func GetHostName() string {
    	hostname, err := os.Hostname()
    	if err != nil {
    		log.Fatal(err)
    	}
    	return hostname
    }
    
    func GetCurrentTime() string {
    	timer := time.Now()
    	return timer.String()
    }
    
    func startGinApp() {
    	app := gin.Default()
    	app.GET("/ping", func(context *gin.Context) {
    		context.JSON(http.StatusOK, gin.H{
    			"message": "当前为您服务的主机为：" + GetHostName(),
    		})
    	})
    	app.GET("/", func(context *gin.Context) {
    		context.JSON(http.StatusOK, gin.H{
    			"message": "当前时间为：" + GetCurrentTime(),
    		})
    	})
    	app.Run(":8080")
    }
    
    func main() {
    	startGinApp()
    }

1.  把服务跑起来

go run app.go

1.  curl一下看看服务是否正确跑起来了

➜  gin curl http://localhost:8080
    {"message":"当前时间为：2018-10-14 11:31:23.016121853 +0800 CST m=+0.254631109"}%                                                                                                 
    ➜  gin curl http://localhost:8080/ping
    {"message":"当前为您服务的主机为：BiaodeMacBook-Pro.local"}%                                                                                                                      
    ➜  gin

## 制作Makefile ##

经过刚才的测试，代码可以正确跑起来了。但是要做到“一次编码，到处运行”，还是需要在构建阶段下点心思的，为了更好的维护，借助Makefile来规范构建过程，是比较合适的方法。

1.  Makefile

# 这个是注释
    # 开头可以声明一大堆变量名
    BUILD_NAME ?= httpserver
    COMPILER ?= go
    BUILD ?= build
    
    
    # 上方留一个空格，区分变量区和构建区
    all: build test deploy clean
    
    build:
    	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 $(COMPILER) $(BUILD) -o $(BUILD_NAME)
    
    test:
    	echo "test over."
    
    deploy:
    	echo "deploy over."
    
    clean:
    	echo "clean over."
    
    .PHONY: build test deploy clean

1.  构建服务

➜  gin ls
    Makefile app.go
    ➜  gin make all
    go build -o httpserver
    echo "test over."
    test over.
    echo "deploy over."
    deploy over.
    echo "clean over."
    clean over.
    ➜  gin ls
    Makefile   app.go     httpserver
    ➜  gin ./httpserver &
    [1] 6450
    ➜  gin [GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.
    
    [GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
     - using env:	export GIN_MODE=release
     - using code:	gin.SetMode(gin.ReleaseMode)
    
    [GIN-debug] GET    /ping                     --> main.startGinApp.func1 (3 handlers)
    [GIN-debug] GET    /                         --> main.startGinApp.func2 (3 handlers)
    [GIN-debug] Listening and serving HTTP on :8080
    
    ➜  gin curl http://localhost:8080/ping
    [GIN] 2018/10/14 - 11:50:23 | 200 |     214.161µs |             ::1 | GET      /ping
    {"message":"当前为您服务的主机为：BiaodeMacBook-Pro.local"}%                                                                                                                      
    ➜  gin

好了基本没什么问题，然后就可以通过scp命令将文件拷贝到linux服务器上了。

## 制作Dockerfile ##

由于golang构建出来的是二进制可执行程序，所以制作Dockerfile很简单。

1.  Dockerfile

FROM ubuntu:latest
    
    MAINTAINER guopu marksinoberg@gmail.com
    
    WORKDIR /app
    
    EXPOSE 8080
    
    ADD . /app
    
    CMD ["./httpserver"]

1.  构建自己的镜像

root@Server218 /h/d/g/d/httpserver# docker images
    REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
    ginserver           latest              6277a0180f4f        19 hours ago        101 MB
    flaskindocker       latest              170c6c0a41db        22 hours ago        131 MB
    python              2.7-slim            14dad3ead5f4        4 days ago          120 MB
    docker/compose      1.23.0-rc2          dc59a0b5e981        5 days ago          45.6 MB
    ubuntu              latest              cd6d8154f1e1        5 weeks ago         84.1 MB
    root@Server218 /h/d/g/d/httpserver# docker build -t httpserver .
    Sending build context to Docker daemon 17.07 MB
    Step 1/6 : FROM ubuntu:latest
     ---> cd6d8154f1e1
    Step 2/6 : MAINTAINER guopu marksinoberg@gmail.com
     ---> Running in 7106748df3ad
     ---> 0ae808029537
    Removing intermediate container 7106748df3ad
    Step 3/6 : WORKDIR /app
     ---> 7278bf9659e7
    Removing intermediate container f7fdc76b19a8
    Step 4/6 : EXPOSE 8080
     ---> Running in bedfabcb4b16
     ---> edf4c123f72f
    Removing intermediate container bedfabcb4b16
    Step 5/6 : ADD . /app
     ---> 36390e554a2f
    Removing intermediate container b14cce9da53e
    Step 6/6 : CMD ./httpserver
     ---> Running in 6682c8364717
     ---> b490fef8a9ca
    Removing intermediate container 6682c8364717
    Successfully built b490fef8a9ca
    root@Server218 /h/d/g/d/httpserver# docker images
    REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
    httpserver          latest              b490fef8a9ca        4 seconds ago       101 MB
    ginserver           latest              6277a0180f4f        19 hours ago        101 MB
    flaskindocker       latest              170c6c0a41db        22 hours ago        131 MB
    python              2.7-slim            14dad3ead5f4        4 days ago          120 MB
    docker/compose      1.23.0-rc2          dc59a0b5e981        5 days ago          45.6 MB
    ubuntu              latest              cd6d8154f1e1        5 weeks ago         84.1 MB
    root@Server218 /h/d/g/d/httpserver#

1.  让服务在docker中跑起来

root@Server218 /h/d/g/d/httpserver# docker run -d  -p 8000:8080 httpserver
    ebb1926206cdaf16eae9f4e13d5a7e70dd695da91463b438f77e45c6f65d3323
    root@Server218 /h/d/g/d/httpserver# docker ps
    CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                    NAMES
    ebb1926206cd        httpserver          "./httpserver"      4 seconds ago       Up 3 seconds        0.0.0.0:8000->8080/tcp   nostalgic_wright
    root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
    {"message":"当前为您服务的主机为：ebb1926206cd"}~                                                                                                                                 
    
    root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/
    {"message":"当前时间为：2018-10-14 04:14:29.116207751 +0000 UTC"}~                                                                                                                
    
    root@Server218 /h/d/g/d/httpserver#

至此，看起来服务已经成功在服务器环境下的docker中运行了。

## 弹性服务 ##

一个容器跑一个服务，有些服务访问峰差很大的场景，就需要做下弹性适配，于是需要用一下docker swarm服务。这个在linux环境下需要进行安装。具体可以参考官网链接： [https://github.com/docker/compose/releases][https_github.com_docker_compose_releases]  
其运行以来一个YAML配置文件，具体细节不多说，上手吧。

1.  docker-compose.yml

version: "3"
    services:
        web:
            image: httpserver:latest
            deploy:
                replicas: 5
                resources:
                    limits:
                        cpus: "0.1"
                        memory: 50M
                restart_policy:
                    condition: on-faliure
            ports:
                - "8000:8080"
            networks:
                - webnet
    networks:
        webnet:

1.  初始化swarm

root@Server218 /h/d/g/d/httpserver# docker swarm init
    Swarm initialized: current node (atiuy6c8k1qcig5w3br1bwf0n) is now a manager.
    
    To add a worker to this swarm, run the following command:
    
        docker swarm join \
        --token SWMTKN-1-5e0sj0glbwl5w5rqytyqokeg91n7piwdyw9ik598x0poiz5s20-do445zhrdr5io93lplov42c2y \
        172.31.237.68:2377
    
    To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
    
    root@Server218 /h/d/g/d/httpserver#

1.  发布服务到swarm中

root@Server218 /h/d/g/d/httpserver# docker stack deploy -c docker-compose.yml httpserver
    Creating service httpserver_web
    root@Server218 /h/d/g/d/httpserver#
    root@Server218 /h/d/g/d/httpserver#
    root@Server218 /h/d/g/d/httpserver#
    root@Server218 /h/d/g/d/httpserver# docker stack ps httpserver
    ID            NAME              IMAGE              NODE       DESIRED STATE  CURRENT STATE           ERROR  PORTS
    kvpvwptlj44c  httpserver_web.1  httpserver:latest  Server218  Running        Running 14 seconds ago
    6549g79dz5iz  httpserver_web.2  httpserver:latest  Server218  Running        Running 14 seconds ago
    xkz42mnetmws  httpserver_web.3  httpserver:latest  Server218  Running        Running 14 seconds ago
    rpziwzmpogn2  httpserver_web.4  httpserver:latest  Server218  Running        Running 14 seconds ago
    y2kfe8bp09ld  httpserver_web.5  httpserver:latest  Server218  Running        Running 6 seconds ago
    root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
    {"message":"当前为您服务的主机为：a5419e3d3f9c"}~                                                                                                                                 
    root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
    {"message":"当前为您服务的主机为：f636819bd9c4"}~                                                                                                                                 
    root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
    {"message":"当前为您服务的主机为：97a6e3c9a064"}~                                                                                                                                 
    root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
    {"message":"当前为您服务的主机为：7f1b28e14970"}~                                                                                                                                 
    root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
    {"message":"当前为您服务的主机为：0ce251661188"}~                                                                                                                                 
    root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
    {"message":"当前为您服务的主机为：a5419e3d3f9c"}~                                                                                                                                 
    root@Server218 /h/d/g/d/httpserver#

1.  实例弹性变化  
    具体的操作只需要修改`docker-compose.yml`中的replicas的数量即可。然后重新使用：

docker stack deploy -c docker-compose.yml httpserver

发布就可以了，可以看出swarm管理下的实例会进行自动的负载均衡。

1.  关停服务

root@Server218 /h/d/g/d/httpserver# docker stack ls
    NAME        SERVICES
    httpserver  1
    root@Server218 /h/d/g/d/httpserver# docker stack rm httpserver
    Removing service httpserver_web
    Removing network httpserver_webnet
    root@Server218 /h/d/g/d/httpserver# docker stack ls
    NAME  SERVICES
    root@Server218 /h/d/g/d/httpserver#

1.  关掉swarm

root@Server218 /h/d/g/d/httpserver# docker swarm leave --force
    Node left the swarm.
    root@Server218 /h/d/g/d/httpserver#

## 总结 ##

最后，回头看看这个目录。

root@Server218 /h/d/g/d/httpserver# ls -al
    total 16688
    drwxr-xr-x 2 root root     4096 Oct 14 12:20 ./
    drwxr-xr-x 5 root root     4096 Oct 14 12:00 ../
    -rw-r--r-- 1 root root      121 Oct 14 12:11 Dockerfile
    -rw-r--r-- 1 root root      362 Oct 14 12:01 Makefile
    -rw-r--r-- 1 root root      682 Oct 14 12:01 app.go
    -rw-r--r-- 1 root root      385 Oct 14 12:27 docker-compose.yml
    -rwxr-xr-x 1 root root 17063672 Oct 14 12:03 httpserver*
    root@Server218 /h/d/g/d/httpserver#

基本上，在docker中弹性部署自己的服务就结束了，基本上也能满足需要。

[https_github.com_docker_compose_releases]: https://github.com/docker/compose/releases