用Docker彈性部署自己的服務

Docker · 發表 2018-10-14 14:47:06

摘要：很久不看docker的東西了，之前瞭解的一些基本命令都忘得差不多了，適逢工作需要，再來複習鞏固下。今天想完成的是：藉助docker不部署下自己的服務。環境準備都說“巧婦難為無米之炊”，所以還是需要先準備下的。 OS：Ubuntu 16.04， 2G記憶體 dock...

很久不看docker的東西了，之前瞭解的一些基本命令都忘得差不多了，適逢工作需要，再來複習鞏固下。今天想完成的是：藉助docker不部署下自己的服務。

環境準備

都說“巧婦難為無米之炊”，所以還是需要先準備下的。

OS：Ubuntu 16.04， 2G記憶體

docker：1.13.2

coding language: golang (gin web framework)

編碼

將服務跑起來，是我們要完成的第一個步驟，而且是最重要的一個步驟。所以這一步需要仔細除錯，為了方便，我就寫的簡單點。

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": "當前為您服務的主機為：" + GetHostName(),
})
})
app.GET("/", func(context *gin.Context) {
context.JSON(http.StatusOK, gin.H{
"message": "當前時間為：" + GetCurrentTime(),
})
})
app.Run(":8080")
}

func main() {
startGinApp()
}

把服務跑起來

go run app.go

curl一下看看服務是否正確跑起來了

➜gin curl http://localhost:8080
{"message":"當前時間為：2018-10-14 11:31:23.016121853 +0800 CST m=+0.254631109"}%
➜gin curl http://localhost:8080/ping
{"message":"當前為您服務的主機為：BiaodeMacBook-Pro.local"}%

➜gin

製作Makefile

經過剛才的測試，程式碼可以正確跑起來了。但是要做到“一次編碼，到處執行”，還是需要在構建階段下點心思的，為了更好的維護，藉助Makefile來規範構建過程，是比較合適的方法。

Makefile

# 這個是註釋
# 開頭可以宣告一大堆變數名
BUILD_NAME ?= httpserver
COMPILER ?= go
BUILD ?= build


# 上方留一個空格，區分變數區和構建區
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

構建服務

➜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
Makefileapp.gohttpserver
➜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":"當前為您服務的主機為：BiaodeMacBook-Pro.local"}%
➜gin

好了基本沒什麼問題，然後就可以通過scp命令將檔案拷貝到linux伺服器上了。

製作Dockerfile

由於golang構建出來的是二進位制可執行程式，所以製作Dockerfile很簡單。

Dockerfile

FROM ubuntu:latest

MAINTAINER guopu [email protected]

WORKDIR /app

EXPOSE 8080

ADD . /app

CMD ["./httpserver"]

構建自己的映象

root@Server218 /h/d/g/d/httpserver# docker images
REPOSITORYTAGIMAGE IDCREATEDSIZE
ginserverlatest6277a0180f4f19 hours ago101 MB
flaskindockerlatest170c6c0a41db22 hours ago131 MB
python2.7-slim14dad3ead5f44 days ago120 MB
docker/compose1.23.0-rc2dc59a0b5e9815 days ago45.6 MB
ubuntulatestcd6d8154f1e15 weeks ago84.1 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 [email protected]
 ---> 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
REPOSITORYTAGIMAGE IDCREATEDSIZE
httpserverlatestb490fef8a9ca4 seconds ago101 MB
ginserverlatest6277a0180f4f19 hours ago101 MB
flaskindockerlatest170c6c0a41db22 hours ago131 MB
python2.7-slim14dad3ead5f44 days ago120 MB
docker/compose1.23.0-rc2dc59a0b5e9815 days ago45.6 MB
ubuntulatestcd6d8154f1e15 weeks ago84.1 MB
root@Server218 /h/d/g/d/httpserver#

讓服務在docker中跑起來

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 IDIMAGECOMMANDCREATEDSTATUSPORTSNAMES
ebb1926206cdhttpserver"./httpserver"4 seconds agoUp 3 seconds0.0.0.0:8000->8080/tcpnostalgic_wright
root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
{"message":"當前為您服務的主機為：ebb1926206cd"}~
root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/
{"message":"當前時間為：2018-10-14 04:14:29.116207751 +0000 UTC"}~root@Server218 /h/d/g/d/httpserver#

至此，看起來服務已經成功在伺服器環境下的docker中運行了。

彈性服務

一個容器跑一個服務，有些服務訪問峰差很大的場景，就需要做下彈性適配，於是需要用一下docker swarm服務。這個在linux環境下需要進行安裝。具體可以參考官網連結：ofollow,noindex">https://github.com/docker/compose/releases

其執行以來一個YAML配置檔案，具體細節不多說，上手吧。

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:

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#

釋出服務到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
IDNAMEIMAGENODEDESIRED STATECURRENT STATEERRORPORTS
kvpvwptlj44chttpserver_web.1httpserver:latestServer218RunningRunning 14 seconds ago
6549g79dz5izhttpserver_web.2httpserver:latestServer218RunningRunning 14 seconds ago
xkz42mnetmwshttpserver_web.3httpserver:latestServer218RunningRunning 14 seconds ago
rpziwzmpogn2httpserver_web.4httpserver:latestServer218RunningRunning 14 seconds ago
y2kfe8bp09ldhttpserver_web.5httpserver:latestServer218RunningRunning 6 seconds ago

root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
{"message":"當前為您服務的主機為：a5419e3d3f9c"}~
root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
{"message":"當前為您服務的主機為：f636819bd9c4"}~
root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
{"message":"當前為您服務的主機為：97a6e3c9a064"}~
root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
{"message":"當前為您服務的主機為：7f1b28e14970"}~
root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
{"message":"當前為您服務的主機為：0ce251661188"}~
root@Server218 /h/d/g/d/httpserver# curl http://localhost:8000/ping
{"message":"當前為您服務的主機為：a5419e3d3f9c"}~
root@Server218 /h/d/g/d/httpserver#

例項彈性變化

具體的操作只需要修改docker-compose.yml 中的replicas的數量即可。然後重新使用：

docker stack deploy -c docker-compose.yml httpserver

釋出就可以了，可以看出swarm管理下的例項會進行自動的負載均衡。

關停服務

root@Server218 /h/d/g/d/httpserver# docker stack ls
NAMESERVICES
httpserver1
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
NAMESERVICES
root@Server218 /h/d/g/d/httpserver#

關掉swarm

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

總結

最後，回頭看看這個目錄。

root@Server218 /h/d/g/d/httpserver# ls -al
total 16688
drwxr-xr-x 2 root root4096 Oct 14 12:20 ./
drwxr-xr-x 5 root root4096 Oct 14 12:00 ../
-rw-r--r-- 1 root root121 Oct 14 12:11 Dockerfile
-rw-r--r-- 1 root root362 Oct 14 12:01 Makefile
-rw-r--r-- 1 root root682 Oct 14 12:01 app.go
-rw-r--r-- 1 root root385 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中彈性部署自己的服務就結束了，基本上也能滿足需要。

用Docker彈性部署自己的服務

環境準備

編碼

製作Makefile

製作Dockerfile

彈性服務

總結

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