Docker-compose編排微服務(wù)順序啟動(dòng)

docker-compose可以方便組合多個(gè) docker 容器服務(wù), 但是, 當(dāng)容器服務(wù)之間存在依賴關(guān)系時(shí), docker-compose 并不能保證服務(wù)的啟動(dòng)順序。docker-compose 中的 depends_on 配置是容器的啟動(dòng)順序, 并不是容器中服務(wù)的啟動(dòng)順序荧库。本章將詳細(xì)敘述如何解決 docker-compose 順序啟動(dòng)微服務(wù)的問題。

1.用restart：always機(jī)制

docker-compose.yml

? version:"3"

??services:

????# 指定服務(wù)名稱

????#服務(wù)注冊與發(fā)現(xiàn)中心

????simonEureka:

??????image: simon/eureka-server:2.0.1-SNAPSHOT

??????hostname: simonEureka

??????ports:

????????- "8100:8100"

????#配置中心 ???

????simonConfig:

??????image: simon/config-server:2.0.1-SNAPSHOT

??????hostname: simonConfig

??????ports:

????????- "8101:8101"

??????depends_on:

????????- simonEureka

??????restart: always

????#路由網(wǎng)關(guān) ?

????apigateway:

??????image: simon/apigateway:2.0.1-SNAPSHOT

??????ports:

????????- "8102:8102"

??????depends_on:

????????- simonEureka

????????- simonConfig

??????restart: always

????#監(jiān)控平臺(tái) ?

????admin:

??????image: simon/admin:2.0.1-SNAPSHOT

??????ports:

????????- "8103:8103"

??????depends_on:

????????- simonEureka

????????- simonConfig

??????restart: always

2.用shell腳本阻止當(dāng)前服務(wù)啟動(dòng),直到所需依賴的服務(wù)全部啟動(dòng)之后再啟動(dòng)當(dāng)前服務(wù)涡拘。

部署的微服務(wù)如下圖所示

（1）shell腳本：entrypoint.sh （鏡像中必須安裝netcat要么通過maven配置要么在dockefile安裝netcat）

#!/bin/bash

: ${SLEEP_SECOND:=2}

wait_for() {

????echo?Waiting for?$1?to listen on $2...

????while?! nc -z $1?$2; do?echo?waiting...; sleep $SLEEP_SECOND; done

}

declare?DEPENDSdeclare?CMD

while?getopts?"d:c:"?argdo

????case?$arg?in

????????d)

????????????DEPENDS=$OPTARG

????????????;;

????????c)

????????????CMD=$OPTARG

????????????;;

?????????)

????????????echo?"unkonw argument"

????????????exit?1

????????????;;

????esacdone

for?var in?${DEPENDS//,/}do

????host=${var%:*}

????port=${var#*:}

????wait_for $host?$portdone

eval?$CMD#避免執(zhí)行完命令之后退出容器

tail -f /dev/null

這個(gè)腳本有2 個(gè)參數(shù)：

-d：需要等待的服務(wù)和端口，例如：simonEureka:8080

-c：等待的服務(wù)和端口啟動(dòng)之后, 自己的啟動(dòng)命令,例如：java -jar eureka.jar

（2）編寫docker-compose.yml

version: '2'

services:

??pig-eureka:

????build:

??????context: ./

??????dockerfile: Dockerfile-eureka

????restart: always

????ports:

??????- 1025:1025

??pig-config:

????links:

??????- pig-eureka:eureka

????build:

??????context: ./

??????dockerfile: Dockerfile-config ?????

????restart: always

????ports:

??????- 4001:4001 ???

????volumes:

??????- ./entrypoint.sh:/entrypoint.sh

????environment:

??????SLEEP_SECOND: 4

????tty: true

????entrypoint: /entrypoint.sh -d pig-eureka:1025 -c 'java -jar /app/pig-config.jar';

??pig-auth:

????links:

??????- pig-config:config

????build:

??????context: ./

??????dockerfile: Dockerfile-auth

????restart: always

????ports:

??????- 3000:3000

????volumes:

??????- ./entrypoint.sh:/entrypoint.sh

????environment:

??????SLEEP_SECOND: 25

????tty: true

????entrypoint: /entrypoint.sh -d pig-config:4001 -c 'java -jar /app/pig-auth.jar';

??pig-gateway:

????links:

??????- pig-eureka:eureka

??????- pig-auth:auth

????build:

??????context: ./

??????dockerfile: Dockerfile-gateway

????restart: always

????ports:

??????- 9999:9999

????volumes:

??????- ./entrypoint.sh:/entrypoint.sh

????environment:

??????SLEEP_SECOND: 26

????tty: true

entrypoint: /entrypoint.sh -d pig-auth:3000 -c 'java -jar ?/app/pig-gateway.jar';

（3）編寫每個(gè)jar包的Dockerfile文件

Dockerfile-eureka:

FROM java:8-jre

ADD ./jar/pig-eureka.jar /app/

CMD ["java", "-Xmx200m", "-jar", "/app/pig-eureka.jar"]

EXPOSE 1025

Dockerfile-config（其他的類似）:

FROM java:8-jre

ADD ./netcat.tar.gz /opt/??????????????????#netcat的壓縮包必須放在同級(jí)目錄下???

ENV NETCAT_HOME /opt/netcat

ENV PATH $PATH:$NETCAT_HOME/bin???????#在容器里安裝netcat命令

ADD ./jar/pig-config.jar /app/

CMD ["java", "-Xmx200m", "-jar", "/app/pig-config.jar"]

EXPOSE 4001

netcat放在同級(jí)目錄下

（4）啟動(dòng)服務(wù)

$ docker-compose up

其他程序都在等待eureka啟動(dòng)這樣就實(shí)現(xiàn)了順序啟動(dòng)的功能

注意問題：

1.?Shell腳本權(quán)限問題（不能執(zhí)行shell腳本）：

docker: Error response from daemon: OCI runtime create failed: container_linux.go:348: starting container process caused "exec: \"docker-entrypoint.sh\": executable file not found in $PATH": unknown.

解決方法（添加權(quán)限）

chmod?+x?docker-entrypoint.sh

2.?Shell腳本報(bào)錯(cuò)"start.sh? /bin/bash^M: 壞的解釋器：沒有那個(gè)文件或目錄”,因?yàn)?.sh文件是從windows拷貝過來的据德，所以多了\r

解決辦法

?sed -i 's/\r$//' start.sh ??

3. 出現(xiàn)網(wǎng)關(guān)不能no host to root

先關(guān)閉防火墻看是否能解決

4. 關(guān)閉防火墻后會(huì)出現(xiàn)NO chain需要重啟docker