Docker 中 YML 文件是什么？

Docker中YML文件一般是指Docker默認(rèn)的模板文件“docker-compose.yml”，該文件用來(lái)定義的每個(gè)服務(wù)都必須通過(guò)image指令指定鏡像，或使用Dockerfile的build指令進(jìn)行自動(dòng)構(gòu)建。

Compose文件

Compose文件是一個(gè)定義服務(wù)services、網(wǎng)絡(luò)networks和卷volumes的YAML文件，默認(rèn)路徑是./docker-compose.yml，可使用.yml或.yaml作為文件擴(kuò)展名。

服務(wù)services定義包含應(yīng)用于為該服務(wù)啟動(dòng)的每個(gè)容器的配置，類(lèi)似傳遞命令行參數(shù)一樣docker container create。同樣，網(wǎng)絡(luò)networks和卷volumes的定義類(lèi)似于docker network create和docker volume create。正如docker container create在Dockerfile指定選項(xiàng)，如CMD、EXPOSE、VOLUME、ENV，在默認(rèn)情況下，不需要在docker-compose.yml配置中再次指定?？梢允褂肂ash類(lèi)${VARIABLE}語(yǔ)法在配置值中使用環(huán)境變量。

version: "3" services:   redis:     image: redis:alpine     ports:       - "6379"     networks:       - frontend     deploy:       replicas: 2       update_config:         parallelism: 2         delay: 10s       restart_policy:         condition: on-failure   db:     image: postgres:9.4     volumes:       - db-data:/var/lib/postgresql/data     networks:       - backend     deploy:       placement:         constraints: [node.role == manager]   vote:     image: dockersamples/examplevotingapp_vote:before     ports:       - 5000:80     networks:       - frontend     depends_on:       - redis     deploy:       replicas: 2       update_config:         parallelism: 2       restart_policy:         condition: on-failure   result:     image: dockersamples/examplevotingapp_result:before     ports:       - 5001:80     networks:       - backend     depends_on:       - db     deploy:       replicas: 1       update_config:         parallelism: 2         delay: 10s       restart_policy:         condition: on-failure   worker:     image: dockersamples/examplevotingapp_worker     networks:       - frontend       - backend     deploy:       mode: replicated       replicas: 1       labels: [APP=VOTING]       restart_policy:         condition: on-failure         delay: 10s         max_attempts: 3         window: 120s       placement:         constraints: [node.role == manager]   visualizer:     image: dockersamples/visualizer:stable     ports:       - "8080:8080"     stop_grace_period: 1m30s     volumes:       - "/var/run/docker.sock:/var/run/docker.sock"     deploy:       placement:         constraints: [node.role == manager] networks:   frontend:   backend: volumes:   db-data:

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