Docker批量容器编排的实现

简介

Dockerfile build run 是手动操作单个容器，假如使用微服务架构，需要启动 100 + 个容器，他们之间的依赖关系如何维护？ Docker Compose 用来轻松高效地管理容器，定义运行多个容器。

三个步骤：

Dockerfile Services & docker-compose.yml docker-compose up

初体验

1.Dockerfile

FROM python:3.7-alpine WORKDIR /code ENV FLASK_APP app.py ENV FLASK_RUN_HOST 0.0.0.0 RUN apk add --no-cache gcc musl-dev linux-headers COPY requirements.txt requirements.txt RUN pip install -r requirements.txt COPY . . CMD ["flask", "run"]

2.Service

import time import redis from flask import Flask app = Flask(__name__) cache = redis.Redis(host='redis', port=6379) def get_hit_count(): retries = 5 while True: try: return cache.incr('hits') except redis.exceptions.ConnectionError as exc: if retries == 0: raise exc retries -= 1 time.sleep(0.5) @app.route('/') def hello(): count = get_hit_count() return 'Hello World! I have been seen {} times.\n'.format(count)

docker-compose.yml

version: '3' services: web: build: . ports: - "5000:5000" volumes: - .:/code - logvolume01:/var/log links: - redis redis: image: redis volumes: logvolume01: {} docker-compose up Starting compose-demo_web_1 ... done Starting compose-demo_redis_1 ... done Attaching to compose-demo_redis_1, compose-demo_web_1 redis_1 | 1:C 12 Sep 2020 07:34:09.654 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo redis_1 | 1:C 12 Sep 2020 07:34:09.655 # Redis version=6.0.7, bits=64, commit=00000000, modified=0, pid=1, just started redis_1 | 1:C 12 Sep 2020 07:34:09.655 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf redis_1 | 1:M 12 Sep 2020 07:34:09.657 * Running mode=standalone, port=6379. redis_1 | 1:M 12 Sep 2020 07:34:09.657 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128. redis_1 | 1:M 12 Sep 2020 07:34:09.657 # Server initialized redis_1 | 1:M 12 Sep 2020 07:34:09.658 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect. redis_1 | 1:M 12 Sep 2020 07:34:09.658 * Loading RDB produced by version 6.0.7 redis_1 | 1:M 12 Sep 2020 07:34:09.658 * RDB age 156 seconds redis_1 | 1:M 12 Sep 2020 07:34:09.658 * RDB memory usage when created 0.77 Mb redis_1 | 1:M 12 Sep 2020 07:34:09.658 * DB loaded from disk: 0.000 seconds web_1 | * Serving Flask app "app.py" web_1 | * Environment: production web_1 | WARNING: This is a development server. Do not use it in a production deployment. web_1 | Use a production WSGI server instead. web_1 | * Debug mode: off YML 文件规则 version: "1.0" #版本 services: #服务列表 service1: #服务配置 container_name: #容器名称 depends_on: #依赖列表 - depend1 - depend2 images: #镜像 - image1 - image2 build:. #构建目录 network: #网络 ...... service2: test2 ...... volumnes: #挂载目录列表 networks: #网络列表 configs: #其他配置