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
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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
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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
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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
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