Docker-compose
大约 5 分钟
Docker-compose容器编排
Docker-Compose是Docker官方的开源项目，负责实现对Docker容器集群的快速编排。
docker建议我们每一个容器中只运行一个服务,因为docker容器本身占用资源极少,所以最好是将每个服务单独的分割开来。但是这样我们又面临了一个问题？
如果需要同时部署多个服务,难道要每个服务单独写Dockerfile然后在构建镜像,构建容器,这样累都累死了,所以docker官方给我们提供了docker-compose多服务部署的工具
例如要实现一个Web微服务项目，除了Web服务容器本身，往往还需要再加上后端的数据库mysql服务容器，redis服务器，注册中心eureka，甚至还包括负载均衡容器等等。。。。。。
Compose允许用户通过一个单独的 docker-compose.yml模板文件 （YAML 格式）来定义 一组相关联的应用容器为一个项目（project）。
可以很容易地用一个配置文件定义一个多容器的应用，然后使用一条指令安装这个应用的所有依赖，完成构建。Docker-Compose 解决了容器与容器之间如何管理编排的问题。
安装流程
Linux 上我们可以从 Github 上下载它的二进制包来使用，最新发行的版本地址：https://github.com/docker/compose/releases。
运行以下命令以下载 Docker Compose 的当前稳定版本：
sudo curl -L "https://github.com/docker/compose/releases/download/v2.20.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
要安装其他版本的 Compose，请替换 版本号即可。
将可执行权限应用于二进制文件：
$ sudo chmod +x /usr/local/bin/docker-compose
创建软链：
$ sudo ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose
测试是否安装成功：
$ docker-compose version
cker-compose version 1.29.2, build 4667896b
核心概念
一文件
docker-compose.yml
两要素
服务(service):
一个个应用容器实例，比如订单微服务、库存微服务、mysql容器、nginx容器或者redis容器。
工程(project):
由一组关联的应用容器组成的一个完整业务单元，在 docker-compose.yml 文件中定义。
三个步骤
- 编写Dockerfile定义各个微服务应用并构建出对应的镜像文件
- 使用 docker-compose.yml 定义一个完整业务单元，安排好整体应用中的各个容器服务。
- 最后，执行docker-compose up命令 来启动并运行整个应用程序，完成一键部署上线
常用命令
docker-compose -h # 查看帮助
docker-compose build # 打包镜像
docker-compose up # 启动所有 docker-compose服务
docker-compose up -d # 启动所有 docker-compose服务 并后台运行
docker-compose down # 停止并删除容器、网络、卷、镜像。
docker-compose exec yml里面的服务id # 进入容器实例内部 docker-compose exec docker-compose.yml文件中写的服务id /bin/bash
docker-compose ps # 展示当前docker-compose编排过的运行的所有容器
docker-compose top # 展示当前docker-compose编排过的容器进程
docker-compose logs yml里面的服务id # 查看容器输出日志
docker-compose config # 检查配置
docker-compose config -q # 检查配置，有问题才有输出
docker-compose restart # 重启服务
docker-compose start # 启动服务
docker-compose stop # 停止服务
Componse 编排微服务
web服务
文件结构
$ tree .
.
├── app
│ ├── Dockerfile
│ ├── app.py
│ └── requirements.txt
├── docker-compose.yml
├── mysql
│ ├── conf
│ │ └── mysql.conf
│ └── data
└── redis
├── conf
│ └── redis.conf
└── data
app.py
from fastapi import FastAPI, HTTPException
import aioredis
import aiomysql
import logging
app = FastAPI()
# Redis configuration
async def get_redis_client():
redis = aioredis.from_url(
"redis://redis", encoding="utf-8", decode_responses=True
)
return redis
# MySQL configuration
async def get_mysql_pool():
return await aiomysql.create_pool(
host="mysql",
user="root",
password="password",
db="mydb",
autocommit=True,
)
# Initialize database on service startup
async def initialize_database():
try:
mysql_pool = await get_mysql_pool()
async with mysql_pool.acquire() as connection:
async with connection.cursor() as cursor:
await cursor.execute("""
CREATE TABLE IF NOT EXISTS user_visits (
id INT AUTO_INCREMENT PRIMARY KEY,
visit_count INT DEFAULT 0
)
""")
except aiomysql.Error as e:
logging.error(f"Failed to initialize database: {e}")
@app.on_event("startup")
async def startup_event():
await initialize_database()
async def get_user_visits():
try:
redis_client = await get_redis_client()
user_visits = await redis_client.get("user_visits")
if user_visits is not None:
return int(user_visits)
mysql_pool = await get_mysql_pool()
async with mysql_pool.acquire() as connection:
async with connection.cursor() as cursor:
await cursor.execute("SELECT visit_count FROM user_visits")
result = await cursor.fetchone()
if result:
user_visits = result[0]
else:
user_visits = 0
await redis_client.set("user_visits", user_visits)
return user_visits
except (aioredis.RedisError, aiomysql.Error) as e:
logging.error(f"Failed to get user visits: {e}")
raise HTTPException(status_code=500, detail="Internal Server Error")
@app.get("/")
async def homepage():
try:
user_visits = await get_user_visits()
user_visits += 1
redis_client = await get_redis_client()
await redis_client.set("user_visits", user_visits)
return {"message": "Welcome to the homepage!", "user_visits": user_visits}
except HTTPException as e:
raise e
@app.get("/user_visits/")
async def get_user_visits_endpoint():
try:
user_visits = await get_user_visits()
return {"user_visits": user_visits}
except HTTPException as e:
raise e
requirements.txt
fastapi
uvicorn
aioredis
aiomysql
cryptography
Dockerfile
# Use the official Python image
FROM python:3.9-slim
# Set the working directory inside the container
WORKDIR /app
# Copy the requirements file and install dependencies
COPY ./requirements.txt requirements.txt
RUN pip config set global.index-url https://mirrors.aliyun.com/pypi/simple/ && pip install -r requirements.txt
# Copy the source code into the container
COPY . .
# Expose the port the FastAPI service will listen on
EXPOSE 8000
# Command to run the FastAPI service
CMD ["uvicorn", "app:app", "--host", "0.0.0.0", "--port", "8000"]
使用Compose
服务编排，一套带走，安排
docker-componse.yml
version: "3"
services:
fastapi:
build:
context: ./app
dockerfile: Dockerfile
ports:
- "8000:8000"
volumes:
- ./app:/app # Mount the web service code directory
depends_on:
- redis
- mysql
redis:
image: "redis:latest"
ports:
- "6379:6379"
volumes:
- ./redis/conf:/usr/local/etc/redis/ # Mount the Redis configuration file
- ./redis/data:/data # Mount the Redis data directory
mysql:
image: "mysql:latest"
restart: always
environment:
MYSQL_ROOT_PASSWORD: "password"
MYSQL_DATABASE: "mydb"
MYSQL_USER: 'liusf'
MYSQL_PASSWORD: 'liusf123'
ports:
- "3306:3306"
volumes:
- ./mysql/conf:/etc/mysql/conf.d/ # Mount the MySQL configuration file
- ./mysql/data:/var/lib/mysql # Mount the MySQL data directory
command: --default-authentication-plugin=mysql_native_password #解决外部无法访问
管理服务
打包镜像
$ docker-compose -f docker-compose.yml build
redis uses an image, skipping
mysql uses an image, skipping
Building fastapi
[+] Building 15.6s (10/10) FINISHED
=> [internal] load build definition from Dockerfile 0.0s
=> => transferring dockerfile: 37B 0.0s
=> [internal] load .dockerignore 0.0s
=> => transferring context: 2B 0.0s
=> [internal] load metadata for docker.io/library/python:3.9-slim 15.4s
=> [1/5] FROM docker.io/library/python:3.9-slim@sha256:f4efbe5d1eb52c221fded79ddf18e4baa0606e7766afe2f07b0b330a9e79564a 0.0s
=> [internal] load build context 0.0s
=> => transferring context: 174B 0.0s
=> CACHED [2/5] WORKDIR /app 0.0s
=> CACHED [3/5] COPY ./requirements.txt requirements.txt 0.0s
=> CACHED [4/5] RUN pip config set global.index-url https://mirrors.aliyun.com/pypi/simple/ && pip install -r requirements.txt 0.0s
=> CACHED [5/5] COPY . . 0.0s
=> exporting to image 0.0s
=> => exporting layers 0.0s
=> => writing image sha256:735268fa6c6c874af02e0be37b098c5f3032215d5787d0bbec78032c95b87582 0.0s
=> => naming to docker.io/library/docker-compose_fastapi
后台启动所有服务
$ docker-compose -f docker-compose.yml up -d
Creating network "docker-compose_default" with the default driver
Creating docker-compose_redis_1 ... done
Creating docker-compose_mysql_1 ... done
Creating docker-compose_fastapi_1 ... done
测试服务
$ curl -v localhost:8000/
* Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 8000 (#0)
> GET / HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.64.1
> Accept: */*
>
< HTTP/1.1 200 OK
< date: Sun, 30 Jul 2023 02:37:11 GMT
< server: uvicorn
< content-length: 55
< content-type: application/json
<
* Connection #0 to host localhost left intact
{"message":"Welcome to the homepage!","user_visits":42}* Closing connection 0
$ curl -v localhost:8000/user_visits/
* Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 8000 (#0)
> GET /user_visits/ HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.64.1
> Accept: */*
>
< HTTP/1.1 200 OK
< date: Sun, 30 Jul 2023 02:37:17 GMT
< server: uvicorn
< content-length: 18
< content-type: application/json
<
* Connection #0 to host localhost left intact
{"user_visits":42}* Closing connection 0