
Docker从入门到精通之Docker Compose
作者 |上海滩虎哥
来源 | 今日头条
Compose是一个用于定义和运行多容器Docker应用程序的工具。使用Compose,您可以使用YAML文件来配置应用程序的服务。然后,只需一个命令,就可以从配置中创建并启动所有服务。
Install Docker Compose
下载docker compose
$ sudo curl -L "https://github.com/docker/compose/releases/download/1.29.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
给docker compose设置可执行权限
$ sudo chmod +x /usr/local/bin/docker-compose
验证
$ docker-compose --version
Uninstallation
$ sudo rm /usr/local/bin/docker-compose
Getting Started
用python构建一个简易网页统计网页点击量,docker-compose进行发布
Step1:创建项目
创建项目目录
$ mkdir test_web
$ cd test_web
在项目目录中创建app.py文件,并把下面代码复制进去
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)
创建requirements.txt文件,以下内容复制进去
flask
redis
Step2:创建Dockerfile文件
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
EXPOSE 5000
COPY . .
CMD ["flask", "run"]
Step3:在docker-compose.yml中定义services
version: "3.9"
services:
web:
build: .
ports:
- "5000:5000"
redis:
image: "redis:alpine"
Step4:用Docker compose构建和运行app
- 进入项目目录,运行docker-compose up
- $ docker-compose up
- 在浏览器访问http://localhost:5000/ ,刷新页面看变化
- 查看使用compose构建的镜像
- $ docker images
Step5:绑定一个数据卷
version: "3.9"
services:
web:
build: .
ports:
- "5000:5000"
volumes:
- .:/code
environment:
FLASK_ENV: development
redis:
image: "redis:alpine"
将当前目录与容器的/code目录绑定,这样可以动态修改代码
Step6:重新构建和运行app
先docker-compose down停止服务,在构建
$ docker-compose down
$ docker-compose up
Compose file
用YAML文件定义服务,默认文件是docker-compose.yml,包含4个顶级key,version、services、networks、volumes
参考compose-spec/spec.md at master · compose-spec/compose-spec · GitHub
version
指定本 yml 依从的 compose版本
services
定义多个应用服务,包含环境配置、镜像构建等
build
指定构建镜像的路径
version: "3.9"
services:
webapp:
build: ./app
blkio_config
定义服务的block IO配置,参考compose-spec/spec.md at master · compose-spec/compose-spec · GitHub
container_name
指定自定义容器名称
depends_on
定义服务间启动或关闭的依赖关系
services:
web:
build: .
depends_on:
- db
- redis
redis:
image: redis
db:
image: postgres
command
覆盖容器启动的默认命令
command: [ "bundle", "exec", "thin", "-p", "3000" ]
domainname
domainname declares a custom domain name to use for the service container.
entrypoint
覆盖容器默认的entrypoint
env_file
从文件中添加环境变量到容器,可以是一个或多个文件
env_file: .env
env_file:
- ./a.env
- ./b.env
文件格式:
# Set Rails/Rack environment
RACK_ENV=development
VAR="quoted"
environment
添加环境变量
environment:
RACK_ENV: development
SHOW: "true"
USER_INPUT:
expose
暴露端口,但不映射到宿主机,只被连接的服务访问,仅可以指定内部端口
expose:
- "3000"
- "8000"
healthcheck
用于检测 docker 服务是否健康运行。
healthcheck:
test: ["CMD", "curl", "-f", "http://localhost"] # 设置检测程序
interval: 1m30s # 设置检测间隔
timeout: 10s # 设置检测超时时间
retries: 3 # 设置重试次数
start_period: 40s # 启动后,多少秒开始启动检测程序
image
指定容器运行的镜像
image: redis:5
labels
设置容器标签
labels:
com.example.description: "Accounting webapp"
com.example.department: "Finance"
labels:
- "com.example.description=Accounting webapp"
- "com.example.department=Finance"
links
连接到另一个容器的网络,简单将就是让容器相互连通
web:
links:
- db
- db:database
- redis
logging
服务的日志记录配置,driver:指定服务容器的日志记录驱动程序,默认值为json-file。有以下三个选项
driver: "json-file"
driver: "syslog"
driver: "none"
仅在 json-file 驱动程序下,可以使用以下参数,限制日志得数量和大小。
logging:
driver: json-file
options:
max-size: "200k" # 单个文件大小为200k
max-file: "10" # 最多10个文件
syslog 驱动程序下,可以使用 syslog-address 指定日志接收地址。
logging:
driver: syslog
options:
syslog-address: "tcp://192.168.0.42:123"
network_mode
设置网络模式,格式如下:
network_mode: "bridge" #桥接模式
network_mode: "host"
network_mode: "none"
network_mode: "service:[service name]"
networks
配置容器连接的网络
services:
some-service:
networks:
- some-network
- other-network
networks:
some-network:
# Use a custom driver
driver: custom-driver-1
other-network:
# Use a custom driver which takes special options
driver: custom-driver-2
services:
frontend:
image: awesome/webapp
networks:
- front-tier
- back-tier
monitoring:
image: awesome/monitoring
networks:
- admin
backend:
image: awesome/backend
networks:
back-tier:
aliases:
- database
admin:
aliases:
- mysql
networks:
front-tier:
back-tier:
admin:
ipv4_address, ipv6_address
指定ip地址
services:
frontend:
image: awesome/webapp
networks:
front-tier:
ipv4_address: 172.16.238.10
ipv6_address: 2001:3984:3989::10
networks:
front-tier:
ipam:
driver: default
config:
- subnet: "172.16.238.0/24"
- subnet: "2001:3984:3989::/64"
ports
端口映射,映射主机与容器端口,格式:Host:ontainer
ports:
- "5000:5000"
restart
容器重启策略
restart: "no"
restart: always
restart: on-failure
restart: unless-stopped
secrets
存储敏感数据,比如密码
services:
frontend:
image: awesome/webapp
secrets:
- server-certificate
secrets:
server-certificate:
file: ./server.cert
volumes
将主机数据卷挂载到容器
services:
db:
image: postgres:latest
volumes:
- "/localhost/postgres.sock:/var/run/postgres/postgres.sock"
- "/localhost/data:/var/lib/postgresql/data"
working_dir
覆盖容器工作目录
Volumes 顶级目录
services:
backend:
image: awesome/database
volumes:
- db-data:/etc/data
backup:
image: backup-service
volumes:
- db-data:/var/lib/backup/data
volumes:
db-data:
Networks 顶级目录
services:
frontend:
image: awesome/webapp
networks:
- front-tier
- back-tier
networks:
front-tier:
back-tier:
driver: bridge
docker-compose 命令
$ docker-compose --help
Define and run multi-container applications with Docker.
Usage:
docker-compose [-f <arg>...] [--profile <name>...] [options] [COMMAND] [ARGS...]
docker-compose -h|--help
Options:
-f, --file FILE Specify an alternate compose file
(default: docker-compose.yml)
-p, --project-name NAME Specify an alternate project name
(default: directory name)
--profile NAME Specify a profile to enable
--verbose Show more output
--log-level LEVEL Set log level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
--no-ansi Do not print ANSI control characters
-v, --version Print version and exit
-H, --host HOST Daemon socket to connect to
--tls Use TLS; implied by --tlsverify
--tlscacert CA_PATH Trust certs signed only by this CA
--tlscert CLIENT_CERT_PATH Path to TLS certificate file
--tlskey TLS_KEY_PATH Path to TLS key file
--tlsverify Use TLS and verify the remote
--skip-hostname-check Don't check the daemon's hostname against the
name specified in the client certificate
--project-directory PATH Specify an alternate working directory
(default: the path of the Compose file)
--compatibility If set, Compose will attempt to convert deploy
keys in v3 files to their non-Swarm equivalent
Commands:
build Build or rebuild services
bundle Generate a Docker bundle from the Compose file
config Validate and view the Compose file
create Create services
down Stop and remove containers, networks, images, and volumes
events Receive real time events from containers
exec Execute a command in a running container
help Get help on a command
images List images
kill Kill containers
logs View output from containers
pause Pause services
port Print the public port for a port binding
ps List containers
pull Pull service images
push Push service images
restart Restart services
rm Remove stopped containers
run Run a one-off command
scale Set number of containers for a service
start Start services
stop Stop services
top Display the running processes
unpause Unpause services
up Create and start containers
version Show the Docker-Compose version information
Swarm集群
