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docker 系列 - (6) Docker compose

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1. Compose 簡介

一個環境的建置可以透過compose 方式來設計與配置。

docker-compose-intro

2. 基本語法結構

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version: "3.8" #compose 版本

services: # 容器
  servicename: # 服務名字，這個名字也是内部 bridge網路可以使用的 DNS name 
    image: # 鏡像的名字
    command: # 可選，如果設置，則會覆蓋默認鏡像裡的 CMD命令
    environment: # 可選，相當於 docker run裡的 --env
    volumes: # 可選，相當於docker run裡的 -v
    networks: # 可選，相當於 docker run裡的 --network
    ports: # 可選，相當於 docker run裡的 -p
  servicename2:

volumes: # 可選，相當於 docker volume create

networks: # 可選，相當於 docker network create

以 Python Flask + Redis练习：为例子，改造成一个docker-compose文件

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docker image pull redis
docker image build -t flask-demo .

# create network
docker network create -d bridge demo-network

# create container
docker container run -d --name redis-server --network demo-network redis
docker container run -d --network demo-network --name flask-demo --env REDIS_HOST=redis-server -p 5000:5000 flask-demo

docker-compose.yml 文件如下

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version: "3.8"

services:
  flask-demo:
    image: flask-demo:latest
    environment:
      - REDIS_HOST=redis-server
    networks:
      - demo-network
    ports:
      - 8080:5000

  redis-server:
    image: redis:latest
    networks:
     - demo-network

networks:
  demo-network: #創建一個deom-network網路，不填寫參數預設建立bridge type網路

3. docker-compose命令行基本使用

先將docker-compose.yml檔案放到上次練習的資料夾底下，並使用之前建立好的flask-demo鏡像檔。

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root@host04:/home/kite/Desktop/flask_redis_practice# tree
.
├── app.py
├── docker-compose.yml
└── Dockerfile

3.1. docker-compose up

我們開始學習的第一個指令：

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docker-compose up

我們會看到container 名稱會以資料夾名稱 + 鏡像名稱 + 數字(flask_redis_practice_redis-server_1) ，這個是跟後續擴容有關的設計，當然我們也可以在compose 檔設定自己定義的名稱

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose up
Creating flask_redis_practice_flask-demo_1   ... done
Creating flask_redis_practice_redis-server_1 ... done
Attaching to flask_redis_practice_redis-server_1, flask_redis_practice_flask-demo_1
redis-server_1  | 1:C 07 Mar 2022 02:41:20.371 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
redis-server_1  | 1:C 07 Mar 2022 02:41:20.371 # Redis version=6.2.6, bits=64, commit=00000000, modified=0, pid=1, just started
redis-server_1  | 1:C 07 Mar 2022 02:41:20.371 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
redis-server_1  | 1:M 07 Mar 2022 02:41:20.372 * monotonic clock: POSIX clock_gettime
redis-server_1  | 1:M 07 Mar 2022 02:41:20.372 * Running mode=standalone, port=6379.
redis-server_1  | 1:M 07 Mar 2022 02:41:20.372 # Server initialized
redis-server_1  | 1:M 07 Mar 2022 02:41:20.372 # 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-server_1  | 1:M 07 Mar 2022 02:41:20.372 * Ready to accept connections
flask-demo_1    |  * Serving Flask app 'app.py' (lazy loading)
flask-demo_1    |  * Environment: production
flask-demo_1    |    WARNING: This is a development server. Do not use it in a production deployment.
flask-demo_1    |    Use a production WSGI server instead.
flask-demo_1    |  * Debug mode: off
flask-demo_1    |  * Running on all addresses.
flask-demo_1    |    WARNING: This is a development server. Do not use it in a production deployment.
flask-demo_1    |  * Running on http://172.19.0.2:5000/ (Press CTRL+C to quit)
flask-demo_1    | 172.19.0.1 - - [07/Mar/2022 02:41:39] "GET / HTTP/1.1" 200 -
flask-demo_1    | 172.19.0.1 - - [07/Mar/2022 02:41:39] "GET /favicon.ico HTTP/1.1" 404 -
flask-demo_1    | 172.19.0.1 - - [07/Mar/2022 02:41:40] "GET / HTTP/1.1" 200 -

3.2. docker-compose up -d

ctrl + c退出互動模式後，如果想讓環境運行在後台，可加參數 -d

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docker-compose up -d

執行如下：

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose up -d
Starting flask_redis_practice_redis-server_1 ... done
Starting flask_redis_practice_flask-demo_1   ... done
kite@host04:~/Desktop/flask_redis_practice$

3.3. docker-compose logs

這個模式下，如果還想看相關log我們可以使用docker-compose logs 或docker-compose logs -f持續動態查看。

3.4. docker-compose ps

透過docker-compose ps查看運行的內容：

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docker-compose ps
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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose ps
               Name                              Command               State                    Ports                  
-----------------------------------------------------------------------------------------------------------------------
flask_redis_practice_flask-demo_1     flask run -h 0.0.0.0             Up      0.0.0.0:8080->5000/tcp,:::8080->5000/tcp
flask_redis_practice_redis-server_1   docker-entrypoint.sh redis ...   Up      6379/tcp

注意：這個指定一定要在docker-compose檔案所在的資料夾執行才有效

我們稍微看一下相關指令

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kite@host04:~/Desktop/flask_redis_practice$ docker-compose
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)
...
...

如果compose檔名稱要指定的話，加-f參數即可，跟dockerfile的概念一樣。另外也有看到一個 project-name這個就是我們剛剛說的container名稱會以資料夾名稱的命名方式，如果不喜歡也可以使用-p的指令方式指定。

3.5. docker-compose stop

如果想要停止compose也是可以做到的，這個方式很聰明，可以一次性將整個環境的容器一起停止處理：

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docker-compose stop

如果去看docker container 、docker network 都會有compose 建立出來的容器與bridge

刪除沒有被使用的資源可以使用以下指令

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docker system prune -f

3.6. docker-compose -p

我們也可以自定義專案名稱

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose -p myproject up -d

使用指令查看

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose -p myproject ps
          Name                        Command               State                    Ports                  
------------------------------------------------------------------------------------------------------------
myproject_flask-demo_1     flask run -h 0.0.0.0             Up      0.0.0.0:8080->5000/tcp,:::8080->5000/tcp
myproject_redis-server_1   docker-entrypoint.sh redis ...   Up      6379/tcp

通過stop指令再批次停止

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose -p myproject stop
Stopping myproject_redis-server_1 ... done
Stopping myproject_flask-demo_1   ... done

3.7. docker-compose-rm

通過rm指令刪除

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose -p myproject rm
Going to remove myproject_redis-server_1, myproject_flask-demo_1
Are you sure? [yN] y
Removing myproject_redis-server_1 ... done
Removing myproject_flask-demo_1   ... done

3.8. docker-compose build

試著使用build方式來玩,，建立一個資料夾名稱為flask_web，將app.py、Dockerfile移至flask_web底下：

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kite@host04:~/Desktop/flask_redis_practice$ tree
.
├── docker-compose.yml
└── flask_web
    ├── app.py
    └── Dockerfile

app.py

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from flask import Flask
from redis import Redis
import os
import socket

app = Flask(__name__)
redis = Redis(host=os.environ.get('REDIS_HOST', '127.0.0.1'), port=6379)


@app.route('/')
def hello():
    redis.incr('hits')
    return f"Hello Container World! I have been seen {redis.get('hits').decode('utf-8')} times and my hostname is {socket.gethostname()}.\n"

Dockerfile

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FROM python:3.9.5-slim

RUN pip install flask redis && \
    groupadd -r flask && useradd -r -g flask flask && \
    mkdir /src && \
    chown -R flask:flask /src

USER flask

COPY app.py /src/app.py

WORKDIR /src

ENV FLASK_APP=app.py REDIS_HOST=redis

EXPOSE 5000

CMD ["flask", "run", "-h", "0.0.0.0"]

修改docker-compose.yml 檔：

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version: "3.8"

services:
  flask-demo:
    build: ./flask_web
    #image: flask-demo:latest
    environment:
      - REDIS_HOST=redis-server
    networks:
      - demo-network
    ports:
      - 8080:5000

  redis-server:
    image: redis:latest
    networks:
     - demo-network

networks:
  demo-network:

我們添加了build: ./flask_web，預設會抓這個資料夾底下的Dockerfile名稱進行build image

compose build 指令玩一下：

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose build
redis-server uses an image, skipping
Building flask-demo
Sending build context to Docker daemon  3.072kB
Step 1/8 : FROM python:3.9.5-slim
 ---> c71955050276
Step 2/8 : RUN pip install flask redis &&     groupadd -r flask && useradd -r -g flask flask &&     mkdir /src &&     chown -R ...
...
Successfully built 626b99e2547c
Successfully tagged flask_redis_practice_flask-demo:latest
kite@host04:~/Desktop/flask_redis_practice$ sudo docker images

看一下image 清單，我們會發現image名稱會以當時的資料夾名稱為前綴：

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker images 
REPOSITORY                        TAG                IMAGE ID       CREATED          SIZE
flask_redis_practice_flask-demo   latest             626b99e2547c   36 seconds ago   129MB

3.9. docker-compose build 文件格式 - add image name

也可以在docker-compose文件中指定image名稱：

docker-compose.yml

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version: "3.8"

services:
  flask-demo:
    build: ./flask_web
    image: flask-kite:latest
    environment:
      - REDIS_HOST=redis-server
    networks:
      - demo-network
    ports:
      - 8080:5000

  redis-server:
    image: redis:latest
    networks:
     - demo-network

networks:
  demo-network:

結果如下：

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker images 
REPOSITORY       TAG                IMAGE ID       CREATED          SIZE
flask-kite       latest             33a0bf4d2428   11 seconds ago   129MB

3.10. docker-compose build 文件格式 - context、dockefile name

先將Dockerfile名稱改為Dockerfile.dev

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kite@host04:~/Desktop/flask_redis_practice$ tree
.
├── docker-compose.yml
└── flask_web
    ├── app.py
    └── Dockerfile.dev

在docker-compose文件中指定dockerfile檔案名稱：

docker-compose.dev

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version: "3.8"

services:
  flask-demo:
    build:
      context: ./flask_web
      dockerfile: Dockerfile.dev
    image: flask-kite:latest
    environment:
      - REDIS_HOST=redis-server
    networks:
      - demo-network
    ports:
      - 8080:5000

  redis-server:
    image: redis:latest
    networks:
     - demo-network

networks:
  demo-network:

3.11. docker-compose pull

也可以使用docker-compose pull進行image build：

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose pull
Pulling flask-demo   ... done
Pulling redis-server ... done

3.12. docker-compose –help

查找相關指令：

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kite@host04:~/Desktop/flask_redis_practice$ sudo 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
  -c, --context NAME          Specify a context name
  --verbose                   Show more output
  --log-level LEVEL           Set log level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
  --ansi (never|always|auto)  Control when to print ANSI control characters
  --no-ansi                   Do not print ANSI control characters (DEPRECATED)
  -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 keys
                              in v3 files to their non-Swarm equivalent (DEPRECATED)
  --env-file PATH             Specify an alternate environment file

Commands:
  build              Build or rebuild services
  config             Validate and view the Compose file
  create             Create services
  down               Stop and remove resources
  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 version information and quit
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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose build --help
Build or rebuild services.

Services are built once and then tagged as `project_service`,
e.g. `composetest_db`. If you change a service's `Dockerfile` or the
contents of its build directory, you can run `docker-compose build` to rebuild it.

Usage: build [options] [--build-arg key=val...] [--] [SERVICE...]

Options:
    --build-arg key=val     Set build-time variables for services.
    --compress              Compress the build context using gzip.
    --force-rm              Always remove intermediate containers.
    -m, --memory MEM        Set memory limit for the build container.
    --no-cache              Do not use cache when building the image.
    --no-rm                 Do not remove intermediate containers after a successful build.
    --parallel              Build images in parallel.
    --progress string       Set type of progress output (auto, plain, tty).
    --pull                  Always attempt to pull a newer version of the image.
    -q, --quiet             Don't print anything to STDOUT

3.13. docker compose build -d –build

試著修改app.py檔

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from flask import Flask
from redis import Redis
import os
import socket

app = Flask(__name__)
redis = Redis(host=os.environ.get('REDIS_HOST', '127.0.0.1'), port=6379)


@app.route('/')
def hello():
    redis.incr('hits')
    return f"Hello Container World!I'm kite. I have been seen {redis.get('hits').decode('utf-8')} times and my hostname is {socket.gethostname()}.\n"

在運行的過程中：

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose ps
               Name                              Command               State                    Ports                  
-----------------------------------------------------------------------------------------------------------------------
flask_redis_practice_flask-demo_1     flask run -h 0.0.0.0             Up      0.0.0.0:8080->5000/tcp,:::8080->5000/tcp
flask_redis_practice_redis-server_1   docker-entrypoint.sh redis ...   Up      6379/tcp

使用--build指令

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docker compose build -d --build

這個指令會發現檔案有發生改變，就會決定重新build，並且會直接重啟與運行容器，不用經過compose stop、compose rm、compose build、 compose up 過程，非常方便，結果如下：

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose up -d --build
Building flask-demo
Sending build context to Docker daemon  3.072kB
Step 1/8 : FROM python:3.9.5-slim
 ---> c71955050276
Step 2/8 : RUN pip install flask redis &&     groupadd -r flask && useradd -r -g flask flask &&     mkdir /src &&     chown -R flask:flask /src
 ---> Using cache
 ---> bbf517f842c7
Step 3/8 : USER flask
 ---> Using cache
 ---> 7b1d7b6407b8
Step 4/8 : COPY app.py /src/app.py
 ---> 47b63bef74ff
Step 5/8 : WORKDIR /src
 ---> Running in 1da9b0391baf
Removing intermediate container 1da9b0391baf
 ---> ccbca4bf8c09
Step 6/8 : ENV FLASK_APP=app.py REDIS_HOST=redis
 ---> Running in 74c8fbb7fd95
Removing intermediate container 74c8fbb7fd95
 ---> cc12a2e1af00
Step 7/8 : EXPOSE 5000
 ---> Running in 201a42960e97
Removing intermediate container 201a42960e97
 ---> 3731d50ee226
Step 8/8 : CMD ["flask", "run", "-h", "0.0.0.0"]
 ---> Running in 3f4fea9f7156
Removing intermediate container 3f4fea9f7156
 ---> df6ac55a1b2d
Successfully built df6ac55a1b2d
Successfully tagged flask-kite:latest
flask_redis_practice_redis-server_1 is up-to-date
Recreating flask_redis_practice_flask-demo_1 ... done
kite@host04:~/Desktop/flask_redis_practice$

3.14. docker compose -d

目前comopose狀態：

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose ps
[sudo] password for kite: 
               Name                              Command               State                    Ports                  
-----------------------------------------------------------------------------------------------------------------------
flask_redis_practice_flask-demo_1     flask run -h 0.0.0.0             Up      0.0.0.0:8080->5000/tcp,:::8080->5000/tcp
flask_redis_practice_redis-server_1   docker-entrypoint.sh redis ...   Up      6379/tcp

3.14.1. add image

我們添加一個busybox ，修改docker-compose檔

docker-compose.dev

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version: "3.8"

services:
  flask-demo:
    build:
      context: ./flask_web
      dockerfile: Dockerfile.dev
    image: flask-kite:latest
    environment:
      - REDIS_HOST=redis-server
    networks:
      - demo-network
    ports:
      - 8080:5000

  redis-server:
    image: redis:latest
    networks:
     - demo-network
  busybox:
    image: busybox:latest
    command: sh -c "while true;do sleep 3600; done"
    networks:
      - demo-network

networks:
  demo-network:

接著，我們再試著下docker-compose up -d，我們會發現有出現create busybox的訊息：

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose up -d
flask_redis_practice_flask-demo_1 is up-to-date
flask_redis_practice_redis-server_1 is up-to-date
Creating flask_redis_practice_busybox_1 ... done

3.14.2. remove image

再試著將剛剛的busybox移除 ，修改docker-compose檔

docker-compose.dev

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version: "3.8"

services:
  flask-demo:
    build:
      context: ./flask_web
      dockerfile: Dockerfile.dev
    image: flask-kite:latest
    environment:
      - REDIS_HOST=redis-server
    networks:
      - demo-network
    ports:
      - 8080:5000

  redis-server:
    image: redis:latest
    networks:
     - demo-network
networks:
  demo-network:

再執行一次docker-compose up -d

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose up -d
WARNING: Found orphan containers (flask_redis_practice_busybox_1) for this project. If you removed or renamed this service in your compose file, you can run this command with the --remove-orphans flag to clean it up.
flask_redis_practice_flask-demo_1 is up-to-date
flask_redis_practice_redis-server_1 is up-to-date

會出現警告：

WARNING: Found orphan containers (flask_redis_practice_busybox_1) for this project. If you removed or renamed this service in your compose file, you can run this command with the –remove-orphans flag to clean it up.

照著指令操作，移除busybox的指令需要--remove-orphans，執行如下：

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kite@host04:~/Desktop/flask_redis_practice$ sudo docker-compose up -d --remove-orphans
Removing orphan container "flask_redis_practice_busybox_1"
flask_redis_practice_flask-demo_1 is up-to-date
flask_redis_practice_redis-server_1 is up-to-date
kite@host04:~/Desktop/flask_redis_practice$

3.14.3. container 配置文件修改

通常container 配置文件(使用volume 掛載本地文件)修改之後，要重啟container。而在compose 可以透過docker compose restart指令重啟。

這個指令只是重啟，並不是重新創建喔。

3.15. 更新操作小總結

我們常在專案會時常更新，比如更新鏡像、配置文件、增加service、刪除service，最常用的有二種

  1. 刪除未使用的service

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    docker-compose up -d --remove-orphans

  2. container 配置文件修改

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    docker-compose restart

  3. image 進行修改

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    docker-compose -d --build

4. docker-compose網路(上)

暫補

5. docker-compose網路(下)

暫補

各別指定network

network default

network subnet