| 知乎专栏 |
Flask 是一个轻量级Web应用框架，简单易用，可以很快速地创建web应用。我们用它来创建一个demo应用。
如果还没有安装Flask库，可以使用下面命令安装:
$ pip install flask
创建 flask 项目
安装成功后，新建一个命名为flask的目录
cd workspace/python mkdir flask cd flask
然后在该目录下创建app.py文件。
from flask import Flask
app = Flask(__name__)
@app.route("/")
def index():
return """
<h1>《Netkiller Python 手札》</h1>
<p>这是一个运行在 Docker 容器中的演示程序.</p>
"""
if __name__ == "__main__":
app.run(debug=True, host='0.0.0.0')
运行项目
➜ flask git:(master) ✗ python3 app.py * Serving Flask app 'app' (lazy loading) * Environment: production WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead. * Debug mode: on * Running on all addresses. WARNING: This is a development server. Do not use it in a production deployment. * Running on http://192.168.3.2:5000/ (Press CTRL+C to quit) * Restarting with watchdog (fsevents) * Debugger is active! * Debugger PIN: 211-304-394
然后在浏览器中访问 http://localhost:5000/ 确认 flask 可以正常运行。
➜ python git:(master) ✗ curl http://localhost:5000 <h1>《Netkiller Python 手札》</h1> <p>这是一个运行在 Docker 容器中的演示程序.</p>
要在Docker上运行应用程序，首先必须使用 Dockerfile 脚本构建一个容器，而且必须包含使用的所有依赖项，包括 python 和 依赖库。
新建一个 requirements.txt 文件，包含所有依赖的 python 包，我们的例子中只有用到了一个 Flask。
flask==2.0.1
创建 Dockerfile 文件用来构建映像
FROM python LABEL org.opencontainers.image.authors="netkiller@msn.com" WORKDIR / COPY ./requirements.txt /requirements.txt RUN pip install --no-cache-dir -r requirements.txt COPY . / ENTRYPOINT [ "python" ] CMD [ "app.py" ]
构建镜像
docker build -t flask:0.0.1 .
启动容器
docker run --name flask -p 5000:5000 flask:0.0.1
容器启动运行后，测试无误，上传docker镜像到仓库
➜ flask git:(master) docker login --username netkiller Password: Login Succeeded
➜ flask git:(master) docker tag flask:0.0.1 netkiller/flask:latest
➜ flask git:(master) docker push netkiller/flask:latest The push refers to repository [docker.io/netkiller/flask] 3591098640e3: Pushed 86c12f640351: Pushed f4559c1df7ec: Pushed cd6b2a9ae627: Pushed 84c97f2e3099: Pushed b0cb6a43f300: Pushed 4b4c002ee6ca: Pushed cdc9dae211b4: Pushed 7095af798ace: Pushed fe6a4fdbedc0: Pushed e4d0e810d54a: Pushed 4e006334a6fd: Pushed latest: digest: sha256:c3be7315046aa8abe6851475658ea1b23ab1b44d411b0a5be650f38d2b197bc3 size: 2842
安装 kubernetes 测试环境
$ brew install minikube $ brew install kubectl
启动 minikube
minikube start --memory 2048mb --cpus 2 --cache-images=true --driver=hyperkit \ --image-mirror-country=cn --registry-mirror="https://registry.docker-cn.com,https://docker.mirrors.ustc.edu.cn" --insecure-registry="127.0.0.1:5000,192.168.3.0/24,192.168.64.0/24,172.17.0.0/16,10.10.0.0/24"
创建密钥
kubectl create secret docker-registry docker-hub \ --docker-server=https://index.docker.io/v2/ \ --docker-username=netkiller \ --docker-password=passw0rd \ --docker-email=netkiller@msn.com
查看密钥，确保 docker-hub 被创建
➜ Python git:(master) ✗ kubectl get secret NAME TYPE DATA AGE default-token-lcmzw kubernetes.io/service-account-token 3 2m24s docker-hub kubernetes.io/dockerconfigjson 1 35s
flask.yaml 文件
apiVersion: v1
kind: Service
metadata:
name: flask
namespace: default
labels:
app: flask
spec:
type: NodePort
ports:
- port: 5000
nodePort: 31000
selector:
app: flask
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: flask
spec:
replicas: 2
selector:
matchLabels:
app: flask
template:
metadata:
labels:
app: flask
spec:
containers:
- name: flask
image: netkiller/flask:latest
imagePullPolicy: IfNotPresent
ports:
- containerPort: 5000
imagePullSecrets:
- name: docker-hub
部署
➜ kubernetes git:(master) ✗ kubectl create -f flask.yaml service/flask created deployment.apps/flask created ➜ kubernetes git:(master) ✗ minikube service list |-------------|------------|--------------|---------------------------| | NAMESPACE | NAME | TARGET PORT | URL | |-------------|------------|--------------|---------------------------| | default | flask | 5000 | http://192.168.64.9:31000 | | default | kubernetes | No node port | | kube-system | kube-dns | No node port | |-------------|------------|--------------|---------------------------|
测试
➜ kubernetes git:(master) ✗ curl http://192.168.64.9:31000 <h1>《Netkiller Python 手札》</h1> <p>这是一个运行在 Docker 容器中的演示程序.</p>
销毁
➜ kubernetes git:(master) ✗ kubectl delete -f flask.yaml service "flask" deleted deployment.apps "flask" deleted