部署你的第一个应用

🗓️实验环境

🤓FastAPI 构建应用

#基于fastapi快速创建一个项目
rkun1@LAPTOP-TUS5FU0D MINGW64 /
$ mkdir k8s-app

rkun1@LAPTOP-TUS5FU0D MINGW64 /
$ cd k8s-app/

#创建虚拟环境
rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ python -m venv ./venv

#激活
rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ source ./venv/Scripts/Activate

#安装库
(venv)
rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ pip install fastapi

(venv)
rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ pip install uvicorn #web服务器

#记录依赖库
rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ pip freeze >> requirements.txt  
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https://fastapi.tiangolo.com/#create-it
参考官方文档：

rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ vim main.py
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main.py

from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}

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启动应用：

rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ uvicorn main:app --reload
INFO:     Will watch for changes in these directories: ['C:\\Serve\\Git\\k8s-app']
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO:     Started reloader process [10408] using StatReload
INFO:     Started server process [7256]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
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访问：

🤡容器化应用

k8s可以运行容器，所以我们要将应用容器化

Dockerfile文件

# python基础镜像
FROM python:3.9

# 设置当前工作目录到/code 我们将requirements.txt和app目录放置在这
WORKDIR /code


COPY ./requirements.txt /code/requirements.txt

# 安装依赖
RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt

# 复制
COPY ./app /code/app

# 运行
CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "80"]

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查看下目录结构：

rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ tree -L 1
.
|-- Dockerfile
|-- app
|-- requirements.txt
`-- venv
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制作docker image：

rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ docker build -t k8s-fast-api .
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测试运行一下：

rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ docker run -p 8000:80 k8s-fast-api
INFO:     Started server process [1]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
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再次访问：

👾推送到DockerHub

https://hub.docker.com/
创建一个仓库：

rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app   #打标签
$ docker build -t rkun422/k8s-images-repo:0.0.1 .

#推送
rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ docker push rkun422/k8s-images-repo:0.0.1
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🤖创建Kubernetes集群

https://dashboard.civo.com/login
可以在云上部署Kubernetes集群，也可以在本地操作
这里我使用Windows本地搭建的minikube
https://minikube.sigs.k8s.io/docs/

👽定义你的集群资源

#创建目录  定义k8s集群资源在这个目录下
rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app
$ mkdir kubernetes
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https://kubernetes.io/zh-cn/docs/concepts/workloads/controllers/deployment/
在部署之前首先要创建集群拉取镜像时的Secret
具体请参考：
https://kubernetes.io/zh-cn/docs/tasks/configure-pod-container/pull-image-private-registry/#create-a-secret-by-providing-credentials-on-the-command-line

😎Deployment

deployment.yml
注意镜像仓库是你自己指定的

apiVersion: apps/v1
kind: Deployment
metadata:
  name: fast-api
  labels:
    app: fast-api
spec:
  replicas: 3
  selector:
    matchLabels:
      app: fast-api
  template:
    metadata:
      labels:
        app: fast-api
    spec:
      containers:
      - name: fast-api
        image: rkun422/k8s-images-repo:0.0.1
        ports:
        - containerPort: 80
      imagePullSecrets:
      - name: repo-key   #你创建的secret
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🧐Service

Servcie可以提供一个固定的地址让我们去访问Pod
https://kubernetes.io/zh-cn/docs/concepts/services-networking/service/
service.yml

apiVersion: v1
kind: Service
metadata:
  name: fast-api
spec:
  selector:
    app: fast-api
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
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👻部署资源进入集群

rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app/kubernetes
$ pwd
/k8s-app/kubernetes
(venv)
rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app/kubernetes
$ kubectl apply -f ./


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查看Pod：

$ kubectl get pod
NAME                        READY   STATUS    RESTARTS   AGE
fast-api-5cbcbcfc56-b9whd   1/1     Running   0          6m19s
fast-api-5cbcbcfc56-bwf7v   1/1     Running   0          6m19s
fast-api-5cbcbcfc56-j9zw5   1/1     Running   0          6m19s
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查看Service:

rkun1@LAPTOP-TUS5FU0D MINGW64 /k8s-app/kubernetes
$ kubectl get svc -o wide
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE    SELECTOR
fast-api     ClusterIP   10.108.66.181   <none>        80/TCP    7m8s   app=fast-api
kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP   10d    <none>
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对一个Pod进行端口转发：

$ kubectl port-forward pods/fast-api-5cbcbcfc56-b9whd 80:80
Forwarding from 127.0.0.1:80 -> 80
Forwarding from [::1]:80 -> 80
Handling connection for 80
Handling connection for 80
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浏览器访问：

通过Service访问：

rkun1@LAPTOP-TUS5FU0D MINGW64 ~
$ minikube service fast-api --url
W1121 22:07:50.931444   22028 main.go:291] Unable to resolve the current Docker CLI context "default": context "default": context not found: open C:\Users\rkun1\.docker\contexts\meta\37a8eec1ce19687d132fe29051dca629d164e2c4958ba141d5f4133a33f0688f\meta.json: The system cannot find the path specified.
😿  service default/fast-api 没有 NodePort
http://127.0.0.1:55001
❗  因为你正在使用 windows 上的 Docker 驱动程序，所以需要打开终端才能运行它。
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说明Service配置正确，后续可以配置Ingress对进入的流量进行路由