无法从 Google Cloud Platform 的 VM SSH Link 访问 Web (Flask) 应用程序

Question

我的目标是运行在来自 Google Cloud Platform 的 VM 上构建一个 docker-compose 集群。我已经成功安装了 docker 和 docker-compose:

$ uname -a
Linux instance-6 4.15.0-1083-gcp #94~16.04.1-Ubuntu SMP Sat Sep 5 22:53:03 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

$ docker -v
Docker version 19.03.13, build 4484c46d9d

$ docker-compose -v
docker-compose version 1.27.3, build 4092ae5d

我正在按照基本教程创建一个 docker-compose 集群，使用：https://docs.docker.com/compose/gettingstarted/（步骤 #1-#4）。

我的 app.py 文件是：

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)

我的 requirements.txt 文件是：

flask
redis

我的Dockerfile是：

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"]

而且，我的 docker-compose.yml 是：

version: '3'
services:
  web:
    build: .
    ports:
      - "5000:5000"
  redis:
    image: "redis:alpine"

运行 docker-compose up 给了我正确的输出。其中一个输出指向 web_1 是运行ning.

$ docker-compose up
...
web_1    |  * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
...

按下 link http://0.0.0.0:5000/ 后，GCP 没有连接。它试图转到 URL：https://ssh.cloud.google.com/devshell/proxy?authuser=2&devshellProxyPath=%2F&port=5000&environment_name&environment_id，但随后出现错误：500. That’s an error. There was an error. Please try again later. That’s all we know.

转到外部 IP 地址并输入端口 5000 也不会 return 任何东西。 (http://IP地址:500)

我检查了端口：

$ sudo docker-compose ps

Name                      Command               State           Ports         
composetest_redis_1   docker-entrypoint.sh redis ...   Up      6379/tcp              
composetest_web_1     flask run                        Up      0.0.0.0:5000->5000/tcp

我不确定是什么原因。我猜这是来自 GCP 的防火墙配置。一切都只是默认设置。我还在 Compute Engine VM 实例设置中允许了 HTTP 和 HTTPS 请求。真的很感激更多关于该做什么的指导。提前致谢！

查看下面的完整输出：

$ sudo docker-compose up
Starting composetest_redis_1 ... done
Starting composetest_web_1   ... done
Attaching to composetest_redis_1, composetest_web_1
redis_1  | 1:C 23 Sep 2020 21:40:27.816 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
redis_1  | 1:C 23 Sep 2020 21:40:27.816 # Redis version=6.0.8, bits=64, commit=00000000, modified=0, pid=1, just started
redis_1  | 1:C 23 Sep 2020 21:40:27.816 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
redis_1  | 1:M 23 Sep 2020 21:40:27.818 * Running mode=standalone, port=6379.
redis_1  | 1:M 23 Sep 2020 21:40:27.818 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
redis_1  | 1:M 23 Sep 2020 21:40:27.818 # Server initialized
redis_1  | 1:M 23 Sep 2020 21:40:27.818 # 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_1  | 1:M 23 Sep 2020 21:40:27.819 * Loading RDB produced by version 6.0.8
redis_1  | 1:M 23 Sep 2020 21:40:27.819 * RDB age 27 seconds
redis_1  | 1:M 23 Sep 2020 21:40:27.819 * RDB memory usage when created 0.77 Mb
redis_1  | 1:M 23 Sep 2020 21:40:27.819 * DB loaded from disk: 0.000 seconds
redis_1  | 1:M 23 Sep 2020 21:40:27.819 * Ready to accept connections
web_1    |  * Serving Flask app "app.py"
web_1    |  * Environment: production
web_1    |    WARNING: This is a development server. Do not use it in a production deployment.
web_1    |    Use a production WSGI server instead.
web_1    |  * Debug mode: off
web_1    |  * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

Answer 1

需要正确地允许通过该端口的流量：

正在创建带有标签的防火墙规则
在 VM 的网络设置中包含该标记

Link 这里：Network Tags

无法从 Google Cloud Platform 的 VM SSH Link 访问 Web (Flask) 应用程序

Can't Access Web (Flask) Application from Google Cloud Platform's VM SSH Link

google-compute-engine

docker-compose