Docker 容器无法从 docker-compose 初始化

Question

我是 Docker 新手，正在学习 Docker Compose，使用 CentOS 8 作为主机系统。所有这些文件都在同一个目录中，并以 0755 模式标记为可执行文件。

我的主要应用在webapp.py:

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)

有一个匹配的requirements.txt文件：

flask
redis

Dockerfile:

FROM python:3.4-alpine
ADD . /code
WORKDIR /code
RUN pip install -r requirements.txt
CMD ["python", "webapp.py"]

还有一个docker-compose.yml 文件：

version: "3"
services:
  web:
    build: .
    ports:
      - "5000:5000"
    stdin_open: true
    tty: true

  redis:
    image: "redis:alpine"

但是，当我运行 docker-compose up 时，它会因退出网络应用而失败。编写输出：

[root@localhost webappl]# docker-compose up
Starting webappl_redis_1 ... done
Starting webappl_web_1   ... done
Attaching to webappl_web_1, webappl_redis_1
redis_1  | 1:C 27 Dec 2021 09:03:35.861 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
redis_1  | 1:C 27 Dec 2021 09:03:35.861 # Redis version=6.2.6, bits=64, commit=00000000, modified=0, pid=1, just started
redis_1  | 1:C 27 Dec 2021 09:03:35.861 # 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 27 Dec 2021 09:03:35.863 * monotonic clock: POSIX clock_gettime
redis_1  | 1:M 27 Dec 2021 09:03:35.864 * Running mode=standalone, port=6379.
redis_1  | 1:M 27 Dec 2021 09:03:35.864 # 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 27 Dec 2021 09:03:35.864 # Server initialized
redis_1  | 1:M 27 Dec 2021 09:03:35.864 # 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 27 Dec 2021 09:03:35.865 * Loading RDB produced by version 6.2.6
redis_1  | 1:M 27 Dec 2021 09:03:35.865 * RDB age 4147 seconds
redis_1  | 1:M 27 Dec 2021 09:03:35.865 * RDB memory usage when created 0.77 Mb
redis_1  | 1:M 27 Dec 2021 09:03:35.865 # Done loading RDB, keys loaded: 0, keys expired: 0.
redis_1  | 1:M 27 Dec 2021 09:03:35.865 * DB loaded from disk: 0.000 seconds
redis_1  | 1:M 27 Dec 2021 09:03:35.865 * Ready to accept connections
webappl_web_1 exited with code 0

为什么会退出？

Answer 1

您可以尝试在您的网络中添加以下内容：在端口之后：？如果 stdin_open 不起作用，请尝试 stdin

stdin_open: true
tty: true