如何以最少的停机时间在docker-compose容器中重新加载环境变量？ [英] How to reload environment variables in docker-compose container with minimum downtime?

问题描述

docker-compose.yml

version: '2'
services:
  app:
    build:
      context: .
    command: python src/app.py
    restart: on-failure
    depends_on:
      - db
    environment:
      - TJBOT_DB_HOST=db
      - TJBOT_API_KEY
      - TJBOT_AUTO_QUESTION_TIME
    env_file:
      - .env
  db:
    image: mongo:3.0.14
    volumes:
      - mongodbdata:/data/db
volumes:
  mongodbdata:

如果我更改 .env 文件，如何重新加载容器以使用新的环境变量，并且停机时间最短？

If I change the .env file, how could I reload the container to use the new environment variables with minimum downtime?

推荐答案

如果使用docker-compose运行yml，则只需运行 docker-compose up -d ，它将重新创建所有进行更改并保留所有不变的服务。

If you are running the yml with docker-compose, you can just run docker-compose up -d and it will recreate any containers that have changes and leave all unchanged services untouched.

$ cat docker-compose.env2.yml
version: '2'

services:
  test:
    image: busybox
    # command: env
    command: tail -f /dev/null
    environment:
      - MY_VAR=hello
      - MY_VAR2=world
  test2:
    image: busybox
    command: tail -f /dev/null
    environment:
      - MY_VAR=same ole same ole

$ docker-compose -f docker-compose.env2.yml up -d                                               
Creating network "test_default" with the default driver
Creating test_test_1
Creating test_test2_1

$ vi docker-compose.env2.yml # edit the file to change MY_VAR

$ docker-compose -f docker-compose.env2.yml up -d
Recreating test_test_1
test_test2_1 is up-to-date

如果将容器作为 docker stack deploy -c docker-compose.yml 使用版本3文件格式运行，则可以滚动更新该服务如果您有多个服务实例在运行，这将防止任何停机时间。此功能仍是非常新的功能，您需要1.13.1修复某些更新问题，并且与所有新功能一样，错误仍在解决中。

If you run the containers as a docker stack deploy -c docker-compose.yml with a version 3 file format, you can do a rolling update of the service which will prevent any downtime if you have multiple instances of your service running. This functionality is still very new, you'll want 1.13.1 to fix some of the issues with updates, and as with anything this new, bugs are still being worked out.

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