如何以最短的停机时间在 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:

如果我更改了 .env 文件，我如何重新加载容器以在最短的停机时间内使用新的环境变量?

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

如果您使用 docker-compose 运行 yml，您只需运行 docker-compose up -d 它将重新创建任何具有更改且所有未更改的服务保持不变的容器.

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

如果您将容器作为具有版本 3 文件格式的 docker stack deploy -c docker-compose.yml 运行，您可以对服务进行滚动更新，这将防止出现任何停机时间运行多个服务实例.此功能仍然很新，您需要 1.13.1 来解决更新中的一些问题，并且与任何新功能一样，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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