码头工人-码头工人运行-总是重新启动实际上是做什么的? [英] Docker - what does `docker run --restart always` actually do?

问题描述

尽管--restart标志看起来很简单明了，但是在尝试它时我提出了许多问题:

Although it seems like the --restart flag is simple and straightforward, I came up with a number of questions when experimenting with it:

1. 关于 ENTRYPOINT 定义-重新启动期间实际定义的语义是什么?
2. 如果我 exec 进入容器(我在DDC上)并杀死-9进程，它将重新启动，但是如果我执行 docker kill 则不会.为什么?
3. 重新启动如何与共享数据容器/命名卷交互?

1. With respect to ENTRYPOINT definitions - what are the actual defined semantics during restart?
2. If I exec into the container (I am on a DDC) and kill -9 the process, it restarts, but if I do docker kill it does not. Why?
3. How does restart interact with Shared Data Containers / Named Volumes?

推荐答案

今天我有一些时间可以调试更多->因为我使用的是官方"码头工人镜像，所以几乎看不到发生了什么.为了解决这个问题，我扩展了官方形象并调用了我自己的入口点.Dockerfile:

I had some time to debug this more today -> because I was using an 'official' docker image I had little to no visibility into what was occurring. To resolve this, I extended the official image and invoked my own entrypoint. The Dockerfile:

FROM officialImage:version

ENV envOne=value1  \
    envTwo=value2
COPY wrapper-entrypoint.sh /
ENTRYPOINT ["/wrapper-entrypoint.sh"]

然后我在 wrapper-entrypoint.sh 脚本中进行了设置-x"并调用了原始脚本:

Then I did a 'set -x' in the wrapper-entrypoint.sh script and invoked the original:

#!/bin/bash
set -x

echo "Be pedantic: all args passed: $@"
bash -x ./original-entrypoint.sh "$@"

由此我发现:

• 重新启动会使用原始参数调用原始的 ENTRYPOINT .我使用的官方图片检测到它已经初始化，因此采取了不同的行动.这就是为什么我对语义感到困惑.使用 -x 可以查看实际情况.
• 我仍然不知道为什么 docker kill 会停止重新启动，但这就是我所看到的-至少在Docker Data Center上如此.
• 我不认为共享数据量会以任何方式影响此，请根据重新启动时的条件保存给定 ENTRYPOINT 脚本可能采取的操作.

• Restart does call the original ENTRYPOINT with the original arguments. The official image I used detected it had already initialized and thus acted differently. This is why I was confused over the semantics. Using -x allowed me to see what was really happening.
• I still don't know why docker kill stops the restart, but that is what I see - at least on Docker Data Center.
• I don't believe Shared Data Volumes affect this in any way, SAVE for the actions a given ENTRYPOINT script might take based upon it's condition at the time of the restart.

这篇关于码头工人-码头工人运行-总是重新启动实际上是做什么的?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！