“expose"和“expose"有什么区别?和“发布"在 Docker 中? [英] What is the difference between "expose" and "publish" in Docker?
问题描述
我正在试验 Dockerfiles,我想我理解大部分逻辑.但是,在这种情况下,我没有看到公开"和发布"端口之间的区别.
I'm experimenting with Dockerfiles, and I think I understand most of the logic. However, I don't see the difference between "exposing" and "publishing" a port in this context.
我第一次看到的所有教程都在 Dockerfile 中包含了 EXPOSE
命令:
All the tutorials I have seen first include the EXPOSE
command in the Dockerfile:
...
EXPOSE 8080
...
然后他们从这个 Dockerfile 构建一个镜像:
They then build an image from this Dockerfile:
$ docker build -t an_image - < Dockerfile
然后在运行图像时发布与上面相同的端口:
And then publish the same port as above when running the image:
$ docker run -d -p 8080 an_image
或使用
$ docker run -d -P an_image
在 Dockerfile 中公开端口有什么意义,如果它无论如何都会被发布?是否需要先公开端口,然后不发布?实际上,我想在创建映像时指定我将在 Dockerfile 中使用的所有端口,然后不再打扰它们,只需简单地运行它们:
What is the point of exposing a port in the Dockerfile, if it will be published anyway? Would there ever be a need to expose a port first, and not publish it later? Effectively, I would like to specify all the ports that I will use in the Dockerfile when creating the image, and then not bother with them again, running them simply with:
$ docker run -d an_image
这可能吗?
推荐答案
基本上,您有三个选择:
Basically, you have three options:
- 既不指定
EXPOSE
也不指定-p
- 只指定
EXPOSE
- 指定
EXPOSE
和-p
- Neither specify
EXPOSE
nor-p
- Only specify
EXPOSE
- Specify
EXPOSE
and-p
1) 如果您既不指定EXPOSE
也不指定-p
,则容器中的服务将只能从容器本身内部 访问.
1) If you specify neither EXPOSE
nor -p
, the service in the container will only be accessible from inside the container itself.
2) 如果你EXPOSE
一个端口,容器中的服务不能从Docker外部访问,而是从其他Docker容器内部访问.所以这有利于容器间通信.
2) If you EXPOSE
a port, the service in the container is not accessible from outside Docker, but from inside other Docker containers. So this is good for inter-container communication.
3) 如果你 EXPOSE
和 -p
一个端口,容器中的服务可以从任何地方访问,甚至在 Docker 之外.
3) If you EXPOSE
and -p
a port, the service in the container is accessible from anywhere, even outside Docker.
两者分开的原因恕我直言,因为:
The reason why both are separated is IMHO because:
- 选择主机端口取决于主机,因此不属于 Dockerfile(否则将取决于主机),
- 通常情况下,如果容器中的服务可以从其他容器访问就足够了.
文档明确指出:
EXPOSE
指令公开链接中使用的端口.
The
EXPOSE
instruction exposes ports for use within links.
它还指向您如何链接容器,这基本上是容器间我谈过的沟通.
It also points you to how to link containers, which basically is the inter-container communication I talked about.
PS:如果你做了-p
,但没有EXPOSE
,Docker 会隐式地执行EXPOSE
.这是因为如果一个端口对公众开放,它也会自动对其他 Docker 容器开放.因此-p
包括EXPOSE
.这就是为什么我没有在上面将其列为第四种情况.
PS: If you do -p
, but do not EXPOSE
, Docker does an implicit EXPOSE
. This is because if a port is open to the public, it is automatically also open to other Docker containers. Hence -p
includes EXPOSE
. That's why I didn't list it above as a fourth case.
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