mirror of
https://github.com/LCTT/TranslateProject.git
synced 2025-02-25 00:50:15 +08:00
geekpi
GitHub
commit
7c3dcf1a35
@ -1,117 +0,0 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (geekpi)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Building Smaller Container Images)
|
||||
[#]: via: (https://fedoramagazine.org/building-smaller-container-images/)
|
||||
[#]: author: (Muayyad Alsadi https://fedoramagazine.org/author/alsadi/)
|
||||
|
||||
Building Smaller Container Images
|
||||
======
|
||||
|
||||
![][1]
|
||||
|
||||
Linux Containers have become a popular topic, making sure that a container image is not bigger than it should be is considered as a good practice. This article give some tips on how to create smaller Fedora container images.
|
||||
|
||||
### microdnf
|
||||
|
||||
Fedora’s DNF is written in Python and and it’s designed to be extensible as it has wide range of plugins. But Fedora has an alternative base container image which uses an smaller package manager called [microdnf][2] written in C. To use this minimal image in a Dockerfile the FROM line should look like this:
|
||||
|
||||
```
|
||||
FROM registry.fedoraproject.org/fedora-minimal:30
|
||||
```
|
||||
|
||||
This is an important saving if your image does not need typical DNF dependencies like Python. For example, if you are making a NodeJS image.
|
||||
|
||||
### Install and Clean up in one layer
|
||||
|
||||
To save space it’s important to remove repos meta data using _dnf clean all_ or its microdnf equivalent _microdnf clean all_. But you should not do this in two steps because that would actually store those files in a container image layer then mark them for deletion in another layer. To do it properly you should do the installation and cleanup in one step like this
|
||||
|
||||
```
|
||||
FROM registry.fedoraproject.org/fedora-minimal:30
|
||||
RUN microdnf install nodejs && microdnf clean all
|
||||
```
|
||||
|
||||
### Modularity with microdnf
|
||||
|
||||
Modularity is a way to offer you different versions of a stack to choose from. For example you might want non-LTS NodeJS version 11 for a project and old LTS NodeJS version 8 for another and latest LTS NodeJS version 10 for another. You can specify which stream using colon
|
||||
|
||||
```
|
||||
# dnf module list
|
||||
# dnf module install nodejs:8
|
||||
```
|
||||
|
||||
The _dnf module install_ command implies two commands one that enables the stream and one that install nodejs from it.
|
||||
|
||||
```
|
||||
# dnf module enable nodejs:8
|
||||
# dnf install nodejs
|
||||
```
|
||||
|
||||
Although microdnf does not offer any command related to modularity, it is possible to enable a module with a configuation file, and libdnf (which microdnf uses) [seems][3] to support modularity streams. The file looks like this
|
||||
|
||||
```
|
||||
/etc/dnf/modules.d/nodejs.module
|
||||
[nodejs]
|
||||
name=nodejs
|
||||
stream=8
|
||||
profiles=
|
||||
state=enabled
|
||||
```
|
||||
|
||||
A full Dockerfile using modularity with microdnf looks like this:
|
||||
|
||||
```
|
||||
FROM registry.fedoraproject.org/fedora-minimal:30
|
||||
RUN \
|
||||
echo -e "[nodejs]\nname=nodejs\nstream=8\nprofiles=\nstate=enabled\n" > /etc/dnf/modules.d/nodejs.module && \
|
||||
microdnf install nodejs zopfli findutils busybox && \
|
||||
microdnf clean all
|
||||
```
|
||||
|
||||
### Multi-staged builds
|
||||
|
||||
In many cases you might have tons of build-time dependencies that are not needed to run the software for example building a Go binary, which statically link dependencies. Multi-stage build are an efficient way to separate the application build and the application runtime.
|
||||
|
||||
For example the Dockerfile below builds [confd][4] a Go application.
|
||||
|
||||
```
|
||||
# building container
|
||||
FROM registry.fedoraproject.org/fedora-minimal AS build
|
||||
RUN mkdir /go && microdnf install golang && microdnf clean all
|
||||
WORKDIR /go
|
||||
RUN export GOPATH=/go; CGO_ENABLED=0 go get github.com/kelseyhightower/confd
|
||||
|
||||
FROM registry.fedoraproject.org/fedora-minimal
|
||||
WORKDIR /
|
||||
COPY --from=build /go/bin/confd /usr/local/bin
|
||||
CMD ["confd"]
|
||||
```
|
||||
|
||||
The multi-stage build is done by adding _AS_ after the _FROM_ instruction and by having another _FROM_ from a base container image then using C _OPY –from=_ instruction to copy content from the _build_ container to the second container.
|
||||
|
||||
This Dockerfile can then be built and run using podman
|
||||
|
||||
```
|
||||
$ podman build -t myconfd .
|
||||
$ podman run -it myconfd
|
||||
```
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://fedoramagazine.org/building-smaller-container-images/
|
||||
|
||||
作者：[Muayyad Alsadi][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]: https://fedoramagazine.org/author/alsadi/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://fedoramagazine.org/wp-content/uploads/2019/05/smaller-container-images-816x345.jpg
|
||||
[2]: https://github.com/rpm-software-management/microdnf
|
||||
[3]: https://bugzilla.redhat.com/show_bug.cgi?id=1575626
|
||||
[4]: https://github.com/kelseyhightower/confd
|
||||
117
translated/tech/20190516 Building Smaller Container Images.md
Normal file
117
translated/tech/20190516 Building Smaller Container Images.md
Normal file
@ -0,0 +1,117 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (geekpi)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Building Smaller Container Images)
|
||||
[#]: via: (https://fedoramagazine.org/building-smaller-container-images/)
|
||||
[#]: author: (Muayyad Alsadi https://fedoramagazine.org/author/alsadi/)
|
||||
|
||||
构建更小的容器镜像
|
||||
======
|
||||
|
||||
![][1]
|
||||
|
||||
Linux 容器已经成为一个热门话题，保证容器镜像较小被认为是一个好习惯。本文提供了有关如何构建较小 Fedora 容器镜像的一些提示。
|
||||
|
||||
### microdnf
|
||||
|
||||
Fedora 的 DNF 是用 Python 编写的，因为它有各种各样的插件，因此它的设计是可扩展的。但是 Fedora 有一个替代的基本容器镜像，它使用一个名为 [microdnf][2] 的较小的包管理器，使用 C 编写。要在 Dockerfile 中使用这个最小的镜像，FROM 行应该如下所示：
|
||||
|
||||
```
|
||||
FROM registry.fedoraproject.org/fedora-minimal:30
|
||||
```
|
||||
|
||||
如果你的镜像不需要像 Python 这样的典型 DNF 依赖项，那么这是一个重要的节省项。例如，如果你在制作 NodeJS 镜像。
|
||||
|
||||
### 在一个层中安装和清理
|
||||
|
||||
为了节省空间，使用 _dnf clean all_ 或其 microdnf 等效的 _microdnf clean all_ 删除仓库元数据非常重要。但是你不应该分两步执行此操作，因为这实际上会将这些文件保存在容器镜像中，然后在另一层中将其标记为删除。要正确地执行此操作，你应该像这样一步完成安装和清理：
|
||||
|
||||
```
|
||||
FROM registry.fedoraproject.org/fedora-minimal:30
|
||||
RUN microdnf install nodejs && microdnf clean all
|
||||
```
|
||||
|
||||
### 使用 microdnf 进行模块化
|
||||
|
||||
模块化是一种给你选择堆栈不同版本的方法。例如，你可能需要在项目中用非 LTS 的 NodeJS v11，旧的 LTS NodeJS v8 用于另一个，最新的 LTS NodeJS v10 用于另一个。你可以使用冒号指定流。
|
||||
|
||||
```
|
||||
# dnf module list
|
||||
# dnf module install nodejs:8
|
||||
```
|
||||
|
||||
_dnf module install_ 命令意味着两个命令，一个启用流，另一个是从它安装 nodejs。
|
||||
|
||||
```
|
||||
# dnf module enable nodejs:8
|
||||
# dnf install nodejs
|
||||
```
|
||||
|
||||
尽管 microdnf 不提供与模块化相关的任何命令，但是可以启用有配置文件的模块，并且 libdnf（被 microdnf 使用）[似乎][3]支持模块化流。该文件看起来像这样：
|
||||
|
||||
```
|
||||
/etc/dnf/modules.d/nodejs.module
|
||||
[nodejs]
|
||||
name=nodejs
|
||||
stream=8
|
||||
profiles=
|
||||
state=enabled
|
||||
```
|
||||
|
||||
使用模块化的 microdnf 的完整 Dockerfile 如下所示：
|
||||
|
||||
```
|
||||
FROM registry.fedoraproject.org/fedora-minimal:30
|
||||
RUN \
|
||||
echo -e "[nodejs]\nname=nodejs\nstream=8\nprofiles=\nstate=enabled\n" > /etc/dnf/modules.d/nodejs.module && \
|
||||
microdnf install nodejs zopfli findutils busybox && \
|
||||
microdnf clean all
|
||||
```
|
||||
|
||||
### 多阶段构建
|
||||
|
||||
在许多情况下，你可能需要大量的无需用于运行软件的构建时依赖项，例如构建一个静态链接依赖项的 Go 二进制文件。多阶段构建是分离应用构建和应用运行时的有效方法。
|
||||
|
||||
例如，下面的 Dockerfile 构建了一个 Go 应用 [confd][4]。
|
||||
|
||||
```
|
||||
# building container
|
||||
FROM registry.fedoraproject.org/fedora-minimal AS build
|
||||
RUN mkdir /go && microdnf install golang && microdnf clean all
|
||||
WORKDIR /go
|
||||
RUN export GOPATH=/go; CGO_ENABLED=0 go get github.com/kelseyhightower/confd
|
||||
|
||||
FROM registry.fedoraproject.org/fedora-minimal
|
||||
WORKDIR /
|
||||
COPY --from=build /go/bin/confd /usr/local/bin
|
||||
CMD ["confd"]
|
||||
```
|
||||
|
||||
通过在 _FROM_ 指令之后添加 _AS_ 并从基本容器镜像中添加另一个 _FROM_ 然后使用 _COPY --from=_ 指令将内容从_构建_的容器复制到第二个容器来完成多阶段构建。
|
||||
|
||||
可以使用 podman 构建并运行此 Dockerfile
|
||||
|
||||
```
|
||||
$ podman build -t myconfd .
|
||||
$ podman run -it myconfd
|
||||
```
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://fedoramagazine.org/building-smaller-container-images/
|
||||
|
||||
作者：[Muayyad Alsadi][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[geekpi](https://github.com/geekpi)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]: https://fedoramagazine.org/author/alsadi/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://fedoramagazine.org/wp-content/uploads/2019/05/smaller-container-images-816x345.jpg
|
||||
[2]: https://github.com/rpm-software-management/microdnf
|
||||
[3]: https://bugzilla.redhat.com/show_bug.cgi?id=1575626
|
||||
[4]: https://github.com/kelseyhightower/confd
|
||||
Loading…
Reference in New Issue
Block a user