为什么在Alpine Linux上安装Pandas会花费很多时间

Question

我注意到，使用基本操作系统Alpine与CentOS或Debian在Docker容器中安装Pandas和Numpy（它的依赖项）需要花费更长的时间。我在下面创建了一个小测试来演示时差。除了Alpine用来更新和下载构建依赖项以安装Pandas和Numpy的几秒钟之外，为什么setup.py所需的时间比Debian的安装要多70倍？

是否有任何方法可以使用Alpine作为基础映像来加快安装速度，或者有另一个与Alpine大小相当的基础映像更适合用于Pandas和Numpy等软件包？

Dockerfile.debian

FROM python:3.6.4-slim-jessie

RUN pip install pandas

用Pandas和Numpy构建Debian图像：

[PandasDockerTest] time docker build -t debian-pandas -f Dockerfile.debian . --no-cache
    Sending build context to Docker daemon  3.072kB
    Step 1/2 : FROM python:3.6.4-slim-jessie
     ---> 43431c5410f3
    Step 2/2 : RUN pip install pandas
     ---> Running in 2e4c030f8051
    Collecting pandas
      Downloading pandas-0.22.0-cp36-cp36m-manylinux1_x86_64.whl (26.2MB)
    Collecting numpy>=1.9.0 (from pandas)
      Downloading numpy-1.14.1-cp36-cp36m-manylinux1_x86_64.whl (12.2MB)
    Collecting pytz>=2011k (from pandas)
      Downloading pytz-2018.3-py2.py3-none-any.whl (509kB)
    Collecting python-dateutil>=2 (from pandas)
      Downloading python_dateutil-2.6.1-py2.py3-none-any.whl (194kB)
    Collecting six>=1.5 (from python-dateutil>=2->pandas)
      Downloading six-1.11.0-py2.py3-none-any.whl
    Installing collected packages: numpy, pytz, six, python-dateutil, pandas
    Successfully installed numpy-1.14.1 pandas-0.22.0 python-dateutil-2.6.1 pytz-2018.3 six-1.11.0
    Removing intermediate container 2e4c030f8051
     ---> a71e1c314897
    Successfully built a71e1c314897
    Successfully tagged debian-pandas:latest
    docker build -t debian-pandas -f Dockerfile.debian . --no-cache  0.07s user 0.06s system 0% cpu 13.605 total

Dockerfile.alpine

FROM python:3.6.4-alpine3.7

RUN apk --update add --no-cache g++

RUN pip install pandas

使用Pandas和Numpy建立高山图像：

[PandasDockerTest] time docker build -t alpine-pandas -f Dockerfile.alpine . --no-cache
Sending build context to Docker daemon   16.9kB
Step 1/3 : FROM python:3.6.4-alpine3.7
 ---> 4b00a94b6f26
Step 2/3 : RUN apk --update add --no-cache g++
 ---> Running in 4b0c32551e3f
fetch http://dl-cdn.alpinelinux.org/alpine/v3.7/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.7/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.7/community/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.7/community/x86_64/APKINDEX.tar.gz
(1/17) Upgrading musl (1.1.18-r2 -> 1.1.18-r3)
(2/17) Installing libgcc (6.4.0-r5)
(3/17) Installing libstdc++ (6.4.0-r5)
(4/17) Installing binutils-libs (2.28-r3)
(5/17) Installing binutils (2.28-r3)
(6/17) Installing gmp (6.1.2-r1)
(7/17) Installing isl (0.18-r0)
(8/17) Installing libgomp (6.4.0-r5)
(9/17) Installing libatomic (6.4.0-r5)
(10/17) Installing pkgconf (1.3.10-r0)
(11/17) Installing mpfr3 (3.1.5-r1)
(12/17) Installing mpc1 (1.0.3-r1)
(13/17) Installing gcc (6.4.0-r5)
(14/17) Installing musl-dev (1.1.18-r3)
(15/17) Installing libc-dev (0.7.1-r0)
(16/17) Installing g++ (6.4.0-r5)
(17/17) Upgrading musl-utils (1.1.18-r2 -> 1.1.18-r3)
Executing busybox-1.27.2-r7.trigger
OK: 184 MiB in 50 packages
Removing intermediate container 4b0c32551e3f
 ---> be26c3bf4e42
Step 3/3 : RUN pip install pandas
 ---> Running in 36f6024e5e2d
Collecting pandas
  Downloading pandas-0.22.0.tar.gz (11.3MB)
Collecting python-dateutil>=2 (from pandas)
  Downloading python_dateutil-2.6.1-py2.py3-none-any.whl (194kB)
Collecting pytz>=2011k (from pandas)
  Downloading pytz-2018.3-py2.py3-none-any.whl (509kB)
Collecting numpy>=1.9.0 (from pandas)
  Downloading numpy-1.14.1.zip (4.9MB)
Collecting six>=1.5 (from python-dateutil>=2->pandas)
  Downloading six-1.11.0-py2.py3-none-any.whl
Building wheels for collected packages: pandas, numpy
  Running setup.py bdist_wheel for pandas: started
  Running setup.py bdist_wheel for pandas: still running...
  Running setup.py bdist_wheel for pandas: still running...
  Running setup.py bdist_wheel for pandas: still running...
  Running setup.py bdist_wheel for pandas: still running...
  Running setup.py bdist_wheel for pandas: still running...
  Running setup.py bdist_wheel for pandas: still running...
  Running setup.py bdist_wheel for pandas: finished with status 'done'
  Stored in directory: /root/.cache/pip/wheels/e8/ed/46/0596b51014f3cc49259e52dff9824e1c6fe352048a2656fc92
  Running setup.py bdist_wheel for numpy: started
  Running setup.py bdist_wheel for numpy: still running...
  Running setup.py bdist_wheel for numpy: still running...
  Running setup.py bdist_wheel for numpy: still running...
  Running setup.py bdist_wheel for numpy: finished with status 'done'
  Stored in directory: /root/.cache/pip/wheels/9d/cd/e1/4d418b16ea662e512349ef193ed9d9ff473af715110798c984
Successfully built pandas numpy
Installing collected packages: six, python-dateutil, pytz, numpy, pandas
Successfully installed numpy-1.14.1 pandas-0.22.0 python-dateutil-2.6.1 pytz-2018.3 six-1.11.0
Removing intermediate container 36f6024e5e2d
 ---> a93c59e6a106
Successfully built a93c59e6a106
Successfully tagged alpine-pandas:latest
docker build -t alpine-pandas -f Dockerfile.alpine . --no-cache  0.54s user 0.33s system 0% cpu 16:08.47 total

Answer 1

基于Debian的映像仅python pip用于安装以下.whl格式的软件包：

  Downloading pandas-0.22.0-cp36-cp36m-manylinux1_x86_64.whl (26.2MB)
  Downloading numpy-1.14.1-cp36-cp36m-manylinux1_x86_64.whl (12.2MB)

WHL格式是一种比每次都从源代码重新构建更快，更可靠的安装Python软件的方法。WHL文件仅需移动到要安装的目标系统上的正确位置，而源分发需要在安装之前进行构建。

轮包pandas和numpy基于高山平台，图像不支持。这就是为什么python pip在构建过程中使用它们进行安装时，我们总是从alpine的源文件中编译它们：

  Downloading pandas-0.22.0.tar.gz (11.3MB)
  Downloading numpy-1.14.1.zip (4.9MB)

我们可以在图像构建过程中看到以下内部容器：

/ # ps aux
PID   USER     TIME   COMMAND
    1 root       0:00 /bin/sh -c pip install pandas
    7 root       0:04 {pip} /usr/local/bin/python /usr/local/bin/pip install pandas
   21 root       0:07 /usr/local/bin/python -c import setuptools, tokenize;__file__='/tmp/pip-build-en29h0ak/pandas/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n
  496 root       0:00 sh
  660 root       0:00 /bin/sh -c gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DTHREAD_STACK_SIZE=0x100000 -fPIC -Ibuild/src.linux-x86_64-3.6/numpy/core/src/pri
  661 root       0:00 gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DTHREAD_STACK_SIZE=0x100000 -fPIC -Ibuild/src.linux-x86_64-3.6/numpy/core/src/private -Inump
  662 root       0:00 /usr/libexec/gcc/x86_64-alpine-linux-musl/6.4.0/cc1 -quiet -I build/src.linux-x86_64-3.6/numpy/core/src/private -I numpy/core/include -I build/src.linux-x86_64-3.6/numpy/core/includ
  663 root       0:00 ps aux

如果我们Dockerfile稍作修改：

FROM python:3.6.4-alpine3.7
RUN apk add --no-cache g++ wget
RUN wget https://pypi.python.org/packages/da/c6/0936bc5814b429fddb5d6252566fe73a3e40372e6ceaf87de3dec1326f28/pandas-0.22.0-cp36-cp36m-manylinux1_x86_64.whl
RUN pip install pandas-0.22.0-cp36-cp36m-manylinux1_x86_64.whl

我们得到以下错误：

Step 4/4 : RUN pip install pandas-0.22.0-cp36-cp36m-manylinux1_x86_64.whl
 ---> Running in 0faea63e2bda
pandas-0.22.0-cp36-cp36m-manylinux1_x86_64.whl is not a supported wheel on this platform.
The command '/bin/sh -c pip install pandas-0.22.0-cp36-cp36m-manylinux1_x86_64.whl' returned a non-zero code: 1

不幸的是，在pandasAlpine映像上安装的唯一方法是等到构建完成。

当然pandas，例如，如果要在CI中使用Alpine映像，最好的方法是将其编译一次，将其推送到任何注册表中，然后将其用作满足您需要的基础映像。

编辑： 如果您想使用Alpine图像，pandas可以拉我的nickgryg / alpine-pandas
docker
图像。这是pandas在Alpine平台上预编译的python图像。它应该可以节省您的时间。