For sake of this question, I have a hello world python script called script.py.
def hello_world():
print("hello world")
if __name__ == "__main__":
hello_world()
And have a corresponding Dockerfile:
FROM python:3.8-alpine
WORKDIR /app
COPY requirements.txt requirements.txt
RUN python3 -m pip install --upgrade pip
RUN python3 -m pip install -r requirements.txt
COPY . .
CMD [ "python3", "script.py"]
Scenario #1 (amd64 as host machine):
When I build for amd64 architecture on this host I am successful doing so.
$ docker buildx build --platform linux/amd64 -t sntshk/cotu:latest .
WARN[0000] No output specified for docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load
[ ] Building 2.6s (11/11) FINISHED
=> [internal] load build definition from Dockerfile 0.0s
=> => transferring dockerfile: 277B 0.0s
=> [internal] load .dockerignore 0.0s
=> => transferring context: 2B 0.0s
=> [internal] load metadata for docker.io/library/python:3.8-alpine 2.4s
=> [auth] library/python:pull token for registry-1.docker.io 0.0s
=> [1/6] FROM docker.io/library/python:3.8-alpine@sha256:9b3ca9c8e9ec086ea825227ac6d819e46794c29590f04d775d517a48ef6 0.0s
=> => resolve docker.io/library/python:3.8-alpine@sha256:9b3ca9c8e9ec086ea825227ac6d819e46794c29590f04d775d517a48ef6 0.0s
=> [internal] load build context 0.1s
=> => transferring context: 7.55kB 0.1s
=> CACHED [2/6] WORKDIR /app 0.0s
=> CACHED [3/6] COPY requirements.txt requirements.txt 0.0s
=> CACHED [4/6] RUN python3 -m pip install --upgrade pip 0.0s
=> CACHED [5/6] RUN python3 -m pip install -r requirements.txt 0.0s
=> CACHED [6/6] COPY . .
But the build fails for arm64 architecture:
[..output trimmed...]
#8 12.03 File "/usr/local/lib/python3.8/site-packages/pip/_vendor/distro.py", line 125, in linux_distribution
#8 12.03 return _distro.linux_distribution(full_distribution_name)
#8 12.03 File "/usr/local/lib/python3.8/site-packages/pip/_vendor/distro.py", line 681, in linux_distribution
#8 12.03 self.version(),
#8 12.03 File "/usr/local/lib/python3.8/site-packages/pip/_vendor/distro.py", line 741, in version
#8 12.03 self.lsb_release_attr('release'),
#8 12.03 File "/usr/local/lib/python3.8/site-packages/pip/_vendor/distro.py", line 903, in lsb_release_attr
#8 12.03 return self._lsb_release_info.get(attribute, '')
#8 12.03 File "/usr/local/lib/python3.8/site-packages/pip/_vendor/distro.py", line 556, in __get__
#8 12.03 ret = obj.__dict__[self._fname] = self._f(obj)
#8 12.03 File "/usr/local/lib/python3.8/site-packages/pip/_vendor/distro.py", line 1014, in _lsb_release_info
#8 12.03 stdout = subprocess.check_output(cmd, stderr=devnull)
#8 12.03 File "/usr/local/lib/python3.8/subprocess.py", line 415, in check_output
#8 12.03 return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
#8 12.03 File "/usr/local/lib/python3.8/subprocess.py", line 516, in run
#8 12.03 raise CalledProcessError(retcode, process.args,
#8 12.03 subprocess.CalledProcessError: Command '('lsb_release', '-a')' returned non-zero exit status 1.
------
Dockerfile:9
--------------------
7 | COPY requirements.txt requirements.txt
8 |
9 | >>> RUN python3 -m pip install --upgrade pip
10 | RUN python3 -m pip install -r requirements.txt
11 |
--------------------
error: failed to solve: process "/dev/.buildkit_qemu_emulator /bin/sh -c python3 -m pip install --upgrade pip" did not complete successfully: exit code: 1
Scenario #2 (arm64 as host machine):
I won't put much noise here, but on arm64, building arm64 image has no issue. But the same error is seen when I try to build amd64 image on arm64 host.
My final question is, how do I build amd64 on a arm64 host?
CodePudding user response：
Don't you need an arm image as suggested by the documentation:
Finally, depending on your project, the language that you use may have good support for cross-compilation. In that case, multi-stage builds in Dockerfiles can be effectively used to build binaries for the platform specified with --platform using the native architecture of the build node. A list of build arguments like BUILDPLATFORM and TARGETPLATFORM is available automatically inside your Dockerfile and can be leveraged by the processes running as part of your build.
FROM --platform=$BUILDPLATFORM python:3.8-alpine AS build
...