Docker: Cannot execute binary file
From this forum thread:
This error occurs when you use a shell in your entrypoint without the "-c" argument
So, if you change your Dockerfile
to end with
ENTRYPOINT [ "/bin/bash", "-l", "-c" ]
then you can run binary files.
Note the purpose of the options for /bin/bash
, from the manpage:
-l
: Make bash act as if it had been invoked as a login shell-c
: If the-c
option is present, then commands are read from the first non-option argumentcommand_string
. If there are arguments after thecommand_string
, the first argument is assigned to$0
and any remaining arguments are assigned to the positional parameters. The assignment to$0
sets the name of the shell, which is used in warning and error messages.
Additionally, this article is a worthwhile read on how to use both ENTRYPOINT
and CMD
together, and what their differences are.
EDIT: Here's another article that goes into a trivial (but clearer than the first article) example using the echo
shell builtin.
EDIT: Here's an adaptation of the trivial example from the second article I linked:
FROM ubuntu
ENTRYPOINT [ "/bin/bash", "-l", "-c" ]
CMD [ "ls" ]
$ docker build -t test .
$ docker run --rm test
bin
boot
...
var
$ docker run --rm test "ls etc"
adduser.conf
alternatives
apt
...
update-motd.d
xattr.conf
Note the "
around ls /etc
. Without the quotes, the argument /etc
doesn't seem to be passed to the ls
command as I might expect.
Entrypoint can't point to /bin/bash
it seems. Removing
ENTRYPOINT ["/bin/bash"]
is enough to make it work.
I hit the same error. Unlike the other answers, my error was related to my docker run
parameters:
# failed
docker run -it $(pwd | xargs basename):latest bash
# worked
docker run -it $(pwd | xargs basename):latest
I didn't need to add bash
as I already had this in my Dockerfile:
ENTRYPOINT ["/bin/bash"]
There are times when we don't have control over the image's Dockerfile but it's original entrypoint has an issue.
We could overwrite it's entrypoint to debug issues:
# example
docker run --rm \
--entrypoint /bin/bash \
-it apache/spark-py:v3.3.0