Need help?

Our experts have had an average response time of 13.14 minutes in February 2024 to fix urgent issues.

We will keep your servers stable, secure, and fast at all times for one fixed price.

Docker exec format error – How do we fix it?

by | Jan 8, 2020

Learn how to resolve the Docker exec format error. Our Docker Support team is here to help you with your questions and concerns.

Docker exec format error – How can we sort it out?

Docker is a software that stores code and all its dependencies. This helps applications run fast and perform consistently well in quality and performance.

The docker container allows OS-level virtualization and is also known as containerization. Docker helps package applications in containers and these containers are portable to Linux or Windows operating systems.

However, sometimes we run into exec format errors while using Docker containers. Let’s see how our Support Engineers fix this error.

Docker Exec format – Causes

Several reasons can cause the error. However, the most common reason is an incorrect build architecture.

Docker Exec format

For example, if we are building the app for Arm but compile for x86 or x64, we will run into this error.

Some of the other causes behind the error include:

  • Incorrect Docker version installed
  • Missing shebang in the script
  • Docker installation is incomplete

At Bobcares, we often get requests to fix docker exec format errors, as a part of our Server Management Services.

A Docker file is a text document that uses all the commands that a user could call on the command line to assemble an image. Additionally, we can write the instructions to build a Docker image in this file.

How to fix the error

  • Missing shebang

    Whenever our customers run into this error, our Support Engineers check the entrypoint in the Docker file.

    A missing shebang in the docker entrypoint script was missing a shebang is a common reason behind the error.

    So, we can easily fix the error by adding the shebang in the script. The shebang is a special character sequence in a script file that specifies which program should be called to run the script.

    It is always the first line of the script, and is composed of #! Characters. Hence, the Shebang (#!/bin/bash) is placed on the first line of the script as the first bytes are checked by the kernel.

    #!/bin/bash

    Alternatively, we can run the following command to fix the docker error caused by a missing shebang:

    $ docker run -entrypoint="/bin/bash" -i test

    This fixes the docker error.

  • Correct Build

    If we are using incorrect build architecture, we are likely to run into the error. To avoid this, we have to check the architecture, version, and target OS of the current build with this command.

    docker image inspect rethkevin/rf:v1

  • Check the Docker registry

    In some cases, the docker implementation may have some flaws causing the API endpoint to return a blank or no value to the content-length header. If we have made changes to the standard docker implementation, we can try reverting these changes to their default settings to resolve the issue.

  • Wrong Character Encoding for Newlines

    Another key reason that gets overlooked is the newline character. It is used to signify the “End Of Line” (EOL).

    While Windows uses CRLF, Linux uses LF.

    If we wrote a file in Windows with the CRLF encoding, may cause the exec format error when sent to staging or production with Linux as an environment. This can be fixed with these steps:

    1. First, open the file in a Linux text editor.
    2. Then, we can use Ctrl+F or find-and-replace functionality to search for “\r\n.”
    3. Now, we have to replace “\r\n” with “\n” everywhere.
    4. Additionally, we can also set it to Linux encoding while writing code.

[Need help in fixing the Docker format error? – We’ll help you.]

Conclusion

In short, Docker exec format error occurs due to several reasons. Today, we saw how our Support Engineers narrowed down the cause behind the error and fixed it.

PREVENT YOUR SERVER FROM CRASHING!

Never again lose customers to poor server speed! Let us help you.

Our server experts will monitor & maintain your server 24/7 so that it remains lightning fast and secure.

GET STARTED

Are you using Docker based apps?

There are proven ways to get even more out of your Docker containers! Let us help you.

Spend your time in growing business and we will take care of Docker Infrastructure for you.

GET STARTED

var google_conversion_label = "owonCMyG5nEQ0aD71QM";

6 Comments

  1. Balazs

    Spot on with the missing shebang – it helped to fix my problem. Actually in my case there was a newline before so it was not in the first line of my script.

    Reply
    • Hiba Razak

      Thanks for the feedback.We are glad to know that it worked for you 🙂 .

      Reply
  2. Joe

    Well, I’m the odd one then because neither of those solutions worked.

    docker run -p 27017:27017 -p 5672:5672 -p 15672:15672 -p 6379:6379 -p 5432:5432 -p 1883:1883 -p 15675:15675 -v /tmp:/elhost -entrypoint=”/bin/bash” -it –name

    Gives exec format error even if I add the shebang in the quotes.

    docker run -p 27017:27017 -p 5672:5672 -p 15672:15672 -p 6379:6379 -p 5432:5432 -p 1883:1883 -p 15675:15675 -v /tmp:/elhost -it –name #!/bin/bash

    Gives exec format error

    Reply
    • Hiba Razak

      Hi Joe,

      Our Experts can help you with the issue, we’ll be happy to talk to you on chat (click on the icon at right-bottom).

      Reply
  3. Larissa

    Olá! No meu caso já possui o shebang na primeira linha e não funciona :/

    Reply
    • Hiba Razak

      Hi,
      Please contact our support through live chat(click on the icon at right-bottom).

      Reply

Submit a Comment

Your email address will not be published. Required fields are marked *

Categories

Tags

Privacy Preference Center

Necessary

Necessary cookies help make a website usable by enabling basic functions like page navigation and access to secure areas of the website. The website cannot function properly without these cookies.

PHPSESSID - Preserves user session state across page requests.

gdpr[consent_types] - Used to store user consents.

gdpr[allowed_cookies] - Used to store user allowed cookies.

PHPSESSID, gdpr[consent_types], gdpr[allowed_cookies]
PHPSESSID
WHMCSpKDlPzh2chML

Statistics

Statistic cookies help website owners to understand how visitors interact with websites by collecting and reporting information anonymously.

_ga - Preserves user session state across page requests.

_gat - Used by Google Analytics to throttle request rate

_gid - Registers a unique ID that is used to generate statistical data on how you use the website.

smartlookCookie - Used to collect user device and location information of the site visitors to improve the websites User Experience.

_ga, _gat, _gid
_ga, _gat, _gid
smartlookCookie
_clck, _clsk, CLID, ANONCHK, MR, MUID, SM

Marketing

Marketing cookies are used to track visitors across websites. The intention is to display ads that are relevant and engaging for the individual user and thereby more valuable for publishers and third party advertisers.

IDE - Used by Google DoubleClick to register and report the website user's actions after viewing or clicking one of the advertiser's ads with the purpose of measuring the efficacy of an ad and to present targeted ads to the user.

test_cookie - Used to check if the user's browser supports cookies.

1P_JAR - Google cookie. These cookies are used to collect website statistics and track conversion rates.

NID - Registers a unique ID that identifies a returning user's device. The ID is used for serving ads that are most relevant to the user.

DV - Google ad personalisation

IDE, test_cookie, 1P_JAR, NID, DV, NID
IDE, test_cookie
1P_JAR, NID, DV
NID
hblid

Security

These are essential site cookies, used by the google reCAPTCHA. These cookies use an unique identifier to verify if a visitor is human or a bot.

SID, APISID, HSID, NID, PREF
SID, APISID, HSID, NID, PREF