If you are using Docker to create and run applications using containers, you may encounter an error like this when building a Docker image:
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/bin/sh: 1: apk: not found
This error can be frustrating and confusing, especially if you are new to Docker or Linux. In this article, we will explain what this error means, what causes it, and how to fix it.
Docker is a tool that allows you to create, run, and share applications using containers. Containers are isolated environments that contain everything an application needs to run, such as code, libraries, dependencies, and configuration. Containers are portable, meaning they can run on any machine that has Docker installed, regardless of the operating system or hardware. Containers are also scalable, meaning they can be easily replicated, distributed, and managed across multiple machines. Containers are also efficient, meaning they use less resources than traditional virtual machines.
Docker offers many benefits for developers and users of applications, such as:
The error "91m/bin/sh 1 apk not found" occurs when you try to use the apk command in a Dockerfile that is based on a non-Alpine Linux distribution. The apk command is the package manager for Alpine Linux, which is a lightweight and secure Linux distribution that is often used for Docker images. The apk command allows you to install, update, and remove packages from Alpine repositories.
The error means that the apk command is not found in the base image that you are using for your Dockerfile. The base image is the image that you specify in the FROM instruction of your Dockerfile. The base image provides the foundation for your Docker image and defines the operating system and the packages that are available. For example, if your Dockerfile looks like this:
FROM python:3.8
RUN apk add --no-cache gcc musl-dev linux-headers
This means that you are using the python:3.8 image as your base image, which is based on Debian Buster, a Debian-based Linux distribution. Debian Buster does not support the apk command, so when you try to run it, you get the error "91m/bin/sh 1 apk not found".
There are two main ways to fix the error "91m/bin/sh 1 apk not found" when building a Docker image: changing the base image or changing the package manager.
You can change the base image to an Alpine Linux image that supports the apk command. Alpine Linux is a lightweight and secure Linux distribution that is often used for Docker images. Alpine Linux images are smaller and faster than most other Linux images, which can improve your Docker performance and reduce your storage and bandwidth costs.
You can find the official Alpine Linux images on Docker Hub or use the python:3.8-alpine image as an example. The python:3.8-alpine image is based on Alpine Linux 3.13 and includes Python 3.8 and pip. To use this image as your base image, you can change your Dockerfile to look like this:
FROM python:3.8-alpine
RUN apk add --no-cache gcc musl-dev linux-headers
This should fix the error "91m/bin/sh 1 apk not found" and allow you to build your Docker image successfully.
You can also change the package manager to apt or apt-get, which are supported by most Debian-based Linux distributions. apt and apt-get are tools that allow you to install, update, and remove packages from Debian repositories.
You can find the official Debian-based images on Docker Hub or use the python:3.8-slim image as an example. The python:3.8-slim image is based on Debian Buster and includes Python 3.8 and pip. To use this image as your base image, you can change your Dockerfile to look like this:
FROM python:3.8-slim
RUN apt-get update && apt-get install -y gcc libc-dev linux-headers && rm -rf /var/lib/apt/lists/*
Note that you may also need to change the package names to match the ones available in the Debian repositories. For example, musl-dev is not available in Debian, so you need to use libc-dev instead.
This should also fix the error "91m/bin/sh 1 apk not found" and allow you to build your Docker image successfully.
In this article, we have explained what the error "91m/bin/sh 1 apk not found" means, what causes it, and how to fix it when building a Docker image. We have shown two main ways to fix the error: changing the base image or changing the package manager. We have also provided some examples of Dockerfiles that use different base images and package managers.
We hope that this article has helped you solve your problem and improve your Docker experience. If you have any questions or feedback, please feel free to leave a comment below.
A Dockerfile is a text file that contains instructions for building a Docker image. A Docker image is a snapshot of an application and its dependencies that can be run as a container using Docker.
A container is an isolated environment that contains everything an application needs to run, such as code, libraries, dependencies, and configuration. Containers are portable, scalable, isolated, and efficient.
Alpine Linux is a security-oriented, lightweight Linux distribution based on musl libc and busybox. Alpine Linux is designed to be small, simple, and secure, making it ideal for Docker images. Alpine Linux uses a technique called position-independent executables to randomize the location of programs in memory, which makes it difficult for an attacker to exploit quirks in the memory and take over a machine. The distro is also minimalist in its configuration, using OpenRC as the init system and apk as the package manager. Alpine Linux has a reputation for being fast, stable, and reliable.
Debian is a free and open-source Linux distribution that is known for its stability, security, and versatility. Debian is one of the oldest and most popular Linux distributions, with a large and active community of developers and users. Debian supports a wide range of architectures, devices, and software packages, making it suitable for various purposes and environments. Debian uses a technique called debconf to configure the system according to the user's preferences, which makes it easy to customize and maintain. The distro uses dpkg as the low-level package manager and apt or apt-get as the high-level package manager. Debian has a reputation for being robust, reliable, and flexible.
There is no definitive answer to this question, as different base images may have different advantages and disadvantages depending on your needs and preferences. However, some general factors that you may want to consider when choosing a base image are:
You may also want to check the documentation, reviews, ratings, and statistics of the base images that you are considering to get more information and feedback from other users.
One way to test if your Docker image works correctly is to run it as a container using the docker run command. The docker run command allows you to create and start a container from an image, optionally with various options and arguments. For example, if you want to run your image in interactive mode with a terminal attached, you can use this command:
docker run -it --rm your_image_name
This will create a container from your image, attach a terminal to it, and remove it when you exit. You can then test your application inside the container by running commands or scripts as you would normally do.
One way to share your Docker image with others is to push it to a registry such as Docker Hub or GitHub Packages. A registry is a service that stores and distributes Docker images. You can create an account on a registry service, create a repository for your image, tag your image with the repository name, and push your image to the repository using the docker push command. For example, if you want to push your image to Docker Hub, you can use these commands:
docker tag your_image_name your_username/your_repository_name
docker push your_username/your_repository_name
This will upload your image to your repository on Docker Hub. You can then share the repository URL with others who can pull your image using the docker pull command.