#Docker run image not working how to#

If you can just replace the Docker Daemon in your Kubernetes cluster without noticing a difference, does it matter which tool you are using? Scott McCarty discusses in detail how different container standards fit together here are some of the benefits of using container standards: This includes the runtime specification and the image specification of containers. OCI stands for Open Container Initiative, which is a project by the Linux Foundation with the goal to define open standards for operating system-level virtualization more specifically, Linux containers. All of the alternatives discussed below can build OCI compatible container images. The next section will discuss alternatives to Docker. This is why you should only trust your own images that you have written and understand. Running the Docker Daemon locally, you risk that any process that breaks out of the Docker Container will have the same rights as the host operating system. This allows you to use a local or remote Docker Daemon. The Docker Daemon is responsible for the state of your containers and images, and facilitates any interaction with “the outside world.” The Docker CLI is merely used to translate commands into API calls that are sent to the Docker Daemon. By default, users can only access the Unix socket using sudo command, which is owned by the user root.

It actually binds to a Unix socket instead of a TCP port. However, running an application with Docker means that you have to run the Docker Daemon with root privileges. In most cases, you will only interact with the Docker CLI. Docker is composed of a variety of different tools. The problem with this is that you cannot use Docker directly on your workstation. Upon running the image, a container is created.īelow is a simplified diagram of the Docker architecture, taken directly from the official documentation. Once you have the image of your Dockerfile, you can run it. Using Docker, we can use the build command to build our container image.

#Docker run image not working how to#

The Dockerfile details how to build an image based on your application and resources. Container images are specified with the Dockerfile.

To understand why the Docker Daemon is running with root access and how this can become a problem, we first have to understand the Docker architecture (at least on a high level). This tutorial will take a look at the downsides of using Docker and Docker alternatives to combat those, namely: We have all read at least once that you should be careful using root access. The most well-known security flaw in Docker is that it requires root access to build your Docker images with the Docker daemon.