Chapter 16. Docker in production: Dealing with challenges
This chapter covers
- Bypassing Docker’s namespace functionality and using the host’s resources directly
- Making sure your host OS doesn’t kill processes in containers due to low memory
- Debugging a container’s network directly, using your host’s tooling
- Tracing system calls to determine why a container isn’t working on your host
In this chapter we’ll discuss what you can do when Docker’s abstractions aren’t working for you. These topics necessarily involve getting under the hood of Docker to understand why such solutions can be needed, and in the process we aim to provide you with a deeper awareness of what can go wrong when using Docker and how to go about fixing it.
Although Docker seeks to abstract the application from the host it’s running on, one can never completely ignore the host. In order to provide its abstractions, Docker must add layers of indirection. These layers can have implications for your running system, and they sometimes need to be understood in order for operational challenges to be fixed or worked around.
In this section we’ll look at how you can bypass some of these abstractions, ending up with a Docker container that has little of Docker left in it. We’ll also show that although Docker appears to abstract away the details of the storage you use, this can sometimes come back to bite you.