A Simple Introduction to Docker IX

What are some concerns about using docker?


  • Shared kernel concern

    Since containers share the same kernel, if one of them panics, everyone of them will panic too.

  • Privilege concern

    if a user or application has superuser privileges within the container, the underlying operating system could, in theory, be cracked.1

    • This concern will no longer be valid in a few months

      Docker has been working on linux user namespace for a while now. And once this feature is completed. Then we can build a docker container without root privileges, and meanwhile in this container, we can still have enough privileges for us to do our job.

  • VM + Container

    Hyper is a chinese startup project to make a lightweight virtual machine based on Docker images, which combines both advantages from container and VM.

    • Its containers are isolated by VM. So it is immune from the "shared kernel" problem in containers.
    • It's almost as lightweight as a container. So it's way more fast than a VM.
    • Since it's a VM, you can choose your own kernel.

Management Complexity

  • DevOps needs to manage too many docker files.
    • Since in docker's world, we need to seperate each of our apps into a single docker image.
    • We must keep our eyes on many different docker files.
    • This can be a problem when our project becomes so much big.
    • But in general you won't face this.