4 ms·

In my experience, if you start hearing: "I don't know what's wrong, it works fine on my localhost!" a lot, then it may be time to think about Docker. In more g

In my experience, if you start hearing: "I don't know what's wrong, it works fine on my localhost!" a lot, then it may be time to think about Docker. In more general terms: more the complex the environment, the more moving pieces, the more developers on the team, the more servers in production, the more likely there's going be a discrepancy between what Developer-A has running on his machine, and what Developer-B has running on theirs. Docker helps keep everybody on the same page. For me personally: I'm a dev on a number of projects, and Docker helps me keep my dependencies straight. I no longer have to change things around locally just to work on Project-A, I just get their latest Docker image, and I'm good to go.

msravi 11y ago
How is this different from sharing a plain old VM image and doing the same thing? Is there any particular advantage that a Docker image brings?
- Matt3o12_ 11y ago
  Docker images use the union file system. That means when a new version of that image is available, you often only pull a few megabytes from the hub because it already has the OS. A docker container is also way more lightweight. Instead of running a full OS, you I only run one process. So your docker image starts within seconds
  - ccozan 11y ago
    Is this more like a Solaris zone or a Linux chroot-ed env?
    - nickstinemates 11y ago
      A lot like Linux chroot, with some additional features, restrictions, and a mechanism to share them easily.
- 16bytes 11y ago
  For one, speed. Provisioning a VM image takes a lot longer than a container. Secondly, composition. Can you provision and link the 10 instances that make up your application? Web servers, app servers, proxies, caches, databases, hadoop etc. I think this second ability is the truly compelling one for me. The features that allow this (swarm and compose for docker, lots of other competing orchestration stuff) are still pretty young, but it would still push me in the direction of containerization over virtualization.
marcusandre 11y ago
This seems pretty fine but it's not a Docker-specific argument. The same arguments fits for a Vagrant-Workflow.

msravi 11y ago

How is this different from sharing a plain old VM image and doing the same thing? Is there any particular advantage that a Docker image brings?

Matt3o12_ 11y ago
Docker images use the union file system. That means when a new version of that image is available, you often only pull a few megabytes from the hub because it already has the OS. A docker container is also way more lightweight. Instead of running a full OS, you I only run one process. So your docker image starts within seconds
- ccozan 11y ago
  Is this more like a Solaris zone or a Linux chroot-ed env?
  - nickstinemates 11y ago
    A lot like Linux chroot, with some additional features, restrictions, and a mechanism to share them easily.
16bytes 11y ago
For one, speed. Provisioning a VM image takes a lot longer than a container. Secondly, composition. Can you provision and link the 10 instances that make up your application? Web servers, app servers, proxies, caches, databases, hadoop etc. I think this second ability is the truly compelling one for me. The features that allow this (swarm and compose for docker, lots of other competing orchestration stuff) are still pretty young, but it would still push me in the direction of containerization over virtualization.

marcusandre 11y ago

This seems pretty fine but it's not a Docker-specific argument. The same arguments fits for a Vagrant-Workflow.