Purpose of Docker vs Jail?

[rmccullough]

I am kind of confused at what Docker gives me over Jails. It seems that Docker is basically a plugin management system. While jails do require a bit more work to setup initially, what else does Docker get you?

Does it make sense to setup docker and move my jails there for things like Plex, Sonarr, Radarr, etc.?

 

[kdragon75]

Docker has WAY more scalable flexibility built in. There are thousands of templates and pre built images that are easy to modify and deploy in massive numbers. They are also intended (for the most part) to be stateless and disposable. All of this can be one with jails too but the ecosystem is just not there. Keep in mind that on FreeBSD, Docker is a VM that runs Linux and on that linux, you run containers. Jails are native to FreeBSD and therefore in the context of FreeBSD, have less overhead.

When it comes down to it, Linux containers and FreeBSD jails are the same thing. Docker just adds a layer of orchestration.

 

[pschatz100]

You can think of Docker as a specialized Linux VM (virtual machine.) Its advantage is that there are more apps available to be installed for Linux than there are for FreeBSD. Its big disadvantage (relative to jails) is that it requires resources from the NAS and takes effort to install and maintain.

If you have your applications running in jails, then leave them there. That is the most efficient way. If there was an app that you wanted to run on your NAS - and that app did not have a FreeBSD version, but did have a Docker version - you could install Docker and then install the app into Docker. There is no advantage to using Docker when an app has a FreeBSD version.

 

[kdragon75]

You can think of Docker as a specialized Linux VM (virtual machine.)

The Docker implementation in FreeNAS IS a VM, Its a bhyve VM. Docker *containers* are just the Linux version of FreeBSD jails.

 

[rmccullough]

Thanks all, this was extremely helpful and confirmed what I thought was the case. I will keep digging into it, but it sounds like I may not have a “need” for docker yet as all the stuff I am running is available for FreeBSD as well and is configured in a jail.