Discussion: Linux jails... Do you use them?

[cyberjock]

So the question is simple, do you use linux jails?

The question has been brought up in bug ticket 5624 "Can we remove the linux jails?" If you have used them or you read the forums a lot you'd know a few things about linux jails:

1. They don't work quite as well as we had hoped.
2. They are limited to 32-bit.
3. They don't work quite as well as we had hoped.

Ok, so 1 and 3 are the same. But they are pretty broken. The general consensus is that they may not handle understanding ZFS free space very well, so many programs that check free space to make sure you have X-MB free wrongly think you have no free space and then won't work. This may require editing the source code for the problematic program and recompiling it. For most users this isn't a feasible solution and this problem basically means many users just can't use the linux jail.

So here's the discussion: If we removed them how many people would be impacted by this change? We're looking for input from the community on how important this feature is and how serious the impact would be to the community.

Keep in mind that 9.2.1.6 has a built-in template for Virtualbox. Virtualbox works very well with linux VMs from my personal experience. There are potential limitations with linux VMs such as needing the Intel VT technology or AMD-V technology for 64-bit VMs, unused RAM in a VM is still not available to the base OS (as opposed to jails where all unused space is available for anything) and of course virtualbox VMs are slower (how much slower depends on many aspects of your usage pattern).

The argument is being made that since the linux jails are so limited in their usefulness, non-functional for many tasks, and generally not used in high numbers that we should coax users to use Virtualbox and get rid of the linux jails to simplify developer resources for more important purposes.

If you *do* use linux jails, please say so below and please mention why you chose to use linux jails. If you'd be okay with getting rid of linux jails and going to Virtualbox VMs please say so below in the thread comments.

Please keep the discussion here in the forums. No need to blow up the ticket with discussions for/against the feature.

Thanks,

-Cyberjock

 

[fracai]

I was excited about Linux jails for two reasons:

1) I thought I'd run Crashplan in a Linux jail and not have to worry about the headaches involved with getting it to run under FreeBSD
Experience: Setting up Crashplan on my own would have just as many headaches in the Linux jail as it would under a regular jail.
Result: I just use the Crashplan plugin.

2) I thought I'd run a "playground" Linux jail for working on new automation tasks and services that I'd previously run under Mac OS X and later Debian on a Raspberry PI.
Experience: The jail was simply unusable and I'd already gotten comfortable installing packages with pkgng and portmaster. I still have the RPi for anything that might actually require Linux. And I can always try out the Virtualbox jail.
Result: I just use regular jails for my automated services.

So basically, I thought Linux jails would be great (in the future they still might be), but for now I don't use or care about them.

 

[anodos]

My experience with linux jails typically follows this form:

"I wonder if this will work in a linux jail... nope doesn't work."

I won't shed a tear if it disappears, especially if it results in dev time being devoted to making other things work better.

 

[DJ9]

Granted right now they don't work so hot, but I'd like to see them stick around. Upcoming support in FreeBSD for 64-bit Linux is supposed to be coming around shortly.

 

[Whattteva]

I don't use anything that doesn't exist on the ports tree so I never bothered to use the Linux jail.
I thought it was cool just in case I need a package that's not available under the ports tree in the future.

 

[cyberjock]

Granted right now they don't work so hot, but I'd like to see them stick around. Upcoming support in FreeBSD for 64-bit Linux is supposed to be coming around shortly.

Really? Last I heard the linux "hypervisor" needed *significant* work and has basically been abandoned for years. Is this incorrect?

 

[DJ9]

I've heard that they are shooting for 64-bit Linux support in FreeBSD 11, but I've heard that rumor before. ;)
We'll see, but I'm hoping.

 

[fracai]

That's at least two years away though. Probably more like three. That seems like a long time to hang on to an incomplete feature waiting for it to improve.

 

[spidernas]

So the question is simple, do you use linux jails?

I use them to run the Arkeia backup agent as they do not have a version for FreeBSD. Works fine.
I also use them to run PlexConnect for ATV Plex support. I'm sure there is probably a way to run it on FreeBSD native, but I ran in to some issue I forget, and it was just easier to run in a Linux jail.

 

[HolyK]

I had some plans with Linux jails but since the images are now "broken" ( #5608 ) i can't say.

 

[DrKK]

I wouldn't wipe my butt with the Linux jails. I'll be pleased to see them go.

 

[Yatti420]

Well the ubuntu jail isn't compliant to run hamachi.. I was hoping it would.. I could always use virtualbox now but it would be slower.. If the jails were linux standard base compliant I think they would work much better.. Ofcourse this means adding things to them and probably making them a security risk..

I would like to see them stay however they will obviously need more work to get them up to snuff.. I think removing them will kill some of the uniqueness of utilizing FreeNAS.. I believe I submitted something regarding hamachi and ubuntu jails either in bugs or on this forum..

I think if linux jails were kept up with LSB standards then they would work much better though running software etc (That's way out of my league however.. I may be totally wrong ) - I think right now the templates are the bare minimum to get them to "run" and not where they need to be..

 

[DrKK]

I've dreamed about using Hamachi on FreeNAS/FreeBSD. But, really, OpenVPN (preferably at the router) is probably the superior solution for smart guys like us.

 

[Yatti420]

Probably easier to use openvpn at this point.. I like doing the hard thing sometimes.. Which is why I wanted hamachi initially..

 

[Oie]

I use the Linux jail configured by the Crashplan plugin. It works fine for me.

My only real concern about switching to a VM is possibly wasted memory overhead to run an entire OS for one application. Granted, I don't have a clear picture of how much memory is used by the Linux jail itself.

 

[cyberjock]

The crashplan plugin uses a linux jail? Really?

 

[Whattteva]

The crashplan plugin uses a linux jail? Really?

Oh, if that is true; Doesn't that mean that you can no longer take out the Linux jail feature without also taking out Crashplan from the list of plugins?

 

[cyberjock]

Oh, if that is true; Doesn't that mean that you can no longer take out the Linux jail feature without also taking out Crashplan from the list of plugins?

Pretty much, yes. I'm really not sure that Crashplan requires the linux plugin. I'm 99% sure it's FreeBSD and the poster is confused on the difference between a linux jail and a FreeBSD jail.

 

[Oie]

My understanding that Crashplan requires a Linux jail is based on the notes at http://www.freenas.org/whats-new/2013/11/update-new-crashplan-plugin-and-free-beer.html and the need to add the linux_load tunable for Crashplan to run. Please let me know if I have misinterpreted this.

 

[fracai]

I think that's outdated. I certainly don't remember entering anything regarding Linux when I installed the plugin. 3.6.3, for example, was only released by Code 42 in February and the plugin took a couple weeks to be updated.