Containers vs. Zones vs. Jails vs. VMs (2017)
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Containers vs. Zones vs. Jails vs. VMs (2017)
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Re: Containers vs. Zones vs. Jails vs. VMs (2017)
#2Note this is from 2017. Previous discussion: https://news.ycombinator.com/item?id=13982620
Re: Containers vs. Zones vs. Jails vs. VMs (2017)
#3Note this is from 2017. Previous discussion: https://news.ycombinator.com/item?id=13982620
Year added. Thanks!
Re: Containers vs. Zones vs. Jails vs. VMs (2017)
#4> A “container” is just a term people use to describe a combination of Linux namespaces and cgroups. Linux namespaces and cgroups ARE first class objects. NOT containers.
Amen.
Somewhat tangential note: most developers I have met do not understand what a 'container' is. There's an aura of magic and mystique around them. And a heavy emphasis on Docker.
A sizable fraction will be concerned about 'container overhead' (and "scalability issues") when asked to move workloads to containers. They are usually not able to explain what the overhead would be, and what could potentially be causing it. No mention to storage, or how networking would be impacted, just CPU. That's usually said without measuring the actual performance first.
When I press further, what I most commonly get is the sense that they believe that containers are "like VMs, but lighter"(also, I've been told that, literally, a few times, specially when interviewing candidates). To this day, I've heard CGroups being mentioned only once.
I wonder if I'm stuck in the wrong bubble, or if this is widespread.
Re: Containers vs. Zones vs. Jails vs. VMs (2017)
#5> A “container” is just a term people use to describe a combination of Linux namespaces and cgroups. Linux namespaces and cgroups ARE first class objects. NOT containers. Amen. Somewhat tangential note: most developers I have met do not understand what a 'container' is. There's an aura of magic and mystique around them. And a heavy emphasis on Docker. A sizable fraction will be concerned about 'container overhead' (a…
This is widespread unfortunately. Developers changed to „users” and no longer pursue the details of solutions. Im not gonna say its the dominant behaviour in the field right now, but I see it more and more often on various experience levels.
Re: Containers vs. Zones vs. Jails vs. VMs (2017)
#6> A “container” is just a term people use to describe a combination of Linux namespaces and cgroups. Linux namespaces and cgroups ARE first class objects. NOT containers. Amen. Somewhat tangential note: most developers I have met do not understand what a 'container' is. There's an aura of magic and mystique around them. And a heavy emphasis on Docker. A sizable fraction will be concerned about 'container overhead' (a…
People love to bring this up, but if Linux did have first-class containers, how would the developer's experience be different?
Re: Containers vs. Zones vs. Jails vs. VMs (2017)
#7> A “container” is just a term people use to describe a combination of Linux namespaces and cgroups. Linux namespaces and cgroups ARE first class objects. NOT containers. Amen. Somewhat tangential note: most developers I have met do not understand what a 'container' is. There's an aura of magic and mystique around them. And a heavy emphasis on Docker. A sizable fraction will be concerned about 'container overhead' (a…
I think it is widespread because containers are (seemingly) marketed as being some kind of magic. The impression I get is that the benefit to containers is that you don't have to think about them. This may be more a product of Docker but I think containers and Docker have become synonymous.
I'm not sure this is a fair comparison but that is my impression. I could be in a bubble too.
Re: Containers vs. Zones vs. Jails vs. VMs (2017)
#8> A “container” is just a term people use to describe a combination of Linux namespaces and cgroups. Linux namespaces and cgroups ARE first class objects. NOT containers. Amen. Somewhat tangential note: most developers I have met do not understand what a 'container' is. There's an aura of magic and mystique around them. And a heavy emphasis on Docker. A sizable fraction will be concerned about 'container overhead' (a…
This is true for many new waves of popular technologies.
1) A new technology or method becomes popular. 2) Developers find new advantages in using the technology. 3) Understanding of tech and original advantage is somewhat lost.
For example: containers are now widely used as part of a scriptable application build process, e.g. the Dockerfile. There are probably many developers out there who care about this and not about how containers are run and how they interact with the kernel. And for their use cases, that is probably the thing that matters most anyways.
Re: Containers vs. Zones vs. Jails vs. VMs (2017)
#9> A “container” is just a term people use to describe a combination of Linux namespaces and cgroups. Linux namespaces and cgroups ARE first class objects. NOT containers. Amen. Somewhat tangential note: most developers I have met do not understand what a 'container' is. There's an aura of magic and mystique around them. And a heavy emphasis on Docker. A sizable fraction will be concerned about 'container overhead' (a…
> Somewhat tangential note: most developers I have met do not understand what a 'container' is.
The problem is at least in part that the term is basically meaningless. It's too broad and flexible to be descriptive. As you quoted:
> A “container” is just a term people use to describe a combination of Linux namespaces and cgroups.
Re: Containers vs. Zones vs. Jails vs. VMs (2017)
#10> A “container” is just a term people use to describe a combination of Linux namespaces and cgroups. Linux namespaces and cgroups ARE first class objects. NOT containers. Amen. Somewhat tangential note: most developers I have met do not understand what a 'container' is. There's an aura of magic and mystique around them. And a heavy emphasis on Docker. A sizable fraction will be concerned about 'container overhead' (a…
The "containers are just XX Linux technology" comes regularly in the comments but it’s untrue: Windows containers are obviously not based on any Linux tech proper.
Also the overhead intuition exists for a reason: on both macOS and Windows when Linux containers are used, there is actually a whole VM running Linux underneath. And Windows containers come in two flavors, one being Hyper-V based, so again a VM tech comes in play.
So there are technical reasons why containers are "misunderstood", it’s because most people don’t run Linux natively, and on their stack containers are more than just cgroups and namespaces.