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WTF is a container?

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Re: WTF is a container?

#181

Post by striking »

eatbitseveryday wrote: post #176
striking wrote: post #172

Earlier quoted context omitted.

I think the assumption arose not from the demographic of people on Hacker News, but from the username of that poster. "Shawn" is a fairly common name, where one in every 2000 people will be named it. [1] Meanwhile, "Shawnee" is a really rare name[2], one you may not be aware of if you didn't grow up in the US (or in particular parts thereof). (Apparently only 4000 of them are alive today!) Just as an aside, using "th…

Thanks for pointing out where the name confusion may have come from. > I definitely do not have time to check every person's profile when I comment on HN. At least then we should not make explicit such gender assumptions, regardless. I have never heard the name "Shawnee" and generally do not assume usernames on web forums are indicative of real-life anything (e.g. you are 'striking', but apparently that is not your n…

As a Polish immigrant, I personally think "singular they" is worse, because it creates ambiguity where there doesn't need to be any... which makes things a bit more confusing. Meanwhile, I think my proposed alternative is native to most other languages, and should translate fairly easily.

I'm not sure I see the point in thinking this long and hard about pronouns, but to each his own.

Re: WTF is a container?

#182

Post by agopaul »

dragonsh wrote: post #85
dancek wrote: post #5

I agree that containers (both for shipping and servers) are a great idea. And because I'm tired of always configuring servers, I decided to give it a try some time ago. I wrapped my IRC client (weechat + glowing-bear) in a Docker container. Oh, not a container though, because I also needed https, which meant I needed either a mechanism to build and update letsencrypt certs in the weird format that weechat expects, or…

Containers!=docker, I think if you used lxd container, your experience might have been different as they work like virtual machine. I am using lxd in production and it has been a pleasure with live migration, snapshots and good old configuration management using ansible.

Still, I'm not sure why I should use containers VS Vagrant + ansible (or just ansible)

Re: WTF is a container?

#183

Post by brazzledazzle »

ChoHag wrote: post #58
nvarsj wrote: post #45

Earlier quoted context omitted.

Docker is a poorly engineered and over-hyped technology. The concept is great - and in fact, many companies have built great tooling around Linux cgroups. It lets you efficiently binpack applications on a single server - which is why 'containers' were created in the first place. The side benefit of letting you define your OS libraries, and other things, is a nice bonus, and way overblown in my opinion. Docker and its…

The concept is great but it's also not original. It's called "processes". Docker is little more than a mass of complication laid atop fork+exec. That's why nobody can get it right - because we already did.

Wouldn't it be more akin to jails?

Re: WTF is a container?

#184

Post by brazzledazzle »

senex wrote: post #159
nine_k wrote: post #141

Earlier quoted context omitted.

Ok, throw Docker away. Did anybody have better experience with e.g. Rkt?

I really like: daemontools + static binary + setuidgid and maybe chroot. Or mesos where everything needs to be in a tarball, which is extracted and sole program run. If stuff is statically linked and related files (config, assets, ...) are part of bundle that can be chrooted, what is the value add of a container?

Containers are easier for folks with less operational experience to understand. Or maybe easier to get started with is a better way to put it. It's easy to underestimate easy to use tooling when you aren't the target demographic.

Re: WTF is a container?

#185

Post by sundarurfriend »

greggman wrote: post #50
lottin wrote: post #44

I guess I'll never get it. Don't most OSs already run processes isolated from each other, have advanced process scheduling mechanisms and manage access to hardware resources? Also with static linking nothing stops you from creating huge binaries that "will run anywhere".

In containers a few more things are virtualized. The file system is semi-virtualized. Network ports are too. So from the pov of stuff inside the container nothing else is running. That's not true of processes in general. From outside the containers you can then choose how to map parts of the virtual file systems to parts of the real file system and what real network ports the virtual ports connect to etc... There's m…

So let me try to understand this from a different angle: what's something that a VM can and does do, that container software like Docker can't? TFA makes it sound like legacy systems is the only place for VMs anymore, but I'm guessing that's probably approximation+exaggeration.

Re: WTF is a container?

#186

Post by waffle_ss »

cookiecaper wrote: post #121
Azeralthefallen wrote: post #101

I remember going to AWS Reinvent last year and having some beers with a bunch of people who did devops. We started talking about tools, and they were utterly flabbergasted, that we had not embraced docker. They went on an on about how simple docker made HA, and handling fail overs/maintenance. More or less made it seem like it was the greatest thing since sliced bread. Me and a few coworkers decided to try and docker…

Yes, Docker is still very young and has a ton of issues like these. I think it will take another 2-3 years before that whole ecosystem has emerged, matured, and is ready for a medium-stability deployment. Unfortunately for us, such considerations don't stop tech fads. Because containers can allow many more applications to cohabit on the same "hardware", it has business momentum behind it too (lower infrastructure exp…

> Docker is still very young and has a ton of issues like these

Very young? It's over 3 1/2 years old

https://webcache.googleusercontent.com/search?q=cache:eYg3Fs...

Re: WTF is a container?

#187

Post by neurostimulant »

cookiecaper wrote: post #121
Azeralthefallen wrote: post #101

I remember going to AWS Reinvent last year and having some beers with a bunch of people who did devops. We started talking about tools, and they were utterly flabbergasted, that we had not embraced docker. They went on an on about how simple docker made HA, and handling fail overs/maintenance. More or less made it seem like it was the greatest thing since sliced bread. Me and a few coworkers decided to try and docker…

Yes, Docker is still very young and has a ton of issues like these. I think it will take another 2-3 years before that whole ecosystem has emerged, matured, and is ready for a medium-stability deployment. Unfortunately for us, such considerations don't stop tech fads. Because containers can allow many more applications to cohabit on the same "hardware", it has business momentum behind it too (lower infrastructure exp…

>> Docker" will be the buzzword until such time as it's actually practical and intelligent to deploy with it.

At that point docker will be considered boring old technology and we'll be flocking to a hip new fad. Repeat ad infinitum.

Re: WTF is a container?

#188

Post by madmax96 »

waffle_ss wrote: post #186
cookiecaper wrote: post #121

Earlier quoted context omitted.

Yes, Docker is still very young and has a ton of issues like these. I think it will take another 2-3 years before that whole ecosystem has emerged, matured, and is ready for a medium-stability deployment. Unfortunately for us, such considerations don't stop tech fads. Because containers can allow many more applications to cohabit on the same "hardware", it has business momentum behind it too (lower infrastructure exp…

> Docker is still very young and has a ton of issues like these Very young? It's over 3 1/2 years old https://webcache.googleusercontent.com/search?q=cache:eYg3Fs...

Keep in mind that young is relative. In a field that still uses software daily originating from the 60's, 3 and a half years is very young.

Re: WTF is a container?

#189

Post by chousuke »

Azeralthefallen wrote: post #101

I remember going to AWS Reinvent last year and having some beers with a bunch of people who did devops. We started talking about tools, and they were utterly flabbergasted, that we had not embraced docker. They went on an on about how simple docker made HA, and handling fail overs/maintenance. More or less made it seem like it was the greatest thing since sliced bread. Me and a few coworkers decided to try and docker…

I feel that sometimes I'm pro containers, and sometimes I'm very much against them. Docker does make deployments and upgrades very easy once you have the initial infrastructure set up, and you can deploy applications directly from upstream as "units" so that each deployment is exactly what you want; deploying containers helps prevent hosts from differentiating too much.

If you have the infrastructure in place to rebuild your virtual machines though, containers offer little benefit other than perhaps not having to package your software.

At work we're mostly deploying docker containers using puppet, and often when docker fails to work, I can just obliterate everything and run puppet once to re-download images and set up everything again. I would not trust docker to manage any data that I can not recover from elsewhere.

My biggest gripe is that configuration management feels like an unsolved problem. Most examples I see on the web seem to simply ignore it, or do the usual "mount a host directory inside a container" thing which has issues with file permissions and host/container UIDs clashing, and just feels inelegant.

I'm also developing a dislike of Docker on account of it simply failing to work at times for no discernible reason, and having stupid issues like IPv6 simply not working correctly.[1] It's also rather inelegant when used on a systemd-based host because it wants to reimplement most systemd functionality.

I'm still waiting for rkt to mature a bit, maybe it will be better.

[1] https://github.com/docker/docker/issues/2174

Re: WTF is a container?

#190

Post by madmax96 »

Azeralthefallen wrote: post #101

I remember going to AWS Reinvent last year and having some beers with a bunch of people who did devops. We started talking about tools, and they were utterly flabbergasted, that we had not embraced docker. They went on an on about how simple docker made HA, and handling fail overs/maintenance. More or less made it seem like it was the greatest thing since sliced bread. Me and a few coworkers decided to try and docker…

Same tune here.

What docker promises is truly amazing and is something that I think everyone wants. However, docker itself still has a lot of problems.

In particular, docker's new builtin swarm (with 1.12) has tons of issues. I've experienced __so many__ problems coordinating container startups on a swarm cluster.

From the documentation:

    > Swarm can build an image from a Dockerfile just like a 
      single-host Docker instance can, but the resulting image   
      will only live on a single node and won’t be distributed 
      to other nodes.
This is a serious weakness.

You have to use __manual scheduling__ if you want to ensure services are started on the same node. This is problematic if your inventory of nodes is dynamic and frequently changing. Allegedly, kubernetes solves this problem.

Swarm (and the whole ecosystem) is still not as mature as it could be, but I think the end result is going to be very awesome and useful.

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