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WTF is a container?

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Re: WTF is a container?

#111

Post by oblio »

pm90 wrote: post #99
haalcion3 wrote: post #93

Earlier quoted context omitted.

And, as probably everyone knows, Google runs everything in containers and has been using containers for a decade: http://www.nextplatform.com/2016/03/22/decade-container-cont... Docker may be flawed, but containers aren't. If you need some enterprise leader to tell you this instead, here are some Gartner posts showing this is the way: VMs may be well established and "magic quadrant", but they are also on decline, and…

What really surprises me about Google is why they don't open source some of these great core technologies (MapReduce, Containers etc.) instead of publishing theory as academic papers. On the one hand, it may be a great way of promoting the creating of these tools from the ground up, inspired by the theory alone. On the other hand, Google's invaluable experience with using these technologies probably means their versi…

It's entirely possible that they consider those core technologies part of their "magic sauce". If their development and production environments are so far ahead of everyone, their development cycle will be much faster.

Re: WTF is a container?

#112

Post by saurik »

pm90 wrote: post #99
haalcion3 wrote: post #93

Earlier quoted context omitted.

And, as probably everyone knows, Google runs everything in containers and has been using containers for a decade: http://www.nextplatform.com/2016/03/22/decade-container-cont... Docker may be flawed, but containers aren't. If you need some enterprise leader to tell you this instead, here are some Gartner posts showing this is the way: VMs may be well established and "magic quadrant", but they are also on decline, and…

What really surprises me about Google is why they don't open source some of these great core technologies (MapReduce, Containers etc.) instead of publishing theory as academic papers. On the one hand, it may be a great way of promoting the creating of these tools from the ground up, inspired by the theory alone. On the other hand, Google's invaluable experience with using these technologies probably means their versi…

Why enable their competitors to such an extent? What benefit is in it for them, when they seem to be at the absolutely forefront of this work? They have to let their researchers publish academic papers or they won't get the best researchers, but when they also have the most experience with ops and such a lead in implementation, the theory only gets competitors so far.

Re: WTF is a container?

#114

Post by jameskegel »

haalcion3 wrote: post #106
pm90 wrote: post #99

Earlier quoted context omitted.

What really surprises me about Google is why they don't open source some of these great core technologies (MapReduce, Containers etc.) instead of publishing theory as academic papers. On the one hand, it may be a great way of promoting the creating of these tools from the ground up, inspired by the theory alone. On the other hand, Google's invaluable experience with using these technologies probably means their versi…

Kubernetes: http://kubernetes.io/ Google Container Engine: https://cloud.google.com/container-engine/ Open-source MapReduce implementation: https://gigaom.com/2015/02/18/google-open-sources-a-mapreduc... https://github.com/google/mr4c

Kubernetes just got a pretty sweet update as well. The improvements to the dashboard alone were worth revisiting.

Re: WTF is a container?

#115

Post by [deleted] »

haalcion3 wrote: post #106
pm90 wrote: post #99

Earlier quoted context omitted.

What really surprises me about Google is why they don't open source some of these great core technologies (MapReduce, Containers etc.) instead of publishing theory as academic papers. On the one hand, it may be a great way of promoting the creating of these tools from the ground up, inspired by the theory alone. On the other hand, Google's invaluable experience with using these technologies probably means their versi…

Kubernetes: http://kubernetes.io/ Google Container Engine: https://cloud.google.com/container-engine/ Open-source MapReduce implementation: https://gigaom.com/2015/02/18/google-open-sources-a-mapreduc... https://github.com/google/mr4c

[deleted]

Re: WTF is a container?

#116

Post by austinjp »

chewchew wrote: post #70
parito wrote: post #39

Earlier quoted context omitted.

Shameless copypaste from well written piece by Flockport: Docker restricts the container to a single process only. The default docker baseimage OS template is not designed to support multiple applications, processes or services like init, cron, syslog, ssh etc. As we saw earlier this introduces a certain amount of complexity for day to day usage scenarios. Since current architectures, applications and services are de…

Distributed storage is still a big issue for sure. There are some options, but none are ideal. One option is to map to host and use NFS to share across hosts. Another option is to use something like Convoy or Flocker, which come with their own complexities and limitations. Hopefully more progress is made on this front. As for the wordpress app and other issues mentioned, it's actually very simple: nginx: build: ./ngi…

This is interesting. I'd been considering mounting drives for persistence of stateful data from containers.

Let's say I want to run a Wordpress hosting service. In my ideal world, I deploy an "immutable" container for each customer, i.e. everyone gets an identical container with Wordpress, Nginx, MySQL etc. So what to do with state info, like configs and the MySQL data files? I'm thinking of mounting a drive at the same point inside each container e.g. /mnt/data/ and /mnt/config/ or similar.

This way the containers can all be identical at time of deployment, and I can manage the volumes that attach to those mount points using some dedicated tool/process.

This is all still on the drawing-board... but what you've said here seems to suggest this approach should work. Or have I optimistically misinterpreted what you've said? :)

Re: WTF is a container?

#117

Post by saurik »

vacri wrote: post #92
parito wrote: post #39

Earlier quoted context omitted.

Shameless copypaste from well written piece by Flockport: Docker restricts the container to a single process only. The default docker baseimage OS template is not designed to support multiple applications, processes or services like init, cron, syslog, ssh etc. As we saw earlier this introduces a certain amount of complexity for day to day usage scenarios. Since current architectures, applications and services are de…

> Docker restricts the container to a single process only. No, there is only a single process treated as init in the container, but you can spawn off multiple child processes. > The default docker baseimage OS template is not designed to support multiple applications, processes or services like init, cron, syslog, ssh etc. If you want init, cron, syslog, ssh, and your app(s) all rolled up into one, you want a VM, not…

> No, there is only a single process treated as init in the container, but you can spawn off multiple child processes.

It was extremely clear that the person who wrote the text you are replying to understands this as they specifically cover this fact with respect to using a service management daemon: you are just being pedantic with the wording to complain about this :/.

> If you want init, cron, syslog, ssh, and your app(s) all rolled up into one, you want a VM, not a container.

No: a virtual machine would burn a ton of performance as it would also come with its own kernel. The entire premise here is to be able to share the kernel but split the userspace in a sane way.

Re: WTF is a container?

#118

Post by jameskegel »

holografix wrote: post #42
chewchew wrote: post #27

Earlier quoted context omitted.

Docker gives you the building blocks, but that means you have more pieces to arrange and manage. Take a look at Docker Compose if you haven't already, since the Docker CLI only gets you so far when you're creating apps that consist of multiple containers. I think the best approach for your cert issue is to abstract that into a separate service (nginx is an option, but I'd recommend the Rancher approach below). Yes, t…

Hey chewchew you seem to be knowledgeable on docker-compose. What's the easiest way to get a .yml on a cloud server somewhere and let it assemble it assemble the containers for you? Also, do you know where containers set environment variables? The official Postgres makes available something like PG_PORT_3542 and u can just refer to it from another container. Where I can't seem to do the same with the Redis one...

kubernetes allows you to upload a yaml snippet and launch, which sounds like what you described.

Re: WTF is a container?

#119

Post by austinjp »

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".

From my perspective, where I'm planning a hosting service with multiple customers, containers promise to allow me to slice machines into dedicated chunks. VMs could do this too, but they'd consume far more disk-space, which would mean my hosting costs would be comparatively higher.

Containers promise to allow me to limit the resources each of my customers can consume without killing the entire box. For example, I can limit RAM, CPU and disk-space per customer. If one customer goes rogue, the shared box remains performant for my other customers. Also there's the data protection: in theory customers would not be able to access each others' data, even if they tried to.

There are other considerations as others here have pointed out. This is just my primary concern at the moment.

Re: WTF is a container?

#120

Post by k__ »

dekz wrote: post #108
k__ wrote: post #75

Earlier quoted context omitted.

> guaranteed to be identical [Citation Needed] As far as I know, this isn't the case. That's why using Nix [0] for deployment is a much saner approach than Docker. But after installation and configuration has been done, containers are a viable technology for the rest. [0] https://blog.wearewizards.io/why-docker-is-not-the-answer-to...

The comment you are replying to mentions once the docker image is built, referring to the built layers. These are guaranteed to be identical. Building from scratch, is not always guaranteed to be identical.

Ah okay, got this wrong :)

Yes, the pre-build images are always identical.

Nix starts a step before this with solving the problem, so building from scratch is also guaranteed to be identical.

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