Dockerless, part 3: Moving development environment to containers with Podman
mkdev.me
mkdev.me
With AWS you already have a virtualization, why do we need another layer?
We packaged a super slim Linux with an init that just has some minimal code reading out of AWS EC2 user info the conf. Downloads docker hub image and runs it as a process.
No virtual networking or ssh access. No magic. Just a process on an aws ec2 instance.
The argument though is that can't run an EC2 (AMI) anywhere except AWS.
The advantage of Virtual box images or Docker/OCI images is that you can run them in multiple places (locally, AWS, GCP, Raspberry Pi, etc.) with consistent results.
Why dedicate an entire ec2 instance to a single container?
You would scale the virtual machines to try and reach optimal resource usage rather than pick a standard fleet of virtual machines for all workloads and let a scheduler do some kind of knapsack scheduling based on available resources.
Meanwhile containers enable you to run multiple services on the same VM, scale them horizontally as you need on the same pre-determined amount of resources, use blue/green deployments to spread your services throughout your VMs automatically, and achieve all of this automatically and effortlessly.
So if you have 10 services deployed on 10 ec2 instances each, you will need 200 ec2 instances to give yourself 50% headroom for each service.
With containers, you can give each container 10x headroom for the same amount of hardware.
Docker has the issue of needing a daemon that runs as another user. Aside from being a security issue it’s just inconvenient and Docker has to go through great lengths to make it all transparent.
You should use what works for you - ultimately you know your context and circumstances better and you can make the decisions that affect you/your team better than any of us.
HN is not an indicator of industry trends, but more of a set of interesting articles and viewpoints that come together, though you will often see authors and commenters pushing hard in certain directions.
In this instance, have a look at the author's part 1 under 'Reasons to switch', see if any of the reasons given work for you.
https://mkdev.me/en/posts/dockerless-part-1-which-tools-to-r...
Being beholden to a desperate competitor isn't just marketing; it could be a matter of survival and a strategic response seems reasonable.
The docker daemon has a large surface area and also has fairly hefty privileges. It's a juicy target of attack.
A platform can take various actions to further lock down the runtime with AppArmor or SELinux, but out of the box you wind up hearing the motto that "containers don't contain".
Notably, the docker daemon has too many responsibilities. It's a builder. It's a shipper. It's a runner. It's everything to everyone, which makes for a convenient installation process but means that a subversion of any of these functions potentially allows someone to drill sideways into one of the others.
> Being beholden to a desperate competitor isn't just marketing; it could be a matter of survival and a strategic response seems reasonable.
I'm prepared to go with: the engineers thought it was a good idea and product management didn't gainsay them. It's been a common theme from multiple tech companies in the past year or two. Google, Amazon, Red Hat, Pivotal (which is where I work) have all been chipping away at breaking off parts of the daemon's responsibilities.
Unfortunately, I don't agree with this whole "it must be more secure because we broke it into bits" argument. That alone is not sufficient in order to increase security. The vast majority of the code in libpod/cri-o is very similar to (generate a config and pass it to runc) or copied directly from Docker (containers/storage, with containers/image honestly having quite a few more problems than Docker's image parsers). When I found CVE-2018-15664, not only was the libpod/cri-o stack also vulnerable but it was as vulnerable as Docker was more than 5 years ago when I fixed the original security flaw in 2014. I feel bad saying this (I don't want to blame the folks working on this, who I do respect immensely) but it really should be a serious consideration if you want to put "more secure" in your advertising.
This is why I argued for several years that we should add OCI runtime (and custom storage driver) support to rkt instead of having to redesign everything (and since we started with cri-o instead of libpod, getting rid of the daemon was a pain there too). But of course, like every other discussion I've had with Dan Walsh, it was brushed away. Whatever.
I do really like the folks behind the project. I just wish we'd spent our collective energy on improving something that already existed instead of repeating mistakes pointlessly. I'm definitely not a fan of Docker's politics either (and at the very least nobody from the cri-o/libpod project has sent me abusive emails calling me stupid and "brainwashed by Red Hat" for criticizing their project's governance model -- which Solomon Hykes did in the past when he was still the CTO of Docker).
Disclaimer: I work for SUSE and maintain runc, and have worked on containers for a depressingly long period of time. Obviously the above are my views not those of my employer (who ships both Docker and cri-o, and my team maintains it in our products). I'm just tired of all the fucking drama.
We are all on the same team, just want to make this stuff better, but people still seem intent on fighting.
But again, I don't like all of this stupid politics over such trivial crap. It's ridiculously draining that I have to deal with people from the Docker project demanding me to apologise for things that Dan Walsh has said (or playing dumb when someone else from the SUSE makes a snide comment about several-year-old PRs that have burned out several of our engineers -- and then asking me to try to force them to apologise for it), as well as having to deal with the issues I outlined above. All of this back-and-forth has no benefit to anyone involved (or outside) and is just a waste of our collective lives. Posting this publicly probably won't help either, but I really don't know what the solution is other than to just quit and work on something else where we aren't just collectively accelerating human entropy.
To be frank, this is the main reason I've been working more with the LXC folks in recent years -- there are more interesting problems there and I don't have to deal with this crap. They also have really brilliant engineering, but that's not the main thing that attracted me to working with them.
I wasn't aware there was any, my perspective comes from working from a different end (dockerless builds).
I know what it can be like to work in communities fraught with vendor politics and other troublesome dynamics and have come close to burning out a few times.
It always feels too important to walk away from, even temporarily, but I promise, it's not true. Your own health is important.
Would be nice to decouple networking, this will take some work.
Docker is more and more becoming an API that sits on top of a bunch of other services. It does take time to make this happen without breaking compatibility, though.
Docker can also run without root as of Docker 19.03. Even so, "docker requires too many privileges" is marketing speak. Setting up cgroups requires root, setting up mounts (w/o fuse) requires root, setting up network devices requires root, etc... anyone who wants to do these things requires root. Rootless mode on all this tech attempts to work around such limitations, but each workaround comes with trade-offs (slower networking, no cgroup support, slower fs access...).
Definitely agree, though if you want to run services through systemd Docker is not well designed for that purpose.
This is loosely similar to how rkt operated, with rktnetes just being a front-end for rkt (though at the time, the CRI didn't exist so it was all hardcoded in Kubernetes).
The goal isn't to have a differently-named daemon required in order to do any operation, and podman enables that (though again, so did rkt).
Which is a good thing. With Cloud Foundry we moved from using a pre-Docker container engine to using runc as soon as it was available; containerd is the next move.
> Even so, "docker requires too many privileges" is marketing speak.
I don't agree. The API surface still exists and includes too many disparate purposes. The modularisation of Docker is improving that risk profile, but it still exists. Fully segregating the API and the modules is worthy.
Unfortunately the documentation is not really there yet[0], but that's the gist of how it's more secure outside of the general reduction-of-responsibility ways that others have mentioned.
[0]: https://github.com/containers/buildah/issues/1469#issuecomme...
Docker is straigh hostile to systemd, tried to bite part of its responsibilities and does not cooperate with it in many parts.
If you want to run a docker image as a system service, its much easier to do that with podman - the docker image will inherit the system.limits and will behave like a Type=simple service with proper start/stop control and logging.
-- add: worth noting, that podman and buildah are very alike "docker" and "docker build" up to the point that you can do alias docker="podman" and can expect all the docker features work. they consume the same docker files, they build the same OCI images and can use the same registries. trying podman/buildah/scopeo really got me thinking - where's the moby inc. business? how can they commercialize a commodity?
> Docker is straigh hostile to systemd, tried to bite part of its responsibilities and does not cooperate with it in many parts.
you had me until the rationale for this was protecting systemd, which is doing the exact same thing..
Since Podman supports rootless containers it should mitigate this security risk. Really there needs to be an easy way to deploy Kubernetes to Podman on Linux. It would make things a lot easier overall and make Podman the ideal option for local Kubernetes on Linux.
https://github.com/kubernetes/minikube/blob/master/docs/vmdr...
https://github.com/rootless-containers
https://github.com/containers/libpod/blob/master/rootless.md