Dramatically Simplify Kubernetes Cluster Creation (kubeadm umbrella issue).

[jbeda]

Description

Creating a new Kubernetes cluster is too hard. We need to simplify the number and types of actions to get a production cluster up and running.

Note that this is different from bringing up a development cluster (single node ala monokube or minikube) or automation around cluster creation (https://github.com/kubernetes/community/wiki/Roadmap:-Cluster-Deployment).

If we do this right, the number of manual steps to get a cluster running should be minimal. This will have the added benefit of making other deployment scenarios (dev cluster, cluster automation) simpler and smaller.

As part of this, we should make simplifying assumptions and have opinionated defaults. An example would be embedding etcd and picking an easy to use network technology. Certificates and trust should be established automatically.

Progress Tracker

• Before Alpha
  • Design Approval
    • Design Proposal. This goes under docs/proposals. Doing a proposal as a PR allows line-by-line commenting from community, and creates the basis for later design documentation. Paste link to merged design proposal here: Proposal: Dramatically Simplify Kubernetes Cluster Creation kubernetes#30360
    • Initial API review (if API). Maybe same PR as design doc. PR-NUMBER
      • Any code that changes an API (/pkg/apis/...)
      • cc @kubernetes/api
  • Write (code + tests + docs) then get them merged. kubeadm kubernetes#33262
    • Code needs to be disabled by default. Verified by code OWNERS
    • Minimal testing
    • Minimal docs [WIP] kubeadm and add-on docs website#1265
      • cc @kubernetes/docs on docs PR
      • cc @kubernetes/feature-reviewers on this issue to get approval before checking this off
      • New apis: Glossary Section Item in the docs repo: kubernetes/kubernetes.github.io
    • Update release notes
• Before Beta
  • Testing is sufficient for beta
  • User docs with tutorials
    • Updated walkthrough / tutorial in the docs repo: kubernetes/kubernetes.github.io
    • cc @kubernetes/docs on docs PR
    • cc @kubernetes/feature-reviewers on this issue to get approval before checking this off
  • Thorough API review
    • cc @kubernetes/api
• Before Stable
  • docs/proposals/foo.md moved to docs/design/foo.md
    • cc @kubernetes/feature-reviewers on this issue to get approval before checking this off
  • Soak, load testing
  • detailed user docs and examples
    • cc @kubernetes/docs
    • cc @kubernetes/feature-reviewers on this issue to get approval before checking this off

FEATURE_STATUS is used for feature tracking and to be updated by @kubernetes/feature-reviewers.
FEATURE_STATUS: IN_DEVELOPMENT

More advice:

Design

• Once you get LGTM from a @kubernetes/feature-reviewers member, you can check this checkbox, and the reviewer will apply the "design-complete" label.

Coding

• Use as many PRs as you need. Write tests in the same or different PRs, as is convenient for you.
• As each PR is merged, add a comment to this issue referencing the PRs. Code goes in the http://github.com/kubernetes/kubernetes repository,
  and sometimes http://github.com/kubernetes/contrib, or other repos.
• When you are done with the code, apply the "code-complete" label.
• When the feature has user docs, please add a comment mentioning @kubernetes/feature-reviewers and they will
  check that the code matches the proposed feature and design, and that everything is done, and that there is adequate
  testing. They won't do detailed code review: that already happened when your PRs were reviewed.
  When that is done, you can check this box and the reviewer will apply the "code-complete" label.

Docs

• Write user docs and get them merged in.
• User docs go into http://github.com/kubernetes/kubernetes.github.io.
• When the feature has user docs, please add a comment mentioning @kubernetes/docs.
• When you get LGTM, you can check this checkbox, and the reviewer will apply the "docs-complete" label.

[jbeda]

Other related efforts/prior art:

• List of core k8s features that will help all deploys: sharing infrastruture between deployments kubernetes-retired/kube-deploy#123
• [closed] Original proposal around this [somewhat outdated]: Dramatically simplify Kubernetes deployment kubernetes#2303
• [closed] Proposal to rework Kubernetes deployment CLI: Proposal to rework Kubernetes deployment CLI kubernetes#5472
• [closed] RFC: kube-bootstrap: RFC: kube-bootstrap kubernetes#16077
• Implement the cluster bootstrap API: Implement the cluster bootstrap API kubernetes#5754 (pulled out of Dramatically simplify Kubernetes deployment kubernetes#2303)
• How to get kargo project into kubernetes github tree How to get kargo project into kubernetes github tree ? kubernetes#27948
• http://kubernetes.io/docs/getting-started-guides/scratch/
• https://github.com/kubernetes/community/wiki/Roadmap:-Cluster-Deployment
• https://github.com/kubernetes/kubernetes-anywhere
• https://github.com/kubernetes/kube-deploy
• https://github.com/coreos/bootkube

[I'll update this comment with new links as they come in]

[jbeda]

@mikedanese -- I know this is a lot of what you've been working on. I'd love to get that reflected here and scoped for 1.4. Do you mind shooting some pointers over?

[philips]

cc @derekparker @aaronlevy @pbx0 from the CoreOS team working on https://github.com/coreos/bootkube and the self-hosted stuff with @mikedanese to realize a k8s driven creation and update story.

[jbeda]

To be extra clear -- I'm proposing that we make this experience part of core kubernetes. The fact that core k8s is a set of things that have to be set up together is a powerful thing but it makes things look very very complex. We should be willing to have a sane set of defaults and embedded solutions built in to the main distribution.

Right now our "manual install" page is incredibly daunting. We should aim to reduce that (at least for a given set of integrated services) to a single screen without the crutch of automation tools that paper over the complexity.

[mikedanese]

There is a class of infrastructure (that doesn't currently exist) that would benefit all deployment automations. We should try to enumerate what these items are, give them relative priorities and advocate for them in v1.4 planning. I started to create a list a couple days ago: kubernetes-retired/kube-deploy#123 cc @justinsb @errordeveloper @bgrant0607

[pires]

@jbeda kubernetes/kubernetes#5472, kubernetes/kubernetes#16077 and kubernetes/kubernetes#5754 are related to this.

[thockin]

Something that crossed my mind with docker 1.12 - built-in kvstoreeans that libnetwork's overlay driver might be viable for us. Having a built-in network mode for Docker installs that works anywhere and doesn't require extra components might be nice.

Might require some work to not assume prefixes per node.

[klizhentas]

Just so I understand it better embedded etcd will be optional right? As in production we would want to still deploy etcd separate from the API/Scheduler/Controller

[smarterclayton]

Network is the hardest part - you can ignore security and edge cases as long as pods can talk to each other. Leveraging libnetwork seems like a practical choice where possible (or just have a daemonset that drops in your favorite network auto provisioner via CNI). Once the node is started we can run any code.

[jbeda]

@klizhentas Yes! The idea is to make small clusters super easy. Folks looking for large clusters will want to manage etcd independently. Users can choose to take on the complexity of breaking everything out but it'll be an advanced move.

[jbeda]

@smarterclayton I think we just need to pick something to get going. The easiest zero-config option would be the way to go.

[derekwaynecarr]

I think the model we present should not look that different from the
production model. I am a fan of making it easy to launch a Kubelet that
then has a static manifest with sensible defaults to launch control plane
that is not hidden in a mess of salt. On that model, etcd can still be a
pod as well as other parts of our control plane.

On Wednesday, June 22, 2016, Joe Beda [email protected] wrote:

@smarterclayton https://github.com/smarterclayton I think we just need
to pick something to get going. The easiest zero-config option would be
the way to go.

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[klizhentas]

@jbeda so in the simple case kube-controller-manager, kube-apiserver,kubelet + etcd will be one go binary?

[jbeda]

@klizhentas @derekwaynecarr I don't know what the binaries will be that we ship. I do know that we have to make it dead easy to download a thing and get it up and running. If we can get stuff self hosted on the cluster in a container, that would be a good solution. The number of steps needs to be reduced to ~1 per node.

Let's start with the ideal set of things we want the end user to type. From there we can figure how to get there in a sustainable way (and with the opportunity to do everything in a more explicit way for advanced users).

[derekwaynecarr]

I think we can demonstrate the composable nature of the platform without
having to build monolithic binaries that are contrary to the spirit of
microservice architecture.

There are two separate but related topics: ability to create a node (and
bring up control plane), ability to have a new node join an existing
cluster easily. I worry moving to monolithic binaries don't necessarily
help either cause.

I also think if we want to advocate being agnostic about a particular
container runtime, the setup process should follow suite. This is why I
like @mikedanese ideas in the space since they start with the Kubelet
(which could work with any container runtime it's pointed against) rather
than starting with a particular container runtime launching the Kubelet.

On Wednesday, June 22, 2016, Alexander Klizhentas [email protected]
wrote:

@jbeda https://github.com/jbeda so in the simple case
kube-controller-manager, kube-apiserver,kubelet + etcd will be one go
binary?

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[derekwaynecarr]

@jbeda - agree on focusing on desired ux command first

On Wednesday, June 22, 2016, Derek Carr [email protected] wrote:

I think we can demonstrate the composable nature of the platform without
having to build monolithic binaries that are contrary to the spirit of
microservice architecture.

There are two separate but related topics: ability to create a node (and
bring up control plane), ability to have a new node join an existing
cluster easily. I worry moving to monolithic binaries don't necessarily
help either cause.

I also think if we want to advocate being agnostic about a particular
container runtime, the setup process should follow suite. This is why I
like @mikedanese ideas in the space since they start with the Kubelet
(which could work with any container runtime it's pointed against) rather
than starting with a particular container runtime launching the Kubelet.

On Wednesday, June 22, 2016, Alexander Klizhentas <
[email protected]
javascript:_e(%7B%7D,'cvml','[email protected]');> wrote:

@jbeda https://github.com/jbeda so in the simple case
kube-controller-manager, kube-apiserver,kubelet + etcd will be one go
binary?

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[aaronlevy]

Biased, because I'm already working on it, but I'd advocate for putting effort into self-hosted (k8s-on-k8s) installations as a means of simplifying both cluster creation, and lifecycle management.

If the installation contract becomes "I can run a kubelet" and everything else is built atop that in containers -- then installation criteria could become as simple as "does your node pass node-e2e tests?"

More or less this is already possible in a simple case with all core components being run as static pods. This is how many installations work, and is well understood. The problem with this approach is that it becomes difficult to transition from "this was easy to install" to "I want to customize/modify/update this installation".

As soon as we want to make modifications to this cluster, we're back to some kind of "modify files on disk" configuration management (salt/ansible/chef/etc). In this case it doesn't preclude us from having a "simple" installation and other "production" deployment tools. Or even decide on standardization/contract where a more complex tool can take over from the other static installation (e.g. kube-apiserver.yaml will exist in /etc/kubernetes/manifests)

Alternatively, in the self-hosted scenario, the static installation can remain simple on first install (in concept, replace your static pod definitions with deployments/daemonsets). But then can be modified / extended without relying on external configuration management (or external deployment tooling that needs to evolve in lock-step with your cluster) -- everything is by definition just a kubernetes object.

Updates to the cluster can become api-driven / or even an update-controller application. Assets (tls, configuration, flags) travel with their components as they are also just kubernetes objects (secrets / configMaps). We get all the niceties of kubernetes lifecycle management.

Now all that being said, networking really is a hard part. Maybe this comes down to figuring out the coordination at the kubelet level + cni (e.g. how do I self-host flannel-client + allow it to configure networking for subsequent pods).

[klizhentas]

For this particular feature I think it would help to go backwards - not from implementation to UX, but vise-versa. If we figure out user experience with this right, the implementation will follow.

Here's the ideal scenario that users can see on k8s quickstart page:

Starting single node k8s

wget https://kuberenetes.io/releases/latest/kube
# starts both node, API, etcd, all components really
kube start

This will let users to explore kubernetes, start containers

Adding node

Then there's a use case when users want to get to run smaller clusters to play with failover, HA and so on.

On first node, execute:

# adds provisioning token to securely add new nodes to the cluster
kube token add
<token1>

On any node to be added in the cluster:

kube start --token=<token1> --cluster=https://<ip of the first node>

That's the minimum amount of steps I can imagine to bootstrap the cluster in dev mode. If we figure out this UX first, everything else will follow.

[bgrant0607]

This has become a discussion issue rather than a tracking issue. It's great that lots of people are interested in this topic. We could use help. I created a github team (sig-cluster-lifecycle) and googlegroup (kubernetes-sig-cluster-lifecycle), which you can request to join. I'm going to rename the sig-install slack channel to sig-cluster-lifecycle. We should brainstorm in the googlegroup rather than generate more github notifications.

Also, a number of people have been working in this area for a while. We're going to summarize the current state and make a prioritized list of work items that have already been identified.

[metral]

I took the liberty of creating a post that summarizes the generic expectations stated here in the googlegroup (kubernetes-sig-cluster-lifecycle) to continue the brainstorming: https://groups.google.com/forum/#!topic/kubernetes-sig-cluster-lifecycle/LRMygt2YNrE

[philips]

On Wed, Jun 22, 2016 at 2:02 PM Tim Hockin [email protected] wrote:

Something that crossed my mind with docker 1.12 - built-in kvstoreeans
that libnetwork's overlay driver might be viable for us. Having a built-in
network mode for Docker installs that works anywhere and doesn't require
extra components might be nice.

Relying on libnetwork for bootstrapping sounds like a mess longterm. I
would much rather figure out bootstrap, reconfiguration, etc of CNI, which
we need to figure out anyways, than make some compromise that puts a new
dependency on the Docker engine.

[aronchick]

Reminder - these issues (ideally) should be for only discussion about the flow of the work items related to the feature. If you would like to discuss (please do!) please do it in the Google group.

[idvoretskyi]

Please, take a look at this proposal - kubernetes/kubernetes#27948

[jbeda]

@aronchick @bgrant0607 @metral Agreed -- let's take this to the mailing list.

https://groups.google.com/forum/#!forum/kubernetes-sig-cluster-lifecycle

[jimmycuadra]

@jbeda For your list of related work: https://github.com/InQuicker/kaws

[neolit123]

this gets my 👍 for GA in 1.12, in terms of docs.
(we do have to covert some other aspects.)

we have decent documentation in place and we haven't had major, negative feedback on the instructions for cluster creation with kubeadm which were improved a lot in 1.11. in the meantime we continue to improve the docs where possible.

pages to note:
https://kubernetes.io/docs/setup/independent/install-kubeadm/
https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/
https://kubernetes.io/docs/setup/independent/high-availability/

[kacole2]

Hi. This is currently being tracked for 1.13. I want to see what changes are being made for 1.13 for the feature to be considered GA/Stable.

This release is targeted to be more ‘stable’ and will have an aggressive timeline. Please only include this enhancement if there is a high level of confidence it will meet the following deadlines:

• Docs (open placeholder PRs): 11/8
• Code Slush: 11/9
• Code Freeze Begins: 11/15
• Docs Complete and Reviewed: 11/27

Thanks!

[timothysc]

Our objective is to take kubeadm to GA this cycle.

[bogdando]

Reading into https://kubernetes.io/docs/setup/independent/high-availability/ I noticed there is now a neat config file (kubeadm-config.yaml in the guide). But I was not sure what is the status for "features flags" support for that config? Can we have init steps executed selectively yet? Or had it lost from the radar?

[dims]

@bogdando see the "full" example in the doc for featureGates:
https://github.com/kubernetes/kubernetes/blob/master/cmd/kubeadm/app/apis/kubeadm/v1alpha3/doc.go#L160-L248

[neolit123]

@bogdando

Can we have init steps executed selectively yet? Or had it lost from the radar?

yes, in 1.12 there is kubeadm alpha phase.... which handles init phases. in 1.13 these would be more widely available.

[AishSundar]

@neolit123 @roberthbailey is this still on track for GA in 1.1.3? do we have a link to list of pending PRs or issues for us to track this better?

[neolit123]

@AishSundar

i don't have powers here to update the OP.
in terms of docs we are in a good state, test coverage might need some attention as much i understand the goals here.

i'm going to have to defer to @timothysc on this one.

[AishSundar]

@timothysc could you please provide a more latest update on the status of Kubeadm for GA in 1.13. Specifically around

(i) how many and which PRs (code and test) are pending
(ii) latest status of docs and links to docs PR
(iii) Status of failing kubeadmn tests in master blocking

With code slush nearing us on 11/9, could you provide us with an ETA of when you expect all pending things to land in master? Given we need sometime to stabilize things before Code freeze on 11/16, it might be a good idea to timebox the remaining work and make a Go/No-Go call for GA in 1.13 before Code freeze. Thanks !

@neolit123 @kacole2 @tfogo

[neolit123]

(iii) Status of failing kubeadmn tests in master blocking

this should have green runs today.

[timothysc]

@AishSundar I wish it were that simple. There are a number of PRs in flight and most of the docs will be minor changes. Progress is good, but I probably won't have a good answer for you until ~ next week. Almost all of the work is not "net-new" features but cleanup and bug fixes in shuffling for GA, which will likely span into slush.

[AishSundar]

Ack that @timothysc and thanks for the update and consolidating all the Kubeadm GA work under this issue. We will check back once in slush.

[claurence]

@timothysc Hi I'm an enhancements shadow for 1.13 - checking in on progress for this issue. Code slush is 11/9 and Code freeze is 11/15, is this issue still on track for those milestones? Thanks!

[kacole2]

@timothysc can you drop in a list of PRs we should be tracking for Kubeadm going GA? Thanks!

[neolit123]

the issue is on track, yes.

kubeadm labels are auto-applied to our PRs, too many to log and track on our side:
https://github.com/kubernetes/kubernetes/pulls?q=is%3Apr+is%3Aopen+label%3Aarea%2Fkubeadm

as explained in a release team meeting these are our 2 GA items:

the list in here is a critical one:
kubernetes/kubeadm#1163

this is for the kubeadm config:
kubernetes/kubeadm#911

docs are mostly command reshuffle and are TBD.

[AishSundar]

@timothysc @neolit123 can one of you attend the Release burndown meeting next week (Mon, Wed or Fri) to give the latest update on Kubeadm GA.

[neolit123]

i can try joining today.

update on docs:
for GA we only need 2 docs PRs, one already merged and one is a WIP placeholder, TBD before 19th:
kubernetes/website#10937 (comment)

[neolit123]

update:

all feature PRs were merged. during code freeze we have time to dig for bugs.
remaining docs PR is WIP:
kubernetes/website#10960

[neolit123]

our docs and all our items for 1.13 are in place.
this tracking issue can finally be closed.
kubeadm is now GA. 🎉

/close

[k8s-ci-robot]

@neolit123: Closing this issue.

In response to this:

our docs and all our items for 1.13 are in place.
this tracking issue can finally be closed.
kubeadm is now GA. 🎉

/close

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