Production-Grade Container Scheduling and Management
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Mike Spreitzer feb4227788 apiserver: finish implementation of borrowing in APF
Also make some design changes exposed in testing and review.

Do not remove the ambiguous old metric
`apiserver_flowcontrol_request_concurrency_limit` because reviewers
though it is too early.  This creates a problem, that metric can not
keep both of its old meanings.  I chose the configured concurrency
limit.

Testing has revealed a design flaw, which concerns the initialization
of the seat demand state tracking.  The current design in the KEP is
as follows.

> Adjustment is also done on configuration change … For a newly
> introduced priority level, we set HighSeatDemand, AvgSeatDemand, and
> SmoothSeatDemand to NominalCL-LendableSD/2 and StDevSeatDemand to
> zero.

But this does not work out well at server startup.  As part of its
construction, the APF controller does a configuration change with zero
objects read, to initialize its request-handling state.  As always,
the two mandatory priority levels are implicitly added whenever they
are not read.  So this initial reconfig has one non-exempt priority
level, the mandatory one called catch-all --- and it gets its
SmoothSeatDemand initialized to the whole server concurrency limit.
From there it decays slowly, as per the regular design.  So for a
fairly long time, it appears to have a high demand and competes
strongly with the other priority levels.  Its Target is higher than
all the others, once they start to show up.  It properly gets a low
NominalCL once other levels show up, which actually makes it compete
harder for borrowing: it has an exceptionally high Target and a rather
low NominalCL.

I have considered the following fix.  The idea is that the designed
initialization is not appropriate before all the default objects are
read.  So the fix is to have a mode bit in the controller.  In the
initial state, those seat demand tracking variables are set to zero.
Once the config-producing controller detects that all the default
objects are pre-existing, it flips the mode bit.  In the later mode,
the seat demand tracking variables are initialized as originally
designed.

However, that still gives preferential treatment to the default
PriorityLevelConfiguration objects, over any that may be added later.

So I have made a universal and simpler fix: always initialize those
seat demand tracking variables to zero.  Even if a lot of load shows
up quickly, remember that adjustments are frequent (every 10 sec) and
the very next one will fully respond to that load.

Also: revise logging logic, to log at numerically lower V level when
there is a change.

Also: bug fix in float64close.

Also, separate imports in some file

Co-authored-by: Han Kang <hankang@google.com>
2022-11-08 21:51:44 -08:00
.github Make root approval non-recursive 2022-10-10 08:26:53 -04:00
api apiserver: add generated files for borrowing in flowcontrol 2022-11-08 13:16:44 -08:00
build Turn on CCM in kube-up when cloudprovider=external 2022-11-03 10:38:23 -07:00
CHANGELOG CHANGELOG: Update directory for v1.26.0-alpha.3 release 2022-11-01 22:49:09 +00:00
cluster cluster: fix cloud-controller-manager.manifest to use priorityClassName instead of priorityClass 2022-11-04 19:35:39 -04:00
cmd Merge pull request #113747 from thockin/safer-controller-init-map 2022-11-08 12:43:25 -08:00
docs Make root approval non-recursive 2022-10-10 08:26:53 -04:00
hack Merge pull request #113314 from cici37/celIntegration 2022-11-07 17:08:33 -08:00
LICENSES Merge pull request #112988 from alexzielenski/update-kube-openapi 2022-10-14 17:31:29 -07:00
logo logo: better alignment of layers 2022-10-19 12:17:25 -07:00
pkg apiserver: finish implementation of borrowing in APF 2022-11-08 21:51:44 -08:00
plugin Deflake limitrange singleflight test 2022-11-08 09:28:21 -05:00
staging apiserver: finish implementation of borrowing in APF 2022-11-08 21:51:44 -08:00
test apiserver: finish implementation of borrowing in APF 2022-11-08 21:51:44 -08:00
third_party Make root approval non-recursive 2022-10-10 08:26:53 -04:00
vendor Merge pull request #113577 from pacoxu/prometheus-client 2022-11-08 12:42:49 -08:00
.generated_files remove clearly unnecessary lingering BUILD file references 2022-10-04 16:47:25 -07:00
.gitattributes
.gitignore Remove refs to .make 2022-10-04 08:58:52 -07:00
.golangci.yaml hack/tools enable additional linter in golangci-lint 2022-10-21 17:58:15 +02:00
CHANGELOG.md
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CONTRIBUTING.md
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SUPPORT.md Update SUPPORT.md 2022-06-27 16:58:44 +02:00

Kubernetes (K8s)

CII Best Practices


Kubernetes, also known as K8s, is an open source system for managing containerized applications across multiple hosts. It provides basic mechanisms for deployment, maintenance, and scaling of applications.

Kubernetes builds upon a decade and a half of experience at Google running production workloads at scale using a system called Borg, combined with best-of-breed ideas and practices from the community.

Kubernetes is hosted by the Cloud Native Computing Foundation (CNCF). If your company wants to help shape the evolution of technologies that are container-packaged, dynamically scheduled, and microservices-oriented, consider joining the CNCF. For details about who's involved and how Kubernetes plays a role, read the CNCF announcement.


To start using K8s

See our documentation on kubernetes.io.

Try our interactive tutorial.

Take a free course on Scalable Microservices with Kubernetes.

To use Kubernetes code as a library in other applications, see the list of published components. Use of the k8s.io/kubernetes module or k8s.io/kubernetes/... packages as libraries is not supported.

To start developing K8s

The community repository hosts all information about building Kubernetes from source, how to contribute code and documentation, who to contact about what, etc.

If you want to build Kubernetes right away there are two options:

You have a working Go environment.
mkdir -p $GOPATH/src/k8s.io
cd $GOPATH/src/k8s.io
git clone https://github.com/kubernetes/kubernetes
cd kubernetes
make
You have a working Docker environment.
git clone https://github.com/kubernetes/kubernetes
cd kubernetes
make quick-release

For the full story, head over to the developer's documentation.

Support

If you need support, start with the troubleshooting guide, and work your way through the process that we've outlined.

That said, if you have questions, reach out to us one way or another.

Community Meetings

The Calendar has the list of all the meetings in Kubernetes community in a single location.

Adopters

The User Case Studies website has real-world use cases of organizations across industries that are deploying/migrating to Kubernetes.

Governance

Kubernetes project is governed by a framework of principles, values, policies and processes to help our community and constituents towards our shared goals.

The Kubernetes Community is the launching point for learning about how we organize ourselves.

The Kubernetes Steering community repo is used by the Kubernetes Steering Committee, which oversees governance of the Kubernetes project.

Roadmap

The Kubernetes Enhancements repo provides information about Kubernetes releases, as well as feature tracking and backlogs.