55ec09d377
There was a data race in the recordToSink function that caused changes
to the events cache to be overriden if events were emitted
simultaneously via Eventf calls.
The race lies in the fact that when recording an Event, there might be
multiple calls updating the cache simultaneously. The lock period is
optimized so that after updating the cache with the new Event, the lock
is unlocked until the Event is recorded on the apiserver side and then
the cache is locked again to be updated with the new value returned by
the apiserver.
The are a few problem with the approach:
1. If two identical Events are emitted successively the changes of the
second Event will override the first one. In code the following
happen:
1. Eventf(ev1)
2. Eventf(ev2)
3. Lock cache
4. Set cache[getKey(ev1)] = &ev1
5. Unlock cache
6. Lock cache
7. Update cache[getKey(ev2)] = &ev1 + Series{Count: 1}
8. Unlock cache
9. Start attempting to record the first event &ev1 on the apiserver side.
This can be mitigated by recording a copy of the Event stored in
cache instead of reusing the pointer from the cache.
2. When the Event has been recorded on the apiserver the cache is
updated again with the value of the Event returned by the server.
This update will override any changes made to the cache entry when
attempting to record the new Event since the cache was unlocked at
that time. This might lead to some inconsistencies when dealing with
EventSeries since the count may be overriden or the client might even
try to record the first isomorphic Event multiple time.
This could be mitigated with a lock that has a larger scope, but we
shouldn't want to reflect Event returned by the apiserver in the
cache in the first place since mutation could mess with the
aggregation by either allowing users to manipulate values to update
a different cache entry or even having two cache entries for the same
Events.
Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>
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| cmd | ||
| docs | ||
| hack | ||
| LICENSES | ||
| logo | ||
| pkg | ||
| plugin | ||
| staging | ||
| test | ||
| third_party | ||
| vendor | ||
| .generated_files | ||
| .gitattributes | ||
| .gitignore | ||
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| code-of-conduct.md | ||
| CONTRIBUTING.md | ||
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| Makefile | ||
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| OWNERS | ||
| OWNERS_ALIASES | ||
| README.md | ||
| SECURITY_CONTACTS | ||
| SUPPORT.md | ||
Kubernetes (K8s)
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.