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Kubernetes Submit Queue 9edf196c01 Merge pull request #67902 from liggitt/http2-buffers

Automatic merge from submit-queue (batch tested with PRs 67694, 64973, 67902). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Size http2 buffers to allow concurrent streams

http/2 requests from a given client multiplex over a single connection via streams, chopped up into frames.

The amount of data the client is allowed to send for a given stream and for the overall connection before acknowledgement is determined by the server's MaxUploadBufferPerStream and MaxUploadBufferPerConnection settings respectively, both defaulting to 1MB.

The number of concurrent streams a client is allowed to send over a single connection is determined by the server's MaxConcurrentStreams setting, defaulting to 250.

We observed a starvation issue with the kube aggregator's proxy client if handling of a POST through the aggregator to a backend server exceeded the 1MB buffer size AND the backend server required a second POST request through the aggregator to be handled before it could drain the first request's body.

Logically, if concurrent streams are allowed in a single connection, the connection buffer should be MaxUploadBufferPerStream*MaxConcurrentStreams to allow individual streams to make progress even when one stream is blocked.

This PR shrinks the `MaxUploadBufferPerStream` size to 256kb (which is still large enough to allow all the resources we saw in our test clusters to be sent in a single frame), and grows the MaxUploadBufferPerConnection to accomodate concurrent streams.

I'm also opening a golang issue, [reproducer](https://gist.github.com/liggitt/00239c99b4c148ac1b23e57f86b3af93), and fix for the defaults for this

```release-note
adjusted http/2 buffer sizes for apiservers to prevent starvation issues between concurrent streams
```

2018-08-28 07:21:21 -07:00

src

Merge pull request #67902 from liggitt/http2-buffers

2018-08-28 07:21:21 -07:00

BUILD

Run hack/update-bazel.sh

2018-06-22 16:22:57 -07:00

OWNERS

…

README.md

Add link to k8s.io/sample-controller

2017-10-19 15:46:36 +01:00

README.md

External Repository Staging Area

This directory is the staging area for packages that have been split to their own repository. The content here will be periodically published to respective top-level k8s.io repositories.

Repositories currently staged here:

The code in the staging/ directory is authoritative, i.e. the only copy of the code. You can directly modify such code.

Using staged repositories from Kubernetes code

Kubernetes code uses the repositories in this directory via symlinks in the vendor/k8s.io directory into this staging area. For example, when Kubernetes code imports a package from the k8s.io/client-go repository, that import is resolved to staging/src/k8s.io/client-go relative to the project root:

// pkg/example/some_code.go
package example

import (
  "k8s.io/client-go/dynamic" // resolves to staging/src/k8s.io/client-go/dynamic
)

Once the change-over to external repositories is complete, these repositories will actually be vendored from k8s.io/<package-name>.