217513e27a
Automatic merge from submit-queue Remove null -> [] slice hack Closes #44593 When 1.6 added protobuf storage, the storage layer lost the ability to persist slice fields with empty but non-null values. As a workaround, we tried to convert empty slice fields to `[]`, rather than `null`. Compressing `null` -> `[]` was just as much of an API breakage as `[]` -> `null`, but was hoped to cause fewer problems in clients that don't do null checks. Because of conversion optimizations around converting lists of objects, the `null` -> `[]` hack was discovered to only apply to individual get requests, not to a list of objects. 1.6 and 1.7 was released with this behavior, and the world didn't explode. 1.7 documented the breaking API change that `null` and `[]` should be considered equivalent, unless otherwise noted on a particular field. This PR: * Reverts the earlier attempt (https://github.com/kubernetes/kubernetes/pull/43422) at ensuring non-null json slice output in conversion * Makes results of `get` consistent with the results of `list` (which helps naive clients that do deepequal comparisons of objects obtained via list/watch and get), and allows empty slice fields to be returned as `null` ```release-note Protobuf serialization does not distinguish between `[]` and `null`. API fields previously capable of storing and returning either `[]` and `null` via JSON API requests (for example, the Endpoints `subsets` field) can now store only `null` when created using the protobuf content-type or stored in etcd using protobuf serialization (the default in 1.6+). JSON API clients should tolerate `null` values for such fields, and treat `null` and `[]` as equivalent in meaning unless specifically documented otherwise for a particular field. ```
Cluster Federation
Kubernetes Cluster Federation enables users to federate multiple Kubernetes clusters. Please see the user guide and the admin guide for more details about setting up and using the Cluster Federation.
Building Kubernetes Cluster Federation
Please see the Kubernetes Development Guide
for initial setup. Once you have the development environment setup
as explained in that guide, you also need to install jq
Building cluster federation artifacts should be as simple as running:
make build
You can specify the docker registry to tag the image using the KUBE_REGISTRY environment variable. Please make sure that you use the same value in all the subsequent commands.
To push the built docker images to the registry, run:
make push
To initialize the deployment run:
(This pulls the installer images)
make init
To deploy the clusters and install the federation components, edit the
${KUBE_ROOT}/_output/federation/config.json file to describe your
clusters and run:
make deploy
To turn down the federation components and tear down the clusters run:
make destroy
Ideas for improvement
-
Continue with
destroyphase even in the face of errors.The bash script sets
set -e errexitwhich causes the script to exit at the very first error. This should be the default mode for deploying components but not for destroying/cleanup.