v4.0.0-alpha.0

This is the first git tag since September. The following is a highlight of what we've done over the past months.

Operator status

A lot of work went into having the operator correctly report available/progressing/failing, we track the versions of our sub-components (the MCC and MCD) and further we are now marked as a required operator in the release payload. This ensures that the CVO will watch our status.

OS updates

#183 was fixed - the MCO now handles operating system updates of machine-os-content which comes from the release payload.

Transient failure handling

We've significantly reduced the amount of calls the MCD makes to the apiserver that can happen to fail if the api server is temporarily down. We keep working on re-trying errors that are truly transient.

Testing

A lot of work went into unit tests, and we now have a "real" e2e test suite in addition to the unit tests that runs against a live cluster. We have even more work in flight for tests.

MCD reconciliation

The MCD now handles "reconciling" and applying changes to MachineConfigs in a much more robust way.

SSH

Enabled users post-install to set and update SSH Keys via a Machine Config.
The MCD now watches logind and will add an annotation that the node was accessed via SSH.

Ignition/MC enhancements

Added validation of Ignition configs coming from user submitted MachineConfigs to allow an easier transition to Ignition v3 e.g. no more MCs without an Igntion version set.

Sub-controllers: kubeletconfig, containerruntimeconfig

These allow configuring the kubelet and cri-o. They are "sub-controllers" that react to CRDs and generate MachineConfig objects.

Once-From

Allows users to run the MCD once using an Ignition config on a single machine not connected to a cluster, in order to update files, configs and, on RHCOS machines, update the OS.