Rename multi cluster kep (kep-0008) so it has an .md extension, not yaml.

Add Proposals for changes to `TestSuite` to support configuring multiple kind clusters for multi-cluster tests.

Author: Miles-Garnsey

keps/0008-multi-cluster.yaml renamed to keps/0008-multi-cluster.md

@@ -4,10 +4,12 @@ short-desc: This KEP describes how we will support more than one cluster under t
 title: KUTTL Mult-Cluster Support
 authors:
   - "@jbarrick-mesosphere"
+  - "miles-Garnsey"
 owners:
   - "@jbarrick-mesosphere"
+  - "miles-Garnsey"
 creation-date: 2021-01-08
-last-updated: 2021-01-08
+last-updated: 2022-03-09
 status: provisional
 ---
 
@@ -32,8 +34,61 @@ Currently, KUTTL only supports a single test cluster. This KEP describes how we
 
 * Support applying resources across more than one test cluster.
 * Support asserting on resources across more than one test cluster.
+* Support configuring more than one cluster for testing (KinD initially).
 
-## Proposal
+## Proposal - cluster configuration and TestSuite changes
+
+We propose to add additional fields to the `TestSuite` API to configure the clusters that the tests will run on. 
+
+In the struct `TestSuite`:
+
+```
+// Config for multiple clusters.
+	MultiClusterConfig MultiClusterConfig `json:"multiClusterConfig"`
+```
+
+The definition for `MultiClusterConfig` and associated supporting API elements:
+
+```
+//KindConfig contains settings for a single kind cluster.
+type KindConfig struct {
+	// Whether or not to start a local kind cluster for the tests.
+	StartKIND bool `json:"startKIND"`
+	// Path to the KIND configuration file to use.
+	KINDConfig string `json:"kindConfig"`
+	// KIND context to use.
+	KINDContext string `json:"kindContext"`
+	// If set, each node defined in the kind configuration will have a docker named volume mounted into it to persist
+	// pulled container images across test runs.
+	KINDNodeCache bool `json:"kindNodeCache"`
+	// Containers to load to each KIND node prior to running the tests.
+	KINDContainers []string `json:"kindContainers"`
+	// If set, do not delete the resources after running the tests (implies SkipClusterDelete).
+	SkipDelete bool `json:"skipDelete"`
+	// If set, do not delete the mocked control plane or kind cluster.
+	SkipClusterDelete bool `json:"skipClusterDelete"`
+}
+type MapKindConfig map[string]KindConfig
+type MultiClusterConfig struct {
+	// Type of cluster, KinD, external, etc.
+	ClusterType      string     `json:"globalKindConfig,omitempty"`
+	// Number of clusters to create from a global cluster spec.
+	NumClusters      *int       `json:"numClusters,omitempty"`
+	// Global config for kind clusters
+	GlobalKindConfig KindConfig `json:"globalKindConfig,omitempty"`
+	// Map of configurations for individual kind clusters.
+	MapKindConfig    `json:",inline,omitempty"`
+}
+```
+
+The objectives of the above structs are as follows:
+
+1. Allow for different kinds of clusters to be used as specified by `ClusterType` (only KinD implemented initially).
+2. Allow these clusters to be configured either at a global level (via `GlobalKindConfig` and a `NumClusters` parameter), or individually via MapKindConfig.
+3. Leave latitude for the addition of other cluster types at a later time.
+4. Provide the interface already present in the API for configuring the kind clusters, but encapsulate it in `KindConfig`.
+
+## Proposal - teststep
 
 The proposal is to add a new setting to the `TestStep` object: `kubeconfig`. This setting would allow the user to specify an alternative kubeconfig path to use for a given test step.