Merge pull request #630 from skriss/release-0.8

Backport PRs 625 & 626 to release-0.8

docs/faq.md

@@ -23,3 +23,16 @@ Examples of cases where Ark is useful:
 Yes, with some exceptions. For example, when Ark restores pods it deletes the `nodeName` from the
 pod so that it can be scheduled onto a new node. You can see some more examples of the differences
 in [pod_action.go](https://github.com/heptio/ark/blob/master/pkg/restore/pod_action.go)
+
+## I'm using Ark in multiple clusters. Should I use the same bucket to store all of my backups?
+
+We **strongly** recommend that you use a separate bucket per cluster to store backups. Sharing a bucket
+across multiple Ark instances can lead to numerous problems - failed backups, overwritten backups,
+inadvertently deleted backups, etc., all of which can be avoided by using a separate bucket per Ark
+instance.
+
+Related to this, if you need to restore a backup from cluster A into cluster B, please use [restore-only][1]
+mode in cluster B's Ark instance while it's configured to use cluster A's bucket. This will ensure no 
+new backups are created, and no existing backups are deleted or overwritten.
+
+[1]: config-definition.md#main-config-parameters

pkg/controller/restore_controller.go

@@ -51,7 +51,19 @@ import (
 
 // nonRestorableResources is a blacklist for the restoration process. Any resources
 // included here are explicitly excluded from the restoration process.
-var nonRestorableResources = []string{"nodes", "events", "events.events.k8s.io"}
+var nonRestorableResources = []string{
+	"nodes",
+	"events",
+	"events.events.k8s.io",
+
+	// Don't ever restore backups - if appropriate, they'll be synced in from object storage.
+	// https://github.com/heptio/ark/issues/622
+	"backups.ark.heptio.com",
+
+	// Restores are cluster-specific, and don't have value moving across clusters.
+	// https://github.com/heptio/ark/issues/622
+	"restores.ark.heptio.com",
+}
 
 type restoreController struct {
 	namespace           string

pkg/controller/restore_controller_test.go

@@ -255,6 +255,28 @@ func TestProcessRestore(t *testing.T) {
 				"Invalid included/excluded resource lists: excludes list cannot contain an item in the includes list: events.events.k8s.io",
 			},
 		},
+		{
+			name:          "restoration of backups.ark.heptio.com is not supported",
+			restore:       NewRestore("foo", "bar", "backup-1", "ns-1", "backups.ark.heptio.com", api.RestorePhaseNew).Restore,
+			backup:        arktest.NewTestBackup().WithName("backup-1").Backup,
+			expectedErr:   false,
+			expectedPhase: string(api.RestorePhaseFailedValidation),
+			expectedValidationErrors: []string{
+				"backups.ark.heptio.com are non-restorable resources",
+				"Invalid included/excluded resource lists: excludes list cannot contain an item in the includes list: backups.ark.heptio.com",
+			},
+		},
+		{
+			name:          "restoration of restores.ark.heptio.com is not supported",
+			restore:       NewRestore("foo", "bar", "backup-1", "ns-1", "restores.ark.heptio.com", api.RestorePhaseNew).Restore,
+			backup:        arktest.NewTestBackup().WithName("backup-1").Backup,
+			expectedErr:   false,
+			expectedPhase: string(api.RestorePhaseFailedValidation),
+			expectedValidationErrors: []string{
+				"restores.ark.heptio.com are non-restorable resources",
+				"Invalid included/excluded resource lists: excludes list cannot contain an item in the includes list: restores.ark.heptio.com",
+			},
+		},
 	}
 
 	for _, test := range tests {