Adds command and client for the clusterctl alpha rollout undo

for MachineDeployment.

Author: Arvinderpal

cmd/clusterctl/client/alpha/rollout.go

@@ -30,6 +30,7 @@ type Rollout interface {
 	ObjectRestarter(cluster.Proxy, util.ResourceTuple, string) error
 	ObjectPauser(cluster.Proxy, util.ResourceTuple, string) error
 	ObjectResumer(cluster.Proxy, util.ResourceTuple, string) error
+	ObjectRollbacker(cluster.Proxy, util.ResourceTuple, string, int64) error
 }
 
 var _ Rollout = &rollout{}

cmd/clusterctl/client/alpha/rollout_rollbacker.go

@@ -0,0 +1,171 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package alpha
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
+	clusterv1 "sigs.k8s.io/cluster-api/api/v1alpha4"
+	"sigs.k8s.io/cluster-api/cmd/clusterctl/client/cluster"
+	"sigs.k8s.io/cluster-api/cmd/clusterctl/internal/util"
+	logf "sigs.k8s.io/cluster-api/cmd/clusterctl/log"
+	"sigs.k8s.io/cluster-api/controllers/mdutil"
+	"sigs.k8s.io/cluster-api/util/patch"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+// ObjectRollbacker will issue a rollback on the specified cluster-api resource.
+func (r *rollout) ObjectRollbacker(proxy cluster.Proxy, tuple util.ResourceTuple, namespace string, toRevision int64) error {
+	switch tuple.Resource {
+	case "machinedeployment":
+		deployment, err := getMachineDeployment(proxy, tuple.Name, namespace)
+		if err != nil || deployment == nil {
+			return errors.Wrapf(err, "failed to fetch %v/%v", tuple.Resource, tuple.Name)
+		}
+		if deployment.Spec.Paused {
+			return errors.Errorf("can't rollback a paused MachineDeployment (run rollout resume first): %v/%v\n", tuple.Resource, tuple.Name)
+		}
+		if err := rollbackMachineDeployment(proxy, deployment, tuple.Name, namespace, toRevision); err != nil {
+			return err
+		}
+	default:
+		return errors.Errorf("invalid resource type %q, valid values are %v", tuple.Resource, validResourceTypes)
+	}
+	return nil
+}
+
+// rollbackMachineDeployment will rollback to a previous MachineSet revision used by this MachineDeployment.
+func rollbackMachineDeployment(proxy cluster.Proxy, d *clusterv1.MachineDeployment, name, namespace string, toRevision int64) error {
+	log := logf.Log
+	c, err := proxy.NewClient()
+	if err != nil {
+		return err
+	}
+
+	if toRevision < 0 {
+		return errors.Errorf("revision number cannot be negative: %v", toRevision)
+	}
+	msList, err := getMachineSetsForDeployment(proxy, d)
+	if err != nil {
+		return err
+	}
+	log.V(7).Info("Found MachineSets", "count", len(msList))
+	msForRevision, err := findMachineDeploymentRevision(toRevision, msList)
+	if err != nil {
+		return err
+	}
+	log.V(7).Info("Found revision", "revision", msForRevision)
+	patchHelper, err := patch.NewHelper(d, c)
+	if err != nil {
+		return err
+	}
+	// Copy template into the machinedeployment (excluding the hash)
+	revMSTemplate := *msForRevision.Spec.Template.DeepCopy()
+	delete(revMSTemplate.Labels, mdutil.DefaultMachineDeploymentUniqueLabelKey)
+
+	d.Spec.Template = revMSTemplate
+	return patchHelper.Patch(context.TODO(), d)
+}
+
+// findMachineDeploymentRevision finds the specific revision in the machine sets
+func findMachineDeploymentRevision(toRevision int64, allMSs []*clusterv1.MachineSet) (*clusterv1.MachineSet, error) {
+
+	var (
+		latestMachineSet   *clusterv1.MachineSet
+		latestRevision     = int64(-1)
+		previousMachineSet *clusterv1.MachineSet
+		previousRevision   = int64(-1)
+	)
+	for _, ms := range allMSs {
+		if v, err := mdutil.Revision(ms); err == nil {
+			if toRevision == 0 {
+				if latestRevision < v {
+					// newest one we've seen so far
+					previousRevision = latestRevision
+					previousMachineSet = latestMachineSet
+					latestRevision = v
+					latestMachineSet = ms
+				} else if previousRevision < v {
+					// second newest one we've seen so far
+					previousRevision = v
+					previousMachineSet = ms
+				}
+			} else if toRevision == v {
+				return ms, nil
+			}
+		}
+	}
+
+	if toRevision > 0 {
+		return nil, errors.Errorf("unable to find specified revision: %v", toRevision)
+	}
+
+	if previousMachineSet == nil {
+		return nil, errors.Errorf("no rollout history found")
+	}
+	return previousMachineSet, nil
+
+}
+
+// getMachineSetsForDeployment returns a list of MachineSets associated with a MachineDeployment.
+func getMachineSetsForDeployment(proxy cluster.Proxy, d *clusterv1.MachineDeployment) ([]*clusterv1.MachineSet, error) {
+	log := logf.Log
+	c, err := proxy.NewClient()
+	if err != nil {
+		return nil, err
+	}
+	// List all MachineSets to find those we own but that no longer match our selector.
+	machineSets := &clusterv1.MachineSetList{}
+	if err := c.List(context.TODO(), machineSets, client.InNamespace(d.Namespace)); err != nil {
+		return nil, err
+	}
+
+	filtered := make([]*clusterv1.MachineSet, 0, len(machineSets.Items))
+	for idx := range machineSets.Items {
+		ms := &machineSets.Items[idx]
+
+		selector, err := metav1.LabelSelectorAsSelector(&d.Spec.Selector)
+		if err != nil {
+			log.V(5).Info("Skipping MachineSet, failed to get label selector from spec selector", "machineset", ms.Name)
+			continue
+		}
+
+		// If a MachineDeployment with a nil or empty selector creeps in, it should match nothing, not everything.
+		if selector.Empty() {
+			log.V(5).Info("Skipping MachineSet as the selector is empty", "machineset", ms.Name)
+			continue
+		}
+
+		// Skip this MachineSet if selector does not matche
+		if !selector.Matches(labels.Set(ms.Labels)) {
+			log.V(5).Info("Skipping MachineSet, label mismatch", "machineset", ms.Name)
+			continue
+		}
+		// Skip this MachineSet if its controller ref is not pointing to this MachineDeployment
+		if !metav1.IsControlledBy(ms, d) {
+			log.V(5).Info("Skipping MachineSet, controller ref does not match MachineDeployment", "machineset", ms.Name)
+			continue
+		}
+
+		filtered = append(filtered, ms)
+	}
+
+	return filtered, nil
+}