[Feature] OptionalReplace Upgrade Mode

CHANGELOG.md

@@ -15,6 +15,7 @@
 - (Feature) (Platform) Enable HTTP to HTTPS Redirect
 - (Bugfix) (Platform) Fix NoAuth Mode
 - (Feature) Define OptionalReplace Upgrade Mode option
+- (Feature) OptionalReplace Upgrade Mode
 
 ## [1.2.50](https://github.com/arangodb/kube-arangodb/tree/1.2.50) (2025-07-04)
 - (Feature) (Platform) MetaV1 Integration Service

pkg/deployment/reconcile/action_compact_member.go

@@ -54,7 +54,7 @@ func (a *actionCompactMember) Start(ctx context.Context) (bool, error) {
 	}
 
 	switch g {
-	case api.ServerGroupDBServers:
+	case api.ServerGroupDBServers, api.ServerGroupSingle:
 		dbc, err := a.actionCtx.GetServerAsyncClient(m.ID)
 		if err != nil {
 			return false, errors.Wrapf(err, "Unable to create client")
@@ -91,7 +91,7 @@ func (a actionCompactMember) CheckProgress(ctx context.Context) (bool, bool, err
 	}
 
 	switch g {
-	case api.ServerGroupDBServers:
+	case api.ServerGroupDBServers, api.ServerGroupSingle:
 		dbc, err := a.actionCtx.GetServerAsyncClient(m.ID)
 		if err != nil {
 			return false, false, errors.Wrapf(err, "Unable to create client")

pkg/deployment/reconcile/plan_builder_rotate_upgrade.go

@@ -287,6 +287,11 @@ func (r *Reconciler) createUpgradePlanInternal(apiObject k8sutil.APIObject, spec
 				return nil, false
 			}
 
+			if m.Member.Conditions.IsTrue(api.ConditionTypeMarkedToRemove) {
+				// Server is supposed to be removed, lets not continue
+				return nil, false
+			}
+
 			if decision.AreGroupsPendingUpgrade(upgradeOrder[:id]...) {
 				// Not all members before were upgraded
 				return nil, false
@@ -313,20 +318,19 @@ func (r *Reconciler) createUpgradePlanInternal(apiObject k8sutil.APIObject, spec
 				switch group {
 				case api.ServerGroupDBServers:
 					// Members are supposed to be replaced
-					if !m.Member.Conditions.IsTrue(api.ConditionTypeMarkedToRemove) {
-						return api.Plan{actions.NewAction(api.ActionTypeMarkToRemoveMember, m.Group, m.Member, "Replace by Upgrade")}, false
-					}
-					return nil, false
+					return api.Plan{actions.NewAction(api.ActionTypeMarkToRemoveMember, m.Group, m.Member, "Replace by Upgrade")}, false
 				}
 			}
 
+			compact := um.Get() == api.ServerGroupUpgradeModeOptionalReplace
+
 			if d.updateAllowed {
 				// We are fine, group is alive so we can proceed
 				r.planLogger.Str("member", m.Member.ID).Str("Reason", d.updateMessage).Info("Upgrade allowed")
-				return r.createUpgradeMemberPlan(m.Member, m.Group, "Version upgrade", spec, status, !d.upgradeDecision.AutoUpgradeNeeded, agencyCache), false
+				return r.createUpgradeMemberPlan(m.Member, m.Group, "Version upgrade", spec, status, !d.upgradeDecision.AutoUpgradeNeeded, compact, agencyCache), false
 			} else if d.unsafeUpdateAllowed {
 				r.planLogger.Str("member", m.Member.ID).Str("Reason", d.updateMessage).Info("Pod needs upgrade but cluster is not ready. Either some shards are not in sync or some member is not ready, but unsafe upgrade is allowed")
-				return r.createUpgradeMemberPlan(m.Member, m.Group, "Version upgrade", spec, status, !d.upgradeDecision.AutoUpgradeNeeded, agencyCache), false
+				return r.createUpgradeMemberPlan(m.Member, m.Group, "Version upgrade", spec, status, !d.upgradeDecision.AutoUpgradeNeeded, compact, agencyCache), false
 			} else {
 				r.planLogger.Str("member", m.Member.ID).Str("Reason", d.updateMessage).Info("Pod needs upgrade but cluster is not ready. Either some shards are not in sync or some member is not ready.")
 				return nil, true
@@ -596,7 +600,7 @@ func (r *Reconciler) createMemberAllowUpgradeConditionPlan(ctx context.Context,
 // createUpgradeMemberPlan creates a plan to upgrade (stop-recreateWithAutoUpgrade-stop-start) an existing
 // member.
 func (r *Reconciler) createUpgradeMemberPlan(member api.MemberStatus,
-	group api.ServerGroup, reason string, spec api.DeploymentSpec, status api.DeploymentStatus, rotateStatefull bool, agencyCache state.State) api.Plan {
+	group api.ServerGroup, reason string, spec api.DeploymentSpec, status api.DeploymentStatus, rotateStatefull, compact bool, agencyCache state.State) api.Plan {
 	upgradeAction := api.ActionTypeUpgradeMember
 	if rotateStatefull || group.IsStateless() {
 		upgradeAction = api.ActionTypeRotateMember
@@ -608,7 +612,7 @@ func (r *Reconciler) createUpgradeMemberPlan(member api.MemberStatus,
 		Str("action", string(upgradeAction)).
 		Info("Creating upgrade plan")
 
-	plan := createRotateMemberPlanWithAction(member, group, upgradeAction, spec, reason, util.CheckConditionalP1Nil(agencyCache.GetRebootID, state.Server(member.ID)))
+	plan := createRotateMemberPlanWithAction(member, group, upgradeAction, spec, reason, util.CheckConditionalP1Nil(agencyCache.GetRebootID, state.Server(member.ID)), compact)
 
 	if member.Image == nil || member.Image.Image != spec.GetImage() {
 		plan = plan.Before(actions.NewAction(api.ActionTypeSetMemberCurrentImage, group, member, reason).SetImage(spec.GetImage()))

pkg/deployment/reconcile/plan_builder_utils.go

@@ -37,19 +37,25 @@ func (r *Reconciler) createRotateMemberPlan(member api.MemberStatus,
 		Str("role", group.AsRole()).
 		Str("reason", reason).
 		Debug("Creating rotation plan")
-	return createRotateMemberPlanWithAction(member, group, api.ActionTypeRotateMember, spec, reason, rebootId)
+	return createRotateMemberPlanWithAction(member, group, api.ActionTypeRotateMember, spec, reason, rebootId, false)
 }
 
 // createRotateMemberPlanWithAction creates a plan to rotate (stop-<action>>-start) an existing
 // member.
 func createRotateMemberPlanWithAction(member api.MemberStatus,
-	group api.ServerGroup, action api.ActionType, spec api.DeploymentSpec, reason string, rebootId *int) api.Plan {
+	group api.ServerGroup, action api.ActionType, spec api.DeploymentSpec, reason string, rebootId *int, compact bool) api.Plan {
 
 	var plan = api.Plan{
 		actions.NewAction(api.ActionTypeCleanTLSKeyfileCertificate, group, member, "Remove server keyfile and enforce renewal/recreation"),
 	}
 	plan = withSecureWrap(member, group, spec, rebootId, plan...)
 
+	if compact {
+		plan = plan.After(
+			actions.NewAction(api.ActionTypeCompactMember, group, member, reason),
+		)
+	}
+
 	plan = plan.After(
 		actions.NewAction(api.ActionTypeKillMemberPod, group, member, reason),
 		actions.NewAction(action, group, member, reason),

pkg/deployment/resources/pod_creator_arangod.go

@@ -638,6 +638,13 @@ func (a *ArangoUpgradeContainer) GetCommand() ([]string, error) {
 		pod.UpgradeDebug().Args(a.input).Sort().AsArgs()...,
 	)
 
+	if a.input.Group == api.ServerGroupDBServers || a.input.Group == api.ServerGroupSingle {
+		if a.input.GroupSpec.UpgradeMode.Get() == api.ServerGroupUpgradeModeOptionalReplace ||
+			(a.input.GroupSpec.UpgradeMode.Get() == api.ServerGroupUpgradeModeManual && a.input.GroupSpec.ManualUpgradeMode.Get() == api.ServerGroupUpgradeModeOptionalReplace) {
+			upgradeArgs = append(upgradeArgs, "--database.auto-upgrade-full-compaction")
+		}
+	}
+
 	return append(args, upgradeArgs...), nil
 }
 

pkg/deployment/resources/pod_inspector.go

@@ -23,6 +23,7 @@ package resources
 import (
 	"context"
 	"fmt"
+	"slices"
 	goStrings "strings"
 	"time"
 
@@ -136,13 +137,24 @@ func (r *Resources) InspectPods(ctx context.Context, cachedStatus inspectorInter
 							switch containers[id] {
 							case api.ServerGroupReservedInitContainerNameVersionCheck:
 								if c, ok := kresources.GetAnyContainerStatusByName(pod.Status.InitContainerStatuses, containers[id]); ok {
-									if t := c.State.Terminated; t != nil && t.ExitCode == 11 {
+									if t := c.State.Terminated; t != nil && t.ExitCode == constants.ArangoDBExitCodeUpgradeRequired {
 										memberStatus.Upgrade = true
 										updateMemberStatusNeeded = true
 									}
 								}
 							case api.ServerGroupReservedInitContainerNameUpgrade:
 								memberStatus.Conditions.Update(api.ConditionTypeUpgradeFailed, true, "Upgrade Failed", "")
+								if group == api.ServerGroupDBServers {
+									if c, ok := kresources.GetAnyContainerStatusByName(pod.Status.InitContainerStatuses, containers[id]); ok {
+										if t := c.State.Terminated; t != nil && slices.Contains([]int32{
+											constants.ArangoDBExitCodeUpgradeFailedCompaction,
+											//constants.ContainerExitCodeSegmentationFault, // Also in case of Segv
+											constants.ArangoDBExitCodeInvalidArgument, // If Arg is not known
+										}, t.ExitCode) {
+											memberStatus.Conditions.Update(api.ConditionTypeMarkedToRemove, true, "Replace Required due to the mismatch", "")
+										}
+									}
+								}
 							}
 						}
 					}

pkg/util/constants/adb_codes.go

@@ -0,0 +1,29 @@
+//
+// DISCLAIMER
+//
+// Copyright 2025 ArangoDB GmbH, Cologne, Germany
+//
+// 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.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+
+package constants
+
+const (
+	ArangoDBExitCodeInvalidArgument         = 3
+	ArangoDBExitCodeUpgradeRequired         = 11
+	ArangoDBExitCodeUpgradeFailedCompaction = 30
+
+	ContainerExitCodeSegmentationFault = 139
+)