Add feature flag for enforcing strictly increasing cluster state versions

Applies to `stor-server` config for both distributors and storage nodes.

Defaults to `false` for now.

3 files changed, 23 insertions, 4 deletions

diff --git a/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java b/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java
index 970597685da..5b144f5950a 100644
--- a/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java
+++ b/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java
@@ -84,6 +84,7 @@ public class TestProperties implements ModelContext.Properties, ModelContext.Fea
     private int persistenceThreadMaxFeedOpBatchSize = 1;
     private boolean logserverOtelCol = false;
     private boolean symmetricPutAndActivateReplicaSelection = false;
+    private boolean enforceStrictlyIncreasingClusterStateVersions = false;
 
     @Override public ModelContext.FeatureFlags featureFlags() { return this; }
     @Override public boolean multitenant() { return multitenant; }
@@ -142,6 +143,7 @@ public class TestProperties implements ModelContext.Properties, ModelContext.Fea
     @Override public int persistenceThreadMaxFeedOpBatchSize() { return persistenceThreadMaxFeedOpBatchSize; }
     @Override public boolean logserverOtelCol() { return logserverOtelCol; }
     @Override public boolean symmetricPutAndActivateReplicaSelection() { return symmetricPutAndActivateReplicaSelection; }
+    @Override public boolean enforceStrictlyIncreasingClusterStateVersions() { return enforceStrictlyIncreasingClusterStateVersions; }
 
     public TestProperties sharedStringRepoNoReclaim(boolean sharedStringRepoNoReclaim) {
         this.sharedStringRepoNoReclaim = sharedStringRepoNoReclaim;
@@ -382,6 +384,11 @@ public class TestProperties implements ModelContext.Properties, ModelContext.Fea
         return this;
     }
 
+    public TestProperties setEnforceStrictlyIncreasingClusterStateVersions(boolean enforce) {
+        this.enforceStrictlyIncreasingClusterStateVersions = enforce;
+        return this;
+    }
+
     public static class Spec implements ConfigServerSpec {
 
         private final String hostName;
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/content/DistributorCluster.java b/config-model/src/main/java/com/yahoo/vespa/model/content/DistributorCluster.java
index 1e35a94db59..f218cedb74e 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/content/DistributorCluster.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/content/DistributorCluster.java
@@ -36,6 +36,7 @@ public class DistributorCluster extends TreeConfigProducer<Distributor> implemen
     private final int maxActivationInhibitedOutOfSyncGroups;
     private final int contentLayerMetadataFeatureLevel;
     private final boolean symmetricPutAndActivateReplicaSelection;
+    private final boolean enforceStrictlyIncreasingClusterStateVersions;
 
     public static class Builder extends VespaDomBuilder.DomConfigProducerBuilderBase<DistributorCluster> {
 
@@ -100,13 +101,15 @@ public class DistributorCluster extends TreeConfigProducer<Distributor> implemen
             int maxInhibitedGroups = featureFlags.maxActivationInhibitedOutOfSyncGroups();
             int contentLayerMetadataFeatureLevel = featureFlags.contentLayerMetadataFeatureLevel();
             boolean symmetricPutAndActivateReplicaSelection = featureFlags.symmetricPutAndActivateReplicaSelection();
+            boolean enforceStrictlyIncreasingClusterStateVersions = featureFlags.enforceStrictlyIncreasingClusterStateVersions();
 
             return new DistributorCluster(parent,
                     new BucketSplitting.Builder().build(new ModelElement(producerSpec)), gc,
                     hasIndexedDocumentType,
                     maxInhibitedGroups,
                     contentLayerMetadataFeatureLevel,
-                    symmetricPutAndActivateReplicaSelection);
+                    symmetricPutAndActivateReplicaSelection,
+                    enforceStrictlyIncreasingClusterStateVersions);
         }
     }
 
@@ -114,7 +117,8 @@ public class DistributorCluster extends TreeConfigProducer<Distributor> implemen
                                GcOptions gc, boolean hasIndexedDocumentType,
                                int maxActivationInhibitedOutOfSyncGroups,
                                int contentLayerMetadataFeatureLevel,
-                               boolean symmetricPutAndActivateReplicaSelection)
+                               boolean symmetricPutAndActivateReplicaSelection,
+                               boolean enforceStrictlyIncreasingClusterStateVersions)
     {
         super(parent, "distributor");
         this.parent = parent;
@@ -124,6 +128,7 @@ public class DistributorCluster extends TreeConfigProducer<Distributor> implemen
         this.maxActivationInhibitedOutOfSyncGroups = maxActivationInhibitedOutOfSyncGroups;
         this.contentLayerMetadataFeatureLevel = contentLayerMetadataFeatureLevel;
         this.symmetricPutAndActivateReplicaSelection = symmetricPutAndActivateReplicaSelection;
+        this.enforceStrictlyIncreasingClusterStateVersions = enforceStrictlyIncreasingClusterStateVersions;
     }
 
     @Override
@@ -159,6 +164,7 @@ public class DistributorCluster extends TreeConfigProducer<Distributor> implemen
         builder.root_folder("");
         builder.cluster_name(parent.getName());
         builder.is_distributor(true);
+        builder.require_strictly_increasing_cluster_state_versions(enforceStrictlyIncreasingClusterStateVersions);
     }
 
     public String getClusterName() {
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/content/storagecluster/StorageCluster.java b/config-model/src/main/java/com/yahoo/vespa/model/content/storagecluster/StorageCluster.java
index 701da93a329..8bde038b160 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/content/storagecluster/StorageCluster.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/content/storagecluster/StorageCluster.java
@@ -31,13 +31,15 @@ public class StorageCluster extends TreeConfigProducer<StorageNode>
         protected StorageCluster doBuild(DeployState deployState, TreeConfigProducer<AnyConfigProducer> ancestor, Element producerSpec) {
             final ModelElement clusterElem = new ModelElement(producerSpec);
             final ContentCluster cluster = (ContentCluster)ancestor;
+            var featureFlags = deployState.getProperties().featureFlags();
 
             return new StorageCluster(ancestor,
                                       ContentCluster.getClusterId(clusterElem),
                                       new FileStorProducer.Builder().build(deployState.getProperties(), cluster, clusterElem),
                                       new StorServerProducer.Builder().build(deployState.getProperties(), clusterElem),
                                       new StorVisitorProducer.Builder().build(clusterElem),
-                                      new PersistenceProducer.Builder().build(clusterElem));
+                                      new PersistenceProducer.Builder().build(clusterElem),
+                                      featureFlags.enforceStrictlyIncreasingClusterStateVersions());
         }
     }
 
@@ -46,19 +48,22 @@ public class StorageCluster extends TreeConfigProducer<StorageNode>
     private final StorServerProducer storServerProducer;
     private final StorVisitorProducer storVisitorProducer;
     private final PersistenceProducer persistenceProducer;
+    private final boolean enforceStrictlyIncreasingClusterStateVersions;
 
     StorageCluster(TreeConfigProducer<?> parent,
                    String clusterName,
                    FileStorProducer fileStorProducer,
                    StorServerProducer storServerProducer,
                    StorVisitorProducer storVisitorProducer,
-                   PersistenceProducer persistenceProducer) {
+                   PersistenceProducer persistenceProducer,
+                   boolean enforceStrictlyIncreasingClusterStateVersions) {
         super(parent, "storage");
         this.clusterName = clusterName;
         this.fileStorProducer = fileStorProducer;
         this.storServerProducer = storServerProducer;
         this.storVisitorProducer = storVisitorProducer;
         this.persistenceProducer = persistenceProducer;
+        this.enforceStrictlyIncreasingClusterStateVersions = enforceStrictlyIncreasingClusterStateVersions;
     }
 
     @Override
@@ -85,6 +90,7 @@ public class StorageCluster extends TreeConfigProducer<StorageNode>
     @Override
     public void getConfig(StorServerConfig.Builder builder) {
         storServerProducer.getConfig(builder);
+        builder.require_strictly_increasing_cluster_state_versions(enforceStrictlyIncreasingClusterStateVersions);
     }
 
     @Override