Revert "Merge pull request #15581 from vespa-engine/revert-15578-bratseth/apply-on-restart-take-10"

This reverts commit 4cf13bc7db215e77f7688e429f700880c115fe76, reversing
changes made to e21f385bd4f21326608f3a69325df4e96d4a65e5.

19 files changed, 131 insertions, 46 deletions

diff --git a/config/src/main/java/com/yahoo/config/subscription/ConfigSubscriber.java b/config/src/main/java/com/yahoo/config/subscription/ConfigSubscriber.java
index 6bfaa992eb1..ad131f8e0dd 100644
--- a/config/src/main/java/com/yahoo/config/subscription/ConfigSubscriber.java
+++ b/config/src/main/java/com/yahoo/config/subscription/ConfigSubscriber.java
@@ -33,6 +33,7 @@ import static java.util.stream.Collectors.toList;
 public class ConfigSubscriber implements AutoCloseable {
 
     private static final Logger log = Logger.getLogger(ConfigSubscriber.class.getName());
+
     private State state = State.OPEN;
     protected final List<ConfigHandle<? extends ConfigInstance>> subscriptionHandles = new CopyOnWriteArrayList<>();
     private final ConfigSource source;
@@ -46,6 +47,13 @@ public class ConfigSubscriber implements AutoCloseable {
     private boolean internalRedeploy = false;
 
     /**
+     * Whether the last generation should only be applied on restart, not immediately.
+     * Once this is set it will not be unset, as no future generation should be applied
+     * once there is a generation which require restart.
+     */
+    private boolean applyOnRestart = false;
+
+    /**
      * Reuse requesters for equal source sets, limit number if many subscriptions.
      */
     protected Map<ConfigSourceSet, JRTConfigRequester> requesters = new HashMap<>();
@@ -235,12 +243,15 @@ public class ConfigSubscriber implements AutoCloseable {
      * @param timeoutInMillis timeout to wait in milliseconds
      * @param requireChange if set, at least one config have to change
      * @return true, if a new config generation has been found for all configs (additionally requires
-     *         that at lest one of them has changed if <code>requireChange</code> is true), false otherwise
+     *         that at lest one of them has changed if <code>requireChange</code> is true), and
+     *         the config should be applied at this time, false otherwise
      */
     private boolean acquireSnapshot(long timeoutInMillis, boolean requireChange) {
+        boolean applyOnRestartOnly;
         synchronized (monitor) {
             if (state == State.CLOSED) return false;
             state = State.FROZEN;
+            applyOnRestartOnly = applyOnRestart;
         }
         long started = System.currentTimeMillis();
         long timeLeftMillis = timeoutInMillis;
@@ -269,9 +280,18 @@ public class ConfigSubscriber implements AutoCloseable {
                 allGenerationsChanged &= config.isGenerationChanged();
                 anyConfigChanged      |= config.isConfigChanged();
                 internalRedeployOnly  &= config.isInternalRedeploy();
+                applyOnRestartOnly    |= requireChange && config.applyOnRestart(); // only if this is reconfig
                 timeLeftMillis = timeoutInMillis + started - System.currentTimeMillis();
             }
-            reconfigDue = (anyConfigChanged || !requireChange) && allGenerationsChanged && allGenerationsTheSame;
+            reconfigDue = ((anyConfigChanged && !applyOnRestartOnly) || !requireChange)
+                          && allGenerationsChanged && allGenerationsTheSame;
+
+            if (requireChange && applyOnRestartOnly) { // if this is a reconfig, disable future reconfigs until restart
+                synchronized (monitor) {
+                    applyOnRestart = applyOnRestartOnly;
+                }
+            }
+
             if (!reconfigDue && timeLeftMillis > 0) {
                 sleep(timeLeftMillis);
             }
diff --git a/config/src/main/java/com/yahoo/config/subscription/impl/ConfigSubscription.java b/config/src/main/java/com/yahoo/config/subscription/impl/ConfigSubscription.java
index 3bf6093e872..15f6395c417 100644
--- a/config/src/main/java/com/yahoo/config/subscription/impl/ConfigSubscription.java
+++ b/config/src/main/java/com/yahoo/config/subscription/impl/ConfigSubscription.java
@@ -40,21 +40,28 @@ public abstract class ConfigSubscription<T extends ConfigInstance> {
         private final T config;
         private final Long generation;
         private final boolean internalRedeploy;
-
-        private ConfigState(boolean generationChanged, Long generation, boolean internalRedeploy, boolean configChanged, T config) {
+        private final boolean applyOnRestart;
+
+        private ConfigState(boolean generationChanged,
+                            Long generation,
+                            boolean internalRedeploy,
+                            boolean applyOnRestart,
+                            boolean configChanged,
+                            T config) {
             this.generationChanged = generationChanged;
             this.generation = generation;
             this.internalRedeploy = internalRedeploy;
+            this.applyOnRestart = applyOnRestart;
             this.configChanged = configChanged;
             this.config = config;
         }
 
         private ConfigState(Long generation, T config) {
-            this(false, generation, false, false, config);
+            this(false, generation, false, false, false, config);
         }
 
         private ConfigState() {
-            this(false, 0L, false, false, null);
+            this(false, 0L, false, false, false, null);
         }
 
         private ConfigState<T> createUnchanged() { return new ConfigState<>(generation, config); }
@@ -68,6 +75,8 @@ public abstract class ConfigSubscription<T extends ConfigInstance> {
          */
         public boolean isInternalRedeploy() { return internalRedeploy; }
 
+        public boolean applyOnRestart() { return applyOnRestart; }
+
         public T getConfig() { return config; }
 
     }
@@ -181,29 +190,34 @@ public abstract class ConfigSubscription<T extends ConfigInstance> {
         return !prev.getGeneration().equals(requiredGen) || prev.isConfigChanged();
     }
 
-    void setConfig(Long generation, boolean internalRedeploy, T config) {
-        this.config.set(new ConfigState<>(true, generation, internalRedeploy, true, config));
+    void setConfig(Long generation, boolean internalRedeploy, boolean applyOnRestart, T config) {
+        this.config.set(new ConfigState<>(true, generation, internalRedeploy, applyOnRestart, true, config));
     }
 
     /** Used by {@link FileConfigSubscription} and {@link ConfigSetSubscription} */
     protected void setConfigIncGen(T config) {
         ConfigState<T> prev = this.config.get();
-        this.config.set(new ConfigState<>(true, prev.getGeneration() + 1, prev.isInternalRedeploy(), true, config));
+        this.config.set(new ConfigState<>(true, prev.getGeneration() + 1, prev.isInternalRedeploy(), prev.applyOnRestart(), true, config));
     }
 
     protected void setConfigIfChanged(T config) {
         ConfigState<T> prev = this.config.get();
-        this.config.set(new ConfigState<>(true, prev.getGeneration(), prev.isInternalRedeploy(), !config.equals(prev.getConfig()), config));
+        this.config.set(new ConfigState<>(true, prev.getGeneration(), prev.isInternalRedeploy(), prev.applyOnRestart(), !config.equals(prev.getConfig()), config));
     }
 
     void setGeneration(Long generation) {
         ConfigState<T> prev = config.get();
-        this.config.set(new ConfigState<>(true, generation, prev.isInternalRedeploy(), prev.isConfigChanged(), prev.getConfig()));
+        this.config.set(new ConfigState<>(true, generation, prev.isInternalRedeploy(), prev.applyOnRestart(), prev.isConfigChanged(), prev.getConfig()));
     }
 
     void setInternalRedeploy(boolean internalRedeploy) {
         ConfigState<T> prev = config.get();
-        this.config.set(new ConfigState<>(prev.isGenerationChanged(), prev.getGeneration(), internalRedeploy, prev.isConfigChanged(), prev.getConfig()));
+        this.config.set(new ConfigState<>(prev.isGenerationChanged(), prev.getGeneration(), internalRedeploy, prev.applyOnRestart(), prev.isConfigChanged(), prev.getConfig()));
+    }
+
+    void setApplyOnRestart(boolean applyOnRestart) {
+        ConfigState<T> prev = config.get();
+        this.config.set(new ConfigState<>(prev.isGenerationChanged(), prev.getGeneration(), prev.isInternalRedeploy(), applyOnRestart, prev.isConfigChanged(), prev.getConfig()));
     }
 
     /**
diff --git a/config/src/main/java/com/yahoo/config/subscription/impl/GenericJRTConfigSubscription.java b/config/src/main/java/com/yahoo/config/subscription/impl/GenericJRTConfigSubscription.java
index eec18b93e71..ba8fc8a5e19 100644
--- a/config/src/main/java/com/yahoo/config/subscription/impl/GenericJRTConfigSubscription.java
+++ b/config/src/main/java/com/yahoo/config/subscription/impl/GenericJRTConfigSubscription.java
@@ -18,7 +18,6 @@ import static java.util.logging.Level.FINE;
  * Used by config proxy.
  *
  * @author Vegard Havdal
- *
  */
 public class GenericJRTConfigSubscription extends JRTConfigSubscription<RawConfig> {
 
@@ -33,7 +32,7 @@ public class GenericJRTConfigSubscription extends JRTConfigSubscription<RawConfi
 
     @Override
     protected void setNewConfig(JRTClientConfigRequest jrtReq) {
-        setConfig(jrtReq.getNewGeneration(), jrtReq.responseIsInternalRedeploy(), RawConfig.createFromResponseParameters(jrtReq) );
+        setConfig(jrtReq.getNewGeneration(), jrtReq.responseIsInternalRedeploy(), jrtReq.responseIsApplyOnRestart(), RawConfig.createFromResponseParameters(jrtReq) );
         log.log(FINE, () -> "in setNewConfig, config=" + this.getConfigState().getConfig());
     }
 
@@ -60,6 +59,17 @@ public class GenericJRTConfigSubscription extends JRTConfigSubscription<RawConfi
         }
     }
 
+    // Override to propagate internal redeploy into the config value in addition to the config state
+    @Override
+    void setApplyOnRestart(boolean applyOnRestart) {
+        super.setApplyOnRestart(applyOnRestart);
+        ConfigState<RawConfig> configState = getConfigState();
+
+        if (configState.getConfig() != null) {
+            configState.getConfig().setApplyOnRestart(applyOnRestart);
+        }
+    }
+
     public RawConfig getRawConfig() {
         return getConfigState().getConfig();
     }
diff --git a/config/src/main/java/com/yahoo/config/subscription/impl/JRTConfigSubscription.java b/config/src/main/java/com/yahoo/config/subscription/impl/JRTConfigSubscription.java
index 44f6d65ee65..e9d5d317995 100644
--- a/config/src/main/java/com/yahoo/config/subscription/impl/JRTConfigSubscription.java
+++ b/config/src/main/java/com/yahoo/config/subscription/impl/JRTConfigSubscription.java
@@ -94,6 +94,7 @@ public class JRTConfigSubscription<T extends ConfigInstance> extends ConfigSubsc
         log.log(FINE, () -> "Polled queue and found config " + jrtReq);
         if (jrtReq.hasUpdatedGeneration()) {
             setInternalRedeploy(jrtReq.responseIsInternalRedeploy());
+            setApplyOnRestart(jrtReq.responseIsApplyOnRestart());
             if (jrtReq.hasUpdatedConfig()) {
                 setNewConfig(jrtReq);
             } else {
@@ -111,7 +112,7 @@ public class JRTConfigSubscription<T extends ConfigInstance> extends ConfigSubsc
         } catch (IllegalArgumentException e) {
             badConfigE = e;
         }
-        setConfig(jrtReq.getNewGeneration(), jrtReq.responseIsInternalRedeploy(), configInstance);
+        setConfig(jrtReq.getNewGeneration(), jrtReq.responseIsInternalRedeploy(), jrtReq.responseIsApplyOnRestart(), configInstance);
         if (badConfigE != null) {
             throw new IllegalArgumentException("Bad config from jrt", badConfigE);
         }
diff --git a/config/src/main/java/com/yahoo/config/subscription/impl/JarConfigSubscription.java b/config/src/main/java/com/yahoo/config/subscription/impl/JarConfigSubscription.java
index 05da9a72837..9fc5d9d3300 100644
--- a/config/src/main/java/com/yahoo/config/subscription/impl/JarConfigSubscription.java
+++ b/config/src/main/java/com/yahoo/config/subscription/impl/JarConfigSubscription.java
@@ -63,7 +63,7 @@ public class JarConfigSubscription<T extends ConfigInstance> extends ConfigSubsc
             } catch (IOException e) {
                 throw new ConfigurationRuntimeException(e);
             }
-            setConfig(0L, false, config);
+            setConfig(0L, false, false, config);
             try {
                 jarFile.close();
             } catch (IOException e) {
diff --git a/config/src/main/java/com/yahoo/config/subscription/impl/MockConnection.java b/config/src/main/java/com/yahoo/config/subscription/impl/MockConnection.java
index 58eed7f9e78..3a284489109 100644
--- a/config/src/main/java/com/yahoo/config/subscription/impl/MockConnection.java
+++ b/config/src/main/java/com/yahoo/config/subscription/impl/MockConnection.java
@@ -115,7 +115,7 @@ public class MockConnection implements ConnectionPool, com.yahoo.vespa.config.Co
             JRTServerConfigRequestV3 jrtReq = JRTServerConfigRequestV3.createFromRequest(request);
             Payload payload = Payload.from(ConfigPayload.empty());
             long generation = 1;
-            jrtReq.addOkResponse(payload, generation, false, ConfigUtils.getMd5(payload.getData()));
+            jrtReq.addOkResponse(payload, generation, false, false, ConfigUtils.getMd5(payload.getData()));
         }
 
     }
diff --git a/config/src/main/java/com/yahoo/config/subscription/impl/RawConfigSubscription.java b/config/src/main/java/com/yahoo/config/subscription/impl/RawConfigSubscription.java
index 68ff6bb0135..1ff0a058a93 100644
--- a/config/src/main/java/com/yahoo/config/subscription/impl/RawConfigSubscription.java
+++ b/config/src/main/java/com/yahoo/config/subscription/impl/RawConfigSubscription.java
@@ -35,7 +35,7 @@ public class RawConfigSubscription<T extends ConfigInstance> extends ConfigSubsc
         if (payload == null) {
             payload = inputPayload;
             ConfigPayload configPayload = new CfgConfigPayloadBuilder().deserialize(Arrays.asList(payload.split("\n")));
-            setConfig(0L, false, configPayload.toInstance(configClass, key.getConfigId()));
+            setConfig(0L, false, false, configPayload.toInstance(configClass, key.getConfigId()));
             return true;
         }
         try {
diff --git a/config/src/main/java/com/yahoo/vespa/config/ConfigPayload.java b/config/src/main/java/com/yahoo/vespa/config/ConfigPayload.java
index 2f3a4bd2172..8153179e49c 100644
--- a/config/src/main/java/com/yahoo/vespa/config/ConfigPayload.java
+++ b/config/src/main/java/com/yahoo/vespa/config/ConfigPayload.java
@@ -17,7 +17,7 @@ import java.io.IOException;
 import java.io.OutputStream;
 
 /**
- * A class that holds a representation of a config payload.
+ * A config payload.
  *
  * @author Ulf Lilleengen
  */
diff --git a/config/src/main/java/com/yahoo/vespa/config/ConfigPayloadApplier.java b/config/src/main/java/com/yahoo/vespa/config/ConfigPayloadApplier.java
index b4df42c802e..d24f09bda12 100644
--- a/config/src/main/java/com/yahoo/vespa/config/ConfigPayloadApplier.java
+++ b/config/src/main/java/com/yahoo/vespa/config/ConfigPayloadApplier.java
@@ -38,6 +38,7 @@ import static java.util.logging.Level.INFO;
  * @author Ulf Lilleengen, hmusum, Tony Vaagenes
  */
 public class ConfigPayloadApplier<T extends ConfigInstance.Builder> {
+
     private final static Logger log = Logger.getLogger(ConfigPayloadApplier.class.getPackage().getName());
 
     private final ConfigInstance.Builder rootBuilder;
diff --git a/config/src/main/java/com/yahoo/vespa/config/GenericConfig.java b/config/src/main/java/com/yahoo/vespa/config/GenericConfig.java
index 2f351cc2bd4..123d7c22093 100644
--- a/config/src/main/java/com/yahoo/vespa/config/GenericConfig.java
+++ b/config/src/main/java/com/yahoo/vespa/config/GenericConfig.java
@@ -12,6 +12,7 @@ import com.yahoo.config.ConfigInstance;
  * @author Ulf Lilleengen
  */
 public class GenericConfig {
+
     public static class GenericConfigBuilder implements ConfigInstance.Builder {
 
         private final ConfigPayloadBuilder payloadBuilder;
@@ -49,6 +50,7 @@ public class GenericConfig {
         public String getDefMd5() {
             return "";
         }
+
     }
 
 }
diff --git a/config/src/main/java/com/yahoo/vespa/config/RawConfig.java b/config/src/main/java/com/yahoo/vespa/config/RawConfig.java
index 96908f055f1..cf0f1243acf 100755
--- a/config/src/main/java/com/yahoo/vespa/config/RawConfig.java
+++ b/config/src/main/java/com/yahoo/vespa/config/RawConfig.java
@@ -32,6 +32,7 @@ public class RawConfig extends ConfigInstance {
     private final Optional<VespaVersion> vespaVersion;
     private long generation;
     private boolean internalRedeploy;
+    private boolean applyOnRestart;
 
     /**
      * Constructor for an empty config (not yet resolved).
@@ -40,29 +41,32 @@ public class RawConfig extends ConfigInstance {
      * @param defMd5  The md5 sum of the .def-file.
      */
     public RawConfig(ConfigKey<?> key, String defMd5) {
-        this(key, defMd5, null, "", 0L, false, 0, Collections.emptyList(), Optional.empty());
+        this(key, defMd5, null, "", 0L, false, false, 0, Collections.emptyList(), Optional.empty());
     }
 
     public RawConfig(ConfigKey<?> key, String defMd5, Payload payload, String configMd5, long generation,
-                     boolean internalRedeploy, List<String> defContent, Optional<VespaVersion> vespaVersion) {
-        this(key, defMd5, payload, configMd5, generation, internalRedeploy, 0, defContent, vespaVersion);
+                     boolean internalRedeploy, boolean applyOnRestart, List<String> defContent,
+                     Optional<VespaVersion> vespaVersion) {
+        this(key, defMd5, payload, configMd5, generation, internalRedeploy, applyOnRestart, 0, defContent, vespaVersion);
     }
 
     /** Copy constructor */
     public RawConfig(RawConfig rawConfig) {
         this(rawConfig.key, rawConfig.defMd5, rawConfig.payload, rawConfig.configMd5,
-             rawConfig.generation, rawConfig.internalRedeploy, rawConfig.errorCode,
-             rawConfig.defContent, rawConfig.getVespaVersion());
+             rawConfig.generation, rawConfig.internalRedeploy, rawConfig.applyOnRestart,
+             rawConfig.errorCode, rawConfig.defContent, rawConfig.getVespaVersion());
     }
 
     public RawConfig(ConfigKey<?> key, String defMd5, Payload payload, String configMd5, long generation,
-                     boolean internalRedeploy, int errorCode, List<String> defContent, Optional<VespaVersion> vespaVersion) {
+                     boolean internalRedeploy, boolean applyOnRestart, int errorCode, List<String> defContent,
+                     Optional<VespaVersion> vespaVersion) {
         this.key = key;
         this.defMd5 = ConfigUtils.getDefMd5FromRequest(defMd5, defContent);
         this.payload = payload;
         this.configMd5 = configMd5;
         this.generation = generation;
         this.internalRedeploy = internalRedeploy;
+        this.applyOnRestart = applyOnRestart;
         this.errorCode = errorCode;
         this.defContent = defContent;
         this.vespaVersion = vespaVersion;
@@ -80,6 +84,7 @@ public class RawConfig extends ConfigInstance {
                              req.getNewConfigMd5(),
                              req.getNewGeneration(),
                              req.responseIsInternalRedeploy(),
+                             req.responseIsApplyOnRestart(),
                              0,
                              req.getDefContent().asList(),
                              req.getVespaVersion());
@@ -97,6 +102,7 @@ public class RawConfig extends ConfigInstance {
                              req.getRequestConfigMd5(),
                              req.getRequestGeneration(),
                              req.isInternalRedeploy(),
+                             req.applyOnRestart(),
                              0,
                              req.getDefContent().asList(),
                              req.getVespaVersion());
@@ -121,12 +127,16 @@ public class RawConfig extends ConfigInstance {
 
     public void setInternalRedeploy(boolean internalRedeploy) { this.internalRedeploy = internalRedeploy; }
 
+    public void setApplyOnRestart(boolean applyOnRestart) { this.applyOnRestart = applyOnRestart; }
+
     /**
      * Returns whether this config generation was created by a system internal redeploy, not an
      * application package change.
      */
     public boolean isInternalRedeploy() { return internalRedeploy; }
 
+    public boolean applyOnRestart() { return applyOnRestart; }
+
     public Payload getPayload() { return payload; }
 
     public int errorCode() { return errorCode; }
@@ -165,24 +175,17 @@ public class RawConfig extends ConfigInstance {
 
     @Override
     public boolean equals(Object o) {
-        if (o == this) {
-            return true;
-        }
-        if (! (o instanceof RawConfig)) {
-            return false;
-        }
+        if (o == this) return true;
+        if (! (o instanceof RawConfig)) return false;
+
         RawConfig other = (RawConfig) o;
-        if (! (key.equals(other.key) &&
-                defMd5.equals(other.defMd5) &&
-                (errorCode == other.errorCode)) ) {
+        if (! (key.equals(other.key) && defMd5.equals(other.defMd5) && (errorCode == other.errorCode)) )
             return false;
-        }
+
         // Need to check error codes before isError, since unequal error codes always means unequal requests,
         // while non-zero and equal error codes means configs are equal.
-        if (isError())
-            return true;
-        if (generation != other.generation)
-            return false;
+        if (isError()) return true;
+        if (generation != other.generation) return false;
         if (configMd5 != null) {
             return configMd5.equals(other.configMd5);
         } else {
diff --git a/config/src/main/java/com/yahoo/vespa/config/buildergen/ConfigDefinition.java b/config/src/main/java/com/yahoo/vespa/config/buildergen/ConfigDefinition.java
index e145f8ee090..3fe42ce90ad 100644
--- a/config/src/main/java/com/yahoo/vespa/config/buildergen/ConfigDefinition.java
+++ b/config/src/main/java/com/yahoo/vespa/config/buildergen/ConfigDefinition.java
@@ -1,13 +1,10 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.config.buildergen;
 
-import com.google.common.io.Files;
 import com.yahoo.config.codegen.DefParser;
 import com.yahoo.config.codegen.InnerCNode;
-import com.yahoo.config.codegen.JavaClassBuilder;
 import com.yahoo.text.StringUtilities;
 
-import java.io.File;
 import java.io.StringReader;
 
 /**
@@ -15,6 +12,7 @@ import java.io.StringReader;
  * @author Ulf Lilleengen
  */
 public class ConfigDefinition {
+
     private final String name;
     private final String[] defSchema;
     private final InnerCNode cnode;
diff --git a/config/src/main/java/com/yahoo/vespa/config/protocol/ConfigResponse.java b/config/src/main/java/com/yahoo/vespa/config/protocol/ConfigResponse.java
index bb0ee2bb935..27f4816849d 100644
--- a/config/src/main/java/com/yahoo/vespa/config/protocol/ConfigResponse.java
+++ b/config/src/main/java/com/yahoo/vespa/config/protocol/ConfigResponse.java
@@ -22,6 +22,8 @@ public interface ConfigResponse {
 
     boolean isInternalRedeploy();
 
+    boolean applyOnRestart();
+
     String getConfigMd5();
 
     void serialize(OutputStream os, CompressionType uncompressed) throws IOException;
diff --git a/config/src/main/java/com/yahoo/vespa/config/protocol/JRTClientConfigRequest.java b/config/src/main/java/com/yahoo/vespa/config/protocol/JRTClientConfigRequest.java
index ab47fec0641..8f85e2353a5 100644
--- a/config/src/main/java/com/yahoo/vespa/config/protocol/JRTClientConfigRequest.java
+++ b/config/src/main/java/com/yahoo/vespa/config/protocol/JRTClientConfigRequest.java
@@ -56,6 +56,9 @@ public interface JRTClientConfigRequest extends JRTConfigRequest {
     /** Returns whether this config change is due to an internal change not an application package change */
     boolean responseIsInternalRedeploy();
 
+    /** Returns true if this config should only be applied at the last restart, false if it should be applied immediately */
+    boolean responseIsApplyOnRestart();
+
     /**
      * Get the config md5 of the config returned by the server. Return an empty string if no response has been returned.
      *
diff --git a/config/src/main/java/com/yahoo/vespa/config/protocol/JRTClientConfigRequestV3.java b/config/src/main/java/com/yahoo/vespa/config/protocol/JRTClientConfigRequestV3.java
index 12e5968ab83..e04a2179602 100644
--- a/config/src/main/java/com/yahoo/vespa/config/protocol/JRTClientConfigRequestV3.java
+++ b/config/src/main/java/com/yahoo/vespa/config/protocol/JRTClientConfigRequestV3.java
@@ -181,6 +181,7 @@ public class JRTClientConfigRequestV3 implements JRTClientConfigRequest {
         sb.append("response='").append(getNewConfigMd5())
                 .append(",").append(getNewGeneration())
                 .append(",").append(responseIsInternalRedeploy())
+                .append(",").append(responseIsApplyOnRestart())
                 .append("'\n");
         return sb.toString();
     }
@@ -295,6 +296,11 @@ public class JRTClientConfigRequestV3 implements JRTClientConfigRequest {
     }
 
     @Override
+    public boolean responseIsApplyOnRestart() {
+        return responseData.getResponseApplyOnRestart();
+    }
+
+    @Override
     public long getRequestGeneration() {
         return requestData.getRequestGeneration();
     }
diff --git a/config/src/main/java/com/yahoo/vespa/config/protocol/JRTServerConfigRequest.java b/config/src/main/java/com/yahoo/vespa/config/protocol/JRTServerConfigRequest.java
index 763f672a513..dbc6a7bb98d 100644
--- a/config/src/main/java/com/yahoo/vespa/config/protocol/JRTServerConfigRequest.java
+++ b/config/src/main/java/com/yahoo/vespa/config/protocol/JRTServerConfigRequest.java
@@ -34,9 +34,12 @@ public interface JRTServerConfigRequest extends JRTConfigRequest, GetConfigReque
      * @param generation The config generation of the given payload.
      * @param internalRedeployment whether this payload was generated from an internal redeployment not an
      *                             application package change
+     * @param applyOnRestart true if this config should only be applied on the next restart,
+     *                       false if it should be applied right away
      * @param configMd5 The md5sum of the given payload.
      */
-    void addOkResponse(Payload payload, long generation, boolean internalRedeployment, String configMd5);
+    void addOkResponse(Payload payload, long generation, boolean internalRedeployment, boolean applyOnRestart,
+                       String configMd5);
 
     /**
      * Get the current config md5 of the client config.
@@ -65,6 +68,8 @@ public interface JRTServerConfigRequest extends JRTConfigRequest, GetConfigReque
      */
     boolean isInternalRedeploy();
 
+    boolean applyOnRestart();
+
     /**
      * Get the request trace for this request. The trace can be used to trace config execution to provide useful
      * debug info in production environments.
diff --git a/config/src/main/java/com/yahoo/vespa/config/protocol/JRTServerConfigRequestV3.java b/config/src/main/java/com/yahoo/vespa/config/protocol/JRTServerConfigRequestV3.java
index 3609ba04424..0bc7c44fe9d 100644
--- a/config/src/main/java/com/yahoo/vespa/config/protocol/JRTServerConfigRequestV3.java
+++ b/config/src/main/java/com/yahoo/vespa/config/protocol/JRTServerConfigRequestV3.java
@@ -37,6 +37,7 @@ public class JRTServerConfigRequestV3 implements JRTServerConfigRequest {
     private final SlimeRequestData requestData;
     /** Response field */
     private boolean internalRedeploy = false;
+    private boolean applyOnRestart = false;
     // Response values
     private boolean isDelayed = false;
     private Trace requestTrace = null;
@@ -67,8 +68,10 @@ public class JRTServerConfigRequestV3 implements JRTServerConfigRequest {
     }
 
     @Override
-    public void addOkResponse(Payload payload, long generation, boolean internalRedeploy, String configMd5) {
+    public void addOkResponse(Payload payload, long generation, boolean internalRedeploy, boolean applyOnRestart,
+                              String configMd5) {
         this.internalRedeploy = internalRedeploy;
+        this.applyOnRestart = applyOnRestart;
         boolean changedConfig = !configMd5.equals(getRequestConfigMd5());
         boolean changedConfigAndNewGeneration = changedConfig && ConfigUtils.isGenerationNewer(generation, getRequestGeneration());
         Payload responsePayload = payload.withCompression(getCompressionType());
@@ -80,6 +83,7 @@ public class JRTServerConfigRequestV3 implements JRTServerConfigRequest {
             setResponseField(jsonGenerator, SlimeResponseData.RESPONSE_CONFIG_MD5, configMd5);
             setResponseField(jsonGenerator, SlimeResponseData.RESPONSE_CONFIG_GENERATION, generation);
             setResponseField(jsonGenerator, SlimeResponseData.RESPONSE_INTERNAL_REDEPLOY, internalRedeploy);
+            setResponseField(jsonGenerator, SlimeResponseData.RESPONSE_APPLY_ON_RESTART, applyOnRestart);
             jsonGenerator.writeObjectFieldStart(SlimeResponseData.RESPONSE_COMPRESSION_INFO);
             if (responsePayload == null) {
                 throw new RuntimeException("Payload is null for ' " + this + ", not able to create response");
@@ -113,6 +117,9 @@ public class JRTServerConfigRequestV3 implements JRTServerConfigRequest {
     @Override
     public boolean isInternalRedeploy() { return internalRedeploy; }
 
+    @Override
+    public boolean applyOnRestart() { return applyOnRestart; }
+
     public static JRTServerConfigRequestV3 createFromRequest(Request req) {
         return new JRTServerConfigRequestV3(req);
     }
diff --git a/config/src/main/java/com/yahoo/vespa/config/protocol/SlimeConfigResponse.java b/config/src/main/java/com/yahoo/vespa/config/protocol/SlimeConfigResponse.java
index ff0b7f964bf..8bdd336fd5c 100644
--- a/config/src/main/java/com/yahoo/vespa/config/protocol/SlimeConfigResponse.java
+++ b/config/src/main/java/com/yahoo/vespa/config/protocol/SlimeConfigResponse.java
@@ -18,12 +18,14 @@ public class SlimeConfigResponse implements ConfigResponse {
     private final CompressionInfo compressionInfo;
     private final long generation;
     private final boolean internalRedeploy;
+    private final boolean applyOnRestart;
     private final String configMd5;
 
     public static SlimeConfigResponse fromConfigPayload(ConfigPayload payload, long generation,
-                                                        boolean internalRedeploy, String configMd5) {
+                                                        boolean internalRedeploy, boolean applyOnRestart,
+                                                        String configMd5) {
         Utf8Array data = payload.toUtf8Array(true);
-        return new SlimeConfigResponse(data, generation, internalRedeploy,
+        return new SlimeConfigResponse(data, generation, internalRedeploy, applyOnRestart,
                                        configMd5,
                                        CompressionInfo.create(CompressionType.UNCOMPRESSED, data.getByteLength()));
     }
@@ -31,11 +33,13 @@ public class SlimeConfigResponse implements ConfigResponse {
     public SlimeConfigResponse(Utf8Array payload,
                                long generation,
                                boolean internalRedeploy,
+                               boolean applyOnRestart,
                                String configMd5,
                                CompressionInfo compressionInfo) {
         this.payload = payload;
         this.generation = generation;
         this.internalRedeploy = internalRedeploy;
+        this.applyOnRestart = applyOnRestart;
         this.configMd5 = configMd5;
         this.compressionInfo = compressionInfo;
     }
@@ -58,6 +62,9 @@ public class SlimeConfigResponse implements ConfigResponse {
     public boolean isInternalRedeploy() { return internalRedeploy; }
 
     @Override
+    public boolean applyOnRestart() { return applyOnRestart; }
+
+    @Override
     public String getConfigMd5() {
         return configMd5;
     }
diff --git a/config/src/main/java/com/yahoo/vespa/config/protocol/SlimeResponseData.java b/config/src/main/java/com/yahoo/vespa/config/protocol/SlimeResponseData.java
index ba1e7a8c72e..1c9afa550d4 100644
--- a/config/src/main/java/com/yahoo/vespa/config/protocol/SlimeResponseData.java
+++ b/config/src/main/java/com/yahoo/vespa/config/protocol/SlimeResponseData.java
@@ -24,6 +24,7 @@ class SlimeResponseData {
     static final String RESPONSE_CONFIG_MD5 = "configMD5";
     static final String RESPONSE_CONFIG_GENERATION = "generation";
     static final String RESPONSE_INTERNAL_REDEPLOY = "internalRedeploy";
+    static final String RESPONSE_APPLY_ON_RESTART = "applyOnRestart";
     static final String RESPONSE_COMPRESSION_INFO = "compressionInfo";
 
     private final Request request;
@@ -72,4 +73,9 @@ class SlimeResponseData {
         return inspector.valid() && inspector.asBool();
     }
 
+    boolean getResponseApplyOnRestart() {
+        Inspector inspector = getResponseField(RESPONSE_APPLY_ON_RESTART);
+        return inspector.valid() && inspector.asBool();
+    }
+
 }