Quotas in the configuration server (#14088)

* Create a quota JSON encoded parameter

* Propagate quota from PrepareParams to ModelContext.Properties

* Persist quota and read it back

* Check maxClusterSize quota in Validator step

* Default to Quota.empty() in TestProperties

* Javadoc and authors

* Fix parameter type after it was changed on master

Co-authored-by: Andreas Eriksen <andreer@verizonmedia.com>

16 files changed, 280 insertions, 10 deletions

diff --git a/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java b/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java
index 64a2906b1be..413a7dbc62e 100644
--- a/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java
+++ b/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java
@@ -121,6 +121,11 @@ public interface ModelContext {
 
         // TODO(bjorncs): Temporary feature flag
         default double feedCoreThreadPoolSizeFactor() { return 1.0; }
+
+        default Quota quota() {
+            return Quota.empty();
+        }
+
     }
 
 }
diff --git a/config-model-api/src/main/java/com/yahoo/config/model/api/Quota.java b/config-model-api/src/main/java/com/yahoo/config/model/api/Quota.java
new file mode 100644
index 00000000000..cb600bc0a5e
--- /dev/null
+++ b/config-model-api/src/main/java/com/yahoo/config/model/api/Quota.java
@@ -0,0 +1,72 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.config.model.api;
+
+import com.yahoo.slime.Inspector;
+import com.yahoo.slime.Slime;
+import com.yahoo.slime.SlimeUtils;
+
+import java.util.Objects;
+import java.util.Optional;
+
+/**
+ * Quota for the application deployed.  If the application exceeds this quota, deployment will fail.
+ *
+ * @author ogronnesby
+ */
+public class Quota {
+    private final Optional<Integer> maxClusterSize;
+    private final Optional<Integer> budget;
+
+    public Quota(Optional<Integer> maybeClusterSize, Optional<Integer> budget) {
+        this.maxClusterSize = maybeClusterSize;
+        this.budget = budget;
+    }
+
+    public static Quota fromSlime(Inspector inspector) {
+        var clusterSize = SlimeUtils.optionalLong(inspector.field("clusterSize"));
+        var budget = SlimeUtils.optionalLong(inspector.field("budget"));
+        return new Quota(clusterSize.map(Long::intValue), budget.map(Long::intValue));
+    }
+
+    public Slime toSlime() {
+        var slime = new Slime();
+        var root = slime.setObject();
+        maxClusterSize.ifPresent(clusterSize -> root.setLong("clusterSize", clusterSize));
+        budget.ifPresent(b -> root.setLong("budget", b));
+        return slime;
+    }
+
+    public static Quota empty() {
+        return new Quota(Optional.empty(), Optional.empty());
+    }
+
+    public Optional<Integer> maxClusterSize() {
+        return maxClusterSize;
+    }
+
+    public Optional<Integer> budget() {
+        return budget;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Quota quota = (Quota) o;
+        return Objects.equals(maxClusterSize, quota.maxClusterSize) &&
+                Objects.equals(budget, quota.budget);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(maxClusterSize, budget);
+    }
+
+    @Override
+    public String toString() {
+        return "Quota{" +
+                "maxClusterSize=" + maxClusterSize +
+                ", budget=" + budget +
+                '}';
+    }
+}
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 abe14fbed32..fc799449379 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
@@ -7,6 +7,7 @@ import com.yahoo.config.model.api.ConfigServerSpec;
 import com.yahoo.config.model.api.ContainerEndpoint;
 import com.yahoo.config.model.api.EndpointCertificateSecrets;
 import com.yahoo.config.model.api.ModelContext;
+import com.yahoo.config.model.api.Quota;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.AthenzDomain;
 import com.yahoo.config.provision.HostName;
@@ -46,6 +47,7 @@ public class TestProperties implements ModelContext.Properties {
     private Optional<EndpointCertificateSecrets> endpointCertificateSecrets = Optional.empty();
     private AthenzDomain athenzDomain;
     private ApplicationRoles applicationRoles;
+    private Quota quota = Quota.empty();
 
     @Override public boolean multitenant() { return multitenant; }
     @Override public ApplicationId applicationId() { return applicationId; }
@@ -78,6 +80,7 @@ public class TestProperties implements ModelContext.Properties {
     @Override public boolean skipCommunicationManagerThread() { return false; }
     @Override public boolean skipMbusRequestThread() { return false; }
     @Override public boolean skipMbusReplyThread() { return false; }
+    @Override public Quota quota() { return quota; }
 
     public TestProperties setJvmGCOptions(String gcOptions) {
         jvmGCOptions = gcOptions;
@@ -164,6 +167,11 @@ public class TestProperties implements ModelContext.Properties {
         return this;
     }
 
+    public TestProperties setQuota(Quota quota) {
+        this.quota = quota;
+        return this;
+    }
+
     public static class Spec implements ConfigServerSpec {
 
         private final String hostName;
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/application/validation/QuotaValidator.java b/config-model/src/main/java/com/yahoo/vespa/model/application/validation/QuotaValidator.java
new file mode 100644
index 00000000000..6670b7ce94a
--- /dev/null
+++ b/config-model/src/main/java/com/yahoo/vespa/model/application/validation/QuotaValidator.java
@@ -0,0 +1,38 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.model.application.validation;
+
+import com.yahoo.config.model.deploy.DeployState;
+import com.yahoo.config.provision.ClusterSpec;
+import com.yahoo.vespa.model.VespaModel;
+
+import java.util.stream.Collectors;
+
+/**
+ * Checks that the generated model does not have resources that exceeds the given quota.
+ *
+ * @author ogronnesby
+ */
+public class QuotaValidator extends Validator {
+    @Override
+    public void validate(VespaModel model, DeployState deployState) {
+        var quota = deployState.getProperties().quota();
+        quota.maxClusterSize().ifPresent(maxClusterSize -> validateMaxClusterSize(maxClusterSize, model));
+    }
+
+    /** Check that all clusters in the application do not exceed the quota max cluster size. */
+    private void validateMaxClusterSize(int maxClusterSize, VespaModel model) {
+        var invalidClusters = model.allClusters().stream()
+                .filter(clusterId -> {
+                    var cluster = model.provisioned().all().get(clusterId);
+                    var clusterSize = cluster.maxResources().nodes();
+                    return clusterSize > maxClusterSize;
+                })
+                .map(ClusterSpec.Id::value)
+                .collect(Collectors.toList());
+
+        if (!invalidClusters.isEmpty()) {
+            var clusterNames = String.join(", ", invalidClusters);
+            throw new IllegalArgumentException("Clusters " + clusterNames + " exceeded max cluster size of " + maxClusterSize);
+        }
+    }
+}
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/application/validation/Validation.java b/config-model/src/main/java/com/yahoo/vespa/model/application/validation/Validation.java
index 22dd0289390..f3ccc2d3447 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/application/validation/Validation.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/application/validation/Validation.java
@@ -61,6 +61,7 @@ public class Validation {
         new AccessControlFilterValidator().validate(model, deployState);
         new CloudWatchValidator().validate(model, deployState);
         new AwsAccessControlValidator().validate(model, deployState);
+        new QuotaValidator().validate(model, deployState);
 
         List<ConfigChangeAction> result = Collections.emptyList();
         if (deployState.getProperties().isFirstTimeDeployment()) {
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/application/validation/QuotaValidatorTest.java b/config-model/src/test/java/com/yahoo/vespa/model/application/validation/QuotaValidatorTest.java
new file mode 100644
index 00000000000..f8aa3fd5298
--- /dev/null
+++ b/config-model/src/test/java/com/yahoo/vespa/model/application/validation/QuotaValidatorTest.java
@@ -0,0 +1,52 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.model.application.validation;
+
+import com.yahoo.config.model.api.Quota;
+import com.yahoo.config.model.deploy.TestProperties;
+import com.yahoo.config.provision.Environment;
+import org.junit.Test;
+
+import java.util.Optional;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+/**
+ * @author ogronnesby
+ */
+public class QuotaValidatorTest {
+
+    private final Quota quota = new Quota(Optional.of(5), Optional.empty());
+
+    @Test
+    public void test_deploy_under_quota() {
+        var tester = new ValidationTester(5, new TestProperties().setHostedVespa(true).setQuota(quota));
+        tester.deploy(null, getServices("testCluster", 5), Environment.prod, null);
+    }
+
+    @Test
+    public void test_deploy_above_quota() {
+        var tester = new ValidationTester(6, new TestProperties().setHostedVespa(true).setQuota(quota));
+        try {
+            tester.deploy(null, getServices("testCluster", 6), Environment.prod, null);
+            fail();
+        } catch (RuntimeException e) {
+            assertEquals("Clusters testCluster exceeded max cluster size of 5", e.getMessage());
+        }
+    }
+
+    private static String getServices(String contentClusterId, int nodeCount) {
+        return "<services version='1.0'>" +
+                "  <content id='" + contentClusterId + "' version='1.0'>" +
+                "    <redundancy>1</redundancy>" +
+                "    <engine>" +
+                "    <proton/>" +
+                "    </engine>" +
+                "    <documents>" +
+                "      <document type='music' mode='index'/>" +
+                "    </documents>" +
+                "    <nodes count='" + nodeCount + "'/>" +
+                "   </content>" +
+                "</services>";
+    }
+}
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/application/validation/ValidationTester.java b/config-model/src/test/java/com/yahoo/vespa/model/application/validation/ValidationTester.java
index 362a083993e..6961ffa682b 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/application/validation/ValidationTester.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/application/validation/ValidationTester.java
@@ -31,6 +31,7 @@ import static com.yahoo.config.model.test.MockApplicationPackage.MUSIC_SEARCHDEF
  */
 public class ValidationTester {
 
+    private final TestProperties properties;
     private final InMemoryProvisioner hostProvisioner;
 
     /** Creates a validation tester with 1 node available */
@@ -38,14 +39,25 @@ public class ValidationTester {
         this(1);
     }
 
+    /** Creates a validation tester with number of nodes available and the given test properties */
+    public ValidationTester(int nodeCount, TestProperties properties) {
+        this(new InMemoryProvisioner(nodeCount), properties);
+    }
+
+    /** Creates a validation tester with a given host provisioner */
+    public ValidationTester(InMemoryProvisioner hostProvisioner) {
+        this(hostProvisioner, new TestProperties().setHostedVespa(true));
+    }
+
     /** Creates a validation tester with a number of nodes available */
     public ValidationTester(int nodeCount) {
-        this(new InMemoryProvisioner(nodeCount));
+        this(new InMemoryProvisioner(nodeCount), new TestProperties().setHostedVespa(true));
     }
 
     /** Creates a validation tester with a given host provisioner */
-    public ValidationTester(InMemoryProvisioner hostProvisioner) {
+    public ValidationTester(InMemoryProvisioner hostProvisioner, TestProperties testProperties) {
         this.hostProvisioner = hostProvisioner;
+        this.properties = testProperties;
     }
 
     /**
@@ -74,7 +86,7 @@ public class ValidationTester {
                                                                             environment,
                                                                             RegionName.defaultName()))
                                                              .applicationPackage(newApp)
-                                                             .properties(new TestProperties().setHostedVespa(true))
+                                                             .properties(properties)
                                                              .modelHostProvisioner(hostProvisioner)
                                                              .provisioned(provisioned)
                                                              .now(now);
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/ModelContextImpl.java b/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/ModelContextImpl.java
index 815cc0a3a18..3d4198c65a9 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/ModelContextImpl.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/ModelContextImpl.java
@@ -14,6 +14,7 @@ import com.yahoo.config.model.api.HostProvisioner;
 import com.yahoo.config.model.api.Model;
 import com.yahoo.config.model.api.ModelContext;
 import com.yahoo.config.model.api.Provisioned;
+import com.yahoo.config.model.api.Quota;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.AthenzDomain;
 import com.yahoo.config.provision.DockerImage;
@@ -162,6 +163,7 @@ public class ModelContextImpl implements ModelContext {
         private final Optional<AthenzDomain> athenzDomain;
         private final Optional<ApplicationRoles> applicationRoles;
         private final double feedCoreThreadPoolSizeFactor;
+        private final Quota quota;
 
         public Properties(ApplicationId applicationId,
                           boolean multitenantFromConfig,
@@ -177,7 +179,8 @@ public class ModelContextImpl implements ModelContext {
                           FlagSource flagSource,
                           Optional<EndpointCertificateSecrets> endpointCertificateSecrets,
                           Optional<AthenzDomain> athenzDomain,
-                          Optional<ApplicationRoles> applicationRoles) {
+                          Optional<ApplicationRoles> applicationRoles,
+                          Optional<Quota> maybeQuota) {
             this.applicationId = applicationId;
             this.multitenant = multitenantFromConfig || hostedVespa || Boolean.getBoolean("multitenant");
             this.configServerSpecs = configServerSpecs;
@@ -218,6 +221,7 @@ public class ModelContextImpl implements ModelContext {
             this.applicationRoles = applicationRoles;
             feedCoreThreadPoolSizeFactor = Flags.FEED_CORE_THREAD_POOL_SIZE_FACTOR.bindTo(flagSource)
                     .with(FetchVector.Dimension.APPLICATION_ID, applicationId.serializedForm()).value();
+            this.quota = maybeQuota.orElseGet(Quota::empty);
         }
 
         @Override
@@ -301,6 +305,8 @@ public class ModelContextImpl implements ModelContext {
         @Override public boolean skipMbusRequestThread() { return skipMbusRequestThread; }
         @Override public boolean skipMbusReplyThread() { return skipMbusReplyThread; }
         @Override public double feedCoreThreadPoolSizeFactor() { return feedCoreThreadPoolSizeFactor; }
+
+        @Override public Quota quota() { return quota; }
     }
 
 }
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/modelfactory/ActivatedModelsBuilder.java b/configserver/src/main/java/com/yahoo/vespa/config/server/modelfactory/ActivatedModelsBuilder.java
index 6b42ca7fa95..7fc6b35722f 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/modelfactory/ActivatedModelsBuilder.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/modelfactory/ActivatedModelsBuilder.java
@@ -149,7 +149,8 @@ public class ActivatedModelsBuilder extends ModelsBuilder<Application> {
                                                        .flatMap(new EndpointCertificateRetriever(secretStore)::readEndpointCertificateSecrets),
                                                zkClient.readAthenzDomain(),
                                                new ApplicationRolesStore(curator, TenantRepository.getTenantPath(tenant))
-                                                       .readApplicationRoles(applicationId));
+                                                       .readApplicationRoles(applicationId),
+                                               zkClient.readQuota());
 
     }
 
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/PrepareParams.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/PrepareParams.java
index 34974c00a84..1fea966503b 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/PrepareParams.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/PrepareParams.java
@@ -5,6 +5,7 @@ import com.yahoo.component.Version;
 import com.yahoo.config.model.api.ApplicationRoles;
 import com.yahoo.config.model.api.ContainerEndpoint;
 import com.yahoo.config.model.api.EndpointCertificateMetadata;
+import com.yahoo.config.model.api.Quota;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.AthenzDomain;
 import com.yahoo.config.provision.DockerImage;
@@ -42,6 +43,7 @@ public final class PrepareParams {
     static final String ATHENZ_DOMAIN = "athenzDomain";
     static final String APPLICATION_HOST_ROLE = "applicationHostRole";
     static final String APPLICATION_CONTAINER_ROLE = "applicationContainerRole";
+    static final String QUOTA_PARAM_NAME = "quota";
 
     private final ApplicationId applicationId;
     private final TimeoutBudget timeoutBudget;
@@ -56,13 +58,14 @@ public final class PrepareParams {
     private final Optional<DockerImage> dockerImageRepository;
     private final Optional<AthenzDomain> athenzDomain;
     private final Optional<ApplicationRoles> applicationRoles;
+    private final Optional<Quota> quota;
 
     private PrepareParams(ApplicationId applicationId, TimeoutBudget timeoutBudget, boolean ignoreValidationErrors,
                           boolean dryRun, boolean verbose, boolean isBootstrap, Optional<Version> vespaVersion,
                           List<ContainerEndpoint> containerEndpoints, Optional<String> tlsSecretsKeyName,
                           Optional<EndpointCertificateMetadata> endpointCertificateMetadata,
                           Optional<DockerImage> dockerImageRepository, Optional<AthenzDomain> athenzDomain,
-                          Optional<ApplicationRoles> applicationRoles) {
+                          Optional<ApplicationRoles> applicationRoles, Optional<Quota> quota) {
         this.timeoutBudget = timeoutBudget;
         this.applicationId = Objects.requireNonNull(applicationId);
         this.ignoreValidationErrors = ignoreValidationErrors;
@@ -76,6 +79,7 @@ public final class PrepareParams {
         this.dockerImageRepository = dockerImageRepository;
         this.athenzDomain = athenzDomain;
         this.applicationRoles = applicationRoles;
+        this.quota = quota;
     }
 
     public static class Builder {
@@ -93,6 +97,7 @@ public final class PrepareParams {
         private Optional<DockerImage> dockerImageRepository = Optional.empty();
         private Optional<AthenzDomain> athenzDomain = Optional.empty();
         private Optional<ApplicationRoles> applicationRoles = Optional.empty();
+        private Optional<Quota> quota = Optional.empty();
 
         public Builder() { }
 
@@ -187,11 +192,18 @@ public final class PrepareParams {
             return this;
         }
 
+        public Builder quota(String serialized) {
+            this.quota = (serialized == null)
+                    ? Optional.empty()
+                    : Optional.of(Quota.fromSlime(SlimeUtils.jsonToSlime(serialized).get()));
+            return this;
+        }
+
         public PrepareParams build() {
             return new PrepareParams(applicationId, timeoutBudget, ignoreValidationErrors, dryRun,
                                      verbose, isBootstrap, vespaVersion, containerEndpoints, tlsSecretsKeyName,
                                      endpointCertificateMetadata, dockerImageRepository, athenzDomain,
-                                     applicationRoles);
+                                     applicationRoles, quota);
         }
     }
 
@@ -208,6 +220,7 @@ public final class PrepareParams {
                             .dockerImageRepository(request.getProperty(DOCKER_IMAGE_REPOSITORY))
                             .athenzDomain(request.getProperty(ATHENZ_DOMAIN))
                             .applicationRoles(ApplicationRoles.fromString(request.getProperty(APPLICATION_HOST_ROLE), request.getProperty(APPLICATION_CONTAINER_ROLE)))
+                            .quota(request.getProperty(QUOTA_PARAM_NAME))
                             .build();
     }
 
@@ -278,4 +291,8 @@ public final class PrepareParams {
     public Optional<ApplicationRoles> applicationRoles() {
         return applicationRoles;
     }
+
+    public Optional<Quota> quota() {
+        return quota;
+    }
 }
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionPreparer.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionPreparer.java
index 35bbc1a8233..7b40184e72a 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionPreparer.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionPreparer.java
@@ -17,6 +17,7 @@ import com.yahoo.config.model.api.EndpointCertificateMetadata;
 import com.yahoo.config.model.api.EndpointCertificateSecrets;
 import com.yahoo.config.model.api.FileDistribution;
 import com.yahoo.config.model.api.ModelContext;
+import com.yahoo.config.model.api.Quota;
 import com.yahoo.config.provision.AllocatedHosts;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.AthenzDomain;
@@ -216,7 +217,8 @@ public class SessionPreparer {
                                                               currentActiveApplicationSet.isEmpty(),
                                                               flagSource,
                                                               endpointCertificateSecrets,
-                                                              athenzDomain, applicationRoles);
+                                                              athenzDomain, applicationRoles,
+                                                              params.quota());
             this.fileDistributionProvider = fileDistributionFactory.createProvider(serverDbSessionDir);
             this.preparedModelsBuilder = new PreparedModelsBuilder(modelFactoryRegistry,
                                                                    permanentApplicationPackage,
@@ -286,7 +288,8 @@ public class SessionPreparer {
                                   logger,
                                   prepareResult.getFileRegistries(), 
                                   prepareResult.allocatedHosts(),
-                                  athenzDomain);
+                                  athenzDomain,
+                                  params.quota());
             checkTimeout("write state to zookeeper");
         }
 
@@ -335,7 +338,8 @@ public class SessionPreparer {
                                        DeployLogger deployLogger,
                                        Map<Version, FileRegistry> fileRegistryMap,
                                        AllocatedHosts allocatedHosts,
-                                       Optional<AthenzDomain> athenzDomain) {
+                                       Optional<AthenzDomain> athenzDomain,
+                                       Optional<Quota> quota) {
         ZooKeeperDeployer zkDeployer = zooKeeperClient.createDeployer(deployLogger);
         try {
             zkDeployer.deploy(applicationPackage, fileRegistryMap, allocatedHosts);
@@ -345,6 +349,7 @@ public class SessionPreparer {
             zooKeeperClient.writeVespaVersion(vespaVersion);
             zooKeeperClient.writeDockerImageRepository(dockerImageRepository);
             zooKeeperClient.writeAthenzDomain(athenzDomain);
+            zooKeeperClient.writeQuota(quota);
         } catch (RuntimeException | IOException e) {
             zkDeployer.cleanup();
             throw new RuntimeException("Error preparing session", e);
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionZooKeeperClient.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionZooKeeperClient.java
index d28a322a05a..ff168e102b9 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionZooKeeperClient.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionZooKeeperClient.java
@@ -7,12 +7,15 @@ import com.yahoo.config.FileReference;
 import com.yahoo.config.application.api.ApplicationPackage;
 import com.yahoo.config.application.api.DeployLogger;
 import com.yahoo.config.model.api.ConfigDefinitionRepo;
+import com.yahoo.config.model.api.Quota;
 import com.yahoo.config.provision.AllocatedHosts;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.AthenzDomain;
 import com.yahoo.config.provision.DockerImage;
 import com.yahoo.config.provision.TenantName;
 import com.yahoo.path.Path;
+import com.yahoo.slime.JsonFormat;
+import com.yahoo.slime.SlimeUtils;
 import com.yahoo.text.Utf8;
 import com.yahoo.transaction.Transaction;
 import com.yahoo.vespa.config.server.UserConfigDefinitionRepo;
@@ -25,10 +28,13 @@ import com.yahoo.vespa.curator.Curator;
 import com.yahoo.vespa.curator.transaction.CuratorOperations;
 import com.yahoo.vespa.curator.transaction.CuratorTransaction;
 
+import java.io.ByteArrayOutputStream;
 import java.time.Instant;
 import java.util.Optional;
 import java.util.logging.Level;
 
+import static com.yahoo.yolean.Exceptions.uncheck;
+
 /**
  * Zookeeper client for a specific session. Path for a session is /config/v2/tenants/&lt;tenant&gt;/sessions/&lt;sessionid&gt;
  * Can be used to read and write session status and create and get prepare and active barrier.
@@ -47,6 +53,7 @@ public class SessionZooKeeperClient {
     private static final String CREATE_TIME_PATH = "createTime";
     private static final String DOCKER_IMAGE_REPOSITORY_PATH = "dockerImageRepository";
     private static final String ATHENZ_DOMAIN = "athenzDomain";
+    private static final String QUOTA_PATH = "quota";
     private final Curator curator;
     private final ConfigCurator configCurator;
     private final TenantName tenantName;
@@ -179,6 +186,10 @@ public class SessionZooKeeperClient {
         return sessionPath.append(ATHENZ_DOMAIN).getAbsolute();
     }
 
+    private String quotaPath() {
+        return sessionPath.append(QUOTA_PATH).getAbsolute();
+    }
+
     public void writeVespaVersion(Version version) {
         configCurator.putData(versionPath(), version.toString());
     }
@@ -240,6 +251,20 @@ public class SessionZooKeeperClient {
                 .map(AthenzDomain::from);
     }
 
+    public void writeQuota(Optional<Quota> maybeQuota) {
+        maybeQuota.ifPresent(quota -> {
+            var bytes = uncheck(() -> SlimeUtils.toJsonBytes(quota.toSlime()));
+            configCurator.putData(quotaPath(), bytes);
+        });
+    }
+
+    public Optional<Quota> readQuota() {
+        if ( ! configCurator.exists(quotaPath())) return Optional.empty();
+        return Optional.ofNullable(configCurator.getData(quotaPath()))
+                .map(SlimeUtils::jsonToSlime)
+                .map(slime -> Quota.fromSlime(slime.get()));
+    }
+
     /**
      * Create necessary paths atomically for a new session.
      *
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/ModelContextImplTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/ModelContextImplTest.java
index 158b8ea55d2..9b827293516 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/ModelContextImplTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/ModelContextImplTest.java
@@ -63,6 +63,7 @@ public class ModelContextImplTest {
                         flagSource,
                         null,
                         Optional.empty(),
+                        Optional.empty(),
                         Optional.empty()),
                 Optional.empty(),
                 Optional.empty(),
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/session/PrepareParamsTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/session/PrepareParamsTest.java
index bf21f800815..941f2726b0e 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/session/PrepareParamsTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/session/PrepareParamsTest.java
@@ -84,6 +84,15 @@ public class PrepareParamsTest {
         assertEquals("containerRole", applicationRoles.get().applicationContainerRole());
     }
 
+    @Test
+    public void testQuotaParsing() {
+        var quotaParam = "{\"clusterSize\": 23, \"budget\": 23232323}";
+        var quotaEncoded = URLEncoder.encode(quotaParam, StandardCharsets.UTF_8);
+        var prepareParams = createParams(request + "&" + PrepareParams.QUOTA_PARAM_NAME + "=" + quotaEncoded, TenantName.from("foo"));
+        assertEquals(23, (int) prepareParams.quota().get().maxClusterSize().get());
+        assertEquals(23232323, (int) prepareParams.quota().get().budget().get());
+    }
+
     // Create PrepareParams from a request (based on uri and tenant name)
     private static PrepareParams createParams(String uri, TenantName tenantName) {
         return PrepareParams.fromHttpRequest(
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionZooKeeperClientTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionZooKeeperClientTest.java
index de55a6677ff..cc1137ad9d8 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionZooKeeperClientTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionZooKeeperClientTest.java
@@ -2,6 +2,7 @@
 package com.yahoo.vespa.config.server.session;
 
 import com.yahoo.config.FileReference;
+import com.yahoo.config.model.api.Quota;
 import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.TenantName;
 import com.yahoo.path.Path;
@@ -17,8 +18,10 @@ import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
 import java.time.Instant;
+import java.util.Optional;
 
 import static org.hamcrest.core.Is.is;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 
@@ -137,6 +140,14 @@ public class SessionZooKeeperClientTest {
         assertThat(zkc.readApplicationPackageReference(), is(testRef));
     }
 
+    @Test
+    public void require_quota_written_and_parsed() {
+        var quota = Optional.of(new Quota(Optional.of(23), Optional.of(32)));
+        var zkc = createSessionZKClient(4);
+        zkc.writeQuota(quota);
+        assertEquals(quota, zkc.readQuota());
+    }
+
     private void assertApplicationIdParse(long sessionId, String idString, String expectedIdString) {
         SessionZooKeeperClient zkc = createSessionZKClient(sessionId);
         String path = sessionPath(sessionId).append(SessionZooKeeperClient.APPLICATION_ID_PATH).getAbsolute();
diff --git a/vespajlib/src/main/java/com/yahoo/slime/SlimeUtils.java b/vespajlib/src/main/java/com/yahoo/slime/SlimeUtils.java
index 5084e6554cb..51a4fc167c7 100644
--- a/vespajlib/src/main/java/com/yahoo/slime/SlimeUtils.java
+++ b/vespajlib/src/main/java/com/yahoo/slime/SlimeUtils.java
@@ -124,6 +124,13 @@ public class SlimeUtils {
         return Optional.of(inspector.asString()).filter(s -> !s.isEmpty());
     }
 
+    public static Optional<Long> optionalLong(Inspector inspector) {
+        if (inspector.type() == Type.LONG) {
+            return Optional.of(inspector.asLong());
+        }
+        return Optional.empty();
+    }
+
     public static Iterator<Inspector> entriesIterator(Inspector inspector) {
         return new Iterator<>() {
             private int current = 0;