diff --git a/resources/sql/autopatches/20141217.almanacdevicelock.sql b/resources/sql/autopatches/20141217.almanacdevicelock.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20141217.almanacdevicelock.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_almanac.almanac_device
+  ADD isLocked BOOL NOT NULL;
diff --git a/resources/sql/autopatches/20141217.almanaclock.sql b/resources/sql/autopatches/20141217.almanaclock.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20141217.almanaclock.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_almanac.almanac_service
+  ADD isLocked BOOL NOT NULL;
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -49,7 +49,9 @@
     'AlmanacInterfacePHIDType' => 'applications/almanac/phid/AlmanacInterfacePHIDType.php',
     'AlmanacInterfaceQuery' => 'applications/almanac/query/AlmanacInterfaceQuery.php',
     'AlmanacInterfaceTableView' => 'applications/almanac/view/AlmanacInterfaceTableView.php',
+    'AlmanacManagementLockWorkflow' => 'applications/almanac/management/AlmanacManagementLockWorkflow.php',
     'AlmanacManagementTrustKeyWorkflow' => 'applications/almanac/management/AlmanacManagementTrustKeyWorkflow.php',
+    'AlmanacManagementUnlockWorkflow' => 'applications/almanac/management/AlmanacManagementUnlockWorkflow.php',
     'AlmanacManagementUntrustKeyWorkflow' => 'applications/almanac/management/AlmanacManagementUntrustKeyWorkflow.php',
     'AlmanacManagementWorkflow' => 'applications/almanac/management/AlmanacManagementWorkflow.php',
     'AlmanacNames' => 'applications/almanac/util/AlmanacNames.php',
@@ -3068,7 +3070,9 @@
     'AlmanacInterfacePHIDType' => 'PhabricatorPHIDType',
     'AlmanacInterfaceQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
     'AlmanacInterfaceTableView' => 'AphrontView',
+    'AlmanacManagementLockWorkflow' => 'AlmanacManagementWorkflow',
     'AlmanacManagementTrustKeyWorkflow' => 'AlmanacManagementWorkflow',
+    'AlmanacManagementUnlockWorkflow' => 'AlmanacManagementWorkflow',
     'AlmanacManagementUntrustKeyWorkflow' => 'AlmanacManagementWorkflow',
     'AlmanacManagementWorkflow' => 'PhabricatorManagementWorkflow',
     'AlmanacNames' => 'Phobject',
diff --git a/src/applications/almanac/application/PhabricatorAlmanacApplication.php b/src/applications/almanac/application/PhabricatorAlmanacApplication.php
--- a/src/applications/almanac/application/PhabricatorAlmanacApplication.php
+++ b/src/applications/almanac/application/PhabricatorAlmanacApplication.php
@@ -26,6 +26,10 @@
     return self::GROUP_UTILITIES;
   }
 
+  public function getHelpURI() {
+    return PhabricatorEnv::getDoclink('Almanac User Guide');
+  }
+
   public function isPrototype() {
     return true;
   }
diff --git a/src/applications/almanac/controller/AlmanacBindingViewController.php b/src/applications/almanac/controller/AlmanacBindingViewController.php
--- a/src/applications/almanac/controller/AlmanacBindingViewController.php
+++ b/src/applications/almanac/controller/AlmanacBindingViewController.php
@@ -38,6 +38,14 @@
       ->setHeader($header)
       ->addPropertyList($property_list);
 
+    if ($binding->getService()->getIsLocked()) {
+      $this->addLockMessage(
+        $box,
+        pht(
+          'This service for this binding is locked, so the binding can '.
+          'not be edited.'));
+    }
+
     $crumbs = $this->buildApplicationCrumbs();
     $crumbs->addTextCrumb($service->getName(), $service_uri);
     $crumbs->addTextCrumb($title);
diff --git a/src/applications/almanac/controller/AlmanacController.php b/src/applications/almanac/controller/AlmanacController.php
--- a/src/applications/almanac/controller/AlmanacController.php
+++ b/src/applications/almanac/controller/AlmanacController.php
@@ -179,4 +179,23 @@
       ->appendChild($table);
   }
 
+  protected function addLockMessage(PHUIObjectBoxView $box, $message) {
+    $doc_link = phutil_tag(
+      'a',
+      array(
+        'href' => PhabricatorEnv::getDoclink('Almanac User Guide'),
+        'target' => '_blank',
+      ),
+      pht('Learn More'));
+
+    $error_view = id(new AphrontErrorView())
+      ->setSeverity(AphrontErrorView::SEVERITY_WARNING)
+      ->setErrors(
+        array(
+          array($message, ' ', $doc_link),
+        ));
+
+    $box->setErrorView($error_view);
+  }
+
 }
diff --git a/src/applications/almanac/controller/AlmanacDeviceViewController.php b/src/applications/almanac/controller/AlmanacDeviceViewController.php
--- a/src/applications/almanac/controller/AlmanacDeviceViewController.php
+++ b/src/applications/almanac/controller/AlmanacDeviceViewController.php
@@ -20,6 +20,10 @@
       return new Aphront404Response();
     }
 
+    // We rebuild locks on a device when viewing the detail page, so they
+    // automatically get corrected if they fall out of sync.
+    $device->rebuildDeviceLocks();
+
     $title = pht('Device %s', $device->getName());
 
     $property_list = $this->buildPropertyList($device);
@@ -35,6 +39,14 @@
       ->setHeader($header)
       ->addPropertyList($property_list);
 
+    if ($device->getIsLocked()) {
+      $this->addLockMessage(
+        $box,
+        pht(
+          'This device is bound to a locked service, so it can not be '.
+          'edited.'));
+    }
+
     $interfaces = $this->buildInterfaceList($device);
 
     $crumbs = $this->buildApplicationCrumbs();
@@ -52,6 +64,7 @@
         $interfaces,
         $this->buildAlmanacPropertiesTable($device),
         $this->buildSSHKeysTable($device),
+        $this->buildServicesTable($device),
         $timeline,
       ),
       array(
@@ -116,7 +129,8 @@
     $table = id(new AlmanacInterfaceTableView())
       ->setUser($viewer)
       ->setInterfaces($interfaces)
-      ->setHandles($handles);
+      ->setHandles($handles)
+      ->setCanEdit($can_edit);
 
     $header = id(new PHUIHeaderView())
       ->setHeader(pht('Device Interfaces'))
@@ -199,4 +213,52 @@
 
   }
 
+  private function buildServicesTable(AlmanacDevice $device) {
+
+    // NOTE: We're loading all services so we can show hidden, locked services.
+    // In general, we let you know about all the things the device is bound to,
+    // even if you don't have permission to see their details. This is similar
+    // to exposing the existence of edges in other applications, with the
+    // addition of always letting you see that locks exist.
+
+    $services = id(new AlmanacServiceQuery())
+      ->setViewer(PhabricatorUser::getOmnipotentUser())
+      ->withDevicePHIDs(array($device->getPHID()))
+      ->execute();
+
+    $handles = $this->loadViewerHandles(mpull($services, 'getPHID'));
+
+    $icon_lock = id(new PHUIIconView())
+      ->setIconFont('fa-lock');
+
+    $rows = array();
+    foreach ($services as $service) {
+      $handle = $handles[$service->getPHID()];
+      $rows[] = array(
+        ($service->getIsLocked()
+          ? $icon_lock
+          : null),
+        $handle->renderLink(),
+      );
+    }
+
+    $table = id(new AphrontTableView($rows))
+      ->setNoDataString(pht('No services are bound to this device.'))
+      ->setHeaders(
+        array(
+          null,
+          pht('Service'),
+        ))
+      ->setColumnClasses(
+        array(
+          null,
+          'wide pri',
+        ));
+
+    return id(new PHUIObjectBoxView())
+      ->setHeaderText(pht('Bound Services'))
+      ->appendChild($table);
+  }
+
+
 }
diff --git a/src/applications/almanac/controller/AlmanacServiceViewController.php b/src/applications/almanac/controller/AlmanacServiceViewController.php
--- a/src/applications/almanac/controller/AlmanacServiceViewController.php
+++ b/src/applications/almanac/controller/AlmanacServiceViewController.php
@@ -35,6 +35,17 @@
       ->setHeader($header)
       ->addPropertyList($property_list);
 
+    $messages = $service->getServiceType()->getStatusMessages($service);
+    if ($messages) {
+      $box->setFormErrors($messages);
+    }
+
+    if ($service->getIsLocked()) {
+      $this->addLockMessage(
+        $box,
+        pht('This service is locked, and can not be edited.'));
+    }
+
     $bindings = $this->buildBindingList($service);
 
     $crumbs = $this->buildApplicationCrumbs();
diff --git a/src/applications/almanac/editor/AlmanacServiceEditor.php b/src/applications/almanac/editor/AlmanacServiceEditor.php
--- a/src/applications/almanac/editor/AlmanacServiceEditor.php
+++ b/src/applications/almanac/editor/AlmanacServiceEditor.php
@@ -15,6 +15,8 @@
     $types = parent::getTransactionTypes();
 
     $types[] = AlmanacServiceTransaction::TYPE_NAME;
+    $types[] = AlmanacServiceTransaction::TYPE_LOCK;
+
     $types[] = PhabricatorTransactions::TYPE_VIEW_POLICY;
     $types[] = PhabricatorTransactions::TYPE_EDIT_POLICY;
 
@@ -27,6 +29,8 @@
     switch ($xaction->getTransactionType()) {
       case AlmanacServiceTransaction::TYPE_NAME:
         return $object->getName();
+      case AlmanacServiceTransaction::TYPE_LOCK:
+        return (bool)$object->getIsLocked();
     }
 
     return parent::getCustomTransactionOldValue($object, $xaction);
@@ -39,6 +43,8 @@
     switch ($xaction->getTransactionType()) {
       case AlmanacServiceTransaction::TYPE_NAME:
         return $xaction->getNewValue();
+      case AlmanacServiceTransaction::TYPE_LOCK:
+        return (bool)$xaction->getNewValue();
     }
 
     return parent::getCustomTransactionNewValue($object, $xaction);
@@ -52,6 +58,9 @@
       case AlmanacServiceTransaction::TYPE_NAME:
         $object->setName($xaction->getNewValue());
         return;
+      case AlmanacServiceTransaction::TYPE_LOCK:
+        $object->setIsLocked((int)$xaction->getNewValue());
+        return;
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
       case PhabricatorTransactions::TYPE_EDGE:
@@ -71,6 +80,23 @@
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
       case PhabricatorTransactions::TYPE_EDGE:
         return;
+      case AlmanacServiceTransaction::TYPE_LOCK:
+        $service = id(new AlmanacServiceQuery())
+          ->setViewer(PhabricatorUser::getOmnipotentUser())
+          ->withPHIDs(array($object->getPHID()))
+          ->needBindings(true)
+          ->executeOne();
+
+        $devices = array();
+        foreach ($service->getBindings() as $binding) {
+          $device = $binding->getInterface()->getDevice();
+          $devices[$device->getPHID()] = $device;
+        }
+
+        foreach ($devices as $device) {
+          $device->rebuildDeviceLocks();
+        }
+        return;
     }
 
     return parent::applyCustomExternalTransaction($object, $xaction);
diff --git a/src/applications/almanac/management/AlmanacManagementLockWorkflow.php b/src/applications/almanac/management/AlmanacManagementLockWorkflow.php
new file mode 100644
--- /dev/null
+++ b/src/applications/almanac/management/AlmanacManagementLockWorkflow.php
@@ -0,0 +1,49 @@
+<?php
+
+final class AlmanacManagementLockWorkflow
+  extends AlmanacManagementWorkflow {
+
+  public function didConstruct() {
+    $this
+      ->setName('lock')
+      ->setSynopsis(pht('Lock a service to prevent it from being edited.'))
+      ->setArguments(
+        array(
+          array(
+            'name' => 'services',
+            'wildcard' => true,
+          ),
+        ));
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    $console = PhutilConsole::getConsole();
+
+    $services = $this->loadServices($args->getArg('services'));
+    if (!$services) {
+      throw new PhutilArgumentUsageException(
+        pht('Specify at least one service to lock.'));
+    }
+
+    foreach ($services as $service) {
+      if ($service->getIsLocked()) {
+        throw new PhutilArgumentUsageException(
+          pht(
+            'Service "%s" is already locked!',
+            $service->getName()));
+      }
+    }
+
+    foreach ($services as $service) {
+      $this->updateServiceLock($service, true);
+
+      $console->writeOut(
+        "**<bg:green> %s </bg>** %s\n",
+        pht('LOCKED'),
+        pht('Service "%s" was locked.', $service->getName()));
+    }
+
+    return 0;
+  }
+
+}
diff --git a/src/applications/almanac/management/AlmanacManagementUnlockWorkflow.php b/src/applications/almanac/management/AlmanacManagementUnlockWorkflow.php
new file mode 100644
--- /dev/null
+++ b/src/applications/almanac/management/AlmanacManagementUnlockWorkflow.php
@@ -0,0 +1,49 @@
+<?php
+
+final class AlmanacManagementUnlockWorkflow
+  extends AlmanacManagementWorkflow {
+
+  public function didConstruct() {
+    $this
+      ->setName('unlock')
+      ->setSynopsis(pht('Unlock a service to allow it to be edited.'))
+      ->setArguments(
+        array(
+          array(
+            'name' => 'services',
+            'wildcard' => true,
+          ),
+        ));
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    $console = PhutilConsole::getConsole();
+
+    $services = $this->loadServices($args->getArg('services'));
+    if (!$services) {
+      throw new PhutilArgumentUsageException(
+        pht('Specify at least one service to unlock.'));
+    }
+
+    foreach ($services as $service) {
+      if (!$service->getIsLocked()) {
+        throw new PhutilArgumentUsageException(
+          pht(
+            'Service "%s" is not locked!',
+            $service->getName()));
+      }
+    }
+
+    foreach ($services as $service) {
+      $this->updateServiceLock($service, false);
+
+      $console->writeOut(
+        "**<bg:green> %s </bg>** %s\n",
+        pht('UNLOCKED'),
+        pht('Service "%s" was unlocked.', $service->getName()));
+    }
+
+    return 0;
+  }
+
+}
diff --git a/src/applications/almanac/management/AlmanacManagementWorkflow.php b/src/applications/almanac/management/AlmanacManagementWorkflow.php
--- a/src/applications/almanac/management/AlmanacManagementWorkflow.php
+++ b/src/applications/almanac/management/AlmanacManagementWorkflow.php
@@ -1,4 +1,46 @@
 <?php
 
 abstract class AlmanacManagementWorkflow
-  extends PhabricatorManagementWorkflow {}
+  extends PhabricatorManagementWorkflow {
+
+
+  protected function loadServices(array $names) {
+    if (!$names) {
+      return array();
+    }
+
+    $services = id(new AlmanacServiceQuery())
+      ->setViewer($this->getViewer())
+      ->withNames($names)
+      ->execute();
+
+    $services = mpull($services, null, 'getName');
+    foreach ($names as $name) {
+      if (empty($services[$name])) {
+        throw new PhutilArgumentUsageException(
+          pht(
+            'Service "%s" does not exist or could not be loaded!',
+            $name));
+      }
+    }
+
+    return $services;
+  }
+
+  protected function updateServiceLock(AlmanacService $service, $lock) {
+    $almanac_phid = id(new PhabricatorAlmanacApplication())->getPHID();
+
+    $xaction = id(new AlmanacServiceTransaction())
+      ->setTransactionType(AlmanacServiceTransaction::TYPE_LOCK)
+      ->setNewValue((int)$lock);
+
+    $editor = id(new AlmanacServiceEditor())
+      ->setActor($this->getViewer())
+      ->setActingAsPHID($almanac_phid)
+      ->setContentSource(PhabricatorContentSource::newConsoleSource())
+      ->setContinueOnMissingFields(true);
+
+    $editor->applyTransactions($service, array($xaction));
+  }
+
+}
diff --git a/src/applications/almanac/query/AlmanacServiceQuery.php b/src/applications/almanac/query/AlmanacServiceQuery.php
--- a/src/applications/almanac/query/AlmanacServiceQuery.php
+++ b/src/applications/almanac/query/AlmanacServiceQuery.php
@@ -7,6 +7,9 @@
   private $phids;
   private $names;
   private $serviceClasses;
+  private $devicePHIDs;
+  private $locked;
+
   private $needBindings;
 
   public function withIDs(array $ids) {
@@ -29,6 +32,16 @@
     return $this;
   }
 
+  public function withDevicePHIDs(array $phids) {
+    $this->devicePHIDs = $phids;
+    return $this;
+  }
+
+  public function withLocked($locked) {
+    $this->locked = $locked;
+    return $this;
+  }
+
   public function needBindings($need_bindings) {
     $this->needBindings = $need_bindings;
     return $this;
@@ -40,8 +53,9 @@
 
     $data = queryfx_all(
       $conn_r,
-      'SELECT * FROM %T %Q %Q %Q',
+      'SELECT service.* FROM %T service %Q %Q %Q %Q',
       $table->getTableName(),
+      $this->buildJoinClause($conn_r),
       $this->buildWhereClause($conn_r),
       $this->buildOrderClause($conn_r),
       $this->buildLimitClause($conn_r));
@@ -49,20 +63,33 @@
     return $table->loadAllFromArray($data);
   }
 
+  protected function buildJoinClause($conn_r) {
+    $joins = array();
+
+    if ($this->devicePHIDs !== null) {
+      $joins[] = qsprintf(
+        $conn_r,
+        'JOIN %T binding ON service.phid = binding.servicePHID',
+        id(new AlmanacBinding())->getTableName());
+    }
+
+    return implode(' ', $joins);
+  }
+
   protected function buildWhereClause($conn_r) {
     $where = array();
 
     if ($this->ids !== null) {
       $where[] = qsprintf(
         $conn_r,
-        'id IN (%Ld)',
+        'service.id IN (%Ld)',
         $this->ids);
     }
 
     if ($this->phids !== null) {
       $where[] = qsprintf(
         $conn_r,
-        'phid IN (%Ls)',
+        'service.phid IN (%Ls)',
         $this->phids);
     }
 
@@ -74,17 +101,31 @@
 
       $where[] = qsprintf(
         $conn_r,
-        'nameIndex IN (%Ls)',
+        'service.nameIndex IN (%Ls)',
         $hashes);
     }
 
     if ($this->serviceClasses !== null) {
       $where[] = qsprintf(
         $conn_r,
-        'serviceClass IN (%Ls)',
+        'service.serviceClass IN (%Ls)',
         $this->serviceClasses);
     }
 
+    if ($this->devicePHIDs !== null) {
+      $where[] = qsprintf(
+        $conn_r,
+        'binding.devicePHID IN (%Ls)',
+        $this->devicePHIDs);
+    }
+
+    if ($this->locked !== null) {
+      $where[] = qsprintf(
+        $conn_r,
+        'service.isLocked = %d',
+        (int)$this->locked);
+    }
+
     $where[] = $this->buildPagingClause($conn_r);
 
     return $this->formatWhereClause($where);
diff --git a/src/applications/almanac/query/AlmanacServiceSearchEngine.php b/src/applications/almanac/query/AlmanacServiceSearchEngine.php
--- a/src/applications/almanac/query/AlmanacServiceSearchEngine.php
+++ b/src/applications/almanac/query/AlmanacServiceSearchEngine.php
@@ -78,6 +78,15 @@
           $service->getServiceType()->getServiceTypeIcon(),
           $service->getServiceType()->getServiceTypeShortName());
 
+      if ($service->getIsLocked() ||
+          $service->getServiceType()->isClusterServiceType()) {
+        if ($service->getIsLocked()) {
+          $item->addIcon('fa-lock', pht('Locked'));
+        } else {
+          $item->addIcon('fa-unlock-alt red', pht('Unlocked'));
+        }
+      }
+
       $list->addItem($item);
     }
 
diff --git a/src/applications/almanac/servicetype/AlmanacClusterServiceType.php b/src/applications/almanac/servicetype/AlmanacClusterServiceType.php
--- a/src/applications/almanac/servicetype/AlmanacClusterServiceType.php
+++ b/src/applications/almanac/servicetype/AlmanacClusterServiceType.php
@@ -11,4 +11,28 @@
     return 'fa-sitemap';
   }
 
+  public function getStatusMessages(AlmanacService $service) {
+    $messages = parent::getStatusMessages($service);
+
+    if (!$service->getIsLocked()) {
+      $doc_href = PhabricatorEnv::getDoclink(
+        'User Guide: Phabricator Clusters');
+
+      $doc_link = phutil_tag(
+        'a',
+        array(
+          'href' => $doc_href,
+          'target' => '_blank',
+        ),
+        pht('Learn More'));
+
+      $messages[] = pht(
+        'This is an unlocked cluster service. After you finish editing '.
+        'it, you should lock it. %s.',
+        $doc_link);
+    }
+
+    return $messages;
+  }
+
 }
diff --git a/src/applications/almanac/servicetype/AlmanacServiceType.php b/src/applications/almanac/servicetype/AlmanacServiceType.php
--- a/src/applications/almanac/servicetype/AlmanacServiceType.php
+++ b/src/applications/almanac/servicetype/AlmanacServiceType.php
@@ -55,6 +55,10 @@
     return array();
   }
 
+  public function getStatusMessages(AlmanacService $service) {
+    return array();
+  }
+
   /**
    * List all available service type implementations.
    *
diff --git a/src/applications/almanac/storage/AlmanacBinding.php b/src/applications/almanac/storage/AlmanacBinding.php
--- a/src/applications/almanac/storage/AlmanacBinding.php
+++ b/src/applications/almanac/storage/AlmanacBinding.php
@@ -143,12 +143,21 @@
   }
 
   public function describeAutomaticCapability($capability) {
-    return array(
+    $notes = array(
       pht('A binding inherits the policies of its service.'),
       pht(
         'To view a binding, you must also be able to view its device and '.
         'interface.'),
     );
+
+    if ($capability === PhabricatorPolicyCapability::CAN_EDIT) {
+      if ($this->getService()->getIsLocked()) {
+        $notes[] = pht(
+          'The service for this binding is locked, so it can not be edited.');
+      }
+    }
+
+    return $notes;
   }
 
 
diff --git a/src/applications/almanac/storage/AlmanacDevice.php b/src/applications/almanac/storage/AlmanacDevice.php
--- a/src/applications/almanac/storage/AlmanacDevice.php
+++ b/src/applications/almanac/storage/AlmanacDevice.php
@@ -15,6 +15,7 @@
   protected $mailKey;
   protected $viewPolicy;
   protected $editPolicy;
+  protected $isLocked;
 
   private $customFields = self::ATTACHABLE;
   private $almanacProperties = self::ATTACHABLE;
@@ -23,7 +24,8 @@
     return id(new AlmanacDevice())
       ->setViewPolicy(PhabricatorPolicies::POLICY_USER)
       ->setEditPolicy(PhabricatorPolicies::POLICY_ADMIN)
-      ->attachAlmanacProperties(array());
+      ->attachAlmanacProperties(array())
+      ->setIsLocked(0);
   }
 
   public function getConfiguration() {
@@ -33,6 +35,7 @@
         'name' => 'text128',
         'nameIndex' => 'bytes12',
         'mailKey' => 'bytes20',
+        'isLocked' => 'bool',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_name' => array(
@@ -67,6 +70,37 @@
   }
 
 
+  /**
+   * Find locked services which are bound to this device, updating the device
+   * lock flag if necessary.
+   *
+   * @return list<phid> List of locking service PHIDs.
+   */
+  public function rebuildDeviceLocks() {
+    $services = id(new AlmanacServiceQuery())
+      ->setViewer(PhabricatorUser::getOmnipotentUser())
+      ->withDevicePHIDs(array($this->getPHID()))
+      ->withLocked(true)
+      ->execute();
+
+    $locked = (bool)count($services);
+
+    if ($locked != $this->getIsLocked()) {
+      $this->setIsLocked((int)$locked);
+      $unguarded = AphrontWriteGuard::beginScopedUnguardedWrites();
+        queryfx(
+          $this->establishConnection('w'),
+          'UPDATE %T SET isLocked = %d WHERE id = %d',
+          $this->getTableName(),
+          $this->getIsLocked(),
+          $this->getID());
+      unset($unguarded);
+    }
+
+    return $this;
+  }
+
+
 /* -(  AlmanacPropertyInterface  )------------------------------------------- */
 
 
@@ -117,7 +151,11 @@
       case PhabricatorPolicyCapability::CAN_VIEW:
         return $this->getViewPolicy();
       case PhabricatorPolicyCapability::CAN_EDIT:
-        return $this->getEditPolicy();
+        if ($this->getIsLocked()) {
+          return PhabricatorPolicies::POLICY_NOONE;
+        } else {
+          return $this->getEditPolicy();
+        }
     }
   }
 
@@ -126,6 +164,14 @@
   }
 
   public function describeAutomaticCapability($capability) {
+    if ($capability === PhabricatorPolicyCapability::CAN_EDIT) {
+      if ($this->getIsLocked()) {
+        return pht(
+          'This device is bound to a locked service, so it can not '.
+          'be edited.');
+      }
+    }
+
     return null;
   }
 
diff --git a/src/applications/almanac/storage/AlmanacInterface.php b/src/applications/almanac/storage/AlmanacInterface.php
--- a/src/applications/almanac/storage/AlmanacInterface.php
+++ b/src/applications/almanac/storage/AlmanacInterface.php
@@ -92,12 +92,21 @@
   }
 
   public function describeAutomaticCapability($capability) {
-    return array(
+    $notes = array(
       pht('An interface inherits the policies of the device it belongs to.'),
       pht(
         'You must be able to view the network an interface resides on to '.
         'view the interface.'),
     );
+
+    if ($capability === PhabricatorPolicyCapability::CAN_EDIT) {
+      if ($this->getDevice()->getIsLocked()) {
+        $notes[] = pht(
+          'The device for this interface is locked, so it can not be edited.');
+      }
+    }
+
+    return $notes;
   }
 
 }
diff --git a/src/applications/almanac/storage/AlmanacService.php b/src/applications/almanac/storage/AlmanacService.php
--- a/src/applications/almanac/storage/AlmanacService.php
+++ b/src/applications/almanac/storage/AlmanacService.php
@@ -15,6 +15,7 @@
   protected $viewPolicy;
   protected $editPolicy;
   protected $serviceClass;
+  protected $isLocked;
 
   private $customFields = self::ATTACHABLE;
   private $almanacProperties = self::ATTACHABLE;
@@ -25,7 +26,8 @@
     return id(new AlmanacService())
       ->setViewPolicy(PhabricatorPolicies::POLICY_USER)
       ->setEditPolicy(PhabricatorPolicies::POLICY_ADMIN)
-      ->attachAlmanacProperties(array());
+      ->attachAlmanacProperties(array())
+      ->setIsLocked(0);
   }
 
   public function getConfiguration() {
@@ -36,6 +38,7 @@
         'nameIndex' => 'bytes12',
         'mailKey' => 'bytes20',
         'serviceClass' => 'text64',
+        'isLocked' => 'bool',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_name' => array(
@@ -141,7 +144,11 @@
       case PhabricatorPolicyCapability::CAN_VIEW:
         return $this->getViewPolicy();
       case PhabricatorPolicyCapability::CAN_EDIT:
-        return $this->getEditPolicy();
+        if ($this->getIsLocked()) {
+          return PhabricatorPolicies::POLICY_NOONE;
+        } else {
+          return $this->getEditPolicy();
+        }
     }
   }
 
@@ -150,6 +157,14 @@
   }
 
   public function describeAutomaticCapability($capability) {
+    switch ($capability) {
+      case PhabricatorPolicyCapability::CAN_EDIT:
+        if ($this->getIsLocked()) {
+          return pht('This service is locked and can not be edited.');
+        }
+        break;
+    }
+
     return null;
   }
 
diff --git a/src/applications/almanac/storage/AlmanacServiceTransaction.php b/src/applications/almanac/storage/AlmanacServiceTransaction.php
--- a/src/applications/almanac/storage/AlmanacServiceTransaction.php
+++ b/src/applications/almanac/storage/AlmanacServiceTransaction.php
@@ -4,6 +4,7 @@
   extends PhabricatorApplicationTransaction {
 
   const TYPE_NAME = 'almanac:service:name';
+  const TYPE_LOCK = 'almanac:service:lock';
 
   public function getApplicationName() {
     return 'almanac';
@@ -37,6 +38,17 @@
             $new);
         }
         break;
+      case self::TYPE_LOCK:
+        if ($new) {
+          return pht(
+            '%s locked this service.',
+            $this->renderHandleLink($author_phid));
+        } else {
+          return pht(
+            '%s unlocked this service.',
+            $this->renderHandleLink($author_phid));
+        }
+        break;
     }
 
     return parent::getTitle();
diff --git a/src/applications/almanac/view/AlmanacInterfaceTableView.php b/src/applications/almanac/view/AlmanacInterfaceTableView.php
--- a/src/applications/almanac/view/AlmanacInterfaceTableView.php
+++ b/src/applications/almanac/view/AlmanacInterfaceTableView.php
@@ -4,6 +4,7 @@
 
   private $interfaces;
   private $handles;
+  private $canEdit;
 
   public function setHandles(array $handles) {
     $this->handles = $handles;
@@ -23,11 +24,26 @@
     return $this->interfaces;
   }
 
+  public function setCanEdit($can_edit) {
+    $this->canEdit = $can_edit;
+    return $this;
+  }
+
+  public function getCanEdit() {
+    return $this->canEdit;
+  }
+
   public function render() {
     $interfaces = $this->getInterfaces();
     $handles = $this->getHandles();
     $viewer = $this->getUser();
 
+    if ($this->getCanEdit()) {
+      $button_class = 'small grey button';
+    } else {
+      $button_class = 'small grey button disabled';
+    }
+
     $rows = array();
     foreach ($interfaces as $interface) {
       $rows[] = array(
@@ -38,7 +54,7 @@
         phutil_tag(
           'a',
           array(
-            'class' => 'small grey button',
+            'class' => $button_class,
             'href' => '/almanac/interface/edit/'.$interface->getID().'/',
           ),
           pht('Edit')),
diff --git a/src/docs/user/configuration/cluster.diviner b/src/docs/user/configuration/cluster.diviner
new file mode 100644
--- /dev/null
+++ b/src/docs/user/configuration/cluster.diviner
@@ -0,0 +1,31 @@
+@title User Guide: Phabricator Clusters
+@group config
+
+Guide on scaling Phabricator across multiple machines, for large installs.
+
+Overview
+========
+
+IMPORTANT: Phabricator clustering is in its infancy and does not work at all
+yet. This document is mostly a placeholder.
+
+Locking Services
+================
+
+Because cluster configuration is defined in Phabricator itself, an attacker
+who compromises an account that can edit the cluster definition has significant
+power. For example, the attacker might be able to configure Phabricator to
+replicate the database to a server they control.
+
+To mitigate this attack, services in Almanac can be locked to prevent them
+from being edited from the web UI. An attacker would then need significantly
+greater access (to the CLI, or directly to the database) in order to change
+the cluster configuration.
+
+You should normally keep cluster services in a locked state, and unlock them
+only to edit them. Once you're finished making changes, lock the service again.
+The web UI will warn you when you're viewing an unlocked cluster service, as
+a reminder that you should lock it again once you're finished editing.
+
+For details on how to lock and unlock a service, see
+@{article:Almanac User Guide}.
diff --git a/src/docs/user/userguide/almanac.diviner b/src/docs/user/userguide/almanac.diviner
new file mode 100644
--- /dev/null
+++ b/src/docs/user/userguide/almanac.diviner
@@ -0,0 +1,40 @@
+@title Almanac User Guide
+@group userguide
+
+Using Almanac to manage services.
+
+= Overview =
+
+IMPORTANT: Almanac is a prototype application. See
+@{article:User Guide: Prototype Applications}.
+
+Locking and Unlocking Services
+==============================
+
+Services can be locked to prevent edits from the web UI. This primarily hardens
+Almanac against attacks involving account compromise. Notably, locking cluster
+services prevents an attacker from modifying the Phabricator cluster definition.
+For more details on this scenario, see
+@{article:User Guide: Phabricator Clusters}.
+
+Beyond hardening cluster definitions, you might also want to lock a service to
+prevent accidental edits.
+
+To lock a service, run:
+
+  phabricator/ $ ./bin/almanac lock <service>
+
+To unlock a service later, run:
+
+  phabricator/ $ ./bin/almanac unlock <service>
+
+Locking a service also locks all of the service's bindings and properties, as
+well as the devices connected to the service. Generally, no part of the
+service definition can be modified while it is locked.
+
+Devices (and their properties) will remain locked as long as they are bound to
+at least one locked service. To edit a device, you'll need to unlock all the
+services it is bound to.
+
+Locked services and devices will show that they are locked in the web UI, and
+editing options will be unavailable.