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
@@ -1002,7 +1002,9 @@
     'HarbormasterController' => 'applications/harbormaster/controller/HarbormasterController.php',
     'HarbormasterCreateArtifactConduitAPIMethod' => 'applications/harbormaster/conduit/HarbormasterCreateArtifactConduitAPIMethod.php',
     'HarbormasterDAO' => 'applications/harbormaster/storage/HarbormasterDAO.php',
+    'HarbormasterDrydockCommandBuildStepImplementation' => 'applications/harbormaster/step/HarbormasterDrydockCommandBuildStepImplementation.php',
     'HarbormasterDrydockLeaseArtifact' => 'applications/harbormaster/artifact/HarbormasterDrydockLeaseArtifact.php',
+    'HarbormasterExecFuture' => 'applications/harbormaster/future/HarbormasterExecFuture.php',
     'HarbormasterExternalBuildStepGroup' => 'applications/harbormaster/stepgroup/HarbormasterExternalBuildStepGroup.php',
     'HarbormasterFileArtifact' => 'applications/harbormaster/artifact/HarbormasterFileArtifact.php',
     'HarbormasterHTTPRequestBuildStepImplementation' => 'applications/harbormaster/step/HarbormasterHTTPRequestBuildStepImplementation.php',
@@ -4789,7 +4791,9 @@
     'HarbormasterController' => 'PhabricatorController',
     'HarbormasterCreateArtifactConduitAPIMethod' => 'HarbormasterConduitAPIMethod',
     'HarbormasterDAO' => 'PhabricatorLiskDAO',
+    'HarbormasterDrydockCommandBuildStepImplementation' => 'HarbormasterBuildStepImplementation',
     'HarbormasterDrydockLeaseArtifact' => 'HarbormasterArtifact',
+    'HarbormasterExecFuture' => 'Future',
     'HarbormasterExternalBuildStepGroup' => 'HarbormasterBuildStepGroup',
     'HarbormasterFileArtifact' => 'HarbormasterArtifact',
     'HarbormasterHTTPRequestBuildStepImplementation' => 'HarbormasterBuildStepImplementation',
diff --git a/src/applications/harbormaster/future/HarbormasterExecFuture.php b/src/applications/harbormaster/future/HarbormasterExecFuture.php
new file mode 100644
--- /dev/null
+++ b/src/applications/harbormaster/future/HarbormasterExecFuture.php
@@ -0,0 +1,50 @@
+<?php
+
+final class HarbormasterExecFuture
+  extends Future {
+
+  private $future;
+  private $stdout;
+  private $stderr;
+
+  public function setFuture(ExecFuture $future) {
+    $this->future = $future;
+    return $this;
+  }
+
+  public function getFuture() {
+    return $this->future;
+  }
+
+  public function setLogs(
+    HarbormasterBuildLog $stdout,
+    HarbormasterBuildLog $stderr) {
+    $this->stdout = $stdout;
+    $this->stderr = $stderr;
+    return $this;
+  }
+
+  public function isReady() {
+    $future = $this->getFuture();
+
+    $result = $future->isReady();
+
+    list($stdout, $stderr) = $future->read();
+    $future->discardBuffers();
+
+    if ($this->stdout) {
+      $this->stdout->append($stdout);
+    }
+
+    if ($this->stderr) {
+      $this->stderr->append($stderr);
+    }
+
+    return $result;
+  }
+
+  protected function getResult() {
+    return $this->getFuture()->getResult();
+  }
+
+}
diff --git a/src/applications/harbormaster/step/HarbormasterBuildStepImplementation.php b/src/applications/harbormaster/step/HarbormasterBuildStepImplementation.php
--- a/src/applications/harbormaster/step/HarbormasterBuildStepImplementation.php
+++ b/src/applications/harbormaster/step/HarbormasterBuildStepImplementation.php
@@ -238,22 +238,21 @@
     return $build->getBuildGeneration() !== $target->getBuildGeneration();
   }
 
-  protected function resolveFuture(
+  protected function resolveFutures(
     HarbormasterBuild $build,
     HarbormasterBuildTarget $target,
-    Future $future) {
+    array $futures) {
 
-    $futures = new FutureIterator(array($future));
+    $futures = new FutureIterator($futures);
     foreach ($futures->setUpdateInterval(5) as $key => $future) {
       if ($future === null) {
         $build->reload();
         if ($this->shouldAbort($build, $target)) {
           throw new HarbormasterBuildAbortedException();
         }
-      } else {
-        return $future->resolve();
       }
     }
+
   }
 
 
diff --git a/src/applications/harbormaster/step/HarbormasterDrydockCommandBuildStepImplementation.php b/src/applications/harbormaster/step/HarbormasterDrydockCommandBuildStepImplementation.php
new file mode 100644
--- /dev/null
+++ b/src/applications/harbormaster/step/HarbormasterDrydockCommandBuildStepImplementation.php
@@ -0,0 +1,90 @@
+<?php
+
+final class HarbormasterDrydockCommandBuildStepImplementation
+  extends HarbormasterBuildStepImplementation {
+
+  public function getName() {
+    return pht('Drydock: Run Command');
+  }
+
+  public function getGenericDescription() {
+    return pht('Run a command on Drydock resource.');
+  }
+
+  public function getBuildStepGroupKey() {
+    return HarbormasterPrototypeBuildStepGroup::GROUPKEY;
+  }
+
+  public function getDescription() {
+    return pht(
+      'Run command %s on %s.',
+      $this->formatSettingForDescription('command'),
+      $this->formatSettingForDescription('artifact'));
+  }
+
+  public function execute(
+    HarbormasterBuild $build,
+    HarbormasterBuildTarget $build_target) {
+    $viewer = PhabricatorUser::getOmnipotentUser();
+
+    $settings = $this->getSettings();
+    $variables = $build_target->getVariables();
+
+    $artifact = $build_target->loadArtifact($settings['artifact']);
+    $impl = $artifact->getArtifactImplementation();
+    $lease = $impl->loadArtifactLease($viewer);
+
+    // TODO: Require active lease.
+
+    $command = $this->mergeVariables(
+      'vcsprintf',
+      $settings['command'],
+      $variables);
+
+    $interface = $lease->getInterface(DrydockCommandInterface::INTERFACE_TYPE);
+
+    $exec_future = $interface->getExecFuture('%C', $command);
+
+    $harbor_future = id(new HarbormasterExecFuture())
+      ->setFuture($exec_future)
+      ->setLogs(
+        $build_target->newLog('remote', 'stdout'),
+        $build_target->newLog('remote', 'stderr'));
+
+    $this->resolveFutures(
+      $build,
+      $build_target,
+      array($harbor_future));
+
+    list($err) = $harbor_future->resolve();
+    if ($err) {
+      throw new HarbormasterBuildFailureException();
+    }
+  }
+
+  public function getArtifactInputs() {
+    return array(
+      array(
+        'name' => pht('Drydock Lease'),
+        'key' => $this->getSetting('artifact'),
+        'type' => HarbormasterWorkingCopyArtifact::ARTIFACTCONST,
+      ),
+    );
+  }
+
+  public function getFieldSpecifications() {
+    return array(
+      'command' => array(
+        'name' => pht('Command'),
+        'type' => 'text',
+        'required' => true,
+      ),
+      'artifact' => array(
+        'name' => pht('Drydock Lease'),
+        'type' => 'text',
+        'required' => true,
+      ),
+    );
+  }
+
+}
diff --git a/src/applications/harbormaster/step/HarbormasterHTTPRequestBuildStepImplementation.php b/src/applications/harbormaster/step/HarbormasterHTTPRequestBuildStepImplementation.php
--- a/src/applications/harbormaster/step/HarbormasterHTTPRequestBuildStepImplementation.php
+++ b/src/applications/harbormaster/step/HarbormasterHTTPRequestBuildStepImplementation.php
@@ -51,9 +51,6 @@
       $settings['uri'],
       $variables);
 
-    $log_body = $build->createLog($build_target, $uri, 'http-body');
-    $start = $log_body->start();
-
     $method = nonempty(idx($settings, 'method'), 'POST');
 
     $future = id(new HTTPSFuture($uri))
@@ -70,16 +67,30 @@
         $key->getPasswordEnvelope());
     }
 
-    list($status, $body, $headers) = $this->resolveFuture(
+    $this->resolveFutures(
       $build,
       $build_target,
-      $future);
+      array($future));
+
+    list($status, $body, $headers) = $future->resolve();
+
+    $header_lines = array();
+    foreach ($headers as $header) {
+      list($head, $tail) = $header;
+      $header_lines[] = "{$head}: {$tail}";
+    }
+    $header_lines = implode("\n", $header_lines);
+
+    $build_target
+      ->newLog($uri, 'http.head')
+      ->append($header_lines);
 
-    $log_body->append($body);
-    $log_body->finalize($start);
+    $build_target
+      ->newLog($uri, 'http.body')
+      ->append($body);
 
     if ($status->getStatusCode() != 200) {
-      $build->setBuildStatus(HarbormasterBuild::STATUS_FAILED);
+      throw new HarbormasterBuildFailureException();
     }
   }
 
diff --git a/src/applications/harbormaster/step/HarbormasterLeaseWorkingCopyBuildStepImplementation.php b/src/applications/harbormaster/step/HarbormasterLeaseWorkingCopyBuildStepImplementation.php
--- a/src/applications/harbormaster/step/HarbormasterLeaseWorkingCopyBuildStepImplementation.php
+++ b/src/applications/harbormaster/step/HarbormasterLeaseWorkingCopyBuildStepImplementation.php
@@ -88,7 +88,7 @@
       array(
         'name' => pht('Working Copy'),
         'key' => $this->getSetting('name'),
-        'type' => HarbormasterHostArtifact::ARTIFACTCONST,
+        'type' => HarbormasterWorkingCopyArtifact::ARTIFACTCONST,
       ),
     );
   }
diff --git a/src/applications/harbormaster/storage/build/HarbormasterBuildLog.php b/src/applications/harbormaster/storage/build/HarbormasterBuildLog.php
--- a/src/applications/harbormaster/storage/build/HarbormasterBuildLog.php
+++ b/src/applications/harbormaster/storage/build/HarbormasterBuildLog.php
@@ -10,6 +10,7 @@
   protected $live;
 
   private $buildTarget = self::ATTACHABLE;
+  private $start;
 
   const CHUNK_BYTE_LIMIT = 102400;
 
@@ -18,6 +19,12 @@
    */
   const ENCODING_TEXT = 'text';
 
+  public function __destruct() {
+    if ($this->live) {
+      $this->finalize($this->start);
+    }
+  }
+
   public static function initializeNewBuildLog(
     HarbormasterBuildTarget $build_target) {
 
@@ -75,6 +82,8 @@
     $this->setLive(1);
     $this->save();
 
+    $this->start = PhabricatorTime::getNow();
+
     return time();
   }
 
diff --git a/src/applications/harbormaster/storage/build/HarbormasterBuildTarget.php b/src/applications/harbormaster/storage/build/HarbormasterBuildTarget.php
--- a/src/applications/harbormaster/storage/build/HarbormasterBuildTarget.php
+++ b/src/applications/harbormaster/storage/build/HarbormasterBuildTarget.php
@@ -249,6 +249,20 @@
     return $artifact;
   }
 
+  public function newLog($log_source, $log_type) {
+    $log_source = id(new PhutilUTF8StringTruncator())
+      ->setMaximumBytes(250)
+      ->truncateString($log_source);
+
+    $log = HarbormasterBuildLog::initializeNewBuildLog($this)
+      ->setLogSource($log_source)
+      ->setLogType($log_type);
+
+    $log->start();
+
+    return $log;
+  }
+
 
 /* -(  Status  )------------------------------------------------------------- */