Use a thread pool with 1 thread instead of throttling

4 files changed, 4 insertions, 16 deletions

diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/ApplicationMaintainer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/ApplicationMaintainer.java
index 4240d2bd158..abee3b6ef7f 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/ApplicationMaintainer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/ApplicationMaintainer.java
@@ -27,8 +27,10 @@ public abstract class ApplicationMaintainer extends Maintainer {
 
     private final Deployer deployer;
 
-    // Use a fixed thread pool to avoid overload on config servers
-    private final Executor deploymentExecutor = Executors.newFixedThreadPool(4, new DaemonThreadFactory("node repo application maintainer"));
+    // Use a fixed thread pool to avoid overload on config servers. Resource usage when deploying varies
+    // a lot between applications, so doing one by one avoids issues where one or more resource-demanding
+    // deployments happen simultaneously
+    private final Executor deploymentExecutor = Executors.newSingleThreadExecutor(new DaemonThreadFactory("node repo application maintainer"));
 
     protected ApplicationMaintainer(Deployer deployer, NodeRepository nodeRepository, Duration interval, JobControl jobControl) {
         super(nodeRepository, interval, jobControl);
@@ -41,7 +43,6 @@ public abstract class ApplicationMaintainer extends Maintainer {
         for (ApplicationId application : applications) {
             if (canDeployNow(application))
                 deploy(application);
-            throttle(applications.size());
         }
     }
 
@@ -61,8 +62,6 @@ public abstract class ApplicationMaintainer extends Maintainer {
 
     protected Deployer deployer() { return deployer; }
 
-    /** Block in this method until the next application should be maintained */
-    protected abstract void throttle(int applicationCount);
 
     private Set<ApplicationId> applicationsNeedingMaintenance() {
         return nodesNeedingMaintenance().stream()
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/OperatorChangeApplicationMaintainer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/OperatorChangeApplicationMaintainer.java
index 57dee7b0dbc..45db9ea90d9 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/OperatorChangeApplicationMaintainer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/OperatorChangeApplicationMaintainer.java
@@ -53,9 +53,6 @@ public class OperatorChangeApplicationMaintainer extends ApplicationMaintainer {
                 .anyMatch(event -> event.agent() == Agent.operator && event.at().isAfter(instant));
     }
 
-    @Override
-    protected void throttle(int applicationCount) { }
-
     /** 
      * Deploy in the maintenance thread to avoid scheduling multiple deployments of the same application if it takes
      * longer to deploy than the (short) maintenance interval of this
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/PeriodicApplicationMaintainer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/PeriodicApplicationMaintainer.java
index c0e2d94ebea..e682f2dc76c 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/PeriodicApplicationMaintainer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/PeriodicApplicationMaintainer.java
@@ -26,12 +26,6 @@ public class PeriodicApplicationMaintainer extends ApplicationMaintainer {
     }
 
     @Override
-    protected void throttle(int applicationCount) {
-        // Sleep for a length of time that will spread deployment evenly over the maintenance period
-        try { Thread.sleep(interval().toMillis() / applicationCount); } catch (InterruptedException e) { return; }
-    }
-
-    @Override
     protected boolean canDeployNow(ApplicationId application) {
         Optional<Instant> lastDeploy = deployer().lastDeployTime(application);
         if (lastDeploy.isPresent() &&
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/PeriodicApplicationMaintainerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/PeriodicApplicationMaintainerTest.java
index 360e8de8d11..edbb965772e 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/PeriodicApplicationMaintainerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/PeriodicApplicationMaintainerTest.java
@@ -251,8 +251,6 @@ public class PeriodicApplicationMaintainerTest {
             deployWithLock(application);
         }
 
-        protected void throttle(int applicationCount) { }
-
         @Override
         protected List<Node> nodesNeedingMaintenance() {
             if (overriddenNodesNeedingMaintenance.isPresent())