Promote WeaklyUp and enable by default, #22197

akka-cluster/src/main/resources/reference.conf

@@ -59,13 +59,11 @@ akka {
     # cluster singleton handover to complete) and then quarantine the removed node.
     quarantine-removed-node-after=30s
 
-    # By default, the leader will not move 'Joining' members to 'Up' during a network
+    # If this is set to "off", the leader will not move 'Joining' members to 'Up' during a network
     # split. This feature allows the leader to accept 'Joining' members to be 'WeaklyUp'
     # so they become part of the cluster even during a network split. The leader will
-    # move 'WeaklyUp' members to 'Up' status once convergence has been reached. This
+    # move 'WeaklyUp' members to 'Up' status once convergence has been reached.
-    # feature must be off if some members are running Akka 2.3.X.
+    allow-weakly-up-members = on
-    # WeaklyUp is an EXPERIMENTAL feature.
-    allow-weakly-up-members = off
 
     # The roles of this member. List of strings, e.g. roles = ["A", "B"].
     # The roles are part of the membership information and can be used by

akka-cluster/src/main/scala/akka/cluster/Member.scala

@@ -183,10 +183,6 @@ sealed abstract class MemberStatus
 
 object MemberStatus {
   @SerialVersionUID(1L) case object Joining extends MemberStatus
-  /**
-   * WeaklyUp is an EXPERIMENTAL feature and is subject to change until
-   * it has received more real world testing.
-   */
   @SerialVersionUID(1L) case object WeaklyUp extends MemberStatus
   @SerialVersionUID(1L) case object Up extends MemberStatus
   @SerialVersionUID(1L) case object Leaving extends MemberStatus
@@ -201,8 +197,6 @@ object MemberStatus {
 
   /**
    * Java API: retrieve the “weaklyUp” status singleton.
-   * WeaklyUp is an EXPERIMENTAL feature and is subject to change until
-   * it has received more real world testing.
    */
   def weaklyUp: MemberStatus = WeaklyUp
 

akka-cluster/src/multi-jvm/scala/akka/cluster/ConvergenceSpec.scala

@@ -19,7 +19,10 @@ final case class ConvergenceMultiNodeConfig(failureDetectorPuppet: Boolean) exte
   val fourth = role("fourth")
 
   commonConfig(debugConfig(on = false).
-    withFallback(ConfigFactory.parseString("akka.cluster.failure-detector.threshold = 4")).
+    withFallback(ConfigFactory.parseString("""
+      akka.cluster.failure-detector.threshold = 4
+      akka.cluster.allow-weakly-up-members = off
+      """)).
     withFallback(MultiNodeClusterSpec.clusterConfig(failureDetectorPuppet)))
 }
 

akka-docs/rst/common/cluster.rst

@@ -277,10 +277,10 @@ marked as ``down`` and new incarnation can rejoin the cluster without manual int
 
 As mentioned before, if a node is ``unreachable`` then gossip convergence is not
 possible and therefore any ``leader`` actions are also not possible. By enabling
-``akka.cluster.allow-weakly-up-members`` it is possible to let new joining nodes be
+``akka.cluster.allow-weakly-up-members`` (enabled by default) it is possible to 
-promoted while convergence is not yet reached. These ``Joining`` nodes will be
+let new joining nodes be promoted while convergence is not yet reached. These 
-promoted as ``WeaklyUp``. Once gossip convergence is reached, the leader will move
+``Joining`` nodes will be promoted as ``WeaklyUp``. Once gossip convergence is 
-``WeaklyUp`` members to ``Up``.
+reached, the leader will move ``WeaklyUp`` members to ``Up``.
 
 Note that members on the other side of a network partition have no knowledge about 
 the existence of the new members. You should for example not count ``WeaklyUp`` 

akka-docs/rst/java/cluster-metrics.rst

@@ -30,7 +30,7 @@ and add the following configuration stanza to your ``application.conf``
 
    akka.extensions = [ "akka.cluster.metrics.ClusterMetricsExtension" ]
 
-Cluster members with status :ref:`WeaklyUp <weakly_up_java>`, if that feature is enabled,
+Cluster members with status :ref:`WeaklyUp <weakly_up_java>`,
 will participate in Cluster Metrics collection and dissemination.
 
 Metrics Collector

akka-docs/rst/java/cluster-singleton.rst

@@ -53,8 +53,7 @@ It's worth noting that messages can always be lost because of the distributed na
 As always, additional logic should be implemented in the singleton (acknowledgement) and in the
 client (retry) actors to ensure at-least-once message delivery.
 
-The singleton instance will not run on members with status :ref:`WeaklyUp <weakly_up_java>` if that feature
+The singleton instance will not run on members with status :ref:`WeaklyUp <weakly_up_java>`.
-is enabled.
 
 Potential problems to be aware of
 ---------------------------------

akka-docs/rst/java/cluster-usage.rst

@@ -206,32 +206,19 @@ If a node is ``unreachable`` then gossip convergence is not possible and therefo
 ``leader`` actions are also not possible. However, we still might want new nodes to join
 the cluster in this scenario.
 
-.. warning::
+``Joining`` members will be promoted to ``WeaklyUp`` and become part of the cluster if 
-
+convergence can't be reached. Once gossip convergence is reached, the leader will move ``WeaklyUp``
-  The WeaklyUp feature is marked as **“experimental”** as of its introduction in Akka 2.4.0. We will continue to
-  improve this feature based on our users’ feedback, which implies that while we try to keep incompatible
-  changes to a minimum the binary compatibility guarantee for maintenance releases does not apply this feature.
-
-This feature is disabled by default. With a configuration option you can allow this behavior::
-
-    akka.cluster.allow-weakly-up-members = on
-
-When ``allow-weakly-up-members`` is enabled and there is no gossip convergence,
-``Joining`` members will be promoted to ``WeaklyUp`` and they will become part of the
-cluster. Once gossip convergence is reached, the leader will move ``WeaklyUp``
 members to ``Up``.
 
+This feature is enabled by default, but it can be disabled with configuration option::
+
+    akka.cluster.allow-weakly-up-members = off
+
 You can subscribe to the ``WeaklyUp`` membership event to make use of the members that are
 in this state, but you should be aware of that members on the other side of a network partition
 have no knowledge about the existence of the new members. You should for example not count
 ``WeaklyUp`` members in quorum decisions.
 
-.. warning::
-
-  This feature is only available from Akka 2.4.0 and cannot be used if some of your
-  cluster members are running an older version of Akka.
-
-
 .. _cluster_subscriber_java:
 
 Subscribe to Cluster Events
@@ -500,8 +487,7 @@ automatically unregistered from the router. When new nodes join the cluster addi
 routees are added to the router, according to the configuration. Routees are also added
 when a node becomes reachable again, after having been unreachable.
 
-Cluster aware routers make use of members with status :ref:`WeaklyUp <weakly_up_java>` if that feature
+Cluster aware routers make use of members with status :ref:`WeaklyUp <weakly_up_java>`.
-is enabled.
 
 There are two distinct types of routers.
 

akka-docs/rst/java/distributed-data.rst

@@ -40,7 +40,7 @@ with a specific role. It communicates with other ``Replicator`` instances with t
 (without address) that are running on other nodes . For convenience it can be used with the
 ``akka.cluster.ddata.DistributedData`` extension.
 
-Cluster members with status :ref:`WeaklyUp <weakly_up_java>`, if that feature is enabled,
+Cluster members with status :ref:`WeaklyUp <weakly_up_java>`, 
 will participate in Distributed Data. This means that the data will be replicated to the
 :ref:`WeaklyUp <weakly_up_java>` nodes with the background gossip protocol. Note that it
 will not participate in any actions where the consistency mode is to read/write from all

akka-docs/rst/java/distributed-pub-sub.rst

@@ -22,7 +22,7 @@ a few seconds. Changes are only performed in the own part of the registry and th
 changes are versioned. Deltas are disseminated in a scalable way to other nodes with
 a gossip protocol.
 
-Cluster members with status :ref:`WeaklyUp <weakly_up_java>`, if that feature is enabled,
+Cluster members with status :ref:`WeaklyUp <weakly_up_java>`, 
 will participate in Distributed Publish Subscribe, i.e. subscribers on nodes with 
 ``WeaklyUp`` status will receive published messages if the publisher and subscriber are on
 same side of a network partition.

akka-docs/rst/project/migration-guide-2.4.x-2.5.x.rst

@@ -314,6 +314,16 @@ used in the test::
   akka.coordinated-shutdown.run-by-jvm-shutdown-hook = off
   akka.cluster.run-coordinated-shutdown-when-down = off 
 
+WeaklyUp
+--------
+
+:ref:`weakly_up_scala` is now enabled by default, but it can be disabled with configuration option::
+
+    akka.cluster.allow-weakly-up-members = off
+
+You should not run a cluster with this feature enabled on some nodes and disabled on some. Therefore
+you might need to enable/disable it in configuration when performing rolling upgrade from 2.4.x to 2.5.0. 
+
 Cluster Management Command Line Tool
 ------------------------------------
 

akka-docs/rst/scala/cluster-singleton.rst

@@ -53,8 +53,7 @@ It's worth noting that messages can always be lost because of the distributed na
 As always, additional logic should be implemented in the singleton (acknowledgement) and in the
 client (retry) actors to ensure at-least-once message delivery.
 
-The singleton instance will not run on members with status :ref:`WeaklyUp <weakly_up_scala>` if that feature
+The singleton instance will not run on members with status :ref:`WeaklyUp <weakly_up_scala>`.
-is enabled.
 
 Potential problems to be aware of
 ---------------------------------

akka-docs/rst/scala/cluster-usage.rst

@@ -202,31 +202,19 @@ If a node is ``unreachable`` then gossip convergence is not possible and therefo
 ``leader`` actions are also not possible. However, we still might want new nodes to join
 the cluster in this scenario.
 
-.. warning::
+``Joining`` members will be promoted to ``WeaklyUp`` and become part of the cluster if 
-
+convergence can't be reached. Once gossip convergence is reached, the leader will move ``WeaklyUp``
-  The WeaklyUp feature is marked as **“experimental”** as of its introduction in Akka 2.4.0. We will continue to
-  improve this feature based on our users’ feedback, which implies that while we try to keep incompatible
-  changes to a minimum the binary compatibility guarantee for maintenance releases does not apply this feature.
-
-This feature is disabled by default. With a configuration option you can allow this behavior::
-
-    akka.cluster.allow-weakly-up-members = on
-
-When ``allow-weakly-up-members`` is enabled and there is no gossip convergence,
-``Joining`` members will be promoted to ``WeaklyUp`` and they will become part of the
-cluster. Once gossip convergence is reached, the leader will move ``WeaklyUp``
 members to ``Up``.
 
+This feature is enabled by default, but it can be disabled with configuration option::
+
+    akka.cluster.allow-weakly-up-members = off
+
 You can subscribe to the ``WeaklyUp`` membership event to make use of the members that are
 in this state, but you should be aware of that members on the other side of a network partition
 have no knowledge about the existence of the new members. You should for example not count
 ``WeaklyUp`` members in quorum decisions.
 
-.. warning::
-
-  This feature is only available from Akka 2.4.0 and cannot be used if some of your
-  cluster members are running an older version of Akka.
-
 
 .. _cluster_subscriber_scala:
 

akka-docs/rst/scala/distributed-data.rst

@@ -40,7 +40,7 @@ with a specific role. It communicates with other ``Replicator`` instances with t
 (without address) that are running on other nodes . For convenience it can be used with the
 ``akka.cluster.ddata.DistributedData`` extension.
 
-Cluster members with status :ref:`WeaklyUp <weakly_up_scala>`, if that feature is enabled,
+Cluster members with status :ref:`WeaklyUp <weakly_up_scala>`, 
 will participate in Distributed Data. This means that the data will be replicated to the
 :ref:`WeaklyUp <weakly_up_scala>` nodes with the background gossip protocol. Note that it
 will not participate in any actions where the consistency mode is to read/write from all

akka-docs/rst/scala/distributed-pub-sub.rst

@@ -22,7 +22,7 @@ a few seconds. Changes are only performed in the own part of the registry and th
 changes are versioned. Deltas are disseminated in a scalable way to other nodes with
 a gossip protocol.
 
-Cluster members with status :ref:`WeaklyUp <weakly_up_scala>`, if that feature is enabled,
+Cluster members with status :ref:`WeaklyUp <weakly_up_scala>`, 
 will participate in Distributed Publish Subscribe, i.e. subscribers on nodes with 
 ``WeaklyUp`` status will receive published messages if the publisher and subscriber are on
 same side of a network partition.