Remove samples (#22288)
Add code, that was used for documentation to the appropriate projects or akka-docs.
This commit is contained in:
Martynas Mickevičius
Johan Andrén
parent
b8cdcf3439
commit
958de6a916
373 changed files with 1201 additions and 17259 deletions
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@ -28,7 +28,41 @@ It joins the cluster and an actor subscribes to cluster membership events and lo
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The ``application.conf`` configuration looks like this:
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/resources/application.conf#snippet
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::
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akka {
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actor {
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provider = "cluster"
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}
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remote {
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log-remote-lifecycle-events = off
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netty.tcp {
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hostname = "127.0.0.1"
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port = 0
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}
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}
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cluster {
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seed-nodes = [
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"akka.tcp://ClusterSystem@127.0.0.1:2551",
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"akka.tcp://ClusterSystem@127.0.0.1:2552"]
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# auto downing is NOT safe for production deployments.
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# you may want to use it during development, read more about it in the docs.
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#
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# auto-down-unreachable-after = 10s
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}
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}
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# Disable legacy metrics in akka-cluster.
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akka.cluster.metrics.enabled=off
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# Enable metrics extension in akka-cluster-metrics.
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akka.extensions=["akka.cluster.metrics.ClusterMetricsExtension"]
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# Sigar native library extract location during tests.
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# Note: use per-jvm-instance folder when running multiple jvm on one host.
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akka.cluster.metrics.native-library-extract-folder=${user.dir}/target/native
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To enable cluster capabilities in your Akka project you should, at a minimum, add the :ref:`remoting-java`
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settings, but with ``cluster``.
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@ -45,13 +79,13 @@ ip-addresses or host names of the machines in ``application.conf`` instead of ``
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An actor that uses the cluster extension may look like this:
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.. literalinclude:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/simple/SimpleClusterListener.java
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.. literalinclude:: code/docs/cluster/SimpleClusterListener.java
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:language: java
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The actor registers itself as subscriber of certain cluster events. It receives events corresponding to the current state
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of the cluster when the subscription starts and then it receives events for changes that happen in the cluster.
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The easiest way to run this example yourself is to download `Lightbend Activator <http://www.lightbend.com/platform/getstarted>`_
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The easiest way to run this example yourself is to download `Lightbend Activator <http://www.lightbend.com/platform/getstarted>`_
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and open the tutorial named `Akka Cluster Samples with Java <http://www.lightbend.com/activator/template/akka-sample-cluster-java>`_.
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It contains instructions of how to run the ``SimpleClusterApp``.
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@ -140,7 +174,7 @@ It can also be performed programmatically with ``Cluster.get(system).down(addres
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A pre-packaged solution for the downing problem is provided by
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`Split Brain Resolver <http://doc.akka.io/docs/akka/akka-commercial-addons-1.0/java/split-brain-resolver.html>`_,
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which is part of the `Lightbend Reactive Platform <http://www.lightbend.com/platform>`_.
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which is part of the `Lightbend Reactive Platform <http://www.lightbend.com/platform>`_.
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If you don’t use RP, you should anyway carefully read the `documentation <http://doc.akka.io/docs/akka/akka-commercial-addons-1.0/java/split-brain-resolver.html>`_
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of the Split Brain Resolver and make sure that the solution you are using handles the concerns
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described there.
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@ -188,13 +222,13 @@ It can also be performed programmatically with:
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Note that this command can be issued to any member in the cluster, not necessarily the
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one that is leaving.
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The :ref:`coordinated-shutdown-java` will automatically run when the cluster node sees itself as
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``Exiting``, i.e. leaving from another node will trigger the shutdown process on the leaving node.
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Tasks for graceful leaving of cluster including graceful shutdown of Cluster Singletons and
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Cluster Sharding are added automatically when Akka Cluster is used, i.e. running the shutdown
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process will also trigger the graceful leaving if it's not already in progress.
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The :ref:`coordinated-shutdown-java` will automatically run when the cluster node sees itself as
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``Exiting``, i.e. leaving from another node will trigger the shutdown process on the leaving node.
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Tasks for graceful leaving of cluster including graceful shutdown of Cluster Singletons and
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Cluster Sharding are added automatically when Akka Cluster is used, i.e. running the shutdown
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process will also trigger the graceful leaving if it's not already in progress.
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Normally this is handled automatically, but in case of network failures during this process it might still
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Normally this is handled automatically, but in case of network failures during this process it might still
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be necessary to set the node’s status to ``Down`` in order to complete the removal.
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.. _weakly_up_java:
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@ -206,7 +240,7 @@ If a node is ``unreachable`` then gossip convergence is not possible and therefo
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``leader`` actions are also not possible. However, we still might want new nodes to join
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the cluster in this scenario.
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``Joining`` members will be promoted to ``WeaklyUp`` and become part of the cluster if
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``Joining`` members will be promoted to ``WeaklyUp`` and become part of the cluster if
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convergence can't be reached. Once gossip convergence is reached, the leader will move ``WeaklyUp``
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members to ``Up``.
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@ -227,7 +261,7 @@ Subscribe to Cluster Events
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You can subscribe to change notifications of the cluster membership by using
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``Cluster.get(system).subscribe``.
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/simple/SimpleClusterListener2.java#subscribe
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.. includecode:: code/docs/cluster/SimpleClusterListener2.java#subscribe
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A snapshot of the full state, ``akka.cluster.ClusterEvent.CurrentClusterState``, is sent to the subscriber
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as the first message, followed by events for incremental updates.
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@ -244,7 +278,7 @@ the events corresponding to the current state to mimic what you would have seen
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listening to the events when they occurred in the past. Note that those initial events only correspond
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to the current state and it is not the full history of all changes that actually has occurred in the cluster.
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/simple/SimpleClusterListener.java#subscribe
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.. includecode:: code/docs/cluster/SimpleClusterListener.java#subscribe
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The events to track the life-cycle of members are:
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@ -280,11 +314,11 @@ added or removed to the cluster dynamically.
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Messages:
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/transformation/TransformationMessages.java#messages
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.. includecode:: code/docs/cluster/TransformationMessages.java#messages
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The backend worker that performs the transformation job:
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/transformation/TransformationBackend.java#backend
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.. includecode:: code/docs/cluster/TransformationBackend.java#backend
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Note that the ``TransformationBackend`` actor subscribes to cluster events to detect new,
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potential, frontend nodes, and send them a registration message so that they know
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@ -292,7 +326,7 @@ that they can use the backend worker.
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The frontend that receives user jobs and delegates to one of the registered backend workers:
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/transformation/TransformationFrontend.java#frontend
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.. includecode:: code/docs/cluster/TransformationFrontend.java#frontend
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Note that the ``TransformationFrontend`` actor watch the registered backend
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to be able to remove it from its list of available backend workers.
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@ -301,8 +335,8 @@ network failures and JVM crashes, in addition to graceful termination of watched
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actor. Death watch generates the ``Terminated`` message to the watching actor when the
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unreachable cluster node has been downed and removed.
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The `Lightbend Activator <http://www.lightbend.com/platform/getstarted>`_ tutorial named
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`Akka Cluster Samples with Java <http://www.lightbend.com/activator/template/akka-sample-cluster-java>`_.
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The Akka sample named
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`Akka Cluster Sample with Java <https://github.com/akka/akka-samples/tree/master/akka-sample-cluster-java>`_.
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contains the full source code and instructions of how to run the **Worker Dial-in Example**.
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Node Roles
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@ -326,20 +360,23 @@ A common use case is to start actors after the cluster has been initialized,
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members have joined, and the cluster has reached a certain size.
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With a configuration option you can define required number of members
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before the leader changes member status of 'Joining' members to 'Up'.
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before the leader changes member status of 'Joining' members to 'Up'.::
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/resources/factorial.conf#min-nr-of-members
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akka.cluster.min-nr-of-members = 3
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In a similar way you can define required number of members of a certain role
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before the leader changes member status of 'Joining' members to 'Up'.
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before the leader changes member status of 'Joining' members to 'Up'.::
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/resources/factorial.conf#role-min-nr-of-members
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akka.cluster.role {
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frontend.min-nr-of-members = 1
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backend.min-nr-of-members = 2
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}
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You can start the actors in a ``registerOnMemberUp`` callback, which will
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be invoked when the current member status is changed to 'Up', i.e. the cluster
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has at least the defined number of members.
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/factorial/FactorialFrontendMain.java#registerOnUp
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.. includecode:: code/docs/cluster/FactorialFrontendMain.java#registerOnUp
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This callback can be used for other things than starting actors.
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@ -508,9 +545,19 @@ Router with Group of Routees
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----------------------------
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When using a ``Group`` you must start the routee actors on the cluster member nodes.
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That is not done by the router. The configuration for a group looks like this:
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That is not done by the router. The configuration for a group looks like this:::
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/multi-jvm/scala/sample/cluster/stats/StatsSampleSpec.scala#router-lookup-config
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akka.actor.deployment {
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/statsService/workerRouter {
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router = consistent-hashing-group
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routees.paths = ["/user/statsWorker"]
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cluster {
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enabled = on
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allow-local-routees = on
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use-role = compute
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}
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}
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}
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.. note::
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The routee actors should be started as early as possible when starting the actor system, because
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@ -527,7 +574,7 @@ Set it to a lower value if you want to limit total number of routees.
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The same type of router could also have been defined in code:
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/stats/Extra.java#router-lookup-in-code
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.. includecode:: code/docs/cluster/StatsService.java#router-lookup-in-code
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See :ref:`cluster_configuration_java` section for further descriptions of the settings.
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@ -545,40 +592,60 @@ the average number of characters per word when all results have been collected.
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Messages:
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/stats/StatsMessages.java#messages
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.. includecode:: code/docs/cluster/StatsMessages.java#messages
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The worker that counts number of characters in each word:
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/stats/StatsWorker.java#worker
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.. includecode:: code/docs/cluster/StatsWorker.java#worker
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The service that receives text from users and splits it up into words, delegates to workers and aggregates:
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/stats/StatsService.java#service
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.. includecode:: code/docs/cluster/StatsService.java#service
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/stats/StatsAggregator.java#aggregator
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.. includecode:: code/docs/cluster/StatsAggregator.java#aggregator
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Note, nothing cluster specific so far, just plain actors.
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All nodes start ``StatsService`` and ``StatsWorker`` actors. Remember, routees are the workers in this case.
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The router is configured with ``routees.paths``:
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The router is configured with ``routees.paths``:::
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/resources/stats1.conf#config-router-lookup
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akka.actor.deployment {
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/statsService/workerRouter {
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router = consistent-hashing-group
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routees.paths = ["/user/statsWorker"]
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cluster {
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enabled = on
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allow-local-routees = on
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use-role = compute
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}
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}
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}
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This means that user requests can be sent to ``StatsService`` on any node and it will use
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``StatsWorker`` on all nodes.
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The `Lightbend Activator <http://www.lightbend.com/platform/getstarted>`_ tutorial named
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`Akka Cluster Samples with Java <http://www.lightbend.com/activator/template/akka-sample-cluster-java>`_.
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The Akka sample named
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`Akka Cluster Sample with Java <https://github.com/akka/akka-samples/tree/master/akka-sample-cluster-java>`_.
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contains the full source code and instructions of how to run the **Router Example with Group of Routees**.
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Router with Pool of Remote Deployed Routees
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-------------------------------------------
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When using a ``Pool`` with routees created and deployed on the cluster member nodes
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the configuration for a router looks like this:
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the configuration for a router looks like this:::
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/multi-jvm/scala/sample/cluster/stats/StatsSampleSingleMasterSpec.scala#router-deploy-config
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akka.actor.deployment {
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/statsService/singleton/workerRouter {
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router = consistent-hashing-pool
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cluster {
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enabled = on
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max-nr-of-instances-per-node = 3
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allow-local-routees = on
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use-role = compute
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}
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}
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}
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It is possible to limit the deployment of routees to member nodes tagged with a certain role by
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specifying ``use-role``.
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@ -590,7 +657,7 @@ Set it to a lower value if you want to limit total number of routees.
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The same type of router could also have been defined in code:
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/stats/Extra.java#router-deploy-in-code
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.. includecode:: code/docs/cluster/StatsService.java#router-deploy-in-code
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See :ref:`cluster_configuration_java` section for further descriptions of the settings.
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@ -601,22 +668,32 @@ Let's take a look at how to use a cluster aware router on single master node tha
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and deploys workers. To keep track of a single master we use the :ref:`cluster-singleton-java`
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in the cluster-tools module. The ``ClusterSingletonManager`` is started on each node.
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/stats/StatsSampleOneMasterMain.java#create-singleton-manager
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.. includecode:: code/docs/cluster/StatsSampleOneMasterMain.java#create-singleton-manager
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We also need an actor on each node that keeps track of where current single master exists and
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delegates jobs to the ``StatsService``. That is provided by the ``ClusterSingletonProxy``.
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/java/sample/cluster/stats/StatsSampleOneMasterMain.java#singleton-proxy
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.. includecode:: code/docs/cluster/StatsSampleOneMasterMain.java#singleton-proxy
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The ``ClusterSingletonProxy`` receives text from users and delegates to the current ``StatsService``, the single
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master. It listens to cluster events to lookup the ``StatsService`` on the oldest node.
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All nodes start ``ClusterSingletonProxy`` and the ``ClusterSingletonManager``. The router is now configured like this:
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All nodes start ``ClusterSingletonProxy`` and the ``ClusterSingletonManager``. The router is now configured like this:::
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.. includecode:: ../../../akka-samples/akka-sample-cluster-java/src/main/resources/stats2.conf#config-router-deploy
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akka.actor.deployment {
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/statsService/singleton/workerRouter {
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router = consistent-hashing-pool
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cluster {
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enabled = on
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max-nr-of-instances-per-node = 3
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allow-local-routees = on
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use-role = compute
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}
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}
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}
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The `Lightbend Activator <http://www.lightbend.com/platform/getstarted>`_ tutorial named
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`Akka Cluster Samples with Java <http://www.lightbend.com/activator/template/akka-sample-cluster-java>`_.
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The Akka sample named
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`Akka Cluster Sample with Java <https://github.com/akka/akka-samples/tree/master/akka-sample-cluster-java>`_.
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contains the full source code and instructions of how to run the **Router Example with Pool of Remote Deployed Routees**.
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Cluster Metrics
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@ -634,7 +711,7 @@ Management
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HTTP
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----
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Information and management of the cluster is available with a HTTP API.
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Information and management of the cluster is available with a HTTP API.
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See documentation of `akka/akka-cluster-management <https://github.com/akka/akka-cluster-management>`_.
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.. _cluster_jmx_java:
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@ -662,7 +739,7 @@ Command Line
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------------
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.. warning::
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**Deprecation warning** - The command line script has been deprecated and is scheduled for removal
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**Deprecation warning** - The command line script has been deprecated and is scheduled for removal
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in the next major version. Use the :ref:`cluster_http_java` API with `curl <https://curl.haxx.se/>`_
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or similar instead.
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