public interface ComputeLoadBalancer
LoadBalancingSpi
to get the balanced node.
Load balancer can be used explicitly from inside ComputeTask.map(List, Object)
method when you implement ComputeTask
interface directly or use
ComputeTaskAdapter
. If you use ComputeTaskSplitAdapter
then
load balancer is accessed implicitly by the adapter so you don't have
to use it directly in your logic.
ComputeTaskSplitAdapter
then load balancing logic
is transparent to your code and is handled automatically by the adapter.
Here is an example of how your task will look:
public class MyFooBarTask extends ComputeTaskSplitAdapter<String> { @Override protected Collection<? extends ComputeJob> split(int gridSize, String arg) throws IgniteCheckedException { List<MyFooBarJob> jobs = new ArrayList<MyFooBarJob>(gridSize); for (int i = 0; i < gridSize; i++) { jobs.add(new MyFooBarJob(arg)); } // Node assignment via load balancer // happens automatically. return jobs; } ... }If you need more fine-grained control over how some jobs within task get mapped to a node and use affinity load balancing for some other jobs within task, then you should use
ComputeTaskAdapter
. Here is an example of how your task will look. Note that in this
case we manually inject load balancer and use it to pick the best node. Doing it in
such way would allow user to map some jobs manually and for others use load balancer.
public class MyFooBarTask extends ComputeTaskAdapter<String, String> { // Inject load balancer. @LoadBalancerResource ComputeLoadBalancer balancer; // Map jobs to grid nodes. public Map<? extends ComputeJob, ClusterNode> map(List<ClusterNode> subgrid, String arg) throws IgniteCheckedException { Map<MyFooBarJob, ClusterNode> jobs = new HashMap<MyFooBarJob, ClusterNode>(subgrid.size()); // In more complex cases, you can actually do // more complicated assignments of jobs to nodes. for (int i = 0; i < subgrid.size(); i++) { // Pick the next best balanced node for the job. ComputeJob myJob = new MyFooBarJob(arg); jobs.put(myJob, balancer.getBalancedNode(myJob, null)); } return jobs; } // Aggregate results into one compound result. public String reduce(List<ComputeJobResult> results) throws IgniteCheckedException { // For the purpose of this example we simply // concatenate string representation of every // job result StringBuilder buf = new StringBuilder(); for (ComputeJobResult res : results) { // Append string representation of result // returned by every job. buf.append(res.getData().toString()); } return buf.toString(); } }
Modifier and Type | Method and Description |
---|---|
ClusterNode |
getBalancedNode(ComputeJob job,
Collection<ClusterNode> exclNodes)
Gets the next balanced node according to the underlying load balancing policy.
|
ClusterNode getBalancedNode(ComputeJob job, Collection<ClusterNode> exclNodes) throws IgniteException
job
- Job to get the balanced node for.exclNodes
- Optional collection of nodes that should be excluded from balanced nodes.
If collection is null
or empty - no nodes will be excluded.null
, an exception will be thrown during Ignite
job mapping process.IgniteException
- If any error occurred when finding next balanced node.
GridGain In-Memory Computing Platform : ver. 8.9.14 Release Date : November 5 2024