User Code Deployment
Hazelcast allows you to deploy your own custom and domain classes to cluster members. From Hazelcast Platform Operator, you can deploy your application code from external buckets and ConfigMap objects in Kubernetes.
This topic explains how to configure code deployments. It also brings together examples of when you might use code deployments as part of the configuration of other features, such as the implementation of an external data store or an executor service for the asynchronous execution of tasks.
Configuring User Code Deployment
Below are the configuration options for the User Code Deployment feature.
Field | Description |
---|---|
|
When set to true, this option enables custom code deployment from Hazelcast clients. |
|
JAR files from an external bucket are placed under the Java classpath when the following parameter values are supplied:
|
|
Files specified in the ConfigMaps are placed under the Java classpath. |
|
Triggers a rolling restart to begin another download of the custom code. |
Example Configuration
The example configuration does the following:
-
Downloads JAR files from the specified external bucket and places them under the classpath of each of the Hazelcast members.
-
Puts all the files specified in the ConfigMap objects under the classpath of each of the Hazelcast members.
apiVersion: hazelcast.com/v1alpha1
kind: Hazelcast
metadata:
name: hazelcast
spec:
userCodeDeployment:
clientEnabled: true
bucketConfig:
secret: map-store-bucket-secret
bucketURI: gs://map-store-bucket/path/to/jars
configMaps:
- domain-classes-cm
- entryprocessor-cm
triggerSequence: "001"
Configuring an External Data Store with Hazelcast Platform Operator
The MapLoader
and MapStore
interfaces in Hazelcast allow you to load map entries from and save map entries to an external data store. See Working with an External Data Store for implementation details.
To use an external data store, you need to create MapLoader
and/or MapStore
classes and add configuration. In Hazelcast Platform Operator:
-
Deploy the
MapLoader
and/orMapStore
classes to the classpath of each Hazelcast member. -
Configure a
Map
resource for the MapLoader or MapStore.
Use the following configuration options in the Map
resource for a MapStore. The example shows how you might implement these options. For more detailed information, see the API Reference.
Field | Description |
---|---|
|
Sets the initial entry loading mode. LAZY is the default load mode, where load is asynchronous. EAGER means map operations are blocked until all partitions are loaded. |
|
Name of your class that implements the |
|
Number of seconds to delay the storing of map entries. |
|
Used to create batches when writing to the map store. In default mode, with a value of less than two, Hazelcast tries to write all map entries in one go. |
|
For use with write-behind mode in a MapStore. When this option is set to true, Hazelcast coalesces updates on a specific key, and so applies only the last update. Set this option to false to store all updates performed on a key to the data store. |
|
You can use properties to give information to the MapStore implementation. In this case, properties are taken from the secret with the given name. |
Example MapStore Configuration
An example Map
resource with MapStore configuration.
apiVersion: hazelcast.com/v1alpha1
kind: Map
metadata:
name: map-sample
spec:
hazelcastResourceName: hazelcast-sample
mapStore:
className: com.example.SimpleStore
propertiesSecretName: props
initialMode: LAZY
writeDelaySeconds: 1
writeBatchSize: 20
writeCoalescing: false
Configuring Executor Services with the Hazelcast Platform Operator
Hazelcast offers an executor service (IExecutorService
), which is an implementation of java.util.concurrent.ExecutorService
. With IExecutorService
, you can execute tasks asynchronously and perform other useful tasks.
To use the executor service, you need to create Callable
and/or Runnable
classes and add configuration. In Hazelcast Platform Operator:
-
Deploy your
Callable
orRunnable
classes to the classpath of each Hazelcast member. -
Configure a
Hazelcast
resource for theCallable
orRunnable
interface.
There are three variants of the executor service:
-
Executor Service
-
Durable Executor Service
-
Scheduled Executor Service.
Configuration options for a Hazelcast
resource to work with all three variants are shown in this section, along with examples of how you might implement these options. For more detailed implementation information, see Java Executor Service.
More information can be found in the API Reference page.
Field | Description |
---|---|
|
The name of the executor service. |
|
The number of executor threads per member. |
|
Task queue capacity of the executor. |
More information can be found in the API Reference page.
Field | Description |
---|---|
|
The name of the executor service. |
|
The number of executor threads per member. |
|
Number of backups in the cluster for the submitted task. |
|
Capacity of the executor task per partition. |
More information can be found in the API Reference page.
Field | Description |
---|---|
|
The name of the executor service. |
|
The number of executor threads per member. |
|
Number of backups in the cluster for the submitted task. |
|
Capacity of the executor task per partition. |
|
The active policy for the capacity setting. |
Example Executor Services
An example Hazelcast
resource with Executor Services configured.
apiVersion: hazelcast.com/v1alpha1
kind: Hazelcast
metadata:
name: hazelcast
spec:
executorServices:
- name: service1
capacity: 8
queueCapacity: 0
apiVersion: hazelcast.com/v1alpha1
kind: Hazelcast
metadata:
name: hazelcast
spec:
durableExecutorServices:
- name: service1
poolSize: 16
capacity: 100
durability: 1
apiVersion: hazelcast.com/v1alpha1
kind: Hazelcast
metadata:
name: hazelcast
spec:
scheduledExecutorServices:
- name: service1
poolSize: 16
capacity: 100
durability: 1
capacityPolicy: PER_NODE
Configuring an Entry Processor with Hazelcast Platform Operator
An entry processor executes your code on a map entry in an atomic way. To implement the EntryProcessor
interface, you can deploy an EntryProcessor
class from the Hazelcast Platform Operator to the classpath of a Hazelcast member. See Entry Processor for more detailed information.