Configuring Dynamic Configuration
You can configure members to keep dynamic configuration changes in memory or persist them to a YAML or XML configuration file.
Glossary
| Term | Definition |
|---|---|
root configuration file |
XML or YAML configuration file that is used to configure a member at startup. |
Production Checklist
Before you start configuring members to persist dynamic configuration changes, consider the following checklist:
-
Does your cluster have enough available disk space, especially if you want to create backups of the configuration file?
-
Does your cluster have read/write permissions for the configuration file? All members must have write permissions to the configuration file.
-
Is your cluster free of configuration conflicts? Hazelcast does not support persistence in clusters that have conflicting configuration files.
-
Are you using a root configuration file to start members? Dynamic configuration changes are persisted to the root configuration file, so you need to configure and start Hazelcast with that file.
| Running clusters must be restarted before any configuration changes take effect. |
Development Checklist
Before you start configuring members to persist dynamic configuration changes, consider the following checklist:
-
Do you start multiple members on a single device? Each member should have a unique root configuration file.
Kubernetes Checklist
If you use Kubernetes, do not configure persistence for dynamic configuration. Dynamic configuration changes are persisted to the root configuration file, not the ConfigMap.
Enabling Persistence
Enterprise
By default, persistence for dynamic configuration changes is disabled on all clusters. To start persisting changes on disk, you must first enable the feature on the member.
To enable persistence for dynamic configuration changes, set the persistence-enabled option to `true.
Creating Backups of the Configuration File
Enterprise
By default, Hazelcast keeps 5 backups of the configuration file in the member’s startup directory.
To change the number of backups, configure the backup-count option. To change the directory in which to store the backups, configure the backup-dir option.
The filenames of backups are in the following format, which includes the date and time when they were created followed by the .backup extension: yyyy-MM-dd—HH-mm-ss-SSS.backup. For example, 2022-01-31—13-23-44-699.backup.
If the backup directory contains existing files with the .backup extension or if time is shifted while the member is running, the order of backups can be corrupted.
|
<hazelcast>
<dynamic-configuration>
<persistence-enabled>true</persistence-enabled>
<backup-dir>/data/dynamic/backups</backup-dir>
<backup-count>7</backup-count>
</dynamic-configuration>
</hazelcast>hazelcast:
dynamic-configuration:
persistence-enabled: true
backup-dir: /data/dynamic/backups
backup-count: 7Configuration Options
Use the following configuration options to configure dynamic configuration for a cluster.
| Option | Description |
|---|---|
|
Root configuration |
|
Whether changes made in dynamic configuration are persisted to a configuration file. Default: false. |
|
Relative or absolute path to a directory in which to store backups of the configuration file. Each new backup will be created inside this directory. Default: A new directory called |
|
Number of backups of the configuration file to keep. To disable backups, set this option to 0. Default: 5. |
Full Example
<hazelcast>
<dynamic-configuration>
<persistence-enabled>true</persistence-enabled>
<backup-dir>/data/dynamic/backups</backup-dir>
<backup-count>7</backup-count>
</dynamic-configuration>
</hazelcast>hazelcast:
dynamic-configuration:
persistence-enabled: true
backup-dir: /data/dynamic/backups
backup-count: 7