Migrating to Axon Server
Are you currently using an RDMS, NoSQL, or other database to store your events and are you considering migrating to Axon Server? This guide will help you with the migration process.
Axon Server packages a migration tool in every downloaded package from the AxonIQ website.
The tool is called axonserver-migration.jar and is located in the root of the downloaded package.
You can also see the source code of the migration tool on GitHub: link:
How the tool works
The tool allows you define a source and a target. It will read events and snapshots from the source, and write them to the target. By default, it will stop when reaching the end of the source event store, but it can be configured to continuously keep reading events from the source when they come in.
The tool currently supports the following sources:
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RDBMS (any database that has a JDBC driver)
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MongoDB
As a target, only Axon Server is currently supported.
Configuration
The tool is configured using properties, such as an application.properties file. It has the potential to configure the following properies:
axoniq.migration.migrateEvents=true # Set to false to only migrate snapshots axoniq.migration.migrateSnapshot=true # Set to false to only migrate snapshots axoniq.migration.ignoredEvents= # A comma-separated list of event types to ignore axoniq.migration.continuous=false # Set to true to keep reading events from the source after reaching the end axoniq.migration.continuousTimeout=100ms # The time to wait before checking for new events axoniq.migration.recentMillis=10000 # What is considered a safe period for database commit consistency, defaults to 10 seconds axoniq.migration.reorderSequenceNumbers=false # Set to true if you have deleted events in your database in the past. This will leave gaps in aggregate sequence numbers and should be corrected during the migration. axon.serializer.events=XSTREAM # Which serializer to use for Metadata. XStream by default, can also be JACKSON or DEFAULT. Note that the events will be migrated as-is.
Configuration of relational database source
When using an RDBMS as a source, you need to configure the following properties:
axoniq.migration.source=RDBMS axoniq.datasource.eventstore.url=jdbc:postgresql://localhost:5432/your-database axoniq.datasource.eventstore.username=your-username axoniq.datasource.eventstore.password=your-password spring.jpa.properties.hibernate.dialect= # OPTIONAL. If you want to use a specific dialect, define this property. You can attach your own Jars containing a dialect in the libs folder. This will be automatically loaded
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Drivers
The application should be supplied a JDBC driver for the configured origin database. This driver should be put in the libs folder. |
Configuration of MongoDB source
When using MongoDB as a source, you need to configure the following properties:
axoniq.migration.source=MONGO spring.data.mongodb.uri=mongodb://localhost:27017/your-database spring.data.mongodb.username=your-username spring.data.mongodb.password=your-password
Other options for the Spring Mongo library can be used as well.
Configuration of Axon Server target
When using Axon Server as a target, you need to configure the following properties:
axoniq.migration.destination=AXONSERVER axoniq.axonserver.servers=localhost:8124 # Comma separated list of hostnames and ports for the Axon Server cluster. axoniq.axonserver.context=default # The context to use in Axon Server axoniq.axonserver.token= # The token to use for authentication
Any other Axon Framework properties for Axon Server can be used as well. This can be useful to configure certificates, access control tokens or other settings.