Appendix D. Upgrade Instructions

Please follow these instructions when upgrading from Titan or an older JanusGraph release.

D.1. Upgrading from Titan 1.0.0, 1.1.0-SNAPSHOT

JanusGraph is based on the latest commit to the titan11 branch of Titan repo.

JanusGraph has made the following changes to Titan, so you will need to adjust your code and configuration accordingly:

  1. module names: titan-* are now janusgraph-*
  2. package names: com.thinkaurelius.titan are now org.janusgraph
  3. class names: Titan* are now JanusGraph* except in cases where this would duplicate a word, e.g., TitanGraph is simply JanusGraph rather than JanusGraphGraph

IMPORTANT If you are pointing JanusGraph at an existing Titan database you will need to set the graph.titan-version property. For more information on how to configure JanusGraph to read data which had previously been written by Titan refer to Chapter 37, Migrating from Titan.

D.2. Upgrading from JanusGraph 0.1.z

D.2.1. Elasticsearch

JanusGraph 0.1.z is compatible with Elasticsearch 1.5.z. There were several configuration options available, including transport client, node client, and legacy configuration track. JanusGraph 0.2.0 is compatible with Elasticsearch versions from 1.y through 6.y, however it offers only a single configuration option using the REST client.

D.2.1.1. Transport client

The TRANSPORT_CLIENT interface has been replaced with REST_CLIENT. When migrating an existing graph to JanusGraph 0.2.0, the interface property must be set when connecting to the graph:

After connecting to the graph, the property update can be made permanent by making the change with JanusGraphManagement:

mgmt = graph.openManagement()
mgmt.set("", "REST_CLIENT")

D.2.1.2. Node client

A node client with JanusGraph can be configured in a few ways. If the node client was configured as a clienty-only or non-data node, follow the steps from the transport client section to connect to the existing cluster using the REST_CLIENT instead. If the node client was a data node (local-mode), then convert it into a standalone Elasticsearch node, running in a separate JVM from your application process. This can be done by using the node’s configuration from the JanusGraph configuration to start a standalone Elasticsearch 1.5.z node. For example, we start with these JanusGraph 0.1.z properties:

where the configuration file es-client.yml has properties: true /var/lib/elasticsearch/data /var/lib/elasticsearch/work
path.logs: /var/log/elasticsearch

The properties found in the configuration file es-client.yml and the* properties can be inserted into $ES_HOME/config/elasticsearch.yml so that a standalone Elasticsearch 1.5.z node can be started with the same properties. Keep in mind that if any path locations have relative paths, those values may need to be updated appropriately. Once the standalone Elasticsearch node is started, follow the directions in the transport client section to complete the migration to the REST_CLIENT interface. Note that the and* properties are not used by the REST_CLIENT interface, so they can be removed from the configuration properties.

D.2.1.3. Legacy configuration

The legacy configuration track was not recommended in JanusGraph 0.1.z and is no longer supported in JanusGraph 0.2.0. Users should refer to the previous sections and migrate to the REST_CLIENT.