Migrating templates

bin/migration.sh nifi migrate-templates \
-i /etc/migration-tool-input/flow.json \
-od /etc/migration-tool-output/templates \
-s STAGE_1

This generates a v1 folder that contains the output files of the migration.

templates
└── v1
    ├── NiFi_Flow_ad3a86a6-0194-1000-78d9-6374298d9a0c
    │   ├── elastic_template.json
    │   └── elastic_template.xml
    └── activity_log.json

The folder name NiFi_Flow_ad3a86a6-0194-1000-78d9-6374298d9a0c indicates that the exported template belongs to the root process group, which is named NiFi Flow in NiFi. The unique ID for this group is ad3a86a6-0194-1000-78d9-6374298d9a0c.

elastic_template.json

• Flow definition containing the contents of the original template

• Equivalent to manually converting a template to a flow definition in NiFi 1 by:

  1. Instantiating the template on the canvas.
  2. Right-clicking the process group.
  3. Selecting Download flow definition without external services.

• Modified by the Migration Tool to ensure compatibility:

  • Variables (not supported in NiFi 2) converted into parameters
  • Parameter context created to hold the new parameters
  • Processors updated to reference parameters instead of variables

• This is still a NiFi 1 flow definition, so do not load this file directly into NiFi 2. Use an empty NiFi 1 instance to review the modification made by the tool. The flow will appear unchanged, but variables will be replaced with parameters of the same name, which are now referenced by the processor instead.

• Changes in syntax:

  Variables were previously referenced using ${}, whereas parameters are now referenced using #{}.

  • NiFi 1 variables: ${variable_name}
  • NiFi 2 parameters: #{parameter_name}

elastic_template.xml

• Original template exported from NiFi 1

• Identical to downloading it from the Templates menu in NiFi 1

• Compatible only with NiFi 1 as NiFi 2 does not support templates and cannot parse XML template files

activity_log.json

• Log of all actions performed during this stage of the migration.

• The following were changes made during the template migration:

  • A new parameter context was created with a new parameter in it.
  • The parameter context was assigned to the process group.
  • The PutElasticsearchJson processor was updated to reference the new parameter.

• Components are referenced by a unique ID, not by name.

bin/migration.sh nifi migrate-templates \
-i /etc/migration-tool-input/flow.json \
-od /etc/migration-tool-output/templates

The contents of the previously generated v1 folder will be overwritten, but this is not a concern as the tool generates the same v1 output as before. Additionally, a v2 directory is created, containing the output files of the Stage 2 part of the migration.

v2
├── NiFi_Flow_ad3a86a6-0194-1000-78d9-6374298d9a0c
│   └── elastic_template.json
└── activity_log.json

elastic_template.json

• NiFi 2-compatible flow definition

• Contains the contents of the original template converted into an exported process group.

• This version is compatible with NiFi 2, but no longer supports NiFi 1.

activity_log.json

• List of all actions performed during this stage of the migration.