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This article only applies to Fusion 4.
The Fusion connector architecture is designed to be scalable. Depending on whether the connector is a V1 or a V2 (SDK) connector, jobs can be scaled by adding new instances of just the connector. The fetching process for these connectors also supports distributed fetching, so that many instances can contribute to the same job. SDK connectors can be hosted within Fusion Server, or can run remotely. In the hosted case, these connectors are cluster aware. This means that when a new instance of Fusion starts up, the connectors on other Fusion nodes become aware of the new connector, and vice versa. This makes scaling connector jobs simple. In the remote case, a connector becomes a client of Fusion. This remote client runs a lightweight process and communicates to Fusion using an efficient messaging format. This option makes it possible to put the connector wherever the data lives. This can be done for performance reasons, or for security or access reasons. The default SDK connector service is connectors-rpc. By default, connectors-rpc runs on port 8771. This service handles connector registration, configuration management, job management, and cluster coordination. Like other Fusion services, it also provides access to non-connector clients.

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The connector client

Fusion comes with a connector client that remote connectors can use to communicate with Fusion. It is located at FUSION_HOME/apps/connectors/connectors-rpc/client/connector-plugin-client-{fusionVersion}.x-uberjar.jar. To run the connector client, you must have a .zip file containing exactly one connector plugin. Download the connector zip file from Fusion 4.x V1 Connector Downloads.

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Basic connector client usage

To start a connector client, on the remote node (for example, the datasource), do the following:
  1. Copy the connector uberjar from Fusion Server onto the remote node. The connector uberjar is at the following location:
FUSION_HOME/apps/connectors/connectors-rpc/client/connector-plugin-client--uberjar.jar 
2. On the remote node, run:

```bash wrap
java -jar path/to/uberjar/connector-plugin-client-{fusionVersion}-uberjar.jar path/to/connector/file.zip

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Known Issues

  • Registering a plugin instance during crawl could result in errors. Only connect plugins when no jobs are running.
  • In order to connect a plugin from a remote instance, you are required to manually set the default.address value in Fusion. This host value is used with the property com.lucidworks.fusion.plugin.hosts. For example, where 10.10.10.10 is the host value in the FUSION_HOME/conf/fusion.properties file: 
java -Dcom.lucidworks.fusion.plugin.hosts=10.10.10.10:8771 -jar path/to/uberjar/connector-plugin-client-FUSION_VERSION-uberjar.jar path/to/connector/file.zip

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Learn more

To start a connector client, on the remote node (for example, the datasource), do the following:
  1. Copy the connector uberjar from Fusion Server onto the remote node. The connector uberjar is at the following location: 
    FUSION_HOME/apps/connectors/connectors-rpc/client/connector-plugin-client-{fusionVersion}-uberjar.jar
  2. On the remote node, run: 
    java -jar path/to/uberjar/connector-plugin-client-{fusionVersion}-uberjar.jar path/to/connector/file.zip
If you need to index data from behind a firewall, you can configure a V2 connector to run remotely on-premises using TLS-enabled gRPC.

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Prerequisites

Before you can set up an on-prem V2 connector, you must configure the egress from your network to allow HTTP/2 communication into the Fusion cloud. You can use a forward proxy server to act as an intermediary between the connector and Fusion.The following is required to run V2 connectors remotely:
  • The plugin zip file and the connector-plugin-standalone JAR.
  • A configured connector backend gRPC endpoint.
  • Username and password of a user with a remote-connectors or admin role.
  • If the host where the remote connector is running is not configured to trust the server’s TLS certificate, you must configure the file path of the trust certificate collection.
If your version of Fusion doesn’t have the remote-connectors role by default, you can create one. No API or UI permissions are required for the role.

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Connector compatibility

Only V2 connectors are able to run remotely on-premises. You also need the remote connector client JAR file that matches your Fusion version. You can download the latest files at V2 Connectors Downloads.
Whenever you upgrade Fusion, you must also update your remote connectors to match the new version of Fusion.
The gRPC connector backend is not supported in Fusion environments deployed on AWS.

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System requirements

The following is required for the on-prem host of the remote connector:
  • (Fusion 5.9.0-5.9.10) JVM version 11
  • (Fusion 5.9.11) JVM version 17
  • Minimum of 2 CPUs
  • 4GB Memory
Note that memory requirements depend on the number and size of ingested documents.

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Enable backend ingress

In your values.yaml file, configure this section as needed:
ingress:
  enabled: false
  pathtype: "Prefix"
  path: "/"
  #host: "ingress.example.com"
  ingressClassName: "nginx"   # Fusion 5.9.6 only
  tls:
    enabled: false
    certificateArn: ""
    # Enable the annotations field to override the default annotations
    #annotations: ""
  • Set enabled to true to enable the backend ingress.
  • Set pathtype to Prefix or Exact.
  • Set path to the path where the backend will be available.
  • Set host to the host where the backend will be available.
  • In Fusion 5.9.6 only, you can set ingressClassName to one of the following:
    • nginx for Nginx Ingress Controller
    • alb for AWS Application Load Balancer (ALB)
  • Configure TLS and certificates according to your CA’s procedures and policies.
    TLS must be enabled in order to use AWS ALB for ingress.

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Connector configuration example

kafka-bridge:
  target: mynamespace-connectors-backend.lucidworkstest.com:443 # mandatory
  plain-text: false # optional, false by default.  
    proxy-server: # optional - needed when a forward proxy server is used to provide outbound access to the standalone connector
    host: host
    port: some-port
    user: user # optional
    password: password # optional
  trust: # optional - needed when the client's system doesn't trust the server's certificate
    cert-collection-filepath: path1

proxy: # mandatory fusion-proxy
  user: admin
  password: password123
  url: https://fusiontest.com/ # needed only when the connector plugin requires blob store access

plugin: # mandatory
  path: ./fs.zip
  type: #optional - the suffix is added to the connector id
    suffix: remote

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Minimal example

kafka-bridge:
  target: mynamespace-connectors-backend.lucidworkstest.com:443

proxy:
  user: admin
  password: "password123"

plugin:
  path: ./testplugin.zip

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Logback XML configuration file example

<configuration>
    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <encoder class="com.lucidworks.logging.logback.classic.LucidworksPatternLayoutEncoder">
            <pattern>%d - %-5p [%t:%C{3.}@%L] - %m{nolookups}%n</pattern>
            <charset>utf8</charset>
        </encoder>
    </appender>

    <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>${LOGDIR:-.}/connector.log</file>
        <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
            <!-- rollover daily -->
            <fileNamePattern>${LOGDIR:-.}/connector-%d{yyyy-MM-dd}.%i.log.gz</fileNamePattern>
            <maxFileSize>50MB</maxFileSize>
            <totalSizeCap>10GB</totalSizeCap>
        </rollingPolicy>
        <encoder class="com.lucidworks.logging.logback.classic.LucidworksPatternLayoutEncoder">
            <pattern>%d - %-5p [%t:%C{3.}@%L] - %m{nolookups}%n</pattern>
            <charset>utf8</charset>
        </encoder>
    </appender>

    <root level="INFO">
        <appender-ref ref="CONSOLE"/>
        <appender-ref ref="FILE"/>
    </root>
</configuration>

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Run the remote connector

java [-Dlogging.config=[LOGBACK_XML_FILE]] \
  -jar connector-plugin-client-standalone.jar [YAML_CONFIG_FILE]
The logging.config property is optional. If not set, logging messages are sent to the console.

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Test communication

You can run the connector in communication testing mode. This mode tests the communication with the backend without running the plugin, reports the result, and exits.
java -Dstandalone.connector.connectivity.test=true -jar connector-plugin-client-standalone.jar [YAML_CONFIG_FILE]

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Encryption

In a deployment, communication to the connector’s backend server is encrypted using TLS. You should only run this configuration without TLS in a testing scenario. To disable TLS, set plain-text to true.

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Egress and proxy server configuration

One of the methods you can use to allow outbound communication from behind a firewall is a proxy server. You can configure a proxy server to allow certain communication traffic while blocking unauthorized communication. If you use a proxy server at the site where the connector is running, you must configure the following properties:
  • Host. The hosts where the proxy server is running.
  • Port. The port the proxy server is listening to for communication requests.
  • Credentials. Optional proxy server user and password.
When you configure egress, it is important to disable any connection or activity timeouts because the connector uses long running gRPC calls.

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Password encryption

If you use a login name and password in your configuration, run the following utility to encrypt the password:
  1. Enter a user name and password in the connector configuration YAML.
  2. Run the standalone JAR with this property: 
    -Dstandalone.connector.encrypt.password=true
  3. Retrieve the encrypted passwords from the log that is created.
  4. Replace the clear password in the configuration YAML with the encrypted password.

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Connector restart (5.7 and earlier)

The connector will shut down automatically whenever the connection to the server is disrupted, to prevent it from getting into a bad state. Communication disruption can happen, for example, when the server running in the connectors-backend pod shuts down and is replaced by a new pod. Once the connector shuts down, connector configuration and job execution are disabled. To prevent that from happening, you should restart the connector as soon as possible.You can use Linux scripts and utilities to restart the connector automatically, such as Monit.

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Recoverable bridge (5.8 and later)

If communication to the remote connector is disrupted, the connector will try to recover communication and gRPC calls. By default, six attempts will be made to recover each gRPC call. The number of attempts can be configured with the max-grpc-retries bridge parameters.

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Job expiration duration (5.9.5 only)

The timeout value for irresponsive backend jobs can be configured with the job-expiration-duration-seconds parameter. The default value is 120 seconds.

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Use the remote connector

Once the connector is running, it is available in the Datasources dropdown. If the standalone connector terminates, it disappears from the list of available connectors. Once it is re-run, it is available again and configured connector instances will not get lost.

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Enable asynchronous parsing (5.9 and later)

To separate document crawling from document parsing, enable Tika Asynchronous Parsing on remote V2 connectors.