Chapter 6. Connecting to remote Fuse applications

The Fuse Console uses Jolokia, an agent-based approach to Java Management Extensions (JMX) that requires extra software (an agent) installed on the client. By default, Red Hat Fuse includes a jolokia agent.

With standalone Fuse Console distributions, you can connect to remote integrations that already have a jolokia agent (https://jolokia.org/) running inside them. If the process that you want to connect to does not have a jolokia agent inside, refer to the jolokia documentation (http://jolokia.org/agent.html).

Procedure

The Fuse Console’s proxy servlet uses whitelist host protection, with which by default the Fuse Console can only connect to localhost. If you want to connect the Fuse Console to other remote Fuse instances, you need to configure the hawtio.proxyWhitelist system property in the main() method of your Spring Boot application: 

System.setProperty("hawtio.proxyWhitelist", "localhost, 127.0.0.1, myhost1, myhost2, myhost3");

6.1. Connecting to a remote Jolokia agent

Before you begin, you need to know the connection details (host name, port, and path) of the remote Jolokia agent.

The default connection URLs for the Jolokia agent on Spring Boot is http://<host>:8080/jolokia

As a system administrator, you can change this default.

Typically, the URL to remotely connect to a Jolokia agent is the URL to open the Fuse Console plus /jolokia. For example, if the URL to open the Fuse Console is http://<host>:1234/hawtio, then the URL to remotely connect to it would probably be http://<host>:1234/hawtio/jolokia.

To connect to a remote Jolokia instance so that you can examine its JVM:

  1. Click the Connect tab.
  2. Click the Remote tab, and then Add connection.
  3. Type the Name, Scheme (HTTP or HTTPS), and the hostname.
  4. Click Test Connection.
  5. Click Add.
Note

The Fuse Console automatically probes the local network interfaces other than localhost and 127.0.0.1 and adds them to the whitelist. Hence, you do not need to manually register the local machine’s addresses to the whitelist.

6.2. Setting data moving preferences

You can change the following Jolokia preferences, for example, if you want to more frequently refresh data that displays in the Fuse Console. Note that increasing the frequency of data updates impacts networking traffic and increases the number of requests made to the server.

  • Update rate - The period between polls to Jolokia to fetch JMX data (the default is 5 seconds).
  • Maximum depth - The number of levels that Jolokia will marshal an object to JSON on the server side before returning (the default is 7).
  • Maximum collection size - The maximum number of elements in an array that Jolokia marshals in a response (the default is 50,000).

To change the values of these settings:

  1. In the upper right of the Fuse Console, click the user icon and then click Preferences.

    mf preferences

  2. Edit the options and then click Close.

6.3. Viewing JVM runtime information

To view JVM runtime information, such as system properties, metrics, and threads, click the Runtime tab.