What could cause "unable to establish connection to collective controllers" with WebSphere Liberty Profile?

Question

I am trying to set up a small collective with WebSphere Liberty Profile 8.5.5.6. The controller and members are all on the same Linux machine. But when I start my member, it cannot connect to the collective controller (I started out with the hostname, but switched to localhost just to see if that made a difference - but the error was the same):

I CWWKX8057I: The collective member is unable to establish a connection to any of the collective controllers. Configured controllers: [rslvm19.dub.usoh.ibm.com:21443]

This is from the controller's log:
I CWWKX0103I: The JMX REST connector is running and is available at the following service URL: service:jmx:rest://rslvm19.dub.usoh.ibm.com:21443/IBMJMXConnectorREST
...
I CWWKX6011I: The collective controller is ready, and can accept requests. The leader is 9.55.50.219:10010. Current active replica set is [9.55.50.219:10010]. The configured replica set is [9.55.50.219:10010].
I CWWKX6046I: The collective controller replica set is starting to upgrade. The current active version is 8.5.5.[1-3]. After upgrading, the active version will be 8.5.5.4.
I CWWKX6047I: The active collective controller replica set was upgraded successfully. The current active replica version is 8.5.5.4.
I CWWKX9000I: The CollectiveRepository MBean is available.

Whenever I start my member, it must be talking to the controller, because the following messages do show up in the controller log at the same time as the member server startup:

I SESN0176I: A new session context will be created for application key default_host/IBMJMXConnectorREST
I SESN0172I: The session manager is using the Java default SecureRandom implementation for session ID generation.
I FFDC1015I: An FFDC Incident has been created: "javax.validation.ValidationException: Validation not enabled for module com.ibm.ws.jmx.connector.server.rest com.ibm.ws.jsf.beanvalidation.extprocessor.JSFBeanValidationExtensionFactory 70" at ffdc_15.07.27_15.14.23.0.log
I DYNA1056I: Dynamic Cache (object cache) initialized successfully.
I Setting the server's publish address to be /
I SRVE0242I: [com.ibm.ws.jmx.connector.server.rest] [/IBMJMXConnectorREST] [MBeanServerConnector]: Initialization successful.
I CWWKS9122I: For URL /* in application com.ibm.ws.jmx.connector.server.rest, the following HTTP methods are uncovered, and accessible: HEAD OPTIONS TRACE

Is there any config value that I might be missing somewhere? Or some way to see more detail about the actual error?

Answer 1

This sounds as though the member(s) has not been joined to the controller. You can see more about joining in the Knowledge Center, for example the latest beta article is here: https://www.ibm.com/support/knowledgecenter/was_beta_liberty/com.ibm.websphere.wlp.nd.multiplatform.doc/ae/tagt_wlp_configure_collective.html

When a member joins a controller, the security configuration necessary for a successful connection is propagated to the member.