Upgrade from 7.0.1 to 7.1.3 data node metrics load error

I upgraded my system from 7.0.1 to 7.1.3, seemed to have gone ok, but under system | cluster configuration, I’m constantly getting the following error pop up…

Could not load Data Node metrics.

Loading metrics for Data Node “” failed: FetchError: There was an error fetching a resource: Internal Server Error. Additional information: No route to host

it seems to just be affecting the metrics and not the system at all, but I’m hoping for some insight into this. Cluster is Healthy, processing messages and searches.

Looking into it, I stumbled upon 1 change in the release notes, but I’m not sure it’s related..

And in my webUI node, I have the following in the server.log

2026-06-16T12:45:20.989-04:00 ERROR [AnyExceptionClassMapper] Unhandled exception in REST resource
java.net.NoRouteToHostException: No route to host
at java.base/sun.nio.ch.Net.pollConnect(Native Method)
at java.base/sun.nio.ch.Net.pollConnectNow(Unknown Source)
at java.base/sun.nio.ch.NioSocketImpl.timedFinishConnect(Unknown Source)
at java.base/sun.nio.ch.NioSocketImpl.connect(Unknown Source)
at java.base/java.net.SocksSocketImpl.connect(Unknown Source)
at java.base/java.net.Socket.connect(Unknown Source)
at okhttp3.internal.platform.Platform.connectSocket(Platform.kt:148)
at okhttp3.internal.connection.ConnectPlan.connectSocket(ConnectPlan.kt:276)
at okhttp3.internal.connection.ConnectPlan.connectTcp(ConnectPlan.kt:135)
at okhttp3.internal.connection.FastFallbackExchangeFinder$launchTcpConnect$1.runOnce(FastFallbackExchangeFinder.kt:141)
at okhttp3.internal.concurrent.TaskRunner$runnable$1.run(TaskRunner.kt:81)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.base/java.lang.Thread.run(Unknown Source)

Any thoughts or advice would be appreciated.

Hey @cawfehman, if you inspect and view the network tab at the point the metrics page loads - can you see any further information on the failing call to the API.

From your Graylog node can you hit port 8999 on the Datanode? Test with curl/nc.