Attention when using SCRAM in PostgreSQL

[mfuhrmann]

Symptom

When monitoring PostgreSQL that uses SCRAM instead of the MD5 authentication method the following data collection and monitor outage will occur.

Unexpected exception while polling PollableService[location=FUL, interface=PollableInterface [PollableNode [1226]:10.10.5.101], svcName=PostgreSQL]. java.util.concurrent.ExecutionException: org.opennms.core.rpc.api.RemoteExecutionException: java.util.concurrent.CompletionException: java.lang.NoClassDefFoundError: javax/security/sasl/SaslException at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:314) at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:319) at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1702) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at java.base/java.lang.Thread.run(Thread.java:834) Caused by: java.lang.NoClassDefFoundError: javax/security/sasl/SaslException at java.base/java.lang.ClassLoader.defineClass1(Native Method) at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016) at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.defineClass(BundleWiringImpl.java:2410) at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.findClass(BundleWiringImpl.java:2194) at org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation(BundleWiringImpl.java:1607) at org.apache.felix.framework.BundleWiringImpl.access$200(BundleWiringImpl.java:80) at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.loadClass(BundleWiringImpl.java:2053) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) at org.postgresql.core.v3.ConnectionFactoryImpl.doAuthentication(ConnectionFactoryImpl.java:659) at org.postgresql.core.v3.ConnectionFactoryImpl.tryConnect(ConnectionFactoryImpl.java:141) at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:192) at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49) at org.postgresql.jdbc.PgConnection.(PgConnection.java:195) at org.postgresql.Driver.makeConnection(Driver.java:454) at org.postgresql.Driver.connect(Driver.java:256) at org.opennms.netmgt.poller.monitors.JDBCMonitor.poll(JDBCMonitor.java:149) at Proxy7bc82e31_d8c9_4727_8fec_bb14aa59a36b.poll(Unknown Source) at org.opennms.netmgt.poller.client.rpc.PollerClientRpcModule$1.get(PollerClientRpcModule.java:77) at org.opennms.netmgt.poller.client.rpc.PollerClientRpcModule$1.get(PollerClientRpcModule.java:71) at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1700) … 3 more Caused by: java.lang.ClassNotFoundException: javax.security.sasl.SaslException not found by org.postgresql.jdbc42 [382] at org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation(BundleWiringImpl.java:1639) at org.apache.felix.framework.BundleWiringImpl.access$200(BundleWiringImpl.java:80) at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.loadClass(BundleWiringImpl.java:2053) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) … 23 more

Solution

OpenNMS v.27.0.0 uses 42.2.5 library. But at least 42.2.7 is required to support SCRAM.

Newer drivers can be obtained here: https://jdbc.postgresql.org/download.html

Default OpenNMS installation

Just delete the postgresql-42.2.5.jar file in folder /opt/opennms/lib/ and copy the newer one into this folder. OpenNMS requires a restart to load the library.

Docker OpenNMS installation

Here it is a little bit more tricky since the OpenNMS Docker images always provide postgresql-42.2.5.jar when creating the container. Also, it is not possible to have 2 versions in the lib folder.

The only approach that worked for me (easily | ugly) is, to mount the new library file as a volume into the old one in my docker-compose.yaml.

....
    volumes:
       - ./postgresql-42.2.18.jar:/opt/opennms/lib/postgresql-42.2.5.jar
....

Jira Issue Tracker

[NMS-13049] Update PostgreSQL JDBC drivers - The OpenNMS Issue Tracker

[NMS-13041] Provide a mechanism to make the lib folder configurable - The...

---

You can fix me, I’m a wiki post.

[mfuhrmann]

It turned out that the JDBC driver is not the cause in this case. SCRAM does also work with 42.2.5.
The issue seems to be caused by a Minion. Corresponding issue tracker.