In the past you could tell the nodes in a test cluster to attach themselves to a waiting debugger on startup by passing the `--debug-server-jvm` option documented here:

https://github.com/elastic/elasticsearch/blob/c0228c73fea5caf279bf7141eabea50813c4528b/TESTING.asciidoc#L383-L390

I think this changed in #92379 and no longer seems to work. In fact I really wanted to attach a debugger to just one of the nodes in the cluster, and I believe #92379 might make this much easier to use (e.g. maybe via a method `LocalNodeSpecBuilder#debuggerPort(int)`). That'd be even better.
test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalClusterFactory.java
.onUnix(() -> distributionDir.resolve("bin").resolve("elasticsearch"))
                ),
                getEnvironmentVariables(),
                true
            );
            ProcessReaper.instance().registerPid(getServiceName(), process.pid());
        }
        private Map<String, String> getEnvironmentVariables() {
            Map<String, String> environment = new HashMap<>(spec.resolveEnvironment());
            environment.put("ES_PATH_CONF", workingDir.resolve("config").toString());
            environment.put("ES_TMPDIR", workingDir.resolve("tmp").toString());
            
            environment.put("TMP", workingDir.resolve("tmp").toString());
            String featureFlagProperties = "";
            if (spec.getFeatures().isEmpty() == false && distributionDescriptor.isSnapshot() == false) {
                featureFlagProperties = spec.getFeatures()
                    .stream()
                    .filter(f -> spec.getVersion().onOrAfter(f.from) && (f.until == null || spec.getVersion().before(f.until)))
                    .map(f -> "-D" + f.systemProperty)
                    .collect(Collectors.joining(" "));
            }
            String systemProperties = "";
            if (spec.getSystemProperties().isEmpty() == false) {
                systemProperties = spec.getSystemProperties()
                    .entrySet()
                    .stream()
                    .map(entry -> "-D" + entry.getKey() + "=" + entry.getValue())
                    .map(p -> p.replace("${ES_PATH_CONF}", configDir.toString()))
                    .collect(Collectors.joining(" "));
            }