There was no ROR on this cluster.
I installed 1.49.1 where https works exactly and the error persists. I am surprised.
ElasticSeach, ROR and configuration are assembled by Ansible, so it is unlikely that the configs are different.
If remove the line http.type: ssl_netty4 then elasticsearch and the ROR plugin will start. This means the plugin was installed correctly.
[2023-12-13T21:29:58,269][INFO ][o.e.t.NettyAllocator ] [server01-client]creating NettyAllocator with the following configs: [name=elasticsearch_configured, chunk_size=1mb, suggested_max_allocation_size=1mb, factors={es.unsafe.use_netty_default_chunk_and_page_size=false, g1gc_enabled=false, g1gc_region_size=0b}]
[2023-12-13T21:29:58,299][ERROR][o.e.b.Bootstrap ] [server01-client]Exception
java.lang.IllegalStateException: Unsupported http.type [ssl_netty4]
at org.elasticsearch.common.network.NetworkModule.getHttpServerTransportSupplier(NetworkModule.java:187) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.node.Node.newHttpTransport(Node.java:1282) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.node.Node.<init>(Node.java:659) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.node.Node.<init>(Node.java:288) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Bootstrap$5.<init>(Bootstrap.java:219) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:219) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:399) [elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:167) [elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:158) [elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:75) [elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:114) [elasticsearch-cli-7.15.1.jar:7.15.1]
at org.elasticsearch.cli.Command.main(Command.java:79) [elasticsearch-cli-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:123) [elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:81) [elasticsearch-7.15.1.jar:7.15.1]
[2023-12-13T21:29:58,303][ERROR][o.e.b.ElasticsearchUncaughtExceptionHandler] [server01-client]uncaught exception in thread [main]
org.elasticsearch.bootstrap.StartupException: java.lang.IllegalStateException: Unsupported http.type [ssl_netty4]
at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:171) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:158) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:75) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:114) ~[elasticsearch-cli-7.15.1.jar:7.15.1]
at org.elasticsearch.cli.Command.main(Command.java:79) ~[elasticsearch-cli-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:123) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:81) ~[elasticsearch-7.15.1.jar:7.15.1]
Caused by: java.lang.IllegalStateException: Unsupported http.type [ssl_netty4]
at org.elasticsearch.common.network.NetworkModule.getHttpServerTransportSupplier(NetworkModule.java:187) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.node.Node.newHttpTransport(Node.java:1282) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.node.Node.<init>(Node.java:659) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.node.Node.<init>(Node.java:288) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Bootstrap$5.<init>(Bootstrap.java:219) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:219) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:399) ~[elasticsearch-7.15.1.jar:7.15.1]
at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:167) ~[elasticsearch-7.15.1.jar:7.15.1]
... 6 more