我有一个本地NiFi实例，我想通过安全的站点到站点通信将数据发送到AWS服务器上的远程NiFi实例。
我使用NiFi TLS工具包为客户端，服务器密钥库和信任库生成了自签名证书。
在本地NiFi实例上，我有一个Remote Processor Group设置，指向远程NiFi实例上的输入端口。本地实例和远程实例之间的初始SSL握手成功，因为我能够看到远程实例的可用输入端口，并在本地实例的Web UI上显示“站点到站点安全”图标通知。
但是，当我尝试通过https通过RPG馈送数据时，我的本地实例日志中出现以下错误：
2019-06-19 15:57:29,186 ERROR [I/O dispatcher 13] o.a.n.r.util.SiteToSiteRestApiClient Failed to create transaction for https://<local-instance-url>/nifi-api/data-transfer/input-ports/<UUID>/transactions
javax.net.ssl.SSLHandshakeException: General SSLEngine problem
at sun.security.ssl.Handshaker.checkThrown(Handshaker.java:1521)
at sun.security.ssl.SSLEngineImpl.checkTaskThrown(SSLEngineImpl.java:528)
at sun.security.ssl.SSLEngineImpl.writeAppRecord(SSLEngineImpl.java:1197)
at sun.security.ssl.SSLEngineImpl.wrap(SSLEngineImpl.java:1165)
at javax.net.ssl.SSLEngine.wrap(SSLEngine.java:469)
at org.apache.http.nio.reactor.ssl.SSLIOSession.doWrap(SSLIOSession.java:266)
at org.apache.http.nio.reactor.ssl.SSLIOSession.doHandshake(SSLIOSession.java:306)
at org.apache.http.nio.reactor.ssl.SSLIOSession.isAppInputReady(SSLIOSession.java:508)
at org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:120)
at org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:162)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:337)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:315)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:276)
at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104)
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:588)
at java.lang.Thread.run(Thread.java:748)
Caused by: javax.net.ssl.SSLHandshakeException: General SSLEngine problem
at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1709)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:318)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:310)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1639)
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:223)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1037)
at sun.security.ssl.Handshaker$1.run(Handshaker.java:970)
at sun.security.ssl.Handshaker$1.run(Handshaker.java:967)
at java.security.AccessController.doPrivileged(Native Method)
at sun.security.ssl.Handshaker$DelegatedTask.run(Handshaker.java:1459)
at org.apache.http.nio.reactor.ssl.SSLIOSession.doRunTask(SSLIOSession.java:284)
at org.apache.http.nio.reactor.ssl.SSLIOSession.doHandshake(SSLIOSession.java:352)
... 9 common frames omitted
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:397)
at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:302)
at sun.security.validator.Validator.validate(Validator.java:262)
at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324)
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:281)
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:136)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1626)
... 17 common frames omitted
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:392)
... 23 common frames omitted
对于在看起来似乎已经成功进行SSL握手之后为什么要尝试第二次SSL握手，我有些困惑。初步研究表明，我的证书不受信任，但是如果是这种情况，我不确定为什么我的第一次握手会成功。
关于NIFI配置。我已经为两个实例以及所有其他SSL属性（包括密钥库/ trustore信息）设置了远程属性
nifi.remote.input.host=<other-instance-host>
nifi.remote.input.secure=true
nifi.remote.input.http.enabled=true
nifi.remote.input.http.transaction.ttl=30 sec
...
nifi.cluster.protocol.is.secure=true