io.netty.handler.codec.DecoderException: javax.net.ssl.SSLException: Session has no PSK

Using Elasticsearch 7.6.1 with SSL enabled we noticed the following error being logged in Elasticsearch logs

[WARN ][o.e.h.AbstractHttpServerTransport] [host] caught exception while handling client http traffic, closing connection Netty4HttpChannel{localAddress=/hostname:9200, remoteAddress=/hostname:52619}
io.netty.handler.codec.DecoderException: javax.net.ssl.SSLException: Session has no PSK
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:473) ~[netty-codec-4.1.43.Final.jar:4.1.43.Final]
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:281) ~[netty-codec-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1422) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:931) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:700) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysPlain(NioEventLoop.java:600) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:554) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:514) [netty-transport-4.1.43.Final.jar:4.1.43.Final]

and also :

'''[WARN ][o.e.h.AbstractHttpServerTransport] [hostname] caught exception while handling client http traffic, closing connection Netty4HttpChannel{localAddress=/hostip:9200, remoteAddress=/hostip:57143}
io.netty.handler.codec.DecoderException: java.lang.NullPointerException
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:473) ~[netty-codec-4.1.43.Final.jar:4.1.43.Final]
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:281) ~[netty-codec-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1422) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:931) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:700) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysPlain(NioEventLoop.java:600) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:554) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:514) [netty-transport-4.1.43.Final.jar:4.1.43.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$6.run(SingleThreadEventExecutor.java:1050) [netty-common-4.1.43.Final.jar:4.1.43.Final]
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) [netty-common-4.1.43.Final.jar:4.1.43.Final]
at java.lang.Thread.run(Thread.java:830) [?:?]
Caused by: java.lang.NullPointerException
at sun.security.ssl.HKDF.extract(HKDF.java:93) ~[?:?]
at sun.security.ssl.HKDF.extract(HKDF.java:119) ~[?:?]

Is this an issue in Elasticsearch ,or am i missing some configuration or something else has to be done ?

This looks like https://bugs.openjdk.java.net/browse/JDK-8241248. Are you running with the bundled jdk ? Can you share your transport TLS configuration and how you generated the keys/certificates you are using?

Yes we are using the bundled JDK
/elastic/elasticsearch-7.6.1/jdk/bin/java -version
openjdk version "13.0.2" 2020-01-14
OpenJDK Runtime Environment AdoptOpenJDK (build 13.0.2+8)
OpenJDK 64-Bit Server VM AdoptOpenJDK (build 13.0.2+8, mixed mode, sharing)

And for the question on TLS configuration and how certificates were generated :

  1. We generated the certicates using the elastic-certutil utility as follows:
    /elasticsearch-certutil cert ca --pem --in /tmp/instances.yml --out /tmp/check/certs.zip
    where instances.yml contains the node information
  2. TLS configuration:
    xpack.security.enabled: true
    xpack.security.http.ssl.enabled: true
    xpack.security.transport.ssl.enabled: true
    xpack.security.http.ssl.key: certs/xxxxxxx.key
    xpack.security.http.ssl.certificate: certs/xxxxxxx.crt
    xpack.security.http.ssl.verification_mode: certificate
    xpack.security.transport.ssl.key: certs/xxxxxxx.key
    xpack.security.transport.ssl.certificate: certs/xxxxxxx.crt
    xpack.security.transport.ssl.verification_mode: certificate

Any updates on this issue is appreciated