Spring Boot 2 using Webflux, Netty and HTTP2, causing invalid certificate, possible misconfiguration

There is not much information that I've found in terms of configuration with Netty and Webflux using HTTP2.

I have used similiar configurations in the past without using reactor based spring boot modules, typically spring boot web. I have posted my steps below.

The problem is SSL not working correctly with Netty. Do I require more work in terms of setup? Hoping to get some pointers or examples to understand how to confiure this correctly please.

Generated Certificate

• generate cert valid for local dev usage: mkcert localhost 127.0.0.1

• output: certificate localhost+1.pem key localhost+1-key.pem

• generate keystore with openssl: openssl pkcs12 -export -in localhost+1.pem -inkey localhost+1-key.pem -out keystore.p12 -name localdev

Application Files

application.yaml

server:
  port: 8443
  shutdown: graceful
  http2:
    enabled: true
  server:
    ssl:
      enabled: true
      #format of the keystore
      key-store-type: PKCS12
      #path to the keystore containing the cert
      key-store: classpath:keystore.p12
      #pw used to gen the keystore
      key-store-password: password
      #alias mapped to the certificate inside the keystore
      key-alias: localdev

build.gradle

plugins {
    id 'org.springframework.boot' version '2.4.2'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
    id "com.google.osdetector" version "1.7.0"
}


dependencies {
    //HTTP2 Reactive Netty (auto-configured version via spring dependency BOM)
    runtimeOnly ("io.netty:netty-tcnative-boringssl-static::${osdetector.classifier}")

    implementation 'org.springframework.boot:spring-boot-starter'
    implementation 'org.springframework.boot:spring-boot-starter-data-r2dbc'  
    implementation 'org.springframework.boot:spring-boot-starter-webflux'
    implementation 'org.springframework.boot:spring-boot-starter-actuator'

    runtimeOnly 'io.micrometer:micrometer-registry-prometheus'
    runtimeOnly 'io.r2dbc:r2dbc-postgresql'

    
    testImplementation ('org.springframework.boot:spring-boot-starter-test') {
        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
    }
    testImplementation 'org.junit.jupiter:junit-jupiter-api'
    testImplementation 'io.projectreactor:reactor-test'
}

Running and Request

application running

2021-02-20 17:20:43.122  INFO 1 --- [main] o.s.b.web.embedded.netty.NettyWebServer  : Netty started on port 8443
2021-02-20 17:20:43.143  INFO 1 --- [main] d.c.test.store.Application               : Started Application in 6.655 seconds (JVM running for 7.826)

curl request

curl --cert --http2 localhost+1.pem --key localhost+1-key.pem --insecure https://localhost:8443/actuator/health

Error response

curl: (35) error:1400410B:SSL routines:CONNECT_CR_SRVR_HELLO:wrong version number`

Performing the same request command but with http returns back actuator data you'd expect, so I'm missing some piece of the netty reactor based configuration, which I'm fairly new with.

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