I have a Spring Boot 2 app that wants to embed Kibana UI in the page. I use an iframe to embed the UI. The iframe url is set to /kibana. In the backend, I use HTTP-Proxy-Servlet to proxy the requests to the actual Kibana server.

Kibana version is 6.5.4 and Spring Boot version is 2.0.8.RELEASE.

Include the HTTP-Proxy-Servlet library first.

<dependency>
  <groupId>org.mitre.dsmiley.httpproxy</groupId>
  <artifactId>smiley-http-proxy-servlet</artifactId>
  <version>1.11</version>
</dependency>

Then add proxy config to application.yml.

proxy:
  kibana:
    servletUrl: /kibana/*
    targetUrl: http://localhost:5601/kibana

Finally, create the ProxyServlet.

@Configuration
class ProxyConfig : EnvironmentAware {
    private lateinit var environment: Environment

    override fun setEnvironment(environment: Environment) {
        this.environment = environment
    }

    @Bean
    fun kibanaProxyServletRegistrationBean() = createProxyServlet("proxy.kibana")

    @Bean
    fun kibanaFilterRegistrationBean(filter: HiddenHttpMethodFilter): FilterRegistrationBean<HiddenHttpMethodFilter> {
        val registration = FilterRegistrationBean(filter)
        registration.isEnabled = false
        return registration
    }

    private fun createProxyServlet(propertyPath: String): ServletRegistrationBean<ProxyServlet> {
        val servletRegistrationBean = ServletRegistrationBean(ProxyServlet(), environment.get("$propertyPath.servletUrl"))
        servletRegistrationBean.addInitParameter("targetUri", environment.get("$propertyPath.targetUrl"))
        servletRegistrationBean.addInitParameter(ProxyServlet.P_HANDLEREDIRECTS, "true")
        servletRegistrationBean.addInitParameter(ProxyServlet.P_LOG, "false")
        return servletRegistrationBean
    }
}

Now accessing http://localhost:8080/kibana shows the Kibana UI.

You need to update Kibana config kibana.yml to set the base path. Check that you can access http://localhost:5601/kibana. This url matches the targetUrl value in application.yml. 

server.basePath: "/kibana"
server.rewriteBasePath: true