15:59:47.285 [pulsar-web-43-1] INFO  org.eclipse.jetty.server.RequestLog - 10.13.2.61 - - [10/Jan/2021:15:59:47 +0000] "GET /metrics HTTP/1.1" 302 0 "-" "Prometheus/2.15.2" 0
15:59:47.289 [prometheus-stats-44-1] WARN  org.apache.pulsar.functions.worker.FunctionsStatsGenerator - Failed to collect metrics for function instance tenantname/namespacename/samplertest:0
java.net.ConnectException: Connection refused (Connection refused)
        at java.net.PlainSocketImpl.socketConnect(Native Method) ~[?:1.8.0_275]
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[?:1.8.0_275]
        at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[?:1.8.0_275]
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[?:1.8.0_275]
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[?:1.8.0_275]
        at java.net.Socket.connect(Socket.java:607) ~[?:1.8.0_275]
        at java.net.Socket.connect(Socket.java:556) ~[?:1.8.0_275]
        at sun.net.NetworkClient.doConnect(NetworkClient.java:180) ~[?:1.8.0_275]
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:463) ~[?:1.8.0_275]
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:558) ~[?:1.8.0_275]
        at sun.net.www.http.HttpClient.<init>(HttpClient.java:242) ~[?:1.8.0_275]
        at sun.net.www.http.HttpClient.New(HttpClient.java:339) ~[?:1.8.0_275]
        at sun.net.www.http.HttpClient.New(HttpClient.java:357) ~[?:1.8.0_275]
        at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1226) ~[?:1.8.0_275]
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1162) ~[?:1.8.0_275]
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1056) ~[?:1.8.0_275]
        at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:990) ~[?:1.8.0_275]
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1570) ~[?:1.8.0_275]
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1498) ~[?:1.8.0_275]
        at org.apache.pulsar.functions.runtime.RuntimeUtils.getPrometheusMetrics(RuntimeUtils.java:427) ~[org.apache.pulsar-pulsar-functions-runtime-2.8.0-SNAPSHOT.jar:2.8.0-SNAPSHOT]
        at org.apache.pulsar.functions.runtime.process.ProcessRuntime.getPrometheusMetrics(ProcessRuntime.java:320) ~[org.apache.pulsar-pulsar-functions-runtime-2.8.0-SNAPSHOT.jar:2.8.0-SNAPSHOT]
        at org.apache.pulsar.functions.worker.FunctionsStatsGenerator.generate(FunctionsStatsGenerator.java:71) ~[org.apache.pulsar-pulsar-functions-worker-2.8.0-SNAPSHOT.jar:2.8.0-SNAPSHOT]
        at org.apache.pulsar.broker.stats.prometheus.PrometheusMetricsGenerator.generate(PrometheusMetricsGenerator.java:96) ~[org.apache.pulsar-pulsar-broker-2.8.0-SNAPSHOT.jar:2.8.0-SNAPSHOT]
        at org.apache.pulsar.broker.stats.prometheus.PrometheusMetricsServlet.lambda$doGet$0(PrometheusMetricsServlet.java:66) ~[org.apache.pulsar-pulsar-broker-2.8.0-SNAPSHOT.jar:2.8.0-SNAPSHOT]
        at org.apache.bookkeeper.mledger.util.SafeRun$1.safeRun(SafeRun.java:32) [org.apache.pulsar-managed-ledger-2.8.0-SNAPSHOT.jar:2.8.0-SNAPSHOT]
        at org.apache.bookkeeper.common.util.SafeRunnable.run(SafeRunnable.java:36) [org.apache.bookkeeper-bookkeeper-common-4.12.0.jar:4.12.0]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_275]
        at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_275]
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) [?:1.8.0_275]
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) [?:1.8.0_275]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_275]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_275]
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [io.netty-netty-common-4.1.51.Final.jar:4.1.51.Final]
        at java.lang.Thread.run(Thread.java:748) [?:1.8.0_275]
15:59:47.291 [prometheus-stats-44-1] INFO  org.eclipse.jetty.server.RequestLog - 10.13.2.61 - - [10/Jan/2021:15:59:47 +0000] "GET /metrics/ HTTP/1.1" 200 63238 "http://10.13.2.236:8080/metrics" "Prometheus/2.15.2" 5