micrometer-metrics/micrometer

StatsdMeterRegistry doesn't renew resolved ip address on DNS change

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#1,252 opened on Feb 27, 2019

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enhancementhelp wantedregistry: statsd

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Description

Hello everyone.

I've faced with the problem that StatsdMeterRegistry doesn't aware of DNS changes after it was start()ed. As a result, metrics aren't delivered to Telegraf and there is no warning or so in logs.

How to reproduce:

  1. Create record in /etc/hosts file, e.g.: 127.0.0.1 telegraf.kube-system.svc.cluster.local.
  2. Start application with StatsdMeterRegistry enabled and use host described above.
  3. Change record in /etc/hosts file to another ip (127.0.0.2 for example)

Actual result: Using wireshark/tcpdump you can see that all metrics are being sent to 127.0.0.1 even after step 3.

Expected result: StatsdMeterRegistry respect DNS name change.

Can be reproduced on real network/DNS server. Security manager disabled. Micrometer version: 1.1.3, reproducible on 1.0.7 as well.

Contributor guide

Research direction
Investigate how StatsdMeterRegistry resolves the hostname initially and whether it uses DNS caching that does not refresh. Check if there is a mechanism to periodically re resolve the address or if the resolved InetSocketAddress is stored permanently.
Tech stack
java
Domain
observability
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
JavaNetworking
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60