https://peng.fyi/tags/network/ Recent content in Network on Hugo -- gohugo.io en map[name:Peng Zhang] map[name:Peng Zhang] Peng Zhang Sat, 01 Aug 2026 00:00:00 +0000 https://peng.fyi/post/apply-sysctl-before-systemd/ Sat, 01 Aug 2026 00:00:00 +0000 map[name:Peng Zhang] https://peng.fyi/post/apply-sysctl-before-systemd/ We run an OpenTelemetry Collector (otel-collector) as a systemd service on Bottlerocket. Its Prometheus metrics endpoint was configured on port 51000, which falls inside the default Linux ephemeral port range. On a small portion of EC2 instances, the otel-collector kept restarting, failing to bind with EADDRINUSE. Sometimes it self-healed, sometimes it kept restarting and we lost logs. This post walks through the fix, which involves a race condition among systemd services and why the sysctl has to be applied before systemd starts.