Our container platform moved from Amazon Linux 2 (AL2) to Bottlerocket. Soon after the migration started, a partner team that runs Spark jobs reported a regression. Their jobs still finished successfully, but far more of them reported zero "storage read bytes": about 23% of tasks on AL2, and about 56% on …

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I recently reviewed code that let a dynamic set of goroutines wait for updates from a single writer. Each waiter wanted to block until the writer had published something newer than what it had already seen. The implementation used channels and was hard to follow. A condition variable (sync.Cond) would have been less …

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I was getting an arm64 build of our Bottlerocket variant ready for production on Graviton EC2 instances. Load tests kept failing at a low rate. Somewhere between 0.3% and 1% of instances froze a few seconds into boot and never came back. The x86_64 build of the same variant has never done this. I never found the root …

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I used NVIDIA's go-dcgm to read GPU health data and stats. It hardcodes the name of the dynamic library it loads, which looked odd at first and turns out to be good practice. go-dcgm uses cgo, and its initDCGM dlopens the literal string libdcgm.so.4 at runtime: 1func initDCGM(m mode, args ...string) (err error) { 2 …

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A while ago I debugged a resource leak caused by a service stuck in a restart loop. Each restart left a process behind, and after a few minutes the host had over a thousand copies of it. Nothing alerted on the loop itself. We noticed CPU and memory climbing, and only found the restart loop after reading the journal. …

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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. …

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I recently ran into an issue after upgrading the containerd client library to v2.3.0. The root cause was a change in one of containerd's dependencies, continuity, that started enforcing fsync when copying files. containerd/continuity is a library in containerd that provides filesystem utilities: file copying, directory …

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A container platform shipped a change to detect CPU architecture mismatches at image pull time. If an image's config says arm64 but the host is amd64, fail fast instead of letting the container start and die with exec format error. The implementation is correct, tests passed and reviewers approved. However, it caused a …

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If you build software that runs in someone else's environment, anything that isn't a SaaS you operate yourself, the following code can break your customers: 1if not hostname.endswith("."): 2 hostname += "." Appending a trailing dot to a domain name before you resolve it feels "more correct" …

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I recently ran into a Go test timeout that turned out to be a deadlock. That was surprising because Go has a built-in deadlock detector. The simplest possible deadlock is a goroutine that locks the same mutex twice. Running the following code exits with fatal error: all goroutines are asleep - deadlock! as expected. …

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