Practical, source-backed guides for instrumenting, operating, and improving production systems.
Locate SSH authentication logs, configure sshd logging safely, analyze failed logins, and build Guance alerts for repeated failures and unexpected successful access.
Configure CSP resource rules, nonces, hashes, strict-dynamic, and violation reporting, then roll out an enforced policy with representative browser testing.
Validate FastAPI uploads, bound file and batch sizes, prevent path traversal, clean up partial writes, and separate upload progress from processing.
Load YAML with PyYAML, validate configuration structure, write nested data, use PyKwalify schemas, and understand type conversion and round-trip limits.
Use Zap typed and sugared APIs, configure JSON and dynamic levels, route events to multiple outputs, and validate file rotation and Guance collection.
Use Zerolog typed events, logger context, stack capture, hooks, sampling, and request propagation, then verify JSON collection in Guance.
Understand CloudWatch pricing in Tokyo through metric series, log ingestion, retention and query scans, with a worked monthly bill and practical cost analysis.
Explore Datadog pricing for Japan AP1, including standalone APM, host and metric billing, log indexing costs, and when Guance changes the calculation.
Calculate Datadog costs for a Korean team using AP1 Japan rates, with Korean support hours, deployment choices, and a log model whose result changes with indexing.
Understand how the API server, etcd, scheduler, controllers and kubelet cooperate, then follow the evidence that separates scheduling, runtime and application failures.
Learn what an SLO means, how SLIs measure service behavior, and how SLAs set commitments. Understand time windows, error budgets, and five ways to write a clearer SLA.
APM monitoring explained — distributed tracing mechanics, RED/USE metrics, sampling strategies, OpenTelemetry vs vendor agents, and how to choose an APM tool.
