https://dylansummerville.com/blog Working notes from building and running production systems: DevOps, infrastructure as code, containers, databases, automation and security. en-au Thu, 29 Oct 2026 14:20:00 +1100 https://dylansummerville.com/blog/thirteen-minutes-of-ci https://dylansummerville.com/blog/thirteen-minutes-of-ci Thu, 29 Oct 2026 14:20:00 +1100 Every change runs about 17,700 tests in thirteen minutes before it merges. Why the slow check stays, and the merge rule I broke today. CI Testing Postgres Practice https://dylansummerville.com/blog/containerising-jas-every-store-on-two-databases https://dylansummerville.com/blog/containerising-jas-every-store-on-two-databases Thu, 29 Oct 2026 06:40:00 +1100 Every store now writes to SQLite and Postgres, the first soak day was clean, and the read switch is rehearsed. What turned up, and what comes next. PostgreSQL Migration Databases Progress https://dylansummerville.com/blog/shadow-writes-slowed-a-job-by-a-third https://dylansummerville.com/blog/shadow-writes-slowed-a-job-by-a-third Thu, 29 Oct 2026 06:30:00 +1100 A job slowed by a third under dual writes to SQLite and Postgres. Measuring it against a control, the per-row round trips behind it, and the batching fix. PostgreSQL Performance Databases Migration https://dylansummerville.com/blog/rehearsing-a-database-read-switch https://dylansummerville.com/blog/rehearsing-a-database-read-switch Thu, 29 Oct 2026 06:20:00 +1100 Moving reads from SQLite to Postgres: identity sequences that fall behind, a seven-second switch window, and a rollback rehearsed with a deliberate fault. PostgreSQL Migration Databases Reliability https://dylansummerville.com/blog/wordpress-to-containers-without-downtime https://dylansummerville.com/blog/wordpress-to-containers-without-downtime Fri, 23 Oct 2026 17:45:00 +1100 My plan for moving a WordPress site from shared hosting into containers behind Cloudflare: two stages, scripted gates, no downtime and no broken links. WordPress Migration Cloudflare Containers https://dylansummerville.com/blog/containerising-jas-progress-october-2026 https://dylansummerville.com/blog/containerising-jas-progress-october-2026 Thu, 22 Oct 2026 18:30:00 +1100 Progress on containerising the Job Adding System: Postgres shadow writes in production, stores moving in waves, and the container half still to come. Containers PostgreSQL Migration Progress https://dylansummerville.com/blog/shadow-writes-nightly-compare https://dylansummerville.com/blog/shadow-writes-nightly-compare Thu, 22 Oct 2026 18:30:00 +1100 A database migration you can prove: one helper for every store, writes to both databases, a nightly compare and a read verifier, then a clean week. Databases PostgreSQL Migration https://dylansummerville.com/blog/container-image-i-would-trust https://dylansummerville.com/blog/container-image-i-would-trust Thu, 22 Oct 2026 18:30:00 +1100 The rules behind a production Python container image: a digest-pinned base, wheels only and no compiler, a minimal runtime, a non-root user, audits. Containers Docker Security https://dylansummerville.com/blog/sqlite-to-postgres-migration https://dylansummerville.com/blog/sqlite-to-postgres-migration Sun, 18 Oct 2026 19:30:00 +1100 How a 125-hour SQLite to Postgres migration became about 21 hours of my time: pgloader, scripted fixes, dual writes and a week of nightly compares. Databases PostgreSQL SQLite Migration https://dylansummerville.com/blog/docker-best-practices https://dylansummerville.com/blog/docker-best-practices Thu, 15 Oct 2026 17:46:00 +1100 Dockerfile best practices: pin base images by digest, prefer slim over Alpine, order layers for caching, build multi-stage, run as non-root and scan weekly. Containers Docker Dockerfiles CI