https://explainit.metacog.co.kr/tags/distributed-systems/Recent content in Distributed-Systems on Explain ItHugoen-usWed, 22 Jul 2026 07:22:28 +0900https://explainit.metacog.co.kr/posts/2026-07-22-how-patroni-keeps-your-database-running-even-when-servers-cr/Wed, 22 Jul 2026 07:22:28 +0900https://explainit.metacog.co.kr/posts/2026-07-22-how-patroni-keeps-your-database-running-even-when-servers-cr/<h2 id="-what-is-it">🤔 What Is It?</h2> <blockquote> <p><strong>Patroni 기반 분산 PostgreSQL, Patroni HA</strong></p> </blockquote> <p>Patroni is smart coach software that watches over a team of database servers — if the main server breaks, it instantly picks a backup to take over so your app never goes offline.</p> <h2 id="-like-a-soccer-team-with-an-automatic-coach">🧩 Like a soccer team with an automatic coach</h2> <p>Imagine a soccer team where one player is chosen as the captain — they call all the plays and everyone follows them. Three other players are backup captains who watch every single move the main captain makes and copy every strategy note into their own notebooks, second by second. A super-smart coach named Patroni watches everyone from the sideline, and the whole team shares one giant whiteboard called etcd that always shows exactly who the current captain is. If the main captain suddenly twists their ankle and can&rsquo;t play, Patroni instantly checks the backups, picks the one whose notebook is most up-to-date, writes the new name on the whiteboard, and the game keeps going — all in a few seconds. Nobody in the stands even notices the switch happened.</p>