first draft of a pgsql maint script

pgsql_maint202412.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+# This script does the following things:
+# - Stop mastodon services
+# - Stop postgresql service
+# - Delete AWS S3 pgbackrest repository
+# - Install postgresql-16
+# - Upgrade existing cluster to postgresql-16
+# - Start postgresql
+
+# Stop relevant services
+systemctl stop mastodon-* && systemctl stop postgresql
+
+# Delete deprecated AWS repository from pgbackrest stanza
+sudo -u postgres pgbackrest --stanza=main --log-level-console=info stop && \
+sudo -u postgres pgbackrest --stanza=main --repo=1 --log-level-console=info stanza-delete
+
+# Install Postgres 16 and make sure postgresql is stopped again
+apt install -y postgresql-16 && systemctl stop postgresql
+
+# Upgrade pgsql14 cluster to 16
+pg_renamecluster 16 main main_pristine && pg_upgradecluster --method=link 14 main
+
+# Start postgresql
+systemctl start postgresql
+
+# REMAINING TODO ITEMS
+# - Upgrade stanza in pgbackrest - https://pgbackrest.org/user-guide.html#upgrade-stanza
+# systemctl start mastodon-* and verify it is working.