WIP Prepare postgres for migration by replication

site-cookbooks/kosmos_postgresql/files/dump_all_databases.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+cd /tmp && \
+(pg_dumpall --globals-only > globals.sql) && \
+psql -Atqc "SELECT datname FROM pg_database WHERE datallowconn AND datname NOT IN (''template0'')" | \
+xargs -I{} -P4 sh -c "
+  pg_dump -Fd -j 4 -d \"{}\" -f dump_{} &&
+  tar -cf - dump_{} | zstd -19 -T0 > dump_{}.tar.zst &&
+  rm -rf dump_{}
+"