More verbose comments

Author: nebirhos

20-replication.sh

@@ -8,6 +8,7 @@ elif [ $REPLICATION_ROLE = "slave" ]; then
     # stop postgres instance and reset PGDATA,
     # confs will be copied by pg_basebackup
     gosu postgres pg_ctl -D "$PGDATA" -m fast -w stop
+    # make sure standby's data directory is empty
     rm -r "$PGDATA"/*
 
     gosu postgres pg_basebackup \

Dockerfile

@@ -19,5 +19,7 @@ ENV POSTGRES_MASTER_SERVICE_PORT 5432
 
 COPY 10-config.sh /docker-entrypoint-initdb.d/
 COPY 20-replication.sh /docker-entrypoint-initdb.d/
-# Evaluate vars inside PGDATA (eg PGDATA=/mnt/$HOSTNAME)
+# Evaluate vars inside PGDATA at runtime.
+# For example HOSTNAME in 'ENV PGDATA=/mnt/$HOSTNAME'
+# is resolved runtime rather then during build
 RUN sed -i 's/set -e/set -e -x\nPGDATA=$(eval echo "$PGDATA")/' /docker-entrypoint.sh