diff --git a/optional/postgresql/Dockerfile b/optional/postgresql/Dockerfile
index dbfc1dc8..14d11864 100644
--- a/optional/postgresql/Dockerfile
+++ b/optional/postgresql/Dockerfile
@@ -16,8 +16,12 @@ COPY start.py /start.py
 COPY conf /conf
 
 ENV LANG en_US.UTF-8
+
+RUN mkdir -p /var/lib/postgresql/data /run/postgresql \
+  && chown -R postgres:postgres /var/lib/postgresql/data /run/postgresql \
+  && chmod 2777 /run/postgresql
+
+VOLUME /var/lib/postgresql/data
 EXPOSE 5432
 
-RUN mkdir -p /run/postgresql && chown -R postgres:postgres /run/postgresql && chmod 2777 /run/postgresql
-
 CMD /start.py
diff --git a/optional/postgresql/start.py b/optional/postgresql/start.py
index f8bfc7d9..5880765e 100755
--- a/optional/postgresql/start.py
+++ b/optional/postgresql/start.py
@@ -20,7 +20,7 @@ def setup():
     conn.close()
 
 # Bootstrap the database if postgresql is running for the first time
-if not os.path.exists('/var/lib/postgresql/data/pg_hba.conf'):
+if not os.path.exists('/var/lib/postgresql/data/pg_wal'):
     os.system("chown -R postgres:postgres /var/lib/postgresql")
     os.system("su - postgres -c 'initdb -D /var/lib/postgresql/data'")