diff --git a/9.0/Dockerfile b/9.0/Dockerfile
index 402d06a64c..7afa3d3833 100644
--- a/9.0/Dockerfile
+++ b/9.0/Dockerfile
@@ -1,8 +1,8 @@
 # vim:set ft=dockerfile:
 FROM debian:jessie
 
-# add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
-RUN groupadd -r postgres && useradd -r -g postgres postgres
+# explicitly set user/group IDs
+RUN groupadd -r postgres --gid=999 && useradd -r -g postgres --uid=999 postgres
 
 # grab gosu for easy step-down from root
 RUN gpg --keyserver pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4
diff --git a/9.1/Dockerfile b/9.1/Dockerfile
index bee13968f9..ad6b698d9d 100644
--- a/9.1/Dockerfile
+++ b/9.1/Dockerfile
@@ -1,8 +1,8 @@
 # vim:set ft=dockerfile:
 FROM debian:jessie
 
-# add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
-RUN groupadd -r postgres && useradd -r -g postgres postgres
+# explicitly set user/group IDs
+RUN groupadd -r postgres --gid=999 && useradd -r -g postgres --uid=999 postgres
 
 # grab gosu for easy step-down from root
 RUN gpg --keyserver pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4
diff --git a/9.2/Dockerfile b/9.2/Dockerfile
index 61bc7afff3..36d58955b3 100644
--- a/9.2/Dockerfile
+++ b/9.2/Dockerfile
@@ -1,8 +1,8 @@
 # vim:set ft=dockerfile:
 FROM debian:jessie
 
-# add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
-RUN groupadd -r postgres && useradd -r -g postgres postgres
+# explicitly set user/group IDs
+RUN groupadd -r postgres --gid=999 && useradd -r -g postgres --uid=999 postgres
 
 # grab gosu for easy step-down from root
 RUN gpg --keyserver pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4
diff --git a/9.3/Dockerfile b/9.3/Dockerfile
index afdb379a60..1f5f1a7848 100644
--- a/9.3/Dockerfile
+++ b/9.3/Dockerfile
@@ -1,8 +1,8 @@
 # vim:set ft=dockerfile:
 FROM debian:jessie
 
-# add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
-RUN groupadd -r postgres && useradd -r -g postgres postgres
+# explicitly set user/group IDs
+RUN groupadd -r postgres --gid=999 && useradd -r -g postgres --uid=999 postgres
 
 # grab gosu for easy step-down from root
 RUN gpg --keyserver pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4
diff --git a/9.4/Dockerfile b/9.4/Dockerfile
index 4031cda3f9..5429bd299f 100644
--- a/9.4/Dockerfile
+++ b/9.4/Dockerfile
@@ -1,8 +1,8 @@
 # vim:set ft=dockerfile:
 FROM debian:jessie
 
-# add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
-RUN groupadd -r postgres && useradd -r -g postgres postgres
+# explicitly set user/group IDs
+RUN groupadd -r postgres --gid=999 && useradd -r -g postgres --uid=999 postgres
 
 # grab gosu for easy step-down from root
 RUN gpg --keyserver pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4
diff --git a/9.5/Dockerfile b/9.5/Dockerfile
index a11f866ca6..ad7266f74e 100644
--- a/9.5/Dockerfile
+++ b/9.5/Dockerfile
@@ -1,8 +1,8 @@
 # vim:set ft=dockerfile:
 FROM debian:jessie
 
-# add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
-RUN groupadd -r postgres && useradd -r -g postgres postgres
+# explicitly set user/group IDs
+RUN groupadd -r postgres --gid=999 && useradd -r -g postgres --uid=999 postgres
 
 # grab gosu for easy step-down from root
 RUN gpg --keyserver pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4