Allow shared local users

.env.sample

@@ -18,6 +18,9 @@ MSSQL_ENABLED="1"
 
 # Comment out if you are using keycloak or oidc
 COMPOSE_FILE="$COMPOSE_FILE:compose.local-users.yml"
+# Share the local user database with other instances
+#COMPOSE_FILE="$COMPOSE_FILE:compose.local-users-shared.yml"
+#LOCAL_USERS_VOLUME=rstudio_example_com_users
 
 # OpenID Connect (SSO)
 #COMPOSE_FILE="$COMPOSE_FILE:compose.oidc.yml"

compose.local-users-shared.yml

@@ -0,0 +1,7 @@
+---
+version: "3.8"
+
+volumes:
+  users:
+    external: true
+    name: ${LOCAL_USERS_VOLUME}

entrypoint.sh.tmpl

@@ -28,9 +28,9 @@ cp /opt/users/group /etc/group || true
 
 copy_users() {
   while true; do
-    cp /etc/passwd /opt/users/passwd
-    cp /etc/shadow /opt/users/shadow
-    cp /etc/group /opt/users/group
+    cp -u /etc/passwd /opt/users/passwd
+    cp -u /etc/shadow /opt/users/shadow
+    cp -u /etc/group /opt/users/group
     sleep 60
   done
 }