Trying to modify run.sh so it waits for the Xvfb server to start accepting connections.

run.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
-start-stop-daemon --start --pidfile ~/xvfb.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -screen 0 1024x768x24 -ac +extension GLX +render -noreset
 
-let p=80
+# Find an open port
+let p=99
 while [ ${p} -lt 3000 ]
  do
     if nc -z localhost ${p}; then
@@ -11,15 +11,20 @@ while [ ${p} -lt 3000 ]
         break
     fi
  done
-echo The port is ${port}
 
 if ${port}; then
+    echo The display port will be ${port}
+    start-stop-daemon --start --pidfile ~/xvfb.pid --make-pidfile --background \
+        --exec /usr/bin/Xvfb -- :${port} -screen 0 1024x768x24 \
+        -ac +extension GLX +render -noreset
+
+    # Wait to be able to connect to the port. This will exit if it cannot in 15 minutes.
     timeout 15 bash -c "until echo > /dev/tcp/localhost/${port}; do sleep 0.5; done"
+    export DISPLAY=:${port}.0
+
+    cd /data
+    node /usr/src/app/ -p 80 "$@"
 else
+    echo "Could get a display port ${port}."
     exit 1
 fi
-
-export DISPLAY=:${port}.0
-
-cd /data
-node /usr/src/app/ -p 80 "$@"