\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{shapes.misc, positioning, backgrounds, fit}

\begin{document}

\tikzset{
  sys/.style = {draw, rectangle, rounded corners=5,
    node distance = 2cm, minimum height=2cm, minimum width=4cm},
}

\begin{tikzpicture}
  %\draw[step=0.5in,black!50,dotted] (-5.5in,-4in) grid (5.5in, 4in);

  %\filldraw (0,0) [red] circle (3pt);

  \node at (-3, -2.5) [sys] (static) {
    \begin{tabular}{c} \textbf{Static Content}\\\tiny{CloudFront}
  \end{tabular}};
  \node at (static.west)[rectangle, xshift=-3pt, rotate=90]  {\tiny\textbf{Port:4201}};

  \node at (-3, 2.5) [sys] (dynamic) {
    \begin{tabular}{c} \textbf{Dynamic Content}\\\tiny{CloudFront}
    \end{tabular}
  };
  \node at (dynamic.west)[rectangle, xshift=-3pt, rotate=90]  {\tiny\textbf{Port:4200}};

  \node at (4, 2.5) [sys] (backend) {
    \begin{tabular}{c}\textbf{Backend}\\
      \tiny{Elastic Beanstalk}\\
      \tiny{Java, Spring, Spring Boot}
    \end{tabular}
  };
  \node at (backend.west)[rectangle, xshift=-3pt, rotate=90] (bport) {\tiny\textbf{Port:5000}};

  \node[inner sep=0pt, outer sep=0pt] (s3) at (2.5, -2.5)
       {
         \includegraphics[width=1.5in]{Storage_AmazonS3_bucket.eps}
       };

  \node[inner sep=0pt] (db) at (5, -2.5)
    {\includegraphics[width=1.5in]{Database_AmazonRDS_SQLmaster.eps}};

  \node at (s3.south) {S3 Bucket};
  \node (dblabel) at (db.south) {Postgres DB};

  \draw[<->] (static) -- node[yshift=4pt, sloped] {\tiny{$refers$}} (dynamic);
  \draw[<-] (static) -- node[yshift=8pt, sloped] {\tiny{$S3 Read$}} (s3);
  \draw[<->] (dynamic) -- node[yshift=8pt] {\tiny{$RESTful API$}} (bport);
  \draw[<-] (dynamic) -- node[yshift=8pt, sloped] {\tiny{$S3 Read$}} (s3);
  \draw[<->] (backend) -- node[yshift=8pt, sloped] {\tiny{$SQL Driver$}} (db);
  \draw[<->] (backend) -- node[yshift=8pt, sloped] {\tiny{$S3 Read/Write$}} (s3);

  \node[text=teal, anchor=center] at (0.25, -5.5) (caption){\huge\textbf{System Overview}};

  \begin{pgfonlayer}{background}
    \node [inner sep=0.5in, fill=red!10,fit=(dynamic) (caption) (db)] {};
  \end{pgfonlayer}
\end{tikzpicture}


\end{document}