feat: architecture diagram and operations explanation

Reviewed-on: http://localhost:3000/Inviscid/SSW590-DevOps/pulls/7
Reviewed-by: victor <vdelriof@stevens.edu>

chapters/devopsGiteaFoundation.tex

@@ -374,9 +374,16 @@ not confirmed. Payton has taken ownership of the remaining Gitea tasks.
 The initial main push is not counted as a reviewed PR.
 
 \section{Architecture and Operation}
-The current private initialization path is shown in
-Figure~\ref{Figure:GiteaInitialPath}. Payton will add a final deployment diagram
-showing browser HTTPS to Caddy and private forwarding to Gitea.
+Figure~\ref{Figure:GiteaArchitecture} shows the deployed request and data paths.
+\begin{figure}[htbp]
+\centering
+\resizebox{\linewidth}{!}{\input{figures/devopsGiteaFoundation/giteaArchitecture}}
+\caption{October 15: deployed architecture. The security group admits 443 and 80 from any source and 22 only from approved team addresses. Caddy is the only container publishing host ports; Gitea, the Color Buttons app, and both data volumes are private.}
+\label{Figure:GiteaArchitecture}
+\end{figure}
+
+The initial October 12 access path, before Caddy was deployed, is kept for
+reference in Figure~\ref{Figure:GiteaInitialPath}.
 \begin{figure}[htbp]
 \centering
 \fbox{\parbox{0.92\linewidth}{\centering
@@ -387,7 +394,7 @@ $\downarrow$ EC2: 100.49.80.94\\
 EC2 loopback:3000 to Gitea container:3000\\
 $\downarrow$ persistent named volume\\
 \texttt{inviscid\_gitea\_data}: repositories, SQLite, configuration}}
-\caption{Initial SSH-tunnel access path. Caddy and hostname-based HTTPS are not yet verified.}
+\caption{October 12: initial SSH-tunnel-only access path, before Caddy and hostname-based HTTPS were deployed.}
 \label{Figure:GiteaInitialPath}
 \end{figure}
 
@@ -406,8 +413,40 @@ The following are operational commands, not additional claimed test results:
 cd ~/gitea
 sudo docker compose ps
 sudo docker compose logs --tail=40 gitea
+sudo docker compose logs --tail=40 caddy
 sudo docker compose restart gitea
+sudo docker compose restart caddy
 \end{minted}
+
+\paragraph{Where data lives.} Repositories, attachments, Gitea configuration,
+and the SQLite database (\path{/data/gitea/gitea.db}) live in the named volume
+\texttt{inviscid\_gitea\_data}. Certificates and the ACME account live in
+\texttt{inviscid\_caddy\_data} (with \texttt{inviscid\_caddy\_config}). All
+three volumes are on the instance's EBS disk, outside the disposable container
+layers. Deployment files are versioned in \path{docker/gitea/} of the repository.
+
+\paragraph{Public and private interfaces.} Public: TCP 443 (HTTPS to Caddy) and
+TCP 80 (redirect to HTTPS, ACME validation, and the Color Buttons app by IP),
+both from any source. Restricted: TCP 22 (administrative SSH) from approved team
+addresses only. Private: Gitea's port 3000 (reachable only on the Compose network
+and EC2 loopback), the Color Buttons container's port 3000, Caddy's admin port
+2019, and the SQLite file, which has no network port.
+
+\paragraph{Troubleshooting.} If \url{https://git.inviscid.dev} fails, check in
+order: (1) \texttt{docker compose ps} shows both services running; (2) the Caddy
+log shows no certificate or upstream errors; (3) the Gitea log shows it listening
+on port 3000; (4) \texttt{curl -I http://127.0.0.1:3000/} on EC2 returns 200,
+which isolates Gitea from Caddy; (5) DNS still resolves to the Elastic IP and the
+security group still admits 443. Restarting one service leaves its volume intact.
+
+\paragraph{Persistence test versus backup/restore.} The container-replacement
+test shows that data survives when the Gitea \emph{container} is discarded,
+because the named volume is reattached. It does not protect against loss of the
+volume, the EBS disk, or the instance, and it creates no copy elsewhere. A
+backup/restore test would copy the volume and database to separate storage and
+prove recovery into a different instance; that optional exercise
+(Section~2.8 of the assignment) was not performed.
+
 Closing a workstation tunnel does not stop Gitea on EC2. Reconnect the tunnel
 for browser access. Container replacement should retain the named volume;
 never delete that volume as part of the persistence check. Before destructive

devopsAssignment.tex

@@ -23,6 +23,8 @@
 \usepackage{minted}
 \setminted{fontsize=\footnotesize,breaklines,frame=single}
 \usepackage{tcolorbox}
+\usepackage{tikz}
+\usetikzlibrary{positioning,arrows.meta,fit,backgrounds}
 \usepackage{makeidx}
 \usepackage[colorlinks=true,citecolor=blue,linkcolor=blue,urlcolor=blue]{hyperref}
 \usepackage[acronym,toc]{glossaries}

figures/devopsGiteaFoundation/giteaArchitecture.tex

@@ -0,0 +1,60 @@
+\begin{tikzpicture}[
+  font=\footnotesize,
+  >={Stealth[length=2mm]},
+  box/.style={draw, rounded corners=2pt, align=center, fill=white, inner sep=3pt},
+  ctr/.style={box, fill=devopsLightBlue, text width=34mm},
+  vol/.style={box, fill=devopsGray!12, text width=36mm},
+  ext/.style={box, text width=30mm},
+  pub/.style={->, thick, devopsBlue},
+  priv/.style={->, thick, devopsGreen},
+  adm/.style={->, thick, devopsGray, dashed},
+  blk/.style={->, thick, devopsRed, densely dotted},
+  lbl/.style={font=\scriptsize, fill=white, inner sep=1pt}
+]
+% External clients
+\node[ext] (browser) at (0, 2.55) {Browser / Git client (any source)};
+\node[ext] (ip)      at (0, 1.5) {Instructor browser\\\texttt{\scriptsize http://100.49.80.94}};
+\node[ext] (admin)   at (0,-0.8) {Team admin (approved /32 sources)};
+\node[ext] (scan)    at (0,-2.5) {Any other source};
+
+% EC2 contents
+\node[vol] (cdata)   at (6.6, 4.8) {\textbf{Volume} \texttt{\scriptsize inviscid\_caddy\_data}\\certificates, ACME account};
+\node[ctr] (caddy)   at (6.6, 2.15) {\textbf{Caddy} \texttt{\scriptsize caddy:2.10.2}\\TLS termination;\\only 80/443 publisher};
+\node[ctr] (gitea)   at (11.4, 3.0) {\textbf{Gitea} \texttt{\scriptsize 28.1.0}\\\texttt{\scriptsize gitea:3000}};
+\node[ctr, text width=40mm] (buttons) at (11.4, 1.3) {\textbf{Color Buttons}\\\texttt{\scriptsize ssw590-group-buttons:3000}};
+\node[vol] (gdata)   at (16.0, 3.0) {\textbf{Volume} \texttt{\scriptsize inviscid\_gitea\_data}\\repositories, config,\\SQLite \texttt{\scriptsize gitea.db}};
+\node[box, text width=34mm] (sshd) at (6.6,-0.8) {\textbf{sshd} (EC2 host), TCP 22};
+
+\begin{scope}[on background layer]
+  \node[draw=devopsGreen, dashed, rounded corners, fill=devopsGreen!5, inner sep=3mm,
+        fit=(caddy)(gitea)(buttons),
+        label={[font=\scriptsize, text=devopsGreen, anchor=north west, yshift=-1pt]south west:Docker network \texttt{inviscid\_services} (private)}] (net) {};
+  \node[draw=devopsBlue, thick, rounded corners, inner sep=4mm,
+        fit=(net)(sshd)(gdata)(cdata),
+        label={[font=\scriptsize\bfseries, text=devopsBlue]above:EC2 \texttt{ssw590-group-web} (\texttt{us-east-1}) --- Elastic IP 100.49.80.94, no IPv6}] (ec2) {};
+\end{scope}
+
+% Security group wall
+\coordinate (sgTop) at (3.25, 5.9);
+\coordinate (sgBot) at (3.25,-3.0);
+\draw[line width=2pt, devopsRed] (sgTop) -- (sgBot);
+\node[font=\scriptsize, text=devopsRed, align=center, anchor=north, fill=white, inner sep=1pt] at ([yshift=-1mm]sgTop) {Security group\\\texttt{ssw590-web-sg}};
+
+% Public flows (allowed by the security group)
+\draw[pub] (browser.east) -- node[lbl, above, pos=0.72]{443; 80$\to$308} (caddy.west |- browser.east);
+\draw[pub] (ip.east) -- node[lbl, above, pos=0.72]{80 HTTP} (caddy.west |- ip.east);
+
+% Private flows
+\draw[priv] (caddy.east |- gitea.west) -- node[lbl, above]{\texttt{\scriptsize git.inviscid.dev}} (gitea.west);
+\draw[priv] (caddy.east |- buttons.west) -- node[lbl, below, pos=0.4]{by IP} (buttons.west);
+\draw[priv] (caddy.north) -- (cdata.south);
+\draw[priv] ([yshift=2mm]gitea.east) -- ([yshift=2mm]gdata.west |- gitea.east);
+
+% Administrative path
+\draw[adm] (admin.east) -- node[lbl, above, pos=0.72]{22 SSH} (sshd.west);
+\draw[adm] (sshd.east) -- node[lbl, below]{SSH tunnel to \texttt{\scriptsize 127.0.0.1:3000}} (13.75,-0.8) |- ([yshift=-3mm]gitea.east);
+
+% Blocked
+\draw[blk] (scan.east) -- node[lbl, above, pos=0.62]{22, 3000, 222, 2019} ([xshift=-1.2mm]sgBot |- scan.east);
+\node[text=devopsRed, font=\large\bfseries] at (sgBot |- scan.east) {$\times$};
+\end{tikzpicture}