fix: resolve container backends dynamically to allow nginx startup

conf.d/10-resolver.conf.template

@@ -0,0 +1,5 @@
+# Docker's embedded DNS is available before the other stacks start.
+# Resolve container names at runtime so a missing backend cannot stop Nginx.
+# Requires Nginx >= 1.27.3 (open-source upstream resolve support).
+resolver 127.0.0.11 valid=10s;
+resolver_timeout 5s;

conf.d/adguardhome.conf.template

@@ -1,3 +1,8 @@
+upstream adguardhome_backend {
+    zone adguardhome_backend 64k;
+    server adguardhome:80 resolve;
+}
+
 server {
     include snippets/https.conf;
 
@@ -6,6 +11,6 @@ server {
     include snippets/proxy.conf;
 
     location / {
-        proxy_pass http://adguardhome;
+        proxy_pass http://adguardhome_backend;
     }
 }

conf.d/backrest.conf.template

@@ -1,3 +1,8 @@
+upstream backrest_backend {
+    zone backrest_backend 64k;
+    server backrest:9898 resolve;
+}
+
 server {
     include snippets/https.conf;
 
@@ -6,6 +11,6 @@ server {
     include snippets/proxy.conf;
 
     location / {
-        proxy_pass http://backrest:9898;
+        proxy_pass http://backrest_backend;
     }
 }

conf.d/gitea.conf.template

@@ -1,3 +1,8 @@
+upstream gitea_backend {
+    zone gitea_backend 64k;
+    server gitea:3000 resolve;
+}
+
 server {
     include snippets/https.conf;
 
@@ -6,7 +11,7 @@ server {
     include snippets/proxy.conf;
 
     location / {
-        proxy_pass http://gitea:3000;
+        proxy_pass http://gitea_backend;
         client_max_body_size 512M;
     }
 }

conf.d/immich.conf.template

@@ -1,3 +1,8 @@
+upstream immich_backend {
+    zone immich_backend 64k;
+    server immich-server:2283 resolve;
+}
+
 server {
     include snippets/https.conf;
 
@@ -20,7 +25,7 @@ server {
     send_timeout       600s;
 
     location / {
-        proxy_pass http://immich-server:2283;
+        proxy_pass http://immich_backend;
         proxy_redirect off;
     }
 

conf.d/openlist.conf.template

@@ -1,3 +1,8 @@
+upstream openlist_backend {
+    zone openlist_backend 64k;
+    server openlist:5244 resolve;
+}
+
 server {
     include snippets/https.conf;
 
@@ -6,7 +11,7 @@ server {
     include snippets/proxy.conf;
 
     location / {
-        proxy_pass http://openlist:5244;
+        proxy_pass http://openlist_backend;
         proxy_redirect off;
     }
 }

conf.d/qbittorrent.conf.template

@@ -1,3 +1,8 @@
+upstream qbittorrent_backend {
+    zone qbittorrent_backend 64k;
+    server qbittorrent:8080 resolve;
+}
+
 server {
     include snippets/https.conf;
 
@@ -6,6 +11,6 @@ server {
     include snippets/proxy.conf;
 
     location / {
-        proxy_pass http://qbittorrent:8080;
+        proxy_pass http://qbittorrent_backend;
     }
 }