From 73805a4e674fc539d6fd38439dc9cf19eaaf428b Mon Sep 17 00:00:00 2001
From: "aspire-repo-bot[bot]"
<268009190+aspire-repo-bot[bot]@users.noreply.github.com>
Date: Wed, 29 Apr 2026 00:09:34 +0000
Subject: [PATCH 1/2] docs: document container tunnel enabled by default in
Aspire 13.3
Add a new section to the What's new in Aspire 13.3 page describing
the container tunnel being enabled by default (aspire/aspire#14557).
- Explains what the tunnel is and why it matters
- Notes the ~3-4s startup delay for containers using host endpoints
- Shows how to opt out via ASPIRE_ENABLE_CONTAINER_TUNNEL=false
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
.../content/docs/whats-new/aspire-13-3.mdx | 42 ++++++++++++++++++-
1 file changed, 40 insertions(+), 2 deletions(-)
diff --git a/src/frontend/src/content/docs/whats-new/aspire-13-3.mdx b/src/frontend/src/content/docs/whats-new/aspire-13-3.mdx
index 0bdf180b0..1e5938179 100644
--- a/src/frontend/src/content/docs/whats-new/aspire-13-3.mdx
+++ b/src/frontend/src/content/docs/whats-new/aspire-13-3.mdx
@@ -1,6 +1,6 @@
---
title: What's new in Aspire 13.3
-description: Aspire 13.3 introduces Azure Network Security Perimeter support and more.
+description: Aspire 13.3 introduces Azure Network Security Perimeter support, enables the container tunnel by default, and more.
sidebar:
label: Aspire 13.3
order: 0
@@ -9,7 +9,7 @@ tableOfContents:
maxHeadingLevel: 2
---
-import { Steps } from '@astrojs/starlight/components';
+import { Steps, Aside } from '@astrojs/starlight/components';
import { Image } from 'astro:assets';
import LearnMore from '@components/LearnMore.astro';
import azureFrontDoorIcon from '@assets/icons/azure-front-door-icon.png';
@@ -98,3 +98,41 @@ NSPs support **Enforced** mode (blocks traffic that violates the rules) and **Le
For more details, see [Azure Virtual Network integration](/integrations/cloud/azure/azure-virtual-network/#add-a-network-security-perimeter).
+
+## 🔗 Container tunnel enabled by default
+
+Aspire 13.3 enables the **Aspire container tunnel** by default, providing uniform container-to-host connectivity regardless of your container orchestrator.
+
+Previously introduced as an opt-in experimental feature in Aspire 13.0, the container tunnel allows containers to reliably communicate with host-based services (such as the Aspire dashboard, OTEL collector, and other projects). Before this change, Docker Desktop users benefited from built-in host connectivity (`host.docker.internal`), while other container runtimes such as Docker Engine on Linux or Podman required manual workarounds.
+
+With the tunnel enabled by default, all supported container orchestrators now behave consistently without any additional configuration.
+
+
+
+### Disabling the container tunnel
+
+If you need to opt out, set the `ASPIRE_ENABLE_CONTAINER_TUNNEL` environment variable to `false` before starting your AppHost:
+
+```bash title="Shell — Disable container tunnel"
+ASPIRE_ENABLE_CONTAINER_TUNNEL=false dotnet run --project MyApp.AppHost
+```
+
+You can also disable it in `launchSettings.json`:
+
+```json title="launchSettings.json"
+{
+ "profiles": {
+ "MyApp.AppHost": {
+ "environmentVariables": {
+ "ASPIRE_ENABLE_CONTAINER_TUNNEL": "false"
+ }
+ }
+ }
+}
+```
+
+
+ For more details on container networking, see [Inner-loop networking overview](/fundamentals/networking-overview/).
+
From e262961c51169c62f172b823dbcb5e63627331e7 Mon Sep 17 00:00:00 2001
From: David Pine
Date: Mon, 4 May 2026 11:23:07 -0500
Subject: [PATCH 2/2] Apply suggestions from code review
Co-authored-by: David Pine
---
src/frontend/src/content/docs/whats-new/aspire-13-3.mdx | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/frontend/src/content/docs/whats-new/aspire-13-3.mdx b/src/frontend/src/content/docs/whats-new/aspire-13-3.mdx
index 1e5938179..c32a65546 100644
--- a/src/frontend/src/content/docs/whats-new/aspire-13-3.mdx
+++ b/src/frontend/src/content/docs/whats-new/aspire-13-3.mdx
@@ -116,7 +116,7 @@ Containers that reference host-based endpoints will start slightly later (~3–4
If you need to opt out, set the `ASPIRE_ENABLE_CONTAINER_TUNNEL` environment variable to `false` before starting your AppHost:
```bash title="Shell — Disable container tunnel"
-ASPIRE_ENABLE_CONTAINER_TUNNEL=false dotnet run --project MyApp.AppHost
+ASPIRE_ENABLE_CONTAINER_TUNNEL=false aspire run
```
You can also disable it in `launchSettings.json`: