Deployment

An ASP.NET Core app is a regular process that hosts the Kestrel web server. Deploying it means publishing the compiled output, running it with production configuration, and usually placing it behind a reverse proxy or inside a container.

dotnet publish

# framework-dependent: the server needs the ASP.NET Core runtime
dotnet publish -c Release -o ./publish
dotnet ./publish/TodoApi.dll

# self-contained for Linux x64: the runtime is included
dotnet publish -c Release -r linux-x64 --self-contained -o ./publish
./publish/TodoApi

Minimal API apps can also be published with Native AOT (<PublishAot>true</PublishAot>, or the webapiaot template) for fast startup and a small footprint, with some limits such as no MVC controllers.

Production configuration

The environment defaults to Production. Supply secrets and connection strings through environment variables or a secret store, and choose the listening address with ASPNETCORE_URLS or ASPNETCORE_HTTP_PORTS:

export ConnectionStrings__Default="Host=db;Database=todo;Username=app;Password=change-me"
export ASPNETCORE_URLS="http://127.0.0.1:5000"
dotnet ./publish/TodoApi.dll

Kestrel behind a reverse proxy

Kestrel is production-ready, but a reverse proxy such as Nginx, Apache, IIS or a cloud load balancer often terminates TLS, hosts several sites on one IP and adds request limits. Because the proxy talks to Kestrel over plain HTTP, the app must read the original scheme and client IP from the X-Forwarded-* headers:

using Microsoft.AspNetCore.HttpOverrides;

builder.Services.Configure<ForwardedHeadersOptions>(options =>
{
    options.ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto;
});

var app = builder.Build();
app.UseForwardedHeaders();   // before other middleware

By default only a proxy on the same machine is trusted; if it runs elsewhere, add its address to KnownProxies. A matching Nginx site:

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_pass         http://127.0.0.1:5000;
        proxy_http_version 1.1;
        proxy_set_header   Host $host;
        proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header   X-Forwarded-Proto $scheme;
    }
}