I would like to setup my apps with High Availability and Security in mind and thinking of using the Azure Application Gateway to provide WAF and Load Balancing (Layer-7) capabilities. I couldn't find any concrete information from official documentation that this is a supported setup (using App Service as AG backends). The official documentation only states VMs:
https://learn.microsoft.com/en-us/azure/application-gateway/overview
Here's a simplified architecture.
Does anyone have first-hand experience with this setup?
Azure Application gateway support app services as the backend. If you want to use the High Availability of app service, you could target two app services in the same backend pool, then the APP GW frontend receiving traffic will go round-robin to the backends in the pool. You could get more details from Configure App Service with Application Gateway
If you just want to host multi-site in the same Azure application gateway, then each site will direct to each backend pool, you could follow this tutorial: Create and configure an application gateway to host multiple web sites using the Azure portal
Related
I am getting to the point of my project where I am ready to deploy it online with my custom domain via Azure once I make the upgrade from my Free Subscription.
So a little context, I have 1 web app service and 4 api services and each one is hosted in a separate app service such as:
www.sitename.azurewebsites.net
www.sitename-api1.azurewebsites.net
www.sitename-api2.azurewebsites.net
www.sitename-api3.azurewebsites.net
www.sitename-api4.azurewebsites.net
And the above web app communicates to all 4 api's and some api's may or may not talk to another. (Would have loved an application gateway so hopefully I'll be changing this architecture later down the road).
So as I get ready to associate my domain to the services, the web container seems pretty straight forward to me as it just becomes www.sitename.com, but I am a little confused about the api services. The way I am thinking about this is that each api service will be in it's own subdomain, such as:
www.api1.sitename.net
www.api2.sitename.net
www.api3.sitename.net
www.api4.sitename.net
where I believe I can register my SSL and domain to each app service somehow, but this leaves me with a few questions.
Do I host each api in a subdomain using the same domain as the web
app, or is there a different way preferred like where I host them
all on the same domain with different exposed ports per API and web
listening 80/443, or maybe just use the IP address of the api app
service and allow www.sitename.com as the origin for CORS?
I am assuming that since I am associating my SSL cert to the web
service, I will need to do the following on the api services?
Would it be better (and still affordable) if I just had a VNET
associated to the app services and the domain only registered with
the web app?
Any insight into this would be greatly appreciated on how I can establish communication between my app services with my custom domain and SSL as I am fairly new to this part of the stack, but excited about learning!
As I known, on Azure cloud, there are two services can help to manage your APIs deployed on multiple app service containers: API Management and Application Gateway.
The Premium tier of API Management has the feature for multiple custom domain names, please see the offical document Feature-based comparison of the Azure API Management tiers as the figure below.
You can refer to the quick start tutorial of Create a new Azure API Management service instance and other related documents to kown how to.
"Azure Application Gateway is a web traffic load balancer that enables you to manage traffic to your web applications." said in the introduce What is Azure Application Gateway?. And as the figure of its architecture below, "With Application Gateway, you can make routing decisions based on additional attributes of an HTTP request, such as URI path or host headers. For example, you can route traffic based on the incoming URL. So if /images is in the incoming URL, you can route traffic to a specific set of servers (known as a pool) configured for images. If /video is in the URL, that traffic is routed to another pool that's optimized for videos."
I recommended to use Azure Application Gateway which be a good choice to manage multiple app services and expose the unified urls of APIs.
I have an environment setup with multiple azure web apps across multiple Azure service plans.
I'm now retrospectively trying to add an azure WAF between the wider internet and the websites.
I have created a WAF, but am now struggling to understand whether it is currently possible to continue to use the *.azurewebsites.net app addresses and route traffic through the WAF?
Is it possible to use the built in *.azurewebsites.net app service addresses as the external entry point to the Azure WAF?
I think I understand your question, what you need to do is route the traffic to the application gateway add azure web app as the backend to the application gateway.
https://learn.microsoft.com/en-us/azure/application-gateway/create-web-app
you cannot azure *.azurewebsites.net as an endpoint for application gateway
I have configured an Application Gateway in front of multiple Azure Web App backend pools as per this article.
In addition to providing a WAF, I use the Application Gateway to offload the SSL connection to the backend pools. I have configured the backend pools to use the FQDN of the App Service instances as they're not currently deployed into a VNET.
Based on the following scenario:
Request to custom.com:443 ---> Application Gateway ---> custom.azurewebsites.net:80
My concern is that the connection from the Application Gateway to the Web App is unencrypted over port 80 and I haven't found anywhere that describes this connectivity as happening over the Azure backbone network. Is there any risk that this traffic could be sniffed and compromised?
Spoke to Microsoft support who said the traffic from my Application Gateway to my Web App will stay on the Microsoft backbone.
He also pointed me to the following knowledge article; which states:
If the destination address is for one of Azure's services, Azure routes the traffic directly to the service over Azure's backbone network, rather than routing the traffic to the Internet. Traffic between Azure services does not traverse the Internet, regardless of which Azure region the virtual network exists in, or which Azure region an instance of the Azure service is deployed in.
I have multiple web apps on Azure that I want to put behind an Application Gateway in order to use a single domain name with path routing.
However, my web apps needs to connect to a db outside of Azure. So I wonder what will the IP of the requests from these web apps to the db would be? I hope it will be the gateway public IP so I only have to authorize one IP at my db provider but I don't find any docs to confirm it (or not).
So I wonder what will the IP of the requests from these web apps to
the db would be?
If you want your web apps to connect a database outside Azure, you may need App service Environment. Because the Web Apps need VNet to connect other resources. Also, due to the date base is outside Azure , you need to create VPN gateway to connect it. This connection is between the Web App and the database, not Application Gateway and Database.
So, the IP of requests from those Web Apps is not the IP of Application Gateway, It depends on the VNet in App Service Environment.
This picture explains how this environment works:
I hope it will be the gateway public IP so I only have to authorize
one IP at my db provider but I don't find any docs to confirm it (or
not).
Also, if you still want to use one IP to connect other resources, you can also add Internal Loadbalancer to achieve that.
You can see more details about Integrating your ILB ASE with an Application Gateway to help your deploy resources.
Please let me know if this answer helps.
I would suggest using the Azure Web App's Hybrid connection. This provides a TCP tunnel in a secured fashion between your azure web app and your SQL db. There is a service bus in between and you have to install the relay agent in your network that does the outgoing communication to this service bus.
Hybrid connection diagram
Details are at:
https://learn.microsoft.com/en-us/azure/app-service/app-service-hybrid-connections
The app gateway's public IP address can't be leveraged nor is it necessary to manage connections between Azure Web Apps and databases outside of Azure. The web apps have their own IP addresses.
On another note, my blog post may be useful to understand how the architecture and configuration between app gateway and azure web app.
In a typical 3-Tier web app, you run web servers in public subnet, while app tier lives in private subnet. Is it possible to run similar architecture with Azure Web apps and Api apps?
I guess you can run Asp.NET Core Web App in Azure Web App and Deploy AspNet Core Web Api to Azure Api App, then make Api end point private so only Web app can talk to it? I see options like Google, Facebook et. as auth providers. Is that what you have to do to make API private?
D.
If you want that level of isolation, one (although expensive) option is an App Service Environment (ASE). Link to docs: https://learn.microsoft.com/en-us/azure/app-service-web/app-service-app-service-environment-intro
App Service Environments are ideal for application workloads requiring:
Very high scale
Isolation and secure network access
The public environment where you deploy by default is public. Your endpoints will be accessible to anyone anywhere, and it is up to your app to do the filtering. This can be done, e.g. through static IP address security settings in Web.config. The problem with that is that even then you can't know for sure what IP address your front-end will use for communication. There are multiple possible addresses it may use for outbound traffic, and those are subject to possible change.
You can see an example of IP restrictions here: restricting IP security
Of course you should also have authentication set up on your API. Documentation links:
https://learn.microsoft.com/en-us/azure/app-service/app-service-authentication-overview
https://learn.microsoft.com/en-us/azure/app-service-api/app-service-api-authentication
In line with what #juunas said above and a slight variant is to introduce Azure API Management Gateway in between Azure web app and Azure Api app. In standard tier API Gateway the IP address is fixed and doesn't change and you can use the API Gateway address in Azure API App web.config to whitelist.