Skip to main content

Different ways to access Azure instances using Public IP

Let's talk about IP Addressing in Microsoft Azure. In this post we will talk about ILPIP (Instance-Level Public IP, used to be known as PIP - Public IP) and Reserved  Public IP (that is a new feature of offered by Microsoft Azure).

Virtual IP (VIP)
Before jumping into this subject, we need to understand what is a Virtual IP (VIP).
A Virtual IP is a public IP that is assigned to a resource like Web Role, Worker Role or Virtual Machine in the moment when we create a cloud service. This VIP is allocated automatically and allow our resource to communicate with external resource. Using VIP, a request from internet can access our Azure Resource.
This VIP will never change as long as the cloud contains at least one instance of that resources. For example we can have 10 instances of Web Roles with a specific deployment. As long as we have at least one, we will not lose the IP. Only when we deprovision the resource we will lose the VIP.
A "fix" for this issue, before having Reserved Public IP was to have all the time a small instance of resources allocated all the time - a small and cheap hack.
 

Using VIP you could connect directly to an instance of your resource only if you would allocate use the VIP and a Port Number. For each instance of your resource you can assign a specific port. As showed below.


Instance-Level Public IP (ILPIP)
This IP can be assigned directly to your instance of your resource (like VM). In this way you can target directly your instance and not the cloud services. Basically it allow us to connect and communicate directly to a specific instance of our resource (directly to a Web Role, Worker Role or Virtual Machine instance).
For example we can connect directly from internet to a VM instance, like in the diagram below.

Even if we can access an instance of our resource directly from internet using a 'Public IP', we still cannot have a fixed and dedicated IP if you recreate your resource. The story is similar with the one from Virtual IP (VIP).

Reserved IP
This feature allows us to reserve a fixed IP to our cloud resource. This means that we can have in front of our Azure resources a public IP that will not change in time, even if we stop or reallocate this resources.

This solution is more similar with Virtual IP because the Reserved IP is in front of our cloud services. There is no public IP reserved for each instance of your cloud services. Only one public IP will be reserved for all cloud services.
This means that if you want to access a specific instance, you will need a similar solution with Virtual IP, where you map a port to a specific instance.


Based on our needs we can reserved a public IP for our cloud services or not. We should be aware that we can control at IP level only for Web Roles, Worker Roles and VMs. For Azure Services like Azure Storage, Service Bus of Event Hub we don't have any kind of control.

Comments

Popular posts from this blog

How to check in AngularJS if a service was register or not

There are cases when you need to check in a service or a controller was register in AngularJS.
For example a valid use case is when you have the same implementation running on multiple application. In this case, you may want to intercept the HTTP provider and add a custom step there. This step don’t needs to run on all the application, only in the one where the service exist and register.
A solution for this case would be to have a flag in the configuration that specify this. In the core you would have an IF that would check the value of this flag.
Another solution is to check if a specific service was register in AngularJS or not. If the service was register that you would execute your own logic.
To check if a service was register or not in AngularJS container you need to call the ‘has’ method of ‘inhector’. It will return TRUE if the service was register.
if ($injector.has('httpInterceptorService')) { $httpProvider.interceptors.push('httpInterceptorService&#…

ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded

Today blog post will be started with the following error when running DB tests on the CI machine:
threw exception: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information. at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName) This error happened only on the Continuous Integration machine. On the devs machines, everything has fine. The classic problem – on my machine it’s working. The CI has the following configuration:

TeamCity.NET 4.51EF 6.0.2VS2013
It seems that there …

[Post-Event] Codecamp Conference Cluj-Napoca - Nov 19, 2016

Last day I was invited to another Codecamp Conference, that took place in Cluj-Napoca. Like other Codecamp Conferences, the event was very big, with more than 1.000 participants and 70 sessions. There were 10 tracks in parallel, so it was pretty hard to decide at  what session you want to join.
It was great to join this conference and I hope that you discovered something new during the conference.
At this event I talked about Azure IoT Hub and how we can use it to connect devices from the field. I had a lot of demos using Raspberry PI 3 and Simplelink SensorTag. Most of the samples were written in C++ and Node.JS and people were impressed that even if we are using Microsoft technologies, we are not limited to C# and .NET. World and Microsoft are changing so fast. Just looking and Azure IoT Hub and new features that were launched and I'm pressed (Jobs, Methods, Device Twin).
On backend my demos covered Stream Analytics, Event Hub, Azure Object Storage and DocumentDB.

Title:
What abo…