How do I connect two VMs in the same cloud service?

Question

I want to setup a DB cluster with two VMs in a single cloud service. My DB (Couchbase) requires being able to reference the other nodes by IP address or hostname. Since VMs change their IP everytime they restart I can't use that, and as far as I can tell
hostname is the same for both VMs in a cloud service. But the Azure docs mention Azure provided name resolution (here https://msdn.microsoft.com/en-us/library/azure/jj156088.aspx). I can't find any information on how this service works, or how I find the permanent
hostnames it assigns to my VMs within a cloud service. Is there anyway to find one VM from another within a cloud service that persists across restarts?

Answer 1

Hi CanuckAlex;
Thank you for your post.
Virtual machines must be in a cloud service, which acts as a container and provides a unique public DNS name, a public IP address, and a set of endpoints to access the virtual machine over the Internet. The cloud service can optionally be in a virtual network.
If a cloud service is not in a virtual network, the virtual machines in that cloud service can only communicate with other virtual machines through the use of the other virtual machines’ public DNS names, and that traffic would travel over the Internet.
If a cloud service is in a virtual network, the virtual machines in that cloud service can communicate with all other virtual machines in the virtual network without sending any traffic over the Internet.
If you place your virtual machines in the same standalone cloud service, you can take advantage of load balancing and availability sets. For details, see
Load balancing virtual machines and
Manage the availability of virtual machines. However, you cannot organize the virtual machines on subnets or connect a standalone cloud service to your on-premises network. Here is an example.
If you place your virtual machines in a virtual network, you can decide how many cloud services you want to use to take advantage of load balancing and availability sets. Additionally, you can organize the virtual machines on subnets in the same way as your
on-premises network and connect the virtual network to your on-premises network. Here is an example.
Virtual networks are the recommended way to connect virtual machines in Azure. The best practice is to configure each tier of your application in a separate cloud service. This enables advanced user rights delegation through Role Based Access Control (RBAC).
For more information, see
Role Based Access Control in Azure Preview Portal. However, you may need to combine some virtual machines from different application tiers into the same cloud service to remain within the maximum of 200 cloud services per subscription.
To connect virtual machines in a virtual network:
Create the virtual network in the Azure Management Portal. For more information, see
Virtual Network Configuration Tasks.
Create the set of cloud services for your deployment in the Azure Management Portal to reflect your design for availability sets and load balancing with
New > Compute > Cloud Service > Custom Create.
When you create each new virtual machine, specify the correct cloud service and your virtual network. If the cloud service has been previously associated with your virtual network, its name will already be selected for you.
Here is an example using the Azure Management Portal.
To connect virtual machines in a standalone cloud service:
Create the cloud service for your deployment in the Azure Management Portal with
New > Compute > Cloud Service > Custom Create.
When you create the virtual machine, specify the name of cloud service created in step 1. Alternately, you can create the cloud service for your deployment when you create your first virtual machine.
Here is an example using the Azure Management Portal for the existing cloud service named EndpointTest.
PS: One can assign static IP address to VM on Azure, You could refer to this
link here.
Hope this helps.
Warm Regards;
Prasant