I have a VNET with a subnet, there are 3 VMs in the subnet, the VNET is connected via a VPN connection to an on-premises server. The on-premises server will send requests to an internal IP of the subnet.
What I'd like to do is host a load balancer with no public IP, but has an IP in the subnet range. The on-premises app would then talk to the single load balancer, which would in turn forward the request on to any of the servers hosting my app in the subnet.
Can anyone tell me if this is possible, or an alternative if possible.
I believe you are looking for an internal load balancer.
You can find documentation for that here: https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-get-started-ilb-arm-portal.
Azure Internal Load Balancer (ILB) provides network load balancing between virtual machines that reside inside a cloud service or a virtual network with a regional scope.
Create a Load Balancer as usual, but specify Type: Internal.
Probably best to make it use a static IP address as well so it won't change.
Then you'll need to configure its back-end pool and health probe so it knows where to route traffic.
Related
I have two virtual machines in azure VNet (IP adresses 10.1.0.4 and 10.1.0.5), and one machine connected to VNet via VPN Gateway (IP 10.3.0.2). Is is possible to create a load balancing in internal load balancer to redirect UPD traffic to VPN connected machine?
Azure Load Balancer supports virtual machines or virtual machine scale sets as it's backend pool endpoints along with addition of instances via network interface or IP addresses. However, a backend pool configured by IP address has the following limitation:
The backend resources must be in the same virtual network as the load balancer.
Reference : https://learn.microsoft.com/en-us/azure/load-balancer/backend-pool-management#limitations
So, you cannot add a VPN connected on-premise machine in the backend pool of the load balancer. There is an active feature request for this and it is under review by the load balancer product group team. You can upvote this feature request in the below forum for future improvements:
https://feedback.azure.com/d365community/idea/49c222f6-8726-ec11-b6e6-000d3a4f0789
I'm facing the Azure Public Load Balancer issue, cannot access the load balancer public IP use by port 80 but I can access to backend pool VM's port 80.
My Azure Public Load Balancer setting all following the Microsoft Azure Documentation.
The Backend Pool VMs also can access port 80 by VMs public IP.
There any troubleshoot for this situation?
Thanks.
If you are unable to connect to your VMs via the load balancer front end IP / port, it is usually an issue with your LB configuration, backend health, or a firewall / NSG blocking the connection.
Please refer the below troubleshooting docs to go through your configuration:
https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-troubleshoot-backend-traffic
Your LB configuration will be setup using the Load Balancing Rules of your load balancer.
Azure Load Balancer will not route traffic to backends that are not reporting healthy via the Health Probes, so make sure your backend is healthy.
A Firewall or NSG can also block the connection, so make sure there are no firewalls in your environment/OS firewalls that block the traffic, and check your Network Security Groups (NSGs) on your Subnet / NICs of the VM are not blocking the load balancing probes (AllowAzureLoadBalancerInBound rule).
You can also run the automated troubleshooter for specific issues on your load balancer from the "Diagnose and solve problems" tab of your load balancer resource in Azure portal as shown in the below picture:
So as the title suggests, I need to make a load-balanced internal gateway with a VPN. I'm a developer, so networking is not my forte.
I have two identical VMs (VM1 in Availability Zone 1 and VM2 in Availability Zone 2) and I need to share VPN traffic between them. My client has provided a range of 5 addresses that will be configured on their firewall, so I will pick one for them to use and they then need to be oblivious to the internal routing.
My ultimate goal is to allow the client to connect through a VPN to one IP address (in the range they have allocated) and let Azure direct the traffic to VM1 primarily, but failover to VM2 if Availability Zone 1 goes down. The client must be oblivious to which VM they ultimately connect to.
My problem is that I cannot create a configuration where the Load Balancer's static IP is in the address range of the Gateway's VPN P2S address pool. Azure requires the P2S address pool to be outside of the VNet's address space and the Load Balancer needs to use the VNet's Subnet (which obviously is INSIDE the VNet's address space, so I'm stuck.
I can create the GW -> Vnet -> subnet -> VM1/VM2 set up no problem using the client's specified IP range for the P2S VPN, but without a Load Balancer, how do I then direct the traffic between the VMs?
e.g. (IPs are hypothetical)
The Vnet address range is 172.10.0.0/16
The Gateway subnet is 172.10.10.0/24
The Gateway's P2S address pool is 172.5.5.5/29
VM1's IP is 172.10.10.4
VM2's IP is 172.10.10.5
I can create a Load Balancer to use the Vnet (and the VMs in a Backend Pool), but then it's static IP has to fall in the VNet's subnet and thus outside the P2S address pool. So how do I achieve this?
I thought of creating a second VNet and corresponding Gateway and linking the Gateways, but I seemed to end up in the same boat
UPDATE: here is an image of my VNet diagram. I have only added one of the VMs (NSPHiAvail1) for now, but VM2 will be in the same LB backend pool
NSP_Address_Range is the range is a subnet of the VNet and is the range dictated by the client. The load balancer has a frontend IP in this range
Firstly, the Azure load balancer does round-robin load balancing for new incoming TCP connections, you could not use it for failover.
My problem is that I cannot create a configuration where the Load
Balancer's static IP is in the address range of the Gateway's VPN P2S
address pool.
You do not need to add the Load balancer frontend IP in the P2S address pool, the address pool is used for clients connecting to your Azure VNet.
Generally, you could configure P2S VPN gateway, create Gateway subnet and vmsubnet and create an internal standard SKU load balancer in the vmsubnet, then you could add the VMs in the vmsubnet into the backend pool as the backend target of the load balancer and configure the healthpro and load balancer rule for load balancing traffic. If so, you could access the backend VMs from clients via the load balancer frontend private IP.
Moreover, you could know some limitations about internal load balancer.
My problem was the Load Balancer Rules - or lack thereof. Once I had added a rule for port 1433 (SQL Server), I was able to query the DB from my local instance of SSMS
There is another solution that is a LOT simpler than the solution I was trying to implement, BUT it does not work allow for an internal load balancer
Azure Virtual Machine Scale Sets implement as many VMs as I specify and will automatically switch to another zone if one goes down. I have no need for the scalability aspect, so I disabled this and I'm only using the Load balancing aspect.
NB This setup only exposes a PUBLIC IP and you cannot assign an internal load balancer in conjunction with the default public load balancer
Here's some info:
Quickstart: Create a virtual machine scale set in the Azure portal
Create a virtual machine scale set that uses Availability Zones
Networking for Azure virtual machine scale sets
Virtual Machine Scale Sets
The cost is exactly what you'd pay for individual VMs, but the loadbalancing is included. So it's cheaper than the solution I described in my question. Bonus!
How can virtual machines behind an Azure internal load balancer access internet? Is there an AWS NAT gateway equivalent in Azure?
A Virtual Machine that is part of the backend pool of a Standard (not Basic) Internal Load Balancer can not make outgoing connections to the Internet.
To make outgoing connections it is necessary to create a second Load Balancer with a public IP with the same backend pool and a dummy rule with a dummy probe. Once the rule is created then it will trigger the creation of an outbound SNAT.
https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-outbound-connections#defaultsnat
By default, Azure VM behind an Azure internal load balancer, that VM can access the internet, but you can't access it from internet.
If you want to access it, you can create a VM in that VM with a public IP address, use that VM work as jumpbox. Also you can assign a public IP address to that VM, then use that public IP address to access it.
I have a very simple Azure VM setup. One VM is behind an Internal Load Balancer, and it's private IP address is 10.0.1.10.
A Web Service is running in that VM. I can access website by using http://localhost, but as per my software requirement, I have to use Load Balancer private IP address instead of localhost. But I can not browse with Internal Load Balancer IP address (http://10.0.1.10 does not work from that VM).
Is that by design that I can't access Internal Load Balancer by it's private IP address? Or I need to do something special to make it work?
There's a difference between public and internal Azure Load Balancer configurations.
When Azure Load Balancer is used in a public load balancer configuration, SNAT is used for outbound requests. This means a VM behind a public can reach the public IP address of the load balancer and the flow will be load balanced accordingly. This will consume an ephemeral port for each connection to the VIP.
Internal load balancer configurations do not offer SNAT today. In turn, an internal load balancer configuration does not allow a pool member to access the IP address of the internal load balancer.
We are looking at addressing this in a future release by allowing an option to enable SNAT for internal load balancers as well. Mandatory SNAT can actually impose constraints for those who don't need to access the IP address of the load balancer, and therefore this needs to be an option rather than the default.
According to your description, do you means that the VM in the load balancer and the web service running on the VM, you want to use the VM to browse the internal load balancer IP, but it doesn’t work.
I had test in my lab, and the same error occurred. By the way, the load balancer can’t work in this way.
Here is my network capture result:
Maybe we should to create a new VM outside of the load balancer, then you can browse the load balancer IP. Because once a network interface is added to a load balancer's back-end IP address pool, the load balancer is able to send load-balanced network traffic based on the load-balanced rules that are created.
If you still have questions, welcome to post back here. Thanks.
Best Regards,