I have created a internal load balancer in azure and backend pool configured two vm's health probe and rule also configured, If I browse the Load balance ip it work fine but while i'm checking the ping request from the VM to Load balancer it shows time out error. Is it possible to make a successful ping request.
Regular icmp traffic is not allowed on Azure load balancers, you should either try a port ping (psping), telnet, nmap, nc, or other utilities to check E2E connectivity.
Some extra details here:
https://social.msdn.microsoft.com/forums/azure/en-US/e9e53e84-a978-46f5-a657-f31da7e4bbe1/icmp-outbound-ping-on-azure-vm
Not only ICMP, any traffic from backend VM to frontend IP of internal load balancer will not work. This is one of the limitation of azure internal load balancer.
Bhuvanesh Kumar Kumaresan, Cloud Solution Architect
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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:
We have a Azure internal load balancer forwarding request to backend VM'S.
Is there a way to find out how many requests are server by each VM ? In other words how many requests are forwarded to each VM from the load balancer.
You could adopt Standard Load Balancer. You will see some differences between Standard Load Balancer and Basic Load Balancer in that linking document. For internal standard LB, you can check the SYN (synchronize) packets metric which collecting flows and their handshakes are always between the source and the VM instance.
For other scenarios, you could collect the network trace by networking capturing tool like Wireshark.
I created an internal load balancer in Azure with 2 vms connected to it, what is the best way to test it?
Thanks
Depending on your end goal, you should be able to set up an IIS/Apache/nginx website, depending on your VM operating system. After that, create a simple load balancing rule for port tcp 80 and see if the configured website responds.
Pretty sure you could also create a load balancing rule for RDP (tcp 3389) or SSH (tcp 22) and test to connect against your load balancer IP address.
If you are unsure whether your LB or back-end services are functional, refer to this: https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-troubleshoot
I've got multiple questions on the setup of a gateway and VM, so here is what I have actually.
I've got an Application Gateway, and two VM Ubuntu, everything hosted on Azure. They are all on the same Virtual Network. Both VM have only a private IP (10.1.0.4 and 10.1.0.5) and the Gateway have a private IP (10.1.1.4) and a public IP. Because only the Gateway have a public IP, I guess that everything have to go through it, and this is what I want to.
The goals I try to achieve :
Make a load balancer on the port 1680, redirected to port 1680.
To redirect the SSH of each VM to connect specifically to one because at the moment, they have no public IP. Is it possible to do this with a path based rule ? Like www.example.com/VM1 to connect by SSH to the first VM ? If no, what can be used to differentiate the SSH connection of the VM1 and of the VM2 ?
To redirect the port 80 of the gateway to the port 8080 of a specific VM. As my previous example, www.example.com/adminPanelVM1 to connect to the first VM on port 80 (redirected to port 8080 on the VM)
I already managed to create the redirection of the port 1680 of the Gateway with an HTTP Parameter, a Listener and a Rule.
Azure Application Gateway
The Azure Application Gateway operates at the layer 7 in the OSI model on the HTTP/HTTPS/WebSocket protocols, because of that any other protocol (like SSH), is not possible to route.
You got a few options tho.
You can use a Network Security Group, or NSG, for access control to your virtual machines. In the NSG you define where the traffic can come from that is allowed access to the VMs.
A NSG behaves like a access-control-list filtering traffic based on source and destination information and evaluating rules in order of priority. See this page for more information about NSGs.
Another option is to use a load balancer.
Azure Load Balancer
If you need to do port mapping, like you describe in your question, then a simple load balancer might be a better solution for you. An Azure Load Balancer works at a lower level in the in the OSI model, namely layer 4 (transport layer), handling TCP/UDP traffic.
So, if you are using a load balancer, then you can set up NAT rules to forward your traffic to specific machines, in other words, if you want to do:
LB port 1234 redirects to VM1 port 22 and
LB port 4312 redirects to VM2 port 22
you can do that using PowerShell as described in the Creating a public load balancer in Resource Manager by using PowerShell article.
There are quite a few steps but it walks you through the whole process of creating NAT rules, NICs and associated virtual machines.
Azure Application Gateway vs Azure Load Balancer?
These two cervices are distinctly different services and are trying to solve different problem, although those problems might look similar :)
The primary uses of an Application Gateway are:
SSL termination
cookie-based session affinity
round robin for load balancing traffic
Where as the Azure Load Balancer service works as the TCP/UDP level and support e.g. port mapping.
Cost wise, the load balancer service is free while the application gateway is billed per hour.
There are many great articles on this topic, when to pick which service. See for example the links for more details
When to use Azure Load Balancer or Application Gateway
Frequently asked questions for Application Gateway
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,