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
Related
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
Disclaimers: I come from AWS background but relatively very new to GCP. I know there are a number of existing similar questions (e.g, here and here etc) but I still cannot get it work since the exact/detailed instructions are still missing. So please bear with me to ask this again.
My simple design:
Public HTTP/S Traffic (Ingress) >> GCP Load Balancer >> GCP Servers
GCP Load Balancer holds the SSL Cert. And then it uses Port 80 for downstream connections to the Servers. Therefore, LB to the Servers are just HTTP.
My question:
How do I prevent the incoming HTTP/S Public Traffic from reaching to the GCP Servers directly? Instead, only allow the Load Balancer (as well as it's Healthcheck Traffic)?
What I tried so far:
I went into Firewall Rules and removed the previously allowing rule of Ports 80/443 (Ingress Traffic) from 0.0.0.0/0. And then, added (allowed) the External IP address of Load Balancer.
At this point, I simply expected the Public Traffic should be rejected but the Load Balancer's. But in reality, both seemed to be rejected. Nothing reached the Servers anymore. The Load Balancer's External IP wasn't seemed to be recognised.
Later I also noticed the "Healthchecks" were also not recognised anymore. Therefore Healthchecks couldn't reach to Servers and then failed. Hence the Instances were dropped by Load Balancer.
Please also note that: I cannot pursue the approach of simply removing the External IPs on the Servers. (Although many people say this would work.) But we still want to maintain the direct SSH accesses to the Servers (by not using a Bastion Instance). Therefore I still need the External IPs, on each and every Web Servers.
Any clear (and kind) instructions will be very much appreciated. Thank you all.
You're able to setup HTTPS connectivity between your load balancer and your back-end servers while using HTTP(S) load balancer. To achieve this goal you should install HTTPS certificates on your back-end servers and configure web-servers to use them. If you decided to completely switch to HTTPS and disable HTTP on your back-end servers you should switch your health check from HTTP to HTTPS also.
To make health check working again after removing default firewall rule that allow connection from 0.0.0.0/0 to ports 80 and 443 you need to whitelist subnets 35.191.0.0/16 and 130.211.0.0/22 which are source IP ranges for health checks. You can find step by step instructions how to do it in the documentation. After that, access to your web servers still be restricted but your load balancer will be able to use health check and serve your customers.
Whenever i'm adding a VM(Windows/Linux) to the backend pool of a Standard(not basic) Internal load balancer, the VM loses internet access(outbound) to all the internet sites(example: www.google.co.in) except Microsoft sites(bing.com).
Things i have tried:
1. Created Health probe and load balancing rules to verify the load balancing is happening - and yes the load balancing works but no internet access
2. DisableOutboundSNAT on the Rule - load balancing works but no internet access
3. Created NSG to allow all outbound traffic (which is enabled by default) - no luck
Finally this issue is resolved.
This is by design as mentioned on here:
So for a conclusion, if we want to access internet from the VM behind a Standard ILB, we need to associate a Public IP to the VM. ( I tested it and it worked).
Also, this seems a very good design as VM is completely private(no outbound implicitly) when it is behind a Standard Load Balancer.
Thanks to Micah for resolving this on this post.
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'm trying to build a simple two-tier wordpress environment on CentOS 7.2 in Azure.
I've defined a virtual network, have connected it to my home-lab via IPsec VPN, and I've defined several subnets in Azure (for Web tier, SQL tier, and utility tier role segregation using Network Security Groups).
I have two web-tier VMs, both members of the same Availability Set, and are both on the web-tier subnet. They have internet access (outbound), I can SSH to them from my home-lab, and the seem fine operationally to me - httpd is listening on 80/tcp, and I can hit the web pages from my home-lab network by visiting each web server directly on its 192.168.x address.
I should mention my web servers DO NOT have public IPs assigned, but I can't see this being an issue.. they're intended to be behind the load balancer.
So, I've created a Load Balancer, and:
assigned a public IP to the LB
added a backend pool (selected my availability set, and chose my two web servers)
added a probe (http probing the two web servers)
added a load balancer rule
Notice I did NOT add an inbound NAT rule. I can't figure out what that's for, or if I need it.
On my web tier, I tcpdump port 80 and see the probes. In httpd logs, I see 200 success messages for the probes. I go to a web browser, hit the external VIP I assigned to the LB, and nothing. It just times out. I cannot connect to the LB VIP.
What am I missing? What are the NAT rules about?
Any help would be appreciated. All I can find online are examples doing this in powershell etc.. and I'm using the Azure web interface.
Thanks!
Edit: Found the issue - Needed the NSG to allow not just the AzureLoadBalancer, but "Internet" to hit port 80/tcp. Should have thought of that sooner..
Found the issue - Needed the NSG to allow not just the AzureLoadBalancer, but "Internet" to hit port 80/tcp. Should have thought of that sooner..