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
Related
Please can someone advise how to restrict access on port 80/443 to some Azure VMs, so that they can only be access via the public IP Address that is associated to an Azure Load Balancer.
Our current setup has load balancing rules passing through traffic from public IP on 80=>80 and 443=>443, to back end pool of 2 VMs. We have health probe setup on port 80. Session persistence is set to client IP and floating IP is disabled.
I thought the answer was to deny access (via Network Security Group) to internet (service tag) on 80/443. Then add rule to allow service tag (AzureLoadBalancer) on the same ports. But that didnt seem to have an effect. Having read up a little more on this, it seems the AzureLoadBalancer tag is only to allow the health probe access and not specifically inbound traffic from that load balancer.
I have also tried adding rules to allow the public IP address of the load balancer, but again no effect.
I was wondering if I need to start looking into Azure Firewalls? and somehow restrict access
to inbound traffic that comes through that?
The only way I can get the VMs to respond on those ports is to add rules to allowing 80/443 from any to any....
After reading your question, my understanding is that you have a Public load balancer and the backend VMs also have instance level Public IPs associated with them and hence direct inbound access to the VMs is possible. But you would like to make sure that the direct inbound access to VMs is restricted only via the load balancer.
The simple solution for you to achieve this is by disassociating the instance level public IP of the VMs, this will make the LB public IP as the only point of contact for your VMs.
Keep in mind that the LB is not a proxy, it is just a layer 4 resource to forward traffic, therefore, your backend VM will still see source IP of the clients and not the LB IP, hence, you will still need to allow the traffic at the NSGs level using as source "Any".
However, if your requirement is to enable outbound connectivity from Azure VMs while avoiding SNAT exhaustion, I would advise you to create NAT Gateway, where you can assign multiple Public IP address for SNAT and remove the Public IP from the VM. This setup will make sure that the inbound access is provided by the Public load balancer only and the outbound access is provided by the NAT gateway as shown below:
Refer : https://learn.microsoft.com/en-us/azure/virtual-network/nat-gateway/nat-gateway-resource#nat-and-vm-with-standard-public-load-balancer
https://learn.microsoft.com/en-us/azure/virtual-network/nat-gateway/tutorial-nat-gateway-load-balancer-public-portal
You could also configure port forwarding in Azure Load Balancer for the RDP/SSH connections to individual instances.
Refer : https://learn.microsoft.com/en-us/azure/load-balancer/manage#-add-an-inbound-nat-rule
https://learn.microsoft.com/en-us/azure/load-balancer/tutorial-load-balancer-port-forwarding-portal
I have having a hard time find a solution for this.
I have an Azure Internal Load Balancer (level 4). And I have ONLY one Virtual Machine act as the backend pool for the said Load Balancer.
And fun part starts here, I have multiple Docker containers running on that Virtual Machine. Running Nginx Web servers on ports 8080 and 8081.
And now I want to balance the load between these two ports. Literally what I want is something like below in the photo:
So according to the photo, the request comes from abc.xyz.com and it should hit the Load Balancer, and then it should route the traffic to the only VM running multiple docker containers in multiple ports.
How can I achieve this behavior?
I have already setup A frontend configuration with private ip, a rule, backend pool
As per this article(https://learn.microsoft.com/en-us/azure/container-instances/container-instances-virtual-network-concepts#unsupported-networking-scenarios), placing an Azure Load Balancer in front of container instances in a networked container group is not supported and similarly it is not possible to route the traffic on containers to their specific ports running on a single Virtual Machine. The above solution works on VM level not on container level.
The only workaround for this scenario would be to use Azure Application gateway as Microservice architecture is supported on App gateway. To probe on different ports, you need to configure multiple HTTP settings. Reference:
https://learn.microsoft.com/en-us/azure/application-gateway/application-gateway-faq#can-one-backend-pool-serve-many-applications-on-different-ports
Azure Application Gateway is a web traffic load balancer that enables you to manage traffic to your web applications. And you can create an internal application gateway. To do that you can create an Application Gateway with both public and private frontend IP address and do not create any listeners for the public frontend IP address. Application Gateway will not listen to any traffic on the public IP address if no listeners are created for it.
Reference: https://learn.microsoft.com/en-us/azure/application-gateway/configuration-front-end-ip ,
https://learn.microsoft.com/en-us/azure/application-gateway/application-gateway-faq#how-do-i-use-application-gateway-v2-with-only-private-frontend-ip-address
What can I do to fix this Advisory message?
The VM this relates to is a webserver, which sits behind an Azure LoadBalancer. The NSG rule that is causing this (only 1 'not default rule' ) is:
Type: Allow
Source: Service Tag - Internet, source port range = *
Destination: ASG for this VM, destination port 80,443, protocol tcp
If I remove this rule, the message disappears (after some hours) but than the internet web traffic can not reach the VM anymore.
Should I ignore the Azure Advisory message? Or am I overlooking something? I was looking forward to getting this nice and tidy, AND have a 'satisfied' advisory state.
You can run your webserver on the VMs on different ports than 80 and 443. The load balancer can translate between port 80/443 on your public IP and whatever port you choose inside the VMs. Since Load Balancers are a fairly simple service, this is probably your only option.
As an alternative, you could try Application Gateway instead of your load balancer. It should act as the reverse proxy you need. Be aware that it is a bit more costly than the load balancer, but it also has a lot more features.
I see that your VM is behind an Azure LoadBalancer. So, the network flow might be similar to :
Then, your web server should not be public to the internet. It should only be accessible from the loadbalancer. You can set the source service tag to AzureLoadBalancer. For more information about service tags, you may check the official documentation: Service tags
Update:
By further researching, the AzureLoadBalancer service tag in NSG rule is used to allow Azure health probes. Actually, there is a default rule for allowing load balancer to probe to endpoints.
So, the suggestions are:
You should not assign public IPs to each instances. In this way, your backends can only be accessed by private IPs. In other words, clients can only access your web via load banlacer.
Add NSG inbound rules with 80 and 443 ports for web service. And 22 or 3389 port for remote management.
In this case, your servers should be secure now. If there are still any warnings, I think you may ignore them. The Azure system may just see that you opened 80 and 443 ports to public. However, your instances do not have public IP.
Hope the above would be helpful to you.
Please forgive my ignorance.
Question:
How can I control network traffic to a publicIP resource and send it to multiple different resources based on destination port?
Background:
I have setup some VMs that are configured with only private IPs in different subnets. All belong to the same Virtual Network. All these VMs have different services and I do not want HA as I do not need it and it costs money.
I just want all the services on these VMs to communicate out using the same single publicIP and I want to split incoming traffic to that same publicIP between my resources based on destination port.
Seems like a straight forward requirement right?
At first I though "this must be a task for the Load Balancer service" as it's operating at L4 and tried to set it up but I was not able to split inbound traffic on different ports to more than a single VM or a single availability set. I do not understand why you can only use Load Balancers NAT rules with a single VM or Availability Set.
I can probably delete/re-create all VMs (thank you Microsoft..) into a single availability set that only has 1 fault and 1 error domain but does this make any sense?
It just seems to me like a dirty workaround using availability sets in a way they are not meant to in order to solve a very basic thing.
Thanks!
Basically, you could create a public-facing Azure Load balancer then target the VMs or Availability Sets to the backend pools of this load balancer. What you need to do is to configure the load balancing rules and some health probes or inbound NAT rules for the backend services with ports forwarding.
Refer to the SO answer.
You would use NAT rule when you have 1 backend server or you know
which backend server to get to and load balancing rules when you want
to load-balance to multiple backend servers.
NAT rule must be explicitly attached to a VM (or network interface) to
complete the path to the target; whereas Load Balancing rule need not
be. In the latter case, a VM is selected (from the back-end address
pool or VMs) to complete the path to the target.
Additionally, Azure Load balancer supports two SKUs: basic and standard. Different SKUs support different backend pool endpoints. Read more details about Load Balancer SKU comparison.
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..