I have 2 separate resource groups in Azure:
Contains some Services including a Linux App Service hosting Python Django
Contains an ElasticSearch cluster which I created using the ARM template from here
I want to connect from the App service in (1) to the ElasticSearch service load balancer in (2)
I tried to create a virtual network peering using
az network vnet peering create -g $webResourceGroup -n web2es --vnet-name vnet --remote-vnet $remote_vnet --allow-vnet-access
where $webResourceGroup => (1) and $remote_vnet => (2)
However, when I try to do an HTTP request to the ElasticSearch Service, it just does not work.
How do I fix or troubleshoot this?
There are some requirements and constraints for virtual network peering.
Resources in one virtual network cannot communicate with the front-end
IP address of a Basic internal load balancer in a globally peered
virtual network. Support for Basic Load Balancer only exists within
the same region. Support for Standard Load Balancer exists for both,
VNet Peering and Global VNet Peering. Services that use a Basic load
balancer which will not work over Global VNet Peering are documented
here.
So, if the peered VNets are in a different region, you cannot connect to resources that are behind a Basic Load Balancer through the Front End IP of the Load Balancer. This restriction does not exist for a Standard Load Balancer. From the parameters, you will see that loadBalancerInternalSku or loadBalancerExternalSku is by default basic, you should use a standard load balancer.
Also, you should have integrated your app with an Azure Virtual Network. Please note that you cannot reach resources across global peering connections(VNets are located in different regions) when you are using Regional VNet Integration which requires the app and the VNet must be in the same region. If so, you need to use Gateway required VNet Integration and VNet peering with gateway transit.
If possible, you could create all resources like VNet, app service, cluster in the same region. Then you do not need a VPN gateway for your VNet Integration. This may have fewer limitations and easier to deploy in your scenario.
Hope this could help you.
Related
Why do we have to create a new subnet or add the app service to an empty subnet in our vnet?
I don't understand the reasoning since I'm trying to use my app service (function app) as a reverse proxy to access the resources in the vnet.
By default, the Azure function is a PaaS as the other Azure Platform-as-a-Services that have inbound and outbound traffic over the Internet. We can host our applications without the need to worry about the maintenance of the servers and their operating systems.
To use Azure Functions to connect to resources in an Azure virtual network, we can use the VNet integration feature. To use this feature, we need to create a subnet in the virtual network for your function app to use. VNet Integration must be configured to use an empty subnet. It doesn't matter that your functions use a different subnet than your VM. The virtual network automatically routes traffic between the two subnets. Read Connect your function app to the virtual network
The extra empty subnet is used to hosting your app instance. To let the app instance outbound traffic work like from a VNet, Azure mounts NICs with assigned private IP addresses in that subnet. With VNet integration, your function app is connected to both the internet and your virtual network.
For more information, you may read How regional VNet Integration works and How gateway-required VNet Integration works
For an app to access resources in a Virtual Network, it needs to be either part of that network, or use a VPN gateway, which in turn can be used access resources inside the Virtual Network.
App Services provides 2 methods to communicate with resources in the Virtual Network:
Regional VNet Integration
Gateway-Required VNet Integration
With Regional VNet Integration, the infrastructure allocates a private IP interface on the VM that is hosting your Web App. This interface is allocated an IP address from the integrated subnets address prefix. This interface is later used to communicate with the VNet hosted resources. This is in a way similar to how IaaS VM work, however the limitation of this interface is that it can be only used for making outbound connections.
This way, if the ASP is configured to scale out to multiple VM's then each VM is allocated a corresponding private IP interface. However, the allocation of these IP address is limited to the subnets Address prefix. Nancy has already included this in her post. App Services have overlapped recycling so during scale up/maintenance, the App Service Plan may run on twice the number of VM's to ensure minimal downtime. However this also means, that the Integrated Subnet should have sufficient addresses available, so that these allocations can happen.
The IP Address of this interface is exposed via the environment variable WEBSITE_PRIVATE_IP. Here is a screenshot of my Kudu Console
If your site is running on multiple instances, then you can use the Instance menu to toggle through the instances.
With Gateway-required VNet Integration, there is a pre-requisite of provisioning a Virtual Network route-based gateway configured with an SSTP point-to-site VPN. In this case, the VM's hosting the Web App download the VPN package on the respective VM's to setup a VPN, and this is used to connect to the resources in the Virtual Network.
Even here, you can use the WEBSITE_PRIVATE_IP environment variable to see the IP Address used by the VPN client on the App Service VM.
HTH,
Kaushal
We have managed AKS Cluster and it has a few applications PODS. In the same subscription, we have a few servers in the different Resource Group and different VNET. We have a requirement to happen a communication between these two VNET's. I have configured vnet peering between two VNET's but we can see that the communication is not happening.
When I add a rule like "Allow port 443 from all networks" on to the NSG of Virtual machines then everything works fine.
Troubleshooting steps are done.
VNET Peering
Got an API Server IP Address from the "kubeconfig" file and added in the NSG of VM's in a diff RG.
But did not resolve an issue. Could you please help me to fix the issue.
AKS Resources are behind the Internal Load Balancer, so peering did not help. I had to use the Public IP Address provisioned during the AKS Creation process in the NSG. After adding PIP(Available in MC_rg-*** resource group) everything started working.
I would suggest to try connecting the VNET's through VPN gateways .
From an Azure virtual network, connecting to another virtual network is essentially the same as connecting to an on premises network via site-to-site (S2S) VPN.
You will need to go through the below listed steps :
Create VNetA and VNetB and the Corresponding Local Networks.
Create the Dynamic Routing VPN Gateways for each virtual network.
Connect the VPN Gateways.
Please find the referred document for implementing the same solution I have mentioned above .
For more information on difference of vnet peering and vnet gateway you can refer this document.
I have an Azure VM with inside custom vpn to 172.254.254.0/24 route.
I am able to reach that VM from another azure VM adding an "user route" to a "route table" in that VM. It works perfectly.
Now I have an Azure App Services web application.
I need to add the route above too.
But I am stuck I am not able to do it.
Integrate your app with an Azure Virtual Network
The VNet Integration feature has two variations.
Regional VNet Integration - When connecting to Resource Manager VNets in the same region, you must have a dedicated subnet in the VNet you are integrating with.
Gateway required VNet Integration - When connecting to VNets in other regions or to a Classic VNet in the same region you need a Virtual Network gateway provisioned in the target VNet.
Gateway required VNet Integration only provides access to resources in the target VNet or in networks connected to the target VNet with peering or VPNs. Gateway required VNet Integration doesn't enable access to resources available across ExpressRoute connections or works with service endpoints.
Refer: https://learn.microsoft.com/en-us/azure/app-service/web-sites-integrate-with-vnet#enable-vnet-integration
When I create kubernetes cluster from kubernetes service of azure in the networking tab , I have the option to create my own virtual network.
Let's say I created a virtual network with 3 subnets , still in the networking tab options , I can only associate 1 of these subnet to my cluster.
Is it a restriction in AKS?
If so, why it allows to create more than 1 subnet in virtual network?
Not sure but you only can specific one subnet when you create an AKS cluster on the Azure portal. It seems a restriction in AKS. Read the prerequisites. At least, you need one subnet, one AKS cluster. Also, AKS supports a single pool for now.
Don't create more than one AKS cluster in the same subnet.
With advanced networking in AKS, you can deploy a AKS cluster in a existing virtual network and define these subnet names and IP address ranges. IP addresses for the pods and the cluster's nodes are assigned from the specified subnet within the virtual network. So you need to plan IP addressing for your cluster. You should consider doing upgrade and scaling operations when you determine the number of IP addresses.
The reason it allows to create more than 1 subnet in virtual network is that essentially you could create many subnets with valid CIDR block in a VNet. You can create VMs in other subnets or create a dedicated Gatewaysubnet used for VPN gateway in the existing VNet. With advanced networking, this existing virtual network often provides connectivity to an on-premises network using Azure ExpressRoute or Site-to-Site VPN.
Also, it's welcome to give feedback on Azure AKS to improve this feature. Hope this helps.
I have two peered VNETs in Azure and I also have an Application Gateway in one of them. I have a couple VMs inside both VNETs and I want to access the Application Gateway from the VMs by its private IP (which is set up). This works from the VNET that the gateway resides in but I can't access it from the other peered network. I can access all the VMs between the networks by their private IPs no problem. What can I be missing? (I am not really that familiar with networking, so it can be something basic...).
Thank you for any suggestion!
You can check if the two peered virtual networks are located in a different region.
If you are using a Global Vnet peering(Vnet to Vnet region is different), there are some limitations that you can not use Global Vnet peering to communicate with VIPs of load balancers in another region. Application Gateway is actually a layer-7 load balancer.
Resources in one virtual network cannot communicate with the IP
address of an Azure internal load balancer in the peered virtual
network. The load balancer and the resources that communicate with it
must be in the same virtual network.
References: How to setup Global VNet peering in Azure
APIM is a service based on Azure Load balancer. For Stv1 APIM Azure uses Basic Load balancer which does not allow traffic via global peering.
[Refer this][1]
In order to facilitate traffic via global peering need to use stv2 APIM.[Refer this][2]
[1]: https://learn.microsoft.com/en-us/azure/virtual-network/virtual-network-manage-peering?tabs=peering-portal#requirements-and-constraints
[2]: https://learn.microsoft.com/en-us/azure/api-management/virtual-network-concepts?tabs=stv1#network-resource-requirements