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Azure Loadbalancer

Step-by-Step Guide: How to setup Azure load balancer?

The role of a load balancer is to improve the availability of services by distributing the load to a pool of back end servers. When it comes to load balancing, Azure has a few different products to choose from. 

• Azure Application Gateway – If you require a load balancer that can provide features such as SSL offloading, reverse proxy and works in the application layer (layer 7), Azure application gateway is the answer.

• Azure Traffic Manager – If you are looking for DNS level load balancing which can distribute traffic to global endpoints, Azure traffic manager will be the product to look at. 

• Azure Load Balancer – Azure load balancer works in layer 4 (transport layer) and can distribute network traffic to endpoints in the same Azure region. It can use to distribute internet traffic as well as internal traffic. In this post, we are going to look into this service in detail. 

Like many other load balancers, Azure load balancer also has the following components. 

• Frontend/Virtual IP address – This is the load balancer IP address that works as a front door to clients. After clients initiate connections to a frontend IP address, the traffic will be distributed to the back-end servers. 

• Server pool – The back-end application servers will be group together in a pool to serve an incoming request from a load balancer. 

• Rules – The incoming traffic will be distributed to the backend servers according to the rules defined in the load balancer.  

• Probes – If a back-end server is down, load balancer needs to know. Then it can stop distributing traffic to the faulty server. The load balancer uses probs to detect the health of the back-end servers. 

• Inbound NAT rules – Inbound NAT rules define how the traffic is forward from the load balancer to the back-end server. 

In this post, I am going to demonstrate how we can load balance a web application using Azure standard load balancer. This demo includes the following tasks,

1. Setup new resource group

2. Setup two new windows VM

3. Setup IIS with sample web page

4. Create Azure load balancer

5. Create a backend pool

6. Create health probes

7. Create load balancer rule

8. Testing

Setup new resource group

Let's go ahead and start the setup process by creating new Azure resource group. 

For the configuration process, I will be using Azure PowerShell. Therefore, please make sure you have an Azure PowerShell module installed. More info about it can find under https://docs.microsoft.com/en-us/powershell/azure/install-az-ps?view=azps-2.6.0

1. Launch PowerShell console and connect to Azure using Connect-AzAccount

2. Then create a new resource group using,

New-AzResourceGroup -Name REBELRG1 -Location "East US"

In the above, REBELRG1 is the resource group name and East US is the resource group location.

Setup two new windows VM

1. In this demo, I am going to use two back end servers. Before VM setup, let's go ahead and create a new virtual network. 

$vmsubnet  = New-AzVirtualNetworkSubnetConfig -Name vmsubnet -AddressPrefix "10.0.2.0/24"

New-AzVirtualNetwork -Name REBELVN1 -ResourceGroupName REBELRG1 -Location "East US" -AddressPrefix "10.0.0.0/16" -Subnet $vmsubnet

In the above, REBELVN1 is the new virtual network name. It has 10.0.0.0/16 address space. It also has a new subnet 10.0.2.0/24 (vmsubnet) for virtual machines.

2. Then I need to create a new availability set. To add back end servers to load balancer, those VMs need to be in the same availability set. 

New-AzAvailabilitySet -Location "EastUS" -Name "REBELAS1" -ResourceGroupName "REBELRG1" -Sku aligned -PlatformFaultDomainCount 2 -PlatformUpdateDomainCount 2

In above REBELAS1 is the availability group name. More info about scale sets can found here https://docs.microsoft.com/en-us/azure/virtual-machine-scale-sets/availability

3. As the next step of the configuration, I am going to create two new virtual machines under REBELRG1 resource group. 

$mylogin = Get-Credential

New-AzVm -ResourceGroupName REBELRG1 -Name "REBELTVM01" -Location "East US" -VirtualNetworkName "REBELVN1" -SubnetName "vmsubnet" -addressprefix 10.0.2.0/24 -PublicIpAddressName "REBELTVM01IP1" -AvailabilitySetName "REBELAS1" -OpenPorts 3389,80 -Image win2019datacenter -Size Standard_D2s_v3 -Credential $mylogin

New-AzVm -ResourceGroupName REBELRG1 -Name "REBELTVM02" -Location "East US" -VirtualNetworkName "REBELVN1" -SubnetName "vmsubnet" -addressprefix 10.0.2.0/24 -PublicIpAddressName "REBELTVM02IP1" -AvailabilitySetName "REBELAS1" -OpenPorts 3389,80 -Image win2019datacenter -Size Standard_D2s_v3 -Credential $mylogin

In the above, I am creating two virtual machines called REBELTVM01 & REBELTVM02. It is running windows server 2019 data center edition. I have specified it using -Image parameter. It also using Standard_D2s_v3 vm size. For networking, It uses REBELVN1 virtual network and subnet 10.0.2.0/24. [Read more…] about Step-by-Step Guide: How to setup Azure load balancer?

Azure virtual machine scale sets – part 02 – Deploy Application to scale set

In my previous post Azure virtual machine scale sets – part 01, we learned what is VM scale set and how we can create a scale set in Azure. if you not read it yet please go through it before we start on this post as reset of the steps in this post depend on it https://www.rebeladmin.com/2018/04/azure-virtual-machine-scale-sets-part-01/ 

In this post we are going to deploy a sample application to scale set. In my previous post I have created a new scale set using,

New-AzureRmVmss `

  -ResourceGroupName "rebelResourceGroup" `

  -Location "canadacentral" `

  -VMScaleSetName "rebelScaleSet" `

  -VirtualNetworkName "rebelVnet" `

  -SubnetName "rebelSubnet" `

  -PublicIpAddressName "rebelPublicIPAddress" `

  -LoadBalancerName "rebelLoadBalancer" `

  -BackendPort "80" `

  -VmSize "Standard_DS3_v2" `

  -ImageName "Win2012Datacenter" `

  -InstanceCount "4" `

  -UpgradePolicy "Automatic"

In above it created an Azure Load balancer and TCP port 80 been load balanced among 4 instances. Under Azure Load Balancer | Inbound NAT rules it does have default rules for port 3389 and 5985. Those ports are mapped to custom TCP ports in order to give external access. 

scaleapp1

As an example, in above sample, I can RDP to instance0 using 52.237.8.186:50000. Likewise, we can connect to each instance and install apps if need. instead of that we can use centralized remote deployment, so the configuration is same across the instance. 

In my config I didn’t use static ip address. You can find public ip address by running following azure PowerShell command,

Get-AzureRmPublicIpAddress -ResourceGroupName rebelResourceGroup | Select IpAddress

scaleapp2

In order to push application, first need to prepare app config. in my demo I got a file in GitHub repository. 

$customConfig = @{

  "fileUris" = (,"https://raw.githubusercontent.com/rebeladm/rebeladm/master/simplewebapp.ps1");

  "commandToExecute" = "powershell -ExecutionPolicy Unrestricted -File simplewebapp.ps1"

}

My config is very simple one. In PowerShell script I have following,

Add-WindowsFeature Web-Server

Set-Content -Path "C:\inetpub\wwwroot\Default.htm" -Value "Test webapp running on host $($env:computername) !"

It will install IIS and then create HTML file which will print text with the instance name. 

scaleapp3

As next step lets go and retrieve info about scale set,

$vmss = Get-AzureRmVmss `

          -ResourceGroupName "rebelResourceGroup" `

          -VMScaleSetName "rebelScaleSet"

scaleapp4

After that, lets create custom script extension

$vmss = Add-AzureRmVmssExtension `

  -VirtualMachineScaleSet $scaleconfig `

  -Name "customScript" `

  -Publisher "Microsoft.Compute" `

  -Type "CustomScriptExtension" `

  -TypeHandlerVersion 1.8 `

  -Setting $customConfig

In above,

 –Publisher specifies the name of the extension publisher. This can find using Get-AzureRmVMImagePublisher 

 –Type specify the extension type. we can use Get-AzureRmVMExtensionImageType find the extension type. 

–TypeHandlerVersion specify the extension version. It can view using Get-AzureRmVMExtensionImage.

scaleapp5

Next step of the configuration is to update scale set with the custom extension,

Update-AzureRmVmss `

  -ResourceGroupName "rebelResourceGroup" `

  -Name "rebelScaleSet" `

  -VirtualMachineScaleSet $vmss

scaleapp6

Now it is time to do testing. Let’s go to public IP address and see if it’s got the app we submit. 

As I refresh we can see the instance number get updated. That means script is successfully running on scale set as expected. 

scaleapp7

scaleapp8

scaleapp9

This marks the end of this blog post. If you have any questions feel free to contact me on rebeladm@live.com also follow me on twitter @rebeladm to get updates about new blog posts.  

Azure Virtual Machine Scale Sets – Part 01 – What is it and How to set it up?

There are many different solutions available to load balance applications. It can be based on separate hardware appliances, virtual appliances or system inbuilt method such as NLB (Network Load Balancer). However, there are few common challenges on these environments. 

• If its third-party solution, additional cost involves for licenses, configuration and maintenance 

• Applications or services not always use all of the allocated resources. It may depend on demand and time. Since its fixed number of instance, infrastructure resource will be wasted in non-peak time. if its cloud service, it going to waste money!

• When the number of server instances increase, it makes it harder to manage systems. Too many manual tasks!

Azure virtual machine scale sets answers all above challenges. It can automatically increase and decreases number of vm instances running based on demand or schedule. No extra virtual appliances or licenses involves. It also allows to centrally manage, configure large number of instances. Following points are recognized as key benefits of Azure virtual machine scale sets.

• It supports Azure load balancer (Layer-4) and Azure Application Gateway (Layer-7) traffic distribution.

• It allows to maintain same VM configuration across the instance including VM size, Network, Disk, OS image, Application installs. 

• Using Azure Availability Zones, if required we can configure to distribute VM instances in scale set to different datacenters. It adds additional availability. 

• It can automatically increase and decrease number of vm instances running based on application demand. It saves money!

• It can grow up to 1000 vm instances, if its own custom images, it supports up to 300 vm instances. 

• It supports Azure Managed Disks and Premium Storage. 

Let’s see how we can setup Azure virtual machine scale set. In my demo I am going to use Azure PowerShell. 

1) Log in to Azure Portal as Global Administrator
 
2) Open Cloud shell (right hand corner)
 
ss1
 
3) Make sure you are using PowerShell Option
 
ss2
 
4) In my demo scale set configuration as following
 
New-AzureRmVmss `
  -ResourceGroupName "rebelResourceGroup" `
  -Location "canadacentral" `
  -VMScaleSetName "rebelScaleSet" `
  -VirtualNetworkName "rebelVnet" `
  -SubnetName "rebelSubnet" `
  -PublicIpAddressName "rebelPublicIPAddress" `
  -LoadBalancerName "rebelLoadBalancer" `
  -BackendPort "80" `
  -VmSize "Standard_DS3_v2" `
  -ImageName "Win2012Datacenter" `
  -InstanceCount "4" `
  -UpgradePolicy "Automatic"
 
In above,
 

Parameter

Description

New-AzureRmVmss

This is the command use to create Azure Virtual Machine Scale Set

-ResourceGroupName

This define the resource group name and it is a new one.

-Location

This defines the resource region. In my demo its Canada Central

-VMScaleSetName

This defines the name for the Scale Set

-VirtualNetworkName

This defines the virtual network name

-SubnetName

This defines the subnet name. if you do not define subnet prefix, it will use default 192.168.1.0/24

-PublicIpAddressName

This defines the name for public IP address. If not define allocation method using -AllocationMethod , it will use dynamic by default.

-LoadBalancerName

This defines the load balancer name

-BackendPort

This creates relevant rules in loadbalancer and load balance the traffic. in my demo I am using TCP port 80.

-VmSize

This defines the VM size. if this is not defined, by default it uses Standard_DS2_v2

-ImageName

This defines the VM image details. If no valuves used it will use default value which is Windows Server 2016 Datacenter

-InstanceCount

This defines the initial number of instance running on the scale set

-UpgradePolicy

This defines upgrade policy for VM instances in scale set

Once this is run it will ask to define login details for instances. After completes, it will create the scale set.

ss3

This also can do using Portal. In order to use GUI, 

1) Log in to Azure Portal as Global Administrator

2) Go to All Services | Virtual Machine Scale Set

ss4

3) In new page, click on Add

ss5

4) Then it will open up the form, once fill in relevant info click on create 

ss6

5) We also can review the existing scale set properties using Virtual machine scale sets page. On page click on scale set name to view the properties. If we click on Instances, we can see the number of instances running

ss7

6) Scaling shows the number of instances used. If need it can also adjust in here. 

ss8

7) Size defines the size of the VM, again if need values can change in same page. 

ss9

8) Also, if we go to Azure Portal | Load Balancers, we can review settings for load balancer used in scale set.

ss10

9) In my demo I used TCP port 80 to load balance. Those info can find under Load Balancing rules

ss11

10) Relevant public ip info for scale set can be find under inbound NAT rules

ss12

 

This marks the end of this blog post. In next post we will look in to further configuration of scale set. If you have any questions feel free to contact me on rebeladm@live.com also follow me on twitter @rebeladm to get updates about new blog posts.