To create a VNET and subnets in Azure, we use:
resource symbolicname 'Microsoft.Network/virtualNetworks#2021-05-01'
We can also defined subnets at the same time as we creating VNETs using the parameters in the above resource group.
There is another way to define subnets in Azure, using
Microsoft.Network/virtualNetworks/subnets
However Azure advises us that it is not a best practice to use this method, as they should be defined using the first method.
“Avoid defining subnets as child resources. This approach can result in downtime for your resources during subsequent deployments, or failed deployments.”
When creating security groups, similar to the above, we can create rules at the same time we are creating the security group as per:
Microsoft.Network networkSecurityGroups
However, we can also create them separately using
networkSecurityGroups/securityRules
Similar to the VNET Scenario above, is it a best practice to create a SG + rules at the same time, or create them independently?
If this question doesn't make sense apologies - new to this.
Similar to the VNET Scenario above, is it a best practice to create a
SG + rules at the same time, or create them independently
AFAIK, Network Security Groups should be deployed in the same way that VMs and other services are. It has to be happening at the same moment. Keeping everything in order.
To do that you can refer Microsoft.Network networkSecurityGroups/securityRules & this blog
Related
Currently for our Azure Disaster recovery plan we replicate workloads from a primary site/region to a secondary site. Where we mirror the source VM config and create required or associated resource groups, storage accounts, virtual networks, etc.
We are looking into an alternate method the wouldn't require a second resource group. This would require:
Use one, already existing resource group; i.e. testGroup-rg in East-US
Deploy new IaC components into the same RG but in Central-US
So in the singular resource group, if we wanted a function app, we would have two sets of components. testFuncApp in East-US and testFuncApp in Central-US.
This way we would only ever have one set of IaC created. Of course we would need to automate how to flow traffic etc. into a particular region if both exist.
Is this a possibility? If it is, is it even necessary/worth it?
Unfortunately there is no way to use the same RG. We need to have a resource group in target region if not Site Recovery creates a new resource group in the target region, with an "asr" suffix.
This would appear to be a fairly simple and basic scenario but I'm frankly at a loss on how to get around this using Terraform and would appreciate any suggestions.
The issue is this. In Azure, I have a number of resource groups, each containing a number of resources, including virtual networks, subnets, storage accounts, etc. What I would now like to do is add new resources to one or two of the resource groups. Typical example, I would like to provision a new virtual machine in each of the resource groups.
Now, so far all of the documentation and blogs I seem to come across only provide guidance on how to create resources whereby you also create a new resource group, vnet, subnet, from scratch. This is definitely not what I wish to do.
All I'm looking to do is get Terraform to add a single virtual machine to an existing resource group, going on to configure it to connect to existing networking resources such as a VNet, Subnet, etc. Any ideas?
I tested for ECS by destroying the launch configuration.
terraform destroy -target module.ecs.module.ec2_alb.aws_launch_configuration.launchcfg
I recreated the launch configuration and it worked:
terraform plan -target=module.ecs.module.ec2_alb.aws_launch_configuration
terraform apply -target=module.ecs.module.ec2_alb.aws_launch_configuration
Also, you can go read more on Terraform target here: https://learn.hashicorp.com/tutorials/terraform/resource-targeting
If you just want to be able to reference your existing resources in your TF script, you normally would use data sources in TF to fetch their information.
So for resource group, you would use data source azurerm_resource_group, for vnet there is azurerm_virtual_network and so forth.
These data sources would allow you to only reference and get details of existing resources, not to manage them in your TF script. Thus if you would like to actually manage these resources using TF (modify, delete, etc), you would have to import them first to TF.
We manage an Azure subscription operated by several countries. Each of them is quite independant about they can do (create/edit/remove resources). A guide of good practices has been sent to them, but we (security team) would like to ensure a set of NSG is systematically applied for every new subnet/vnet created.
Giving a look to Azure Triggers, I am not sure that subnet creation belongs to the auditable events. I also was told to give a look to Azure policy, but once again I am not sure this will match our expectations which are : For every new vnet/subnet, automatically apply a set of predefined NSG.
Do you have any idea about a solution for our need ?
I have done work like this in the past (not this exact issue) and the way I solved it was with an Azure Function that walked the subscription and looked for these kinds of issues. You could have the code run as a Managed Identity with Reader rights on the subscription to report issues, or as a Contributor to update the setting. Here's some code that shows how you could do this with PowerShell https://github.com/Azure/azure-policy/tree/master/samples/Network/enforce-nsg-on-subnet
You could consider using a Policy that has a DeployIfNotExists Action, to deploy an ARM template that contains all the data for the NSG. https://learn.microsoft.com/en-us/azure/governance/policy/samples/pattern-deploy-resources
You can get the ARM template by creating the NSG and getting the template:
GettingNSGTemplate
Note also that creating a subnet is audited, you can see it in the Activity Log for the VNet. See the screen shot.
AddingASubnet
I have one resource group that I set up with the portal and another that I tried to configure the same way using Terraform.
Each group contains
Application Gateway with Web App Firewall
Virtual networks and subnets
VMs and associated storage
Public IPs, NSGs, NIC etc
Is there a way for me to compare the two sets of configurations?
For you, I assume you want to create the same resources with the same configurations in another group through Terraform. On my side, there are not many things you need to care about. Just according to the configuration of the resources to create the terraform script.
each resource region
the public IP and the NIC allocation method
NSG rules
vnet and the subnet address prefix
application gateway properties and the rules
The above points are that I think you need to care about. And the properties of the resources in Terraform also need to according to. I think there is no other way to compare two sets of configurations. If you really want, you can compare the template of each group when you create them. The group template shows below:
No, i dont think there is a reasonable straight forward way of doing this, you can create a powershell script that would get resources in each resource group and then try and compare properties, but its hard to give some sort of estimation how accurate it would be, there is a Compare-Object cmdlet in powershell, which might help you with that.
I would like to keep each VM in separate resource group for ease for lifecycle management. I have a cluster containing n VLMs.
So I create one resource group for common things like public IP, load balancer and put availabilitySet declaration into it because is also must be shared between VMs.
Then I create VM in separate resource group and reference to availabilitySet with
"availabilitySet": {
"id": "[resourceId('Microsoft.Compute/availabilitySets',variables('availabilitySetName'))]"
},
Of cause 'availabilitySetName' is defined.
When I deploy my template I get an error saying
{"error":{"code":"BadRequest","message":"Entity resourceGroupName in resource reference id /subscriptions/a719381f-1fa0-4b06-8e29-ad6ea7d3c90b/resourceGroups/TB_PIP_OPSRV_UAT/providers/Microsoft.Compute/availabilitySets/tb_avlbs_opsrv_uat is invalid."}}
I double checked that resource and availability set name are specified correctly.
Does it mean that I can't put a set in separate resource group from VM?
Unfortunately, having a VM use an availabilitySet in a different resource group is not supported :(.
First of all, let me ask you why you want different resource groups? I strongly believe that you're overthinking it with multiple resource groups. A resource group is basically your "Entire System" and within the boundaries of one solution, you should only have one resource group for production, one for beta/staging etc, but never mix.
If you're selling SaaS to your customers it would make sense to have one resource group for each of your customers.
And as you know, a Resource group is simply a way for you to link together and manage all of the assets in your solution; vm's, storage, databases etc under one common name. I am very doubtful as to why one would want to consider multiple resource groups in a single solution, however, I am always willing to learn :)
Availability groups
Now, Availability groups are a different thing. This has to do with "Update Domains" and "Fault Domains" for your VM instances. Because Azure does not keep 3 separate VM's for you, as it does with most of it's PaaS services, you have to manage these yourself to ensure full uptime. Basically, when you're adding two or more VM's in an Availability Set, you're ensured that planned or unplanned events, at least one of the VM's will be available to meet the SLA.
Trying to combine the two in an effort of preventing downtime may sound like a good idea, but it is not solving any problems that I'm aware of. Like the old saying goes: if it aint broke, don't fix it :)