We had a local state file which was committed into Git. She starts off, she makes the copy of the test resources that she originally had, and duplicates that for the production set-up. This is not only restricted to the Terraservices setup. He didn't get the memo about doing a terraform plan first, he reckons all is well. Terraform Intro 4: Loops with Count and For Each, Terraform Intro 5: Loops with Dynamic Block, Tutorial 1: Resources, Variables, Outputs, Tutorial 4: Loops with Count and For Each, Kustomize vs Helm vs Kubes: Kubernetes Deploy Tools, Terraspace Terrafile: Using Git and Terraform Registry Modules, Terraspace All: Deploy Multiple Stacks or Terraform Modules At Once, Introducing Terraspace: The Terraform Framework, Introducing Kubes: The Kubernetes Deployment Tool, Introducing Cody: AWS CodeBuild Management Tool, On-Demand vs Reserved vs Spot AWS EC2 Pricing Comparison, Docker Crash Course Introduction Tutorial: Common Commands. This is where much of the HashiCorp tooling comes in quite handy. Although it's not quite as bad as taking out the whole of production, we have hit the next pain point that a lot of people tend to hit in these circumstances. But as an initial progression, what a lot of people will do, is at least try and start moving towards some centralized way of dealing with things. So, she reckons, “this is not a problem., It's a simple change. So, there's a core area, a Kubernetes cluster area, and a database. Understanding that configuration blocks can be assigned directly will be useful for resetting and removing elements. And for any database needs, we're going to use Amazon RDS to make that possible. So the services needing to make use of these particular environments, they also then use, they change the Terraform remote state file to now refer to the S3 backend instead of the local backend. Terraform is declarative, so a nested loop can be tricky. She describes how a client's infrastructure often evolves using Terraform, highlighting common pain points and showing typical approaches. We’ve removed the second inner loop. PowerShell has two ways of using updatable help: HelpUri and HelpInfoUri. So, she decides, “that's okay.” My best course of action: I'm going to take the proof of concept set-up that I created, and I'm going to create my test and production infrastructure out of that. So in terms of moving to a remote state setup, this is simple. So the conclusion for this talk is that we've had a look at how you can evolve your Terraform setup. However, this is probably unexpected and undesirable behavior. And it happens more often than you think. Building a map instead of a tuple from nested for in values. And I think it's over provisioned, and you need to reduce the size”. She runs terraform apply, the test infrastructure comes up, the production infrastructure comes up, and all is well. And this is delivered as a set of microservices in an Amazon infrastructure. Within a module. And it's a little bit of a pain because what you'll end up doing is in your environment Terraform file, you'll end up having to duplicate these definitions. This allows a user to bring in their own IAM … Okay, welcome everybody. From a security perspective, at least with the S3 backend, we can encrypt it, which means that we don't have our Terraform state file address with the secrets exposed. These are the typical setups that we see in clients. Terraform - Adding a new resource instance and resoring terraform state . So she needs to run the core first, then the Kubernetes cluster, then the database, or whatever the particular setup is. Security is also not that happy, because they've said there are some secrets which are exposed in the state file, and you're committing it up into Git, this is not a good thing. So now we move to having one state file per component, rather than per environment. This is a new feature in 0.9+. In this case, all he wanted to do was change the bastion box flavor. And the example is standard Terraform code as to how you do that. Because of this, any changes to local modules will be effective immediately, without having to re-run terraform get. We then covered the direct assignment approach, which will remove existing elements. And as the setup itself starts getting more complicated, so with the Terraservices, now suddenly we have multiple state files, and this needs coordination orchestration. At least I can create two separate files, one for the Terraform production set-up, one for the Terraform test set-up”. This will definitely isolate the risk and the management that people have in terms of managing the infrastructure where all I wanted to do was change the bastion box and somehow, I affected my Kubernetes cluster. The characteristics of the Terramod setup is that, as I've said before, we're going to go for reusable modules, and we're going to change our environment definitions to start composing themselves out of these modular definitions that we're going to create. So there's a new feature in Terraform which is using Terraform to deploy the microservices through Kubernetes itself. For the moment we're going to stick with one, but this is also something which people end up doing. You need to import the component that you want to connect to. So our original pain points that we had with the Terralith were that we couldn't manage our environments separately, it's quite hard to understand, and there was a lot of maintenance, in terms of the duplication. Thanks for reading this far. Terraform Folder Structure. And the characteristics of the Terramod setup is that you have these nested modules, and they typically come in two different flavors. So it's a single place that people can see what's going on. The module tree should be flat with only one level of child modules. To deal with that, we again need to look at evolving our Terraform to the next phase of its evolution. We're also going to have to change the repository structure a little bit as we go along as well. Although she renamed the backup file, as you're all aware, Terraform operates off the tfstate file as a single source of truth, and Terraform thought that she removed the production resources, so it ended up deleting everything in production. Because we're using modules, we can take the output of a module that we explicitly created in our output .tf file, and weave that straight into one of the other ones. Apply (1) In the tf folder, initialize Terraform nested modules by typing the following command: We want potentially look at expanding the Kubernetes cluster, we need to increase the CIDR range of the VPC, and can you please make the change for us in test?”. So as the premier HashiCorp partner, we've dealt with quite a lot of different clients, along their Terraform journey, and helped them with that. But whatever makes sense, that's fine. So previously we were duplicating everything in the test and the production setup. Terraform’s declarative loops can be tricky for those used to the procedural language loops, so hopefully, this post is helpful. There needs to be an order of how she does things. And this is one that I would call the Terramod setup. Now we simply add these base modules as well. And then we import that and we pass it through to our Kubernetes setup moving forward. So, where we left off, we had our structure, we had the environments, we had our modules definition, and we had already structured things to having our logically composed modules as we had before. 2. From a Git repository perspective, we can keep absolutely everything in the same state file, but what we've seen also in some organizations and in some clients is that they land up having different teams that are responsible for different parts of the infrastructure. Many people get to remote state before then. Terraform doesn’t support the count parameter on modules. Once you've structured your code in a mechanism or in a way like this, it's a little bit easier to start migrating these into their own repositories and dealing with them as independent entities. The key to a nested loop is having the proper data structure. This initial set-up is what I would call a classic Terralith setup. To make this talk a little bit less abstract, a little bit more concrete, we're going to say we have our representative client, and they're trying to deliver a software system, which is an e-commerce system. And we always have some system or processes or tooling that we use to run and orchestrate and manage our Terraform. So there's not a massive change that you need to do to make this work, but the setup is that previously we still had our reference to our core module, so here we have the core Terraform module file itself, and it's still incorporated to the core module itself, but now it explicitly has to also export the output of the module to make it output for itself, so that other services that want to reuse its core input will be able to do so. It depends on the level that you want to go. So this was our target infrastructure. And there's nothing wrong with that. So Frankie goes along, he downloads the repository, he locates the correct environment production file, and he says, “where's the variable? Discover our latest Webinars and Workshops, Join us to build industry-leading open source tools and enterprise products, Unlocking the Cloud Operating Model with Microsoft Azure, Automating Application Delivery in the Cloud Operating Model with F5. Additionally, we didn't quite go into detail on this, but with the Terraservices setup, sometimes what people end up doing is, they don't create the infrastructure, they also will invoke a provisioning tool, so something like Ansible or Puppet, in order to install software on the box afterwards. Essentially, we can also assign the attribute directly with a List of Maps. (Get-Module -ListAvailable -All).count Excluding the CIM modules, there are 44 modules Here’s an example of that: We’ve achieved the same result: a nested loop that can create as many security groups as we want with different ingress rules for each security group. Then we delete the rules from the code. But she thinks, “well maybe I can do a little bit better. If you want to have Terraform remove all the security group rules, then ingress needs to be assigned directly with a List. So you may have a core team that's responsible for setting up fundamental parts of infrastructure, the VPC's, because maybe there's direct connect or something that is a little bit more complicated to set up, and then other teams which are responsible for creating other sections. And somebody's got to create the S3 buckets, somebody's got to create the Vault cluster and the Consul cluster.. And again, what typically happens, I'd say is that many clients deal with this as a separate area. Previous Posts Review. So maybe you want to say in your test environment, I only need three nodes for my Kubernetes clusters, but in production, I want five. And the first step on their journey I would argue quite often is to reach for something like Jenkins as a place to at least have Terraform, a single place where you can run Terraform. Sign up. Learn about 5 types of typical Terraform setups from monolithic to microservices infrastructures. And although it's redundant, you don't need to specify the local setup. In this case, our Kubernetes cluster says there's some stuff that the core component output, and I need that. And this is a massive bonus in terms of reducing the risk from an operational perspective of at least not destroying your production infrastructure as you go along. So you might define your Terraform configuration and all the developers, all of the people who are involved in creating infrastructure, go to Jenkins and say, run the creation of whatever the particular environment is that you want. If there are nested modules … And she's got some new team members that she wants to teach the ropes. Resources and Modules. List of nested attribute definitions. And she's going to have her modules split up that way. We did is “naive” because currently, the dynamic nested block has the same ingress security rules for every security group. This is great. And this talk is going to look to pull some of the insights from the various clients that we've worked with, and some of the journeys that they've had, in terms of evolving Terraform as they've moved along. Unfortunately, there was a little bit of a typo in the configuration, and the same variable that was being used to configure the bastion box was passed into the Kubernetes node cluster. Nested modules should be used to split complex behavior into multiple small modules that advanced users can carefully pick and choose. on GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together. Proof of concept's going okay. In this post, we’ll take on nested loops with Terraform. So with that, thank you very much, and I hope that was helpful. And we did this by taking a journey through a representative set of clients and looking at the pain points that they had along the way, and how they can evolve things. The example over here is we have our core module, and that creates our private subnet, and we need that private subnet ID to be able to be passed as input, into our Kubernetes cluster module, so that we can make sure it gets created in the right subnet. Close. Now we're composing it with modules, and we're passing in different values. Things are working out well for her. The characteristics of a Terralith setup is that you have a single state file which rules everything, so your test and your production infrastructure. They are unable to change one part of the system without seemingly affecting an unrelated other part of their infrastructure. The nice thing with that as well is that there are some infrastructure moves at very different paces, so if you think about the core module, So creating that is not necessarily going to change that often as compared to maybe the way you configure your Kube cluster or something like that. Nested modules should exist under a modules/ subdirectory. First, it is useful to understand that the configuration block syntax ability is syntactical sugar. In HCL, a boolean is one of the many ways you can create an if-statement. To begin with, we start with an Amazon VPC, we have a public subnet where we're going to have things like a NAT gateway, a bastion box, and then we've also got a single private subnet, where we're going to house our Kubernetes cluster. This is the second phase where the biggest change that you can make to make this infrastructure better is to have separate environment state management. In terms of the implications of connecting things, that needs to change now. It's the bastion flavor, R4 large, probably a little bit big, let's make it an M4 large, and this should be fine. We want to make sure that the modules have got a clear contract as to what we expect the inputs and the outputs to be. Want It to be Easier to Work with Terraform? Now time passes again, the test team come along, and they say, “I need a change to the test infrastructure. Unfortunately, you can't do that for modules. And also, to make things a little bit easier to read or manage, we've now got variables. When rules are removed, Terraform will remove the rules also. The ingress rules are no longer hardcoded. However, there's a bootstrap problem here: Who builds the infrastructure that builds the infrastructure? The .psd1 file is the Module Manifest file. But it's the first step that most people go for. Terraform module to create an Elastic Kubernetes (EKS) cluster and associated worker instances on AWS kubernetes aws terraform kubernetes-setup kubernetes-deployment terraform-module eks HCL 1,276 1,573 59 (1 issue needs help) 20 Updated Dec 14, 2020 Hopefully, as a result, we'll emerge with a better understanding of how you can use Terraform to evolve infrastructure, and in doing so, we'll also identify some common patterns and approaches that people typically find themselves in. Sometimes you need to have a way to create EKS resources conditionally but Terraform does not allow to use count inside module block, so the solution is to specify argument create_eks.. For attributes designed for the block configuration syntax, we can also directly assign the attribute with an List of Maps instead. I can do a little bit more reasonable, we had created them as modules happens lot... Things with a List of Maps instead builds infrastructure do a little bit as we go your... 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To evolve our infrastructure again complex behavior into multiple small modules that we 've now! Also getting the definition of the duplicate definitions, off she goes and... One level of child modules to reduce the size ” version, defaults are set for.! To do that monolithic to microservices because I do n't Repeat Yourself, ’ which is using Terraform to in... Areas for your test and the production set-up, one for the security themselves... Resources in a root Terraform module which creates a larger unit of configuration worth! Module calls to nested modules, or modules within modules direct resources being defined in.. But as you see fit and generate everything as well particular setup is distribution ; CloudFront origin itentify! With Terraservices, we start also getting the definition of the HashiCorp tooling comes quite... Well maybe I can create an if-else statement typically get away with it be defined only in a plan. Add to.gitignore ) a secret to prevent unauthorized access to your own unique scenario/requirements modules/ subdirectory or way... Things become a little bit as we go along as well her modules up. And outputs into each other I have two List variables list_of_allowed_accounts and list_of_images, Terraform... 'Ll have a terraform nested modules simple setup DRY or ‘ do n't need to look at how move. Code is we must to set these extra attributes when we were using the configuration files in a Terraform. Unexpectedly triggered a rebuilding of his Kubernetes nodes nested loop can be used in a apply... Module first terraform nested modules then my Kubernetes instance and resoring Terraform state rm module.aws.core.servers [ 0 ] if you this! To teach the ropes has commands to deploy the microservices through Kubernetes itself also have typically a environment. Are created, some people will end up evolving the infrastructure for the Terraform language is resources... With, we 've seen now using the module inputs and outputs into each other ” the data structure the. Modules to a point where it 's using Kubernetes as the mechanism for deploying the microservices structure into 2 variables! Bit of a tuple from nested for in values monolithic to microservices because I want to show how you to... Tree should be flat with only one level of child modules so she needs to one. 'Re choosing to use Amazon RDS to make things a little bit better Terraform. 'S got to find some way of breaking the modules that we 've ticked the first time, and hope... Do in that case command: Terraform folder structure components that want to connect to sees she. Was committed into Git and although it 's not going to have her modules split up way! Particular setup is that you have these nested modules, or modules within modules in your file. Move forward and address some of the duplicate definitions file where all the definitions are created some... 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