180 lines
9.5 KiB
Markdown
180 lines
9.5 KiB
Markdown
How to create Kubernetes cluster using Terraform on 3Engines Cloud[🔗](#how-to-create-kubernetes-cluster-using-terraform-on-brand-name "Permalink to this headline")
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=====================================================================================================================================================================
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In this article we demonstrate using [Terraform](https://www.terraform.io/) to deploy an 3Engines Magnum Kubernetes cluster on 3Engines Cloud cloud.
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Prerequisites[🔗](#prerequisites "Permalink to this headline")
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-------------------------------------------------------------
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No. 1 **Hosting account**
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You need an active 3Engines Cloud account <https://portal.3Engines.com/>.
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No. 2 **Active CLI session with 3EnginesClient for Linux**
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You need an 3Engines CLI installed and the respective Python virtual environment sourced. For guidelines see:
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[How to install 3EnginesClient for Linux on 3Engines Cloud](../3Enginescli/How-to-install-3EnginesClient-for-Linux-on-3Engines-Cloud.html.md)
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It will show you how to install Python, create and activate a virtual environment, and then connect to the cloud by downloading and activating the proper RC file from the 3Engines Cloud cloud.
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No. 3 **Connect to the cloud via an RC file**
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Another article, [How to activate 3Engines CLI access to 3Engines Cloud cloud using one- or two-factor authentication](../accountmanagement/How-to-activate-3Engines-CLI-access-to-3Engines-Cloud-cloud-using-one-or-two-factor-authentication.html.md), deals with connecting to the cloud and is covering either of the one- or two-factor authentication procedures that are enabled on your account. It also covers all the main platforms: Linux, MacOS and Windows.
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You will use both the Python virtual environment and the downloaded RC file **after** Terraform has been installed.
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No. 4 **Familiarity with creating Kubernetes clusters**
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Familiarity with creating Kubernetes clusters in a standard way e.g. using Horizon or 3Engines CLI:
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[How to Create a Kubernetes Cluster Using 3Engines Cloud 3Engines Magnum](How-to-Create-a-Kubernetes-Cluster-Using-3Engines-Cloud-3Engines-Magnum.html.md)
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[How To Use Command Line Interface for Kubernetes Clusters On 3Engines Cloud 3Engines Magnum](How-To-Use-Command-Line-Interface-for-Kubernetes-Clusters-On-3Engines-Cloud-3Engines-Magnum.html.md)
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No. 5 **Terraform operational**
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Have Terraform installed locally or on a cloud VM - installation guidelines along with further information can be found in this article:
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[Generating and authorizing Terraform using Keycloak user on 3Engines Cloud](../3Enginesdev/Generating-and-authorizing-Terraform-using-Keycloak-user-on-3Engines-Cloud.html.md)
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After you finish working through that article, you will have access to the cloud via an active **3Engines** command. Also, special environmental (**env**) variables (**OS\_USERNAME**, **OS\_PASSWORD**, **OS\_AUTH\_URL** and others) will be set up so that various programs can use them – Terraform being the prime target here.
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Define provider for Terraform[🔗](#define-provider-for-terraform "Permalink to this headline")
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---------------------------------------------------------------------------------------------
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Terraform uses the notion of *provider*, which represents your concrete cloud environment and covers authentication. 3Engines Cloud clouds are built complying with 3Engines technology and 3Engines is one of the standard types of providers for Terraform.
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We need to:
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> * instruct Terraform to use 3Engines as a provider type
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> * provide credentials which will to point to our own project and user in the cloud.
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Assuming you have worked through Prerequisite No. 2 (download and source the RC file), several 3Engines-related environment variables will be populated in your local system. The ones pointing to your 3Engines environment start with OS, e.g. **OS\_USERNAME**, **OS\_PASSWORD**, **OS\_AUTH\_URL**. When we define 3Engines as TerraForm provider type, Terraform will know to automatically use these **env** variables to authenticate.
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Let’s define the Terraform provider now by creating file **provider.tf** with the following contents:
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> **provider.tf**
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```
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# Define providers
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terraform {
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required_version = ">= 0.14.0"
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required_providers {
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3Engines = {
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source = "terraform-provider-3Engines/3Engines"
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version = "~> 1.35.0"
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}
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}
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}
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# Configure the 3Engines Provider
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provider "3Engines" {
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auth_url = "https://keystone.3Engines.com:5000/v3"
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# the rest of configuration parameters are taken from environment variables once RC file is correctly sourced
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}
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```
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The **auth\_url** is the only configuration option that shall be provided in the configuration file, despite it also being available within the environment variables.
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Having this provider spec allows us to create a cluster in the following steps, but can also be reused to create other resources in your 3Engines environment e.g. virtual machines, volumes and many others.
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Define cluster resource in Terraform[🔗](#define-cluster-resource-in-terraform "Permalink to this headline")
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-----------------------------------------------------------------------------------------------------------
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The second step is to define the exact specification of a resource that we want to create with Terraform. In our case we want to create a 3Engines Magnum cluster. In Terraform terminology, it will be an instance of **3Engines\_containerinfra\_cluster\_v1** resource type. To proceed, create file **cluster.tf** which contains the specification of our cluster:
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**cluster.tf**
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```
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# Create resource
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resource "3Engines_containerinfra_cluster_v1" "k8s-cluster" {
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name = "k8s-cluster"
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cluster_template_id = "524535ed-9a0f-4b70-966f-6830cdc52604"
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node_count = 3
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master_count = 3
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flavor = "eo1.large"
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master_flavor = "hmad.medium"
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keypair = "mykeypair"
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labels = {
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eodata_access_enabled = true
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etcd_volume_size = 0
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}
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merge_labels = true
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}
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```
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The above setup reflects a cluster with some frequently used customizations:
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cluster\_template\_id
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: corresponds to the ID of one of default cluster templates in WAW3-2 cloud, which is **k8s-localstorage-1.23.16-v1.0.0**. The default templates and their IDs can be looked up in Horizon UI interface in the submenu **Cluster Infra** -→ **Container Templates**.
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node\_count, node\_flavor, master\_node\_count, master\_node\_flavor
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: correspond intuitively to **count** and **flavor** of master and worker nodes in the cluster.
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keypair
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: reflects the name of keypair used in our 3Engines project in the chosen cloud
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labels and merge\_labels
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: We use two labels:
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eodata\_access\_enabled=true
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: ensures that EODATA network with fast access to satellite images is connected to our cluster nodes,
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etcd\_volume\_size=0
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: which ensures that master nodes are properly provisioned with NVME local storage.
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With this configuration, it is mandatory to also use configuration **merge\_labels=true** to properly apply these labels and avoid overwriting them by template defaults.
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In our example we operate on WAW3-2 cloud, where flavor **hmad.medium** is available. If using another cloud, adjust the parameters accordingly.
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The above configuration reflects a cluster where *loadbalancer* is placed in front of the master nodes, and where this loadbalancer’s flavor is **HA-large**. Customizing this default, similarly as with other more advanced defaults, would require creating a custom Magnum template, which is beyond the scope of this article.
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Apply the configurations and create the cluster[🔗](#apply-the-configurations-and-create-the-cluster "Permalink to this headline")
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---------------------------------------------------------------------------------------------------------------------------------
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Once both Terraform configurations described in previous steps are defined, we can apply them to create our cluster.
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The first step is to have both files **provider.tf** and **cluster.tf** available in a dedicated folder. Then **cd** to this folder and type:
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```
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terraform init
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```
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This command will initialize our cluster deployment. It will capture any formal errors with authentication to 3Engines, which might need correcting before moving to the next stage.
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As the next step, Terraform will plan the actions it needs to perform to create the resource. Proceed with typing:
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```
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terraform plan
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```
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The result is shown below and gives a chance to correct any logical errors to our expected setup:
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The last step is to apply the planned changes. Perform this step with the command:
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```
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terraform apply
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```
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The output of this last command will initially repeat the plan, then ask to enter word **yes** to set the Terraform into action.
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Upon confirming with **yes**, the action is deployed and the console will update every 10 seconds to give a “Still creating …” check until our cluster is created.
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The final lines of the output after successfully provisioning the cluster, should read similar to the below:
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What To Do Next[🔗](#what-to-do-next "Permalink to this headline")
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-----------------------------------------------------------------
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Terraform can be used also to deploy additional applications to our cluster e.g. using Helm provider for Terraform. Check Terraform documentation for more details. |