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Azure Linux virtual machine not booting – disk issue

There could be cases that you have not configured the disk correctly inside a Linux azure virtual machine , or the disk mount point to change because of a disk increase. This circumstance will make your virtual machine fail and boot into emergency mode. In order to fix this issue you should first get a terminal windows on the Azure virtual machine as you cannot ssh. This can be done by selecting Help -> Serial Console

By checking the boot logs you can find the issue which in my case is the mounting of the data disk. The data disk is added as an entry on /etc/fstab but the mount point changed and Linux filesystem cannot locate it.

In order to resolve this issue you should mount the disk using the UUID to be 100% sure for the mount point. First locate the disk by using

fdisk -l

After locating the mount point run blkid command to find the UUID of the disk.

blkid

When you find the UUID use it in your /etc/fstab file instead of the mount point as shown below.

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Deploying kubernetes applications with 2-clicks | Azure DevOps & Terraform

When you read the title you may think that this article can be a clickbait. That’s the reason you should continue reading until this end to figure out that deploying k8s application with Azure DevOps and terraform can be very easy when you create everything through infrastructure as code.

In this example we will utilize Azure DevOps pipelines and terraform to deploy a yaml definition on an AKS cluster that runs on Azure. For this output we will need three steps.

The first step is to create an AKS cluster on Azure. When we have the infrastructure ready we can then continue and bind Azure DevOps pipelines with the AKS resource so that we can deploy on the cluster. The last step is to have the yaml definition of the application that we need to deploy and run the application deployment process inside azure devops.

The project is structure as shown in the below picture.

  • The code folder contains the yaml k8s definition file.
  • The iac_aks creates the AKS cluster inside Azure
  • The iac_devops creates the Azure Devops resources needed (Service connection with AKS)
  • And finally the azure-pipeline and application-pipeline are the pipelines that will run the automation and do the job.

In order to try out the example the first think that you need to do is to create a variable group inside azure devops and store two values. The first value will be the secret Personal access token that will be used to create the Azure DevOps resources. The second one is the URL of your Azure DevOps organization.

When those are set you will need to change the tfvars files and add the names that you prefer for the resources creation. Finally you can have your deployment ready with just two clicks. One for the infra pipelines and one for the application pipeline.

Code is hosted on Github
https://github.com/geralexgr/globalazuregreece2024

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Pass terraform provider variables as secrets

Many times you need to provide values in provider information when using terraform. Lets take as an example the below code block. The azuredevops provider needs some variables in order to deploy successfully and we need to pass those values as secrets because they contain sensitive information.

terraform {
required_providers {
azuredevops = {
source = "microsoft/azuredevops"
version = ">=1.0.0"
}
}
}

provider "azuredevops" {
org_service_url = URL
personal_access_token = TOKEN
}

We should never hardcode such information in the application as this information may get leaked. In order to pass those as secrets we will need to create a variable group or standalone variables and place the secrets there.

Then we will need to create some terraform variables and pass the values for those through the pipeline.

variable "org_service_url" {
description = "The URL of your Azure DevOps organization."
}

variable "personal_access_token" {
description = "The personal access token for authentication."
}

The provider block should be updated accordingly.

provider "azuredevops" {
org_service_url = var.org_service_url
personal_access_token = var.personal_access_token
}

Finally we pass those values through the pipeline step by providing those with -var argument on terraform.

    - task: TerraformTaskV4@4
displayName: terraform apply
inputs:
provider: 'azurerm'
command: 'apply'
workingDirectory: '$(System.DefaultWorkingDirectory)/src/iac_devops'
commandOptions: '-var="org_service_url=$(URL)" -var="personal_access_token=$(PAT)"'
environmentServiceNameAzureRM: 'SUBSCRIPTION'

Finally the pipeline will succeed.

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Azure DevOps Terraform Provider

If you work everywhere as a code you will probably need to check Azure DevOps terraform provider. It is created and maintained from Microsoft and you can use it in order to have your DevOps tool as a code.

https://registry.terraform.io/providers/microsoft/azuredevops/latest/docs

In order to getting started you will need to create a PAT token and give it the access based on the actions that you need to do.

When the token is ready you will need to set two environmental variables on the machine that you work. The first one is AZDO_PERSONAL_ACCESS_TOKEN which should be your token. The second one will be your org URL AZDO_ORG_SERVICE_URL

export AZDO_PERSONAL_ACCESS_TOKEN= TOKEN
export AZDO_ORG_SERVICE_URL= https://dev.azure.com/geralexgr

Finally you are ready to deploy your IAC Azure DevOps configurations.

Lets see the below example.

# Make sure to set the following environment variables:
#   AZDO_PERSONAL_ACCESS_TOKEN
#   AZDO_ORG_SERVICE_URL
terraform {
  required_providers {
    azuredevops = {
      source = "microsoft/azuredevops"
      version = ">=0.1.0"
    }
  }
}

resource "azuredevops_project" "project" {
  name = "My Awesome Project"
  description  = "All of my awesomee things"
}

resource "azuredevops_git_repository" "repository" {
  project_id = azuredevops_project.project.id
  name       = "My Awesome Repo"
  initialization {
    init_type = "Clean"
  }
}

resource "azuredevops_build_definition" "build_definition" {
  project_id = azuredevops_project.project.id
  name       = "My Awesome Build Pipeline"
  path       = "\\"

  repository {
    repo_type   = "TfsGit"
    repo_id     = azuredevops_git_repository.repository.id
    branch_name = azuredevops_git_repository.repository.default_branch
    yml_path    = "azure-pipelines.yml"
  }
}

When above code runs it will create a new project with the name My Awesome Project. Inside the project a new git repo will be initialized and a new pipeline will be created inside this repository.

You can find the usage example below.

https://github.com/microsoft/terraform-provider-azuredevops

Youtube video: