Azure Pipeline Agent Cloud Config (Terraform merge)

pipeline-agent-cloud-config.tf

data cloudinit_config user_data {
  gzip                         = false
  base64_encode                = false

  part {
    content                    = templatefile("${path.root}/../cloudinit/cloud-config-userdata.yaml",
    {
      # Propagate virtual network information, so cloudinit can set up environment variables
      subnet_id                = azurerm_subnet.agent_subnet.id
      virtual_network_id       = azurerm_virtual_network.pipeline_network.id
    })
    content_type               = "text/cloud-config"
  }
  
  merge_type                   = "list(append)+dict(recurse_array)+str()"
}
# Show relevant attributes only
resource azurerm_linux_virtual_machine_scale_set linux_agents {
  # ...
  
  custom_data                  = base64encode(data.cloudinit_config.user_data.rendered)

  # ...

  lifecycle {
    # Let Azure DevOps manage the number of instances
    ignore_changes             = [instances]
  }
}