Automatic Docker image scan on push using Terraform

To configure automatic vulnerability scans of Docker images on push to Yandex Container Registry using Terraform:

1. Get your cloud ready.
2. Set up your environment.
3. Create the infrastructure.
4. Push the Docker image.
5. Check the result.

If you no longer need the resources you created, delete them.

Get your cloud readyGet your cloud ready

Sign up for Yandex Cloud and create a billing account:

1. Navigate to the management console and log in to Yandex Cloud or create a new account.
2. On the Yandex Cloud Billing page, make sure you have a billing account linked and it has the ACTIVE or TRIAL_ACTIVE status. If you do not have a billing account, create one and link a cloud to it.

If you have an active billing account, you can create or select a folder for your infrastructure on the cloud page.

Learn more about clouds and folders here.

Required paid resourcesRequired paid resources

The infrastructure support cost includes:

• Fee for storing a Docker image in the registry, a vulnerability scanner, and outgoing traffic (see Yandex Container Registry pricing).
• Fee for function calls (see Yandex Cloud Functions pricing).

Set up your environmentSet up your environment

1. Install and configure Docker.

Create the infrastructureCreate the infrastructure

With Terraform, you can quickly create a cloud infrastructure in Yandex Cloud and manage it using configuration files. These files store the infrastructure description written in HashiCorp Configuration Language (HCL). If you change the configuration files, Terraform automatically detects which part of your configuration is already deployed, and what should be added or removed.

Terraform is distributed under the Business Source License. The Yandex Cloud provider for Terraform is distributed under the MPL-2.0 license.

For more information about the provider resources, see the guides on the Terraform website or its mirror.

To create an infrastructure to automatically scan a Docker image on push using Terraform:

1. Install Terraform and get the authentication data.

2. Specify the source for installing the Yandex Cloud provider (see Configure your provider, step 1).

3. Prepare your infrastructure description files:

   Ready-made configuration

   Manually

   1. Clone the repository containing the configuration files.

      git clone https://github.com/yandex-cloud-examples/yc-cr-image-scanning
      

   2. Navigate to the repository directory. It should now contain the following files:

      • image-auto-scan.tf: New infrastructure configuration.
      • image-auto-scan.auto.tfvars: User data file.
      • function.zip: ZIP archive with the function code.

   1. Create a folder for configuration files.

   2. Create a configuration file named image-auto-scan.tf in the folder:

      image-auto-scan.tf

      # Declaring variables for custom parameters
      
      variable "zone" {
        type = string
      }
      
      variable "folder_id" {
        type = string
      }
      
      # Adding other variables
      
      locals {
        sa_scanner_name    = "scanner"
        sa_invoker_name    = "invoker"
        registry_name      = "my-registry"
        function_name      = "scan-on-push"
        trigger_name       = "trigger-for-reg"
      }
      
      # Configuring a provider 
      
      terraform {
        required_providers {
          yandex    = {
            source  = "yandex-cloud/yandex"
            version = ">= 0.47.0"
          }
        }
      }
      
      provider "yandex" {
        folder_id = var.folder_id
      }
      
      # Creating service accounts
      
      resource "yandex_iam_service_account" "scanner" {
        name        = local.sa_scanner_name
        description = "SA for Container Registry"
        folder_id   = var.folder_id
      }
      
      resource "yandex_iam_service_account" "invoker" {
        name        = local.sa_invoker_name
        description = "SA for Cloud Functions"
        folder_id   = var.folder_id
      }
      
      # Assigning roles to service accounts
      
      resource "yandex_resourcemanager_folder_iam_member" "sa-role-scanner" {
        folder_id   = var.folder_id
        role        = "container-registry.images.scanner"
        member      = "serviceAccount:${yandex_iam_service_account.scanner.id}"
      }
      
      resource "yandex_resourcemanager_folder_iam_member" "sa-role-invoker" {
        folder_id   = var.folder_id
        role        = "functions.functionInvoker"
        member      = "serviceAccount:${yandex_iam_service_account.invoker.id}"
      }
      
      # Creating a registry in Container Registry
      
      resource "yandex_container_registry" "my-reg" {
        name      = local.registry_name
        folder_id = var.folder_id
      }
      
      # Creating a function
      
      resource "yandex_function" "test-function" {
        name               = local.function_name
        user_hash          = "my-first-function"
        runtime            = "bash"
        entrypoint         = "handler.sh"
        memory             = "128"
        execution_timeout  = "60"
        service_account_id = yandex_iam_service_account.scanner.id
        content {
          zip_filename   = "function.zip"
        }
      }
      
      # Creating a trigger
      
      resource "yandex_function_trigger" "my-trigger" {
      
        name = local.trigger_name
        function {
          id                 = yandex_function.test-function.id
          service_account_id = yandex_iam_service_account.invoker.id
        }
        container_registry {
          registry_id      = yandex_container_registry.my-reg.id
          create_image_tag = true
          batch_cutoff     = "10"
          batch_size       = "1"
        }
      }
      

   3. Create a file with user data named image-auto-scan.auto.tfvars:

      image-auto-scan.auto.tfvars

      zone      = "<availability_zone>"
      folder_id = "<folder_ID>"
      

   4. Prepare a ZIP archive with the function code.

      1. Create the handler.sh file and paste the following code to it:

         handler.sh

         Warning

         If you are creating a file in Windows, make sure that newline characters are in \n Unix format rather than \r\n. You can replace line breaks in a text editor, such as Notepad++, or with such tools as dos2unix or Tofrodos.

         DATA=$(cat | jq -sr '.[0].messages[0].details')
         ID=$(echo $DATA | jq -r '.image_id')
         NAME=$(echo $DATA | jq -r '.repository_name')
         TAG=$(echo $DATA | jq -r '.tag')
         yc container image scan --id ${ID} --async 1>&2
         

      2. Create a ZIP archive named function.zip with the handler.sh file.

   Learn more about the properties of resources in these Terraform provider guides:

   • Service account: yandex_iam_service_account.
   • Assigning access permissions for a folder: yandex_resourcemanager_folder_iam_member.
   • Registry: yandex_container_registry.
   • Function: yandex_function.
   • Trigger: yandex_function_trigger.

4. In the image-auto-scan.auto.tfvars file, set the following user-defined properties:

   • zone: Availability zone to create the infrastructure in.
   • folder_id: ID of the folder to create the infrastructure in.

5. Create the resources:

   1. In the terminal, navigate to the configuration file directory.

   2. Make sure the configuration is correct using this command:

      terraform validate
      

      If the configuration is valid, you will get this message:

      Success! The configuration is valid.
      

   3. Run this command:

      terraform plan
      

      You will see a list of resources and their properties. No changes will be made at this step. Terraform will show any errors in the configuration.

   4. Apply the configuration changes:

      terraform apply
      

   5. Type yes and press Enter to confirm the changes.

Push the Docker imagePush the Docker image

1. Run Docker Desktop.

2. Log in to the registry under your username with:

   Docker credential helper

   OAuth token

   IAM token

   1. Configure Docker to use docker-credential-yc:

      yc container registry configure-docker
      

      Result:

      Credential helper is configured in '/home/<user>/.docker/config.json'
      

      The current user’s profile stores the settings.

      Warning

      The credential helper only works if you use Docker without sudo. To learn how to configure Docker to run on behalf of the current user without sudo, see this Docker guide.

   2. Make sure Docker is configured.

      The /home/<user>/.docker/config.json configuration file should now contain this line:

      "cr.yandex": "yc"
      

   3. You can now use Docker, e.g., to push Docker images. You do not need to run the docker login command for that.

   OAuth token authentication is deprecated

   This authentication method will no longer be supported. Consider using IAM tokens or API keys.

   1. If you do not have an OAuth token yet, get one at this link.

   2. Run this command:

      echo <OAuth_token> | docker login --username oauth --password-stdin cr.yandex
      

      Result:

      Login Succeeded
      

   Note

   The IAM token has a short lifetime of up to 12 hours. This makes it a good method for applications that automatically request an IAM token.

   1. Get an IAM token.

   2. Run this command:

      yc iam create-token | docker login --username iam --password-stdin cr.yandex
      

      Result:

      Login Succeeded
      

3. Pull a Docker image from Docker Hub:

   docker pull ubuntu:20.04
   

   Result:

   20.04: Pulling from library/ubuntu
   Digest: sha256:cf31af331f38d1d7158470e095b132acd126a7180a54f263d386da88********
   Status: Image is up to date for ubuntu:20.04
   docker.io/library/ubuntu:20.04
   

4. Assign a tag to the Docker image:

   docker tag ubuntu:20.04 cr.yandex/<registry_ID>/ubuntu:20.04
   

5. Push the Docker image to Container Registry:

   docker push cr.yandex/<registry_ID>/ubuntu:20.04
   

   Result:

   The push refers to repository [cr.yandex/crpu20rpdc2f********/ubuntu]
   2f140462f3bc: Layer already exists
   63c99163f472: Layer already exists
   ccdbb80308cc: Layer already exists
   20.04: digest: sha256:86ac87f73641c920fb42cc9612d4fb57b5626b56ea2a19b894d0673f******** size: 943
   

Check the resultCheck the result

1. View the logs of the scan-on-push function and make sure it has executed.

   Management console

   CLI

   1. In the management console, select Cloud Functions.
   2. Go to the Functions section and select the scan-on-push function.
   3. In the window that opens, go to Logs and specify the time period. The default time period is one hour.

   To find out the name or ID of a function, get the list of functions in the folder.

   View the function execution log:

   yc serverless function logs scan-on-push
   

   Result:

   2021-05-18 09:27:43  START RequestID: 34dc9533-ed6e-4468-b9f2-2aa0******** Version: b09i2s85a0c1********
   2021-05-18 09:27:43  END RequestID: 34dc9533-ed6e-4468-b9f2-2aa0********
   2021-05-18 09:27:43  REPORT RequestID: 34dc9533-ed6e-4468-b9f2-2aa0******** Duration: 538.610 ms Billed Duration: 538.700 ms Memory Size: 128 MB Max Memory Used: 13 MB
   2021-05-18 09:29:25  START RequestID: 5b6a3779-dcc8-44ec-8ee2-2e7f******** Version: b09i2s85a0c1********
   2021-05-18 09:29:26  END RequestID: 5b6a3779-dcc8-44ec-8ee2-2e7f********
   2021-05-18 09:29:26  REPORT RequestID: 5b6a3779-dcc8-44ec-8ee2-2e7f******** Duration: 554.904 ms Billed Duration: 555.000 ms Memory Size: 128 MB Max Memory Used: 13 MB
   ...
   

2. Make sure that a new scan started when you pushed the Docker image.

   Management console

   CLI

   1. In the management console, select the parent folder of the registry containing the Docker image.
   2. Select Container Registry.
   3. Select the registry where you pushed your Docker image.
   4. Open the repository with the Docker image.
   5. Select the relevant Docker image and check the Date of last scan parameter value.

   To view scans by Docker image, run the command:

   yc container image list-scan-results --repository-name=<registry_ID>/<Docker_image_name>
   

   Result:

   +----------------------+----------------------+---------------------+--------+--------------------------------+
   |          ID          |        IMAGE         |     SCANNED AT      | STATUS |        VULNERABILITIES         |
   +----------------------+----------------------+---------------------+--------+--------------------------------+
   | crpu20rpdc2f******** | crpqmsqp5mtb******** | 2021-05-18 14:34:02 | READY  | medium:6, low:13, negligible:3 |
   +----------------------+----------------------+---------------------+--------+--------------------------------+
   

How to delete the resources you createdHow to delete the resources you created

To stop paying for the resources you created:

1. Open the image-auto-scan.tf file and delete your infrastructure description from it.

2. Apply the changes:

   1. In the terminal, navigate to the configuration file directory.

   2. Make sure the configuration is correct using this command:

      terraform validate
      

      If the configuration is valid, you will get this message:

      Success! The configuration is valid.
      

   3. Run this command:

      terraform plan
      

      You will see a list of resources and their properties. No changes will be made at this step. Terraform will show any errors in the configuration.

   4. Apply the configuration changes:

      terraform apply
      

   5. Type yes and press Enter to confirm the changes.

Useful linksUseful links

• Automatic Docker image scans on push using the management console, CLI, and API