Allow the Trivy Operator to access private registries
In this tutorial, we will detail multiple ways on setting up the Trivy Operator to access and scan container images from private container registries.
Prerequisites
To follow this tutorial, you need the following installed on your machine:
- The Helm CLI tool
- kubectl and connected to a running Kubernetes cluster
- a container images in a private registy, running as a pod inside your cluster
Note that we will be using a local Kubernetes KinD cluster and a private container image stored on a private GitHub repository for the examples.
First Option: Filesystem Scanning
For this tutorial, we will use the Operator Helm Chart.
The configuration options for the Helm Chart can be found in the values.yaml manifest.
Navigate to the section Trivy.command. The default will be:
trivy:
# command. One of `image`, `filesystem` or `rootfs` scanning, depending on the target type required for the scan.
# For 'filesystem' and `rootfs` scanning, ensure that the `trivyOperator.scanJobPodTemplateContainerSecurityContext` is configured
# to run as the root user (runAsUser = 0).
command: image
By default, the command that trivy is supposed to run inside your cluster is trivy image for container image scanning. However, we want to change it to scan the filesystem in your nodes instead. Container images are ultimately stored as files on the node level of your cluster. This way, trivy is going to scan the files of your container images for vulnerabilities. This is a little bit of a work-around with the downside that the Trivy Operator will have to run as root. However, remember that security scanning already requires the operator to have lots of cluster privileges.
Next, we will change the the command and the trivyOperator.scanJobPodTemplateContainerSecurityContextof the values.yaml manifest. For this, we can create a new values.yaml manifest with our desired modifications:
trivy:
command: fs
ignoreUnfixed: true
trivyOperator:
scanJobPodTemplateContainerSecurityContext:
# For filesystem scanning, Trivy needs to run as the root user
runAsUser: 0
Lastly, we can deploy the operator inside our cluster with referencing our new values.yaml manifest to override the default values:
helm upgrade --install trivy-operator aqua/trivy-operator \
--namespace trivy-system \
--create-namespace \
--version 0.16.1
--values ./values.yaml
Alternatively, it is possible to set the values directly through Helm instead of referencing an additional values.yaml file:
helm upgrade --install trivy-operator aqua/trivy-operator \
--namespace trivy-system \
--create-namespace \
--version 0.16.1
--set="trivy.command=fs"
--set="trivyOperator.scanJobPodTemplateContainerSecurityContext.runAsUser=0"
Once installed, make sure that
- the operator is running in your cluster
- the operator has created a VulnerabilityReport for the container image from the private registry
❯ kubectl get deployment -n trivy-system
NAME READY UP-TO-DATE AVAILABLE AGE
trivy-operator 1/1 1 1 99s
Second Option: Using an ImagePullSecret to access containers from the Private Registry
Note that you might be using an ImagePullSecret already to allow pods to pull the container images from a private registry.
To set-up an ImagePullSecret, we first need an access token to our private registry. For GitHub private registries, you can create a new access token under the following link. In comparison, the official Kubernetes documentation shows how to create the ImagePullSecret for the DockerHub.
Next, we will base64 encode the access token:
echo -n "YOUR_GH_ACCOUNT_NAME:YOUR_TOKEN" | base64
And take the output of the previous command and parse it into the following to base64 encode it again:
echo -n '{"auths":{"ghcr.io":{"auth":"OUTPUT"}}}' | base64
Lastly, we are going to store the output in a Kubernetes Secret YAML manifest:
imagepullsecret.yaml
kind: Secret
type: kubernetes.io/dockerconfigjson
apiVersion: v1
metadata:
name: dockerconfigjson-github-com
labels:
app: app-name
data:
.dockerconfigjson: OUTPUT
Note that base64 encoding is not encryption, thust, you should not commit this file. If you are looking to store secrets in Kubernetes, have a look at e.g. Hashicorp Secret Vault, or with an External Secrets Operator (ESO).
Make sure to reference the ImagePullSecret in your container spec:
containers:
- name: cns-website
image: ghcr.io/account-name/image-id:tag
imagePullSecrets:
- name: dockerconfigjson-github-com
And finally, we can apply the secret to the same namespace as our application:
kubectl apply -f imagepullsecret.yaml -n app
If you have to modify your deployment.yaml manifest, make sure to update that as well.
Once you have defined your ImagePullSecret, the Operator will have access to the container image automatically with the defaul configuration.
Third Option: Define an ImagePullSecret through a ServiceAccount
Alternatively to defining an ImagePullSecret on the pod level, we can also define the secret through a Kubernetes Service Account. Our workload will be associated with the service account and can pull the secret from our private registry.
Similar to the Second Option, once we have the key associated to our workload, the Trivy operator scan job has access to the secret and can pull the image.
Again, you can have a look at the official Kubernetes documentation for further details.
imagepullsecret.yaml
apiVersion: v1
kind: Secret
metadata:
name: dockerconfigjson-sa-github-com
annotations:
kubernetes.io/service-account.name: cns-website
type: kubernetes.io/dockerconfigjson
data:
.dockerconfigjson: OUTPUT
serviceaccount.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
name: cns-website
imagePullSecrets:
- name: dockerconfigjson-sa-github-com
deployment.yaml
*or where you have defined your container
spec:
containers:
- name: cns-website
image: ghcr.io/account-name/image-id:tag
serviceAccountName: cns-website
Fourth Option: Define Secrets through Trivy-Operator configuration
If there are no ImagePullSecret on pod or Service Account level (for example, valid credentials are placed in container runtime configuration) you can add them in Trivy-Operator configuration.
It's very similar to Second Option. First of all you need to create a secret. To do it, we first need an access token to our private registry. For GitHub private registries, you can create a new access token under the following link. In comparison, the official Kubernetes documentation shows how to create the ImagePullSecret for the DockerHub.
Next, we will base64 encode the access token:
echo -n "YOUR_GH_ACCOUNT_NAME:YOUR_TOKEN" | base64
And take the output of the previous command and parse it into the following to base64 encode it again:
echo -n '{"auths":{"ghcr.io":{"auth":"OUTPUT"}}}' | base64
Lastly, we are going to store the output in a Kubernetes Secret YAML manifest:
imagepullsecret.yaml
kind: Secret
type: kubernetes.io/dockerconfigjson
apiVersion: v1
metadata:
name: dockerconfigjson-github-com
labels:
app: app-name
data:
.dockerconfigjson: OUTPUT
Note that base64 encoding is not encryption, thust, you should not commit this file. If you are looking to store secrets in Kubernetes, have a look at e.g. Hashicorp Secret Vault, or with an External Secrets Operator (ESO).
And finally, we can apply the secret to the same namespace as our application:
kubectl apply -f imagepullsecret.yaml -n app
Next, we will change the privateRegistryScanSecretsNames of the values.yaml manifest. For this, we can create a new values.yaml manifest with our desired modification. We need to provide desired namespace and secret name. In our example they are app and dockerconfigjson-github-com accordingly.
operator:
privateRegistryScanSecretsNames: {"app":"dockerconfigjson-github-com"}
If you want you can add additional namespaces and secret names to privateRegistryScanSecretsNames separated by comma.
Lastly, we can deploy the operator inside our cluster with referencing our new values.yaml manifest to override the default values:
helm upgrade --install trivy-operator aqua/trivy-operator \
--namespace trivy-system \
--create-namespace \
--version 0.16.1
--values ./values.yaml
Alternatively, it is possible to set the values directly through Helm instead of referencing an additional values.yaml file:
helm upgrade --install trivy-operator aqua/trivy-operator \
--namespace trivy-system \
--create-namespace \
--version 0.16.1
--set-json='operator.privateRegistryScanSecretsNames={"app":"dockerconfigjson-github-com"}'
Works only with helm 3.10+, because --set-json flag was added in 3.10.0. Otherwise you can use values.yaml instead.
Once installed, make sure that
- the operator is running in your cluster
- the operator has created a VulnerabilitReport for the container image from the private registry
❯ kubectl get deployment -n trivy-system
NAME READY UP-TO-DATE AVAILABLE AGE
trivy-operator 1/1 1 1 99s
Fifth Option: configure gcr service account json
this option is similar to forth option but using gcr json_key for gcr service account and creating a secret
echo -n "_json_key:{
"type": "service_account",
"project_id": "test",
"private_key_id": "3adas34asdas34wadad",
"private_key": "-----BEGIN PRIVATE KEY-----\n-----END PRIVATE KEY-----\n",
"client_email": "<test@test.iam.gserviceaccount.com>",
"client_id": "34324234324324",
"auth_uri": "<https://accounts.google.com/o/oauth2/auth>",
"token_uri": "<https://oauth2.googleapis.com/token>",
"auth_provider_x509_cert_url": "<https://www.googleapis.com/oauth2/v1/certs>",
"client_x509_cert_url": "<https://www.googleapis.com/robot/v1/metadata/x509/test-gcr-f5dh3h5g%40test.iam.gserviceaccount.com>"
}" | base64
And take the output of the previous command and parse it into the following to base64 encode it again:
echo -n '{"auths":{"us.gcr.io":{"auth":"OUTPUT"}}}' | base64
Lastly, we are going to store the output in a Kubernetes Secret YAML manifest:
gcr_secret.yaml
kind: Secret
type: kubernetes.io/dockerconfigjson
apiVersion: v1
metadata:
name: dockerconfigjson-github-com
labels:
app: app-name
data:
.dockerconfigjson: OUTPUT
Sixth Option: Grant access through managed registries
The last way that you could give the Trivy operator access to your private container registry is through managed registries. In this case, the container registry and your Kubernetes cluster would have to be on the same cloud provider; then you can define access to your container namespace as part of the IAM account. Once defined, trivy will already have the permissions for the registry.
For additional information, please refer to the documentation on managed registries.