Getting Started¶
Before you Begin¶
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by installing minikube or kind, or you can use one of these Kubernetes playgrounds:
You also need the Starboard Operator to be installed in the starboard-system namespace, e.g. with
kubectl or Helm.
Workloads Scanning¶
Assuming that you installed the operator in the starboard-system namespace, and it's configured to discover
Kubernetes workloads in the default namespace, let's create the nginx Deployment that we know is vulnerable:
kubectl create deployment nginx --image nginx:1.16
When the first ReplicaSet controlled by the nginx Deployment is created, the operator immediately detects that and
creates the Kubernetes Job in the starboard-system namespace to scan the nginx:1.16 image for vulnerabilities.
It also creates the Job to audit the Deployment's configuration for common pitfalls such as running the nginx
container as root:
kubectl get job -n starboard-operator
Result
NAME COMPLETIONS DURATION AGE
scan-configauditreport-c4956cb9d 0/1 1s 1s
scan-vulnerabilityreport-c4956cb9d 0/1 1s 1s
If everything goes fine, the scan Jobs are deleted, and the operator saves scan reports as custom resources in the
default namespace, named after the Deployment's active ReplicaSet. For image vulnerability scans, the operator creates
a VulnerabilityReport for each different container defined in the active ReplicaSet. In this example there is just one
container image called nginx:
kubectl get vulnerabilityreports -o wide
Result
NAME REPOSITORY TAG SCANNER AGE CRITICAL HIGH MEDIUM LOW UNKNOWN
replicaset-nginx-7ff78f74b9-nginx library/nginx 1.16 Trivy 12s 4 40 26 90 0
Similarly, the operator creates a ConfigAuditReport holding the result of auditing the configuration of the active
ReplicaSet controlled by the nginx Deployment:
kubectl get configauditreports -o wide
Result
NAME SCANNER AGE DANGER WARNING PASS
replicaset-nginx-7ff78f74b9 Polaris 33s 1 9 7
Notice that scan reports generated by the operator are controlled by Kubernetes workloads. In our example,
VulnerabilityReport and ConfigAuditReport objects are controlled by the active ReplicaSet of the nginx Deployment:
kubectl tree deploy nginx
Result
NAMESPACE NAME READY REASON AGE
default Deployment/nginx - 51s
default └─ReplicaSet/nginx-6d4cf56db6 - 51s
default ├─ConfigAuditReport/replicaset-nginx-6d4cf56db6 - 46s
default ├─VulnerabilityReport/replicaset-nginx-6d4cf56db6-nginx - 31s
default └─Pod/nginx-6d4cf56db6-fhbm9 True 51s
Note
The tree command is a kubectl plugin to browse Kubernetes object hierarchies as a tree.
Moving forward, let's update the container image of the nginx Deployment from nginx:1.16 to nginx:1.17. This will
trigger a rolling update of the Deployment and eventually create another ReplicaSet.
kubectl set image deployment nginx nginx=nginx:1.17
Even this time the operator will pick up changes and rescan our Deployment with updated configuration:
kubectl tree deploy nginx
Result
NAMESPACE NAME READY REASON AGE
default Deployment/nginx - 86s
default ├─ReplicaSet/nginx-6d4cf56db6 - 86s
default │ ├─ConfigAuditReport/replicaset-nginx-6d4cf56db6 - 81s
default │ └─VulnerabilityReport/replicaset-nginx-6d4cf56db6-nginx - 66s
default └─ReplicaSet/nginx-db749865c - 19s
default ├─ConfigAuditReport/replicaset-nginx-db749865c - 17s
default ├─VulnerabilityReport/replicaset-nginx-db749865c-nginx - 9s
default └─Pod/nginx-db749865c-lfcp5 True 19s
By following this guide you could realize that the operator knows how to attach VulnerabilityReport and
ConfigAuditReport objects to build-in Kubernetes objects so that looking them up is easy. What's more, in this
approach where a custom resource inherits a life cycle of the built-in resource we could leverage Kubernetes garbage
collection. For example, when the previous ReplicaSet named nginx-6d4cf56db6 is deleted the VulnerabilityReport named
replicaset-nginx-6d4cf56db6-nginx as well as the ConfigAuditReport named replicaset-nginx-6d4cf56db6 are
automatically garbage collected.
Tip
If you only want the latest ReplicaSet in your Deployment to be scanned for vulnerabilities you can set the value
of the OPERATOR_VULNERABILITY_SCANNER_SCAN_ONLY_CURRENT_REVISIONS environment variable to true in the operator's
deployment descriptor. This is useful to identify vulnerabilities that impact only the running workloads.
Tip
You can get and describe vulnerabilityreports and configauditreports as built-in Kubernetes objects:
kubectl get vulnerabilityreport replicaset-nginx-db749865c-nginx -o json
kubectl describe configauditreport replicaset-nginx-db749865c
Notice that scaling up the nginx Deployment will not schedule new scan Jobs because all replica Pods refer to the
same Pod templated defined by the nginx-db749865c ReplicaSet.
kubectl scale deploy nginx --replicas 3
kubectl tree deploy nginx
Result
NAMESPACE NAME READY REASON AGE
default Deployment/nginx - 2m22s
default ├─ReplicaSet/nginx-6d4cf56db6 - 2m22s
default │ ├─ConfigAuditReport/replicaset-nginx-6d4cf56db6 - 2m17s
default │ └─VulnerabilityReport/replicaset-nginx-6d4cf56db6-nginx - 2m2s
default └─ReplicaSet/nginx-db749865c - 75s
default ├─ConfigAuditReport/replicaset-nginx-db749865c - 73s
default ├─VulnerabilityReport/replicaset-nginx-db749865c-nginx - 65s
default ├─Pod/nginx-db749865c-lfcp5 True 75s
default ├─Pod/nginx-db749865c-tn5k7 True 12s
default └─Pod/nginx-db749865c-vjlr9 True 12s
Finally, when you delete the nginx Deployment, orphaned security reports will be deleted in the background by the
Kubernetes garbage collection controller.
kubectl delete deploy nginx
kubectl get vuln,configaudit
Result
No resources found in default namespace.
Tip
Use vuln and configaudit as short names for vulnerabilityreports and configauditreports resources.
Note
You can define the validity period for VulnerabilityReports by setting the duration as the value of the
OPERATOR_VULNERABILITY_SCANNER_REPORT_TTL environment variable. For example, setting the value to 24h
would delete reports after 24 hours. When a VulnerabilityReport gets deleted Starboard Operator will automatically
rescan the underlying workload. Assuming that the vulnerability scanner has updated its vulnerability database,
new VulnerabilityReports will contain the latest vulnerabilities.
Infrastructure Scanning¶
The operator discovers also Kubernetes nodes and runs CIS Kubernetes Benchmark checks on each of them. The results are stored as CISKubeBenchReport objects. In other words, for a cluster with 3 nodes the operator will eventually create 3 benchmark reports:
kubectl get node
Result
NAME STATUS ROLES AGE VERSION
kind-control-plane Ready master 3h27m v1.18.8
kind-worker Ready <none> 3h26m v1.18.8
kind-worker2 Ready <none> 3h26m v1.18.8
kubectl get ciskubebenchreports -o wide
Result
NAME SCANNER AGE FAIL WARN INFO PASS
kind-control-plane kube-bench 8s 12 40 0 70
kind-worker kube-bench 9s 2 27 0 18
kind-worker2 kube-bench 9s 2 27 0 18
Notice that each CISKubeBenchReport is named after a node and is controlled by that node to inherit its life cycle:
kubectl tree node kind-control-plane -A
Result
NAMESPACE NAME READY REASON AGE
Node/kind-control-plane True KubeletReady 48m
├─CISKubeBenchReport/kind-control-plane - 44m
├─CSINode/kind-control-plane - 48m
kube-node-lease ├─Lease/kind-control-plane - 48m
kube-system ├─Pod/etcd-kind-control-plane True 48m
kube-system ├─Pod/kube-apiserver-kind-control-plane True 48m
kube-system ├─Pod/kube-controller-manager-kind-control-plane True 48m
kube-system └─Pod/kube-scheduler-kind-control-plane True 48m
What's Next?¶
- Find out how the operator scans workloads that use container images from Private Registries.
- By default, the operator uses Trivy as Vulnerability Scanner and Polaris as Configuration Checker, but you can choose other tools that are integrated with Starboard or even implement you own plugins.