Outcold Solutions LLC

Monitoring Kubernetes - Version 5

Forwarding Audit Logs

Our solution provides detailed Audit dashboards. By default, Kubernetes does not provide audit logs. You can enable them by following instructions from Kubernetes documentation Auditing .

You need to enable audit log only on Masters. For that, you need to edit definition of Kubernetes API Server. In case of clusters bootstrapped by kubeadm you can find the definition of Kubernetes API Server in file /etc/kubernetes/manifests/kube-apiserver.yaml. In other cases Kubernetes API Server Pod definition can be stored in /etc/kubernetes/manifests/apiserver.json.

Create Audit Policy file. Use our example as a reference and save the file in /etc/kubernetes/policies/audit-policy.yaml.

Another good example of the audit-policy.yaml file is an audit profile used by GCE.
apiVersion: audit.k8s.io/v1beta1
kind: Policy
rules:
  # Do not log from kube-system accounts
  - level: None
    userGroups:
    - system:serviceaccounts:kube-system
  - level: None
    users:
    - system:apiserver
    - system:kube-scheduler
    - system:volume-scheduler
    - system:kube-controller-manager
    - system:node

  # Do not log from collector
  - level: None
    users:
    - system:serviceaccount:collectorforkubernetes:collectorforkubernetes

  # Don't log nodes communications
  - level: None
    userGroups:
    - system:nodes

  # Don't log these read-only URLs.
  - level: None
    nonResourceURLs:
    - /healthz*
    - /version
    - /swagger*

  # Log configmap and secret changes in all namespaces at the metadata level.
  - level: Metadata
    resources:
    - resources: ["secrets", "configmaps"]

  # A catch-all rule to log all other requests at the request level.
  - level: Request

Configuration provided below set the policy file and tells to write logs directly to the standard output. Because Kubernetes API Server is running inside of the container, the collector forwards these logs automatically. We also need to mount audit policy file in the container that runs Kubernetes API Server. Modify /etc/kubernetes/manifests/kube-apiserver.yaml with the suggested changes.

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...
spec:
  containers:
  - command:
    - kube-apiserver
...
    - --audit-policy-file=/etc/kubernetes/policies/audit-policy.yaml
    - --audit-log-path=-
    - --audit-log-format=json
...
    volumeMounts:
    - mountPath: /etc/kubernetes/pki
      name: k8s-certs
      readOnly: true
    - mountPath: /etc/ssl/certs
      name: ca-certs
      readOnly: true
    - mountPath: /etc/kubernetes/policies
      name: policies
      readOnly: true
  hostNetwork: true
  volumes:
  - hostPath:
      path: /etc/kubernetes/pki
      type: DirectoryOrCreate
    name: k8s-certs
  - hostPath:
      path: /etc/ssl/certs
      type: DirectoryOrCreate
    name: ca-certs
  - hostPath:
      path: /etc/kubernetes/policies
      type: DirectoryOrCreate
    name: policies

To apply these changes you might need to restart kubelet.

sudo systemctl restart kubelet

Application has a macro, that defines how to find the audit logs macro_kubernetes_audit_logs.

(`macro_kubernetes_logs` OR `macro_kubernetes_host_logs`) "audit.k8s.io"

About Outcold Solutions

Outcold Solutions provides solutions for monitoring Kubernetes, OpenShift and Docker clusters in Splunk Enterprise and Splunk Cloud. We offer certified Splunk applications, which gives you insights across all containers environments. We are helping businesses reduce complexity related to logging and monitoring by providing easy-to-use and deploy solutions for Linux and Windows containers. We deliver applications, which helps developers monitor their applications and operators to keep their clusters healthy. With the power of Splunk Enterprise and Splunk Cloud, we offer one solution to help you keep all the metrics and logs in one place, allowing you to quickly address complex questions on container performance.