Tracing Tutorial with Jaeger
On the prepared cluster we will deploy Kyverno with tracing enabled and a couple of policies.
Finally we will exercise the Kyverno webhooks by creating a Pod, then we will use Jaeger to find and examine the corresponding trace.
Please note that this walkthrough uses kind to create a local cluster with a specific label on the control plane node. This is necessary as we are using an ingress-nginx deployment specifically crafted to work with kind. All other components setup should not be kind specific but may require different configuration depending on the target cluster.
In this first step we are going to create a local cluster using kind.
The created cluster will have two nodes, one master node and one worker node.
Note that the master node maps host ports
443 to the container node.
If those ports are already in use they can be changed by editing the
hostPort stanza in the config manifest below.
To create the local cluster, run the following command:
1kind create cluster --config - <<EOF 2kind: Cluster 3apiVersion: kind.x-k8s.io/v1alpha4 4nodes: 5 - role: control-plane 6 kubeadmConfigPatches: 7 - |- 8 kind: InitConfiguration 9 nodeRegistration: 10 kubeletExtraArgs: 11 node-labels: "ingress-ready=true" 12 extraPortMappings: 13 - containerPort: 80 14 hostPort: 80 15 protocol: TCP 16 - containerPort: 443 17 hostPort: 443 18 protocol: TCP 19 - role: worker 20EOF
Ingress NGINX Setup
In order to access Grafana from our browser, we need to deploy an ingress controller.
We are going to install ingress-nginx with the following command:
1kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/main/deploy/static/provider/kind/deploy.yaml 2sleep 15 3kubectl wait --namespace ingress-nginx --for=condition=ready pod --selector=app.kubernetes.io/component=controller --timeout=90s
Jaeger will allow us to store, search and visualise traces.
Jaeger is made of multiple components and is capable of using multiple storage solutions like Elasticsearch or Cassandra. In this tutorial, we will deploy the all-in-one version of Jaeger and storage will be done in memory.
We can deploy Jaeger using Helm with the following command:
1helm install jaeger --namespace monitoring --create-namespace --wait \ 2 --repo https://jaegertracing.github.io/helm-charts jaeger \ 3 --values - <<EOF 4storage: 5 type: none 6provisionDataStore: 7 cassandra: false 8agent: 9 enabled: false 10collector: 11 enabled: false 12query: 13 enabled: false 14allInOne: 15 enabled: true 16 ingress: 17 enabled: true 18 hosts: 19 - localhost 20EOF
At this point, the Jaeger UI should be available at http://localhost.
We now need to install Kyverno with tracing enabled and pointing to our Jaeger collector.
We can deploy Kyverno using Helm with the following command:
1helm install kyverno --namespace kyverno --create-namespace --wait \ 2 --repo https://kyverno.github.io/kyverno kyverno \ 3 --values - <<EOF 4admissionController: 5 tracing: 6 # enable tracing 7 enabled: true 8 # jaeger backend url 9 address: jaeger-collector.monitoring 10 # jaeger backend port for opentelemetry traces 11 port: 4317 12 13backgroundController: 14 tracing: 15 # enable tracing 16 enabled: true 17 # jaeger backend url 18 address: jaeger-collector.monitoring 19 # jaeger backend port for opentelemetry traces 20 port: 4317 21 22cleanupController: 23 tracing: 24 # enable tracing 25 enabled: true 26 # jaeger backend url 27 address: jaeger-collector.monitoring 28 # jaeger backend port for opentelemetry traces 29 port: 4317 30 31reportsController: 32 tracing: 33 # enable tracing 34 enabled: true 35 # jaeger backend url 36 address: jaeger-collector.monitoring 37 # jaeger backend port for opentelemetry traces 38 port: 4317 39EOF
Kyverno policies Setup
Finally we need to deploy some policies in the cluster so that Kyverno can configure admission webhooks accordingly.
We are going to deploy the
kyverno-policies Helm chart (with the
Baseline profile of PSS) using the following command:
1helm install kyverno-policies --namespace kyverno --create-namespace --wait \ 2 --repo https://kyverno.github.io/kyverno kyverno-policies \ 3 --values - <<EOF 4validationFailureAction: Enforce 5EOF
Note that we are setting
Audit-mode policies are processed asynchronously and will produce a separate trace from the main one (both traces are linked together though, but not with a parent/child relationship).
Create a Pod and observe the corresponding trace
With everything in place we can exercise the Kyverno admission webhooks by creating a Pod and locating the corresponding trace in Jaeger.
Run the following command to create a Pod:
1kubectl run nginx --image=nginx
After that, navigate to the Jaeger UI and search for traces with the following criteria:
kyverno, every trace defines a service name and all traces coming from Kyverno will use the
ADMISSION POST /validate/fail, every span defines a span name and root spans created by Kyverno when receiving an admission request have their name computed from the http operation and path (
ADMISSION <HTTP OPERATION> <HTTP PATH>. The
/validate/failpath indicates that it’s a validating webhook that was configured to fail the admission request in case of error. Fail mode is the default).
The list should show the trace for the previous Pod creation request:
Clicking on the trace will take you to the trace details, showing all spans covered by the Pod admission request:
The trace shows individual spans of all the policies that were just installed, with child spans for every rule that was checked (but not necessarily evaluated). The sum of all spans equals the trace time or the entire time Kyverno spent processing the Pod admission request.