Running your first simulation #
Once you've gone through the steps to install SimKube in your environment, you're ready to run your first simulation!
Step 1: Collect a trace #
Use the skctl CLI tool to collect a trace from your production cluster (where you're running sk-tracer):
> kubectl port-forward -n simkube pod/sk-tracer-depl-6d559b799-ln8gk 7777:7777
> skctl export -o s3://your-simkube-bucket/path/to/trace
Alternately, if you don't have sk-tracer running anywhere, you can generate a "point-in-time" snapshot of your
production cluster with the following command:
> skctl snapshot -c config.yml
The config file referenced should be in the same format as expected by sk-tracer. Here's a basic one you can use:
# config.yml
trackedObjects:
apps/v1.Deployment:
podSpecTemplatePath: /spec/template
Step 2: Create some virtual nodes #
SimKube is going to create a bunch of fake pods during the simulation run, and it will need someplace to schedule them. We're going to create a virtual node, managed by KWOK, for this.
# node.yml
apiVersion: v1
kind: Node
metadata:
annotations:
kwok.x-k8s.io/node: fake
labels:
node.kubernetes.io/instance-type: c5d.9xlarge
topology.kubernetes.io/zone: us-west-1a
type: virtual
name: fake-node-1
spec:
taints:
- effect: NoSchedule
key: kwok-provider
value: "true"
status:
allocatable:
cpu: 35
ephemeral-storage: 900Gi
memory: 71Gi
pods: 110
capacity:
cpu: 36
ephemeral-storage: 900Gi
memory: 72Gi
pods: 110
> kubectl apply -f node.yml
Now, you should see your node appear in the list of cluster nodes, posting a "Ready" status:
> kubectl get nodes
NAME STATUS ROLES AGE VERSION
fake-node-1 Ready <none> 82s kwok-v0.5.1
simkube-control-plane Ready control-plane 12m v1.27.3
simkube-worker Ready <none> 12m v1.27.3
Step 3: Run your simulation! #
> skctl run my-first-simulation --trace-path s3://your-simkube-bucket/path/to/trace +5m
running simulation my-first-simulation
You should see that the simulation object has been created:
> kubectl get simulation my-first-simulation
NAME START TIME END TIME STATE
testing Initializing
During the "Initializing" phase, sk-ctrl is setting up a temporary high-resolution Prometheus pod to scrape data from
the simulation, as well as configuring other needed components. After 30-50 seconds, you should see the simulation
transition to "Running":
> kubectl get simulation my-first-simulation
NAME START TIME END TIME STATE
testing 2024-03-01T04:58:48Z Running
Once your simulation is over, it should move into the "Finished" state:
> kubectl get simulation my-first-simulation
NAME START TIME END TIME STATE
testing 2024-03-01T04:58:48Z 2024-03-01T04:59:06Z Finished
Congratulations! You did it! Read on to learn more about how you can do some more advanced things in your simulated environment.