This is a fake kubelet. that can simulate any number of nodes and maintain pods on those nodes. It is useful for test control plane.
What's the difference with Kind
Kind is run Kubernetes in Docker that is a real cluster.
fake-kubelet is simulation an nodes of Kubernetes.
There is a fake-k8s here, that can start a cluster using the fake-kubelet simulation nodes.
It can be used as an alternative to Kind in some scenarios where you don’t need to actually run the Pod.
What's the difference with Kubemark
Kubemark is directly implemented with the code of kubelet, replacing the runtime part, except that it does not actually start the container, other behaviors are exactly the same as kubelet, mainly used for Kubernetes own e2e test, simulating a large number of nodes and pods will occupy the same memory as the real scene.
fake-kubelet that only does the minimum work of maintaining nodes and pods, and is very suitable for simulating a large number of nodes and pods for pressure testing on the control plane.
Deploying the fake-kubelet.
kubectl apply -f https://raw.githubusercontent.com/wzshiming/fake-kubelet/master/deploy.yamlkubectl get node You will find an fake nodes.
> kubectl get node -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
fake-0 Ready agent 10s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>
fake-1 Ready agent 10s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>
fake-2 Ready agent 10s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>
fake-3 Ready agent 10s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>
fake-4 Ready agent 10s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>Deploying an application.
> kubectl apply -f - <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
name: fake-pod
namespace: default
spec:
replicas: 10
selector:
matchLabels:
app: fake-pod
template:
metadata:
labels:
app: fake-pod
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: type
operator: In
values:
- fake-kubelet
tolerations: # A taints was added to an automatically created Node. You can remove taints of Node or add this tolerations
- key: "fake-kubelet/provider"
operator: "Exists"
effect: "NoSchedule"
# nodeName: fake-0 # Or direct scheduling to a fake node
containers:
- name: fake-pod
image: fake
EOFkubectl get pod You will find that it has been started, although the image does not exist.
> kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
fake-pod-78884479b7-52qcx 1/1 Running 0 6s 10.0.0.23 fake-4 <none> <none>
fake-pod-78884479b7-bd6nk 1/1 Running 0 6s 10.0.0.13 fake-2 <none> <none>
fake-pod-78884479b7-dqjtn 1/1 Running 0 6s 10.0.0.15 fake-2 <none> <none>
fake-pod-78884479b7-h2fv6 1/1 Running 0 6s 10.0.0.31 fake-0 <none> <none>
fake-pod-78884479b7-hc9kd 1/1 Running 0 6s 10.0.0.29 fake-4 <none> <none>
fake-pod-78884479b7-m4rb8 1/1 Running 0 6s 10.0.0.19 fake-1 <none> <none>
fake-pod-78884479b7-p9zmn 1/1 Running 0 6s 10.0.0.27 fake-0 <none> <none>
fake-pod-78884479b7-pmgmf 1/1 Running 0 6s 10.0.0.21 fake-0 <none> <none>
fake-pod-78884479b7-rzbs2 1/1 Running 0 6s 10.0.0.17 fake-0 <none> <none>
fake-pod-78884479b7-scsjb 1/1 Running 0 6s 10.0.0.25 fake-1 <none> <none>By adding the specified Annotation, the status of Pods can be modified independently.
Modify a container of pod as unready, and you will see the pod is 0/1 of ready.
> kubectl annotate pod fake-pod-78884479b7-52qcx --overwrite fake=custom
pod/fake-pod-78884479b7-52qcx annotated
> kubectl edit pod fake-pod-78884479b7-52qcx --subresource=status
> kubectl get pod fake-pod-78884479b7-52qcx -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
fake-pod-78884479b7-52qcx 0/1 Running 0 6s 10.0.0.23 fake-4 <none> <none>Create a custom node, that content can be fully customized.
using Kubectl to modify node status must be added --subresource=status.
> kubectl apply -f - <<EOF
apiVersion: v1
kind: Node
metadata:
annotations:
node.alpha.kubernetes.io/ttl: "0"
labels:
app: fake-kubelet
beta.kubernetes.io/arch: arm64
beta.kubernetes.io/os: linux
kubernetes.io/arch: arm64
kubernetes.io/hostname: fake-arm-0
kubernetes.io/os: linux
kubernetes.io/role: agent
node-role.kubernetes.io/agent: ""
type: fake-kubelet # Matches to fake-kubelet's environment variable TAKE_OVER_LABELS_SELECTOR, this node will be taken over by fake-kubelet
name: fake-arm-0
spec:
taints: # Avoid scheduling actual running pods to fake Node
- effect: NoSchedule
key: fake-kubelet/provider
value: fake
status:
allocatable:
cpu: 32
memory: 256Gi
pods: 110
capacity:
cpu: 32
memory: 256Gi
pods: 110
nodeInfo:
architecture: arm64
bootID: ""
containerRuntimeVersion: ""
kernelVersion: ""
kubeProxyVersion: fake
kubeletVersion: fake
machineID: ""
operatingSystem: linux
osImage: ""
systemUUID: ""
phase: Running
EOFkubectl get node You will find the newly created fake-arm-0 node, and that it is ready.
> kubectl get node -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
fake-0 Ready agent 12s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>
fake-1 Ready agent 12s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>
fake-2 Ready agent 12s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>
fake-3 Ready agent 12s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>
fake-4 Ready agent 12s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>
fake-arm-0 Ready agent 2s fake 10.88.0.136 <none> <unknown> <unknown> <unknown>Licensed under the MIT License. See LICENSE for the full license text.