concept Node object in category kubernetes
This is an excerpt from Manning's book Kubernetes in Action, Second Edition MEAP V05.
Figure 4.5 Cluster nodes are represented by Node objects
Node objects are slightly different from other objects because they are usually created by the Kubelet - the node agent running on the cluster node - rather than by users. When you add a machine to the cluster, the Kubelet registers the node by creating a Node object that represents the host. Users can then edit (some of) the fields in the Spec section.
Understanding the kubectl describe output for a Node object
Let’s try running the kubectl describe command on a Node object. To keep things interesting, let’s now take one of the worker nodes instead of the master. The following listing shows what the kubectl describe command displays for one of my two worker nodes.
Listing 4.6 Inspecting a Node object with kubectl describe $ kubectl describe node kind-worker-2 Name: kind-worker2 Roles: <none> Labels: beta.kubernetes.io/arch=amd64 beta.kubernetes.io/os=linux kubernetes.io/arch=amd64 kubernetes.io/hostname=kind-worker2 kubernetes.io/os=linux Annotations: kubeadm.alpha.kubernetes.io/cri-socket: /run/contain... node.alpha.kubernetes.io/ttl: 0 volumes.kubernetes.io/controller-managed-attach-deta... CreationTimestamp: Sun, 03 May 2020 17:09:48 +0200 Taints: <none> Unschedulable: false Lease: HolderIdentity: kind-worker2 AcquireTime: <unset> RenewTime: Sun, 17 May 2020 16:15:03 +0200 Conditions: Type Status ... Reason Message ---- ------ --- ------ ------- MemoryPressure False ... KubeletHasSufficientMemory ... DiskPressure False ... KubeletHasNoDiskPressure ... PIDPressure False ... KubeletHasSufficientPID ... Ready True ... KubeletReady ... Addresses: InternalIP: 172.18.0.4 Hostname: kind-worker2 Capacity: cpu: 8 ephemeral-storage: 401520944Ki hugepages-1Gi: 0 hugepages-2Mi: 0 memory: 32720824Ki pods: 110 Allocatable: ... System Info: ... PodCIDR: 10.244.1.0/24 PodCIDRs: 10.244.1.0/24 Non-terminated Pods: (2 in total) Namespace Name CPU Requests CPU Limits ... AGE --------- ---- ------------ ---------- ... --- kube-system kindnet-4xmjh 100m (1%) 100m (1%) ... 13d kube-system kube-proxy-dgkfm 0 (0%) 0 (0%) ... 13d Allocated resources: (Total limits may be over 100 percent, i.e., overcommitted.) Resource Requests Limits -------- -------- ------ cpu 100m (1%) 100m (1%) memory 50Mi (0%) 50Mi (0%) ephemeral-storage 0 (0%) 0 (0%) hugepages-1Gi 0 (0%) 0 (0%) hugepages-2Mi 0 (0%) 0 (0%) Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Starting 3m50s kubelet, kind-worker2 ... Normal NodeAllocatableEnforced 3m50s kubelet, kind-worker2 ... Normal NodeHasSufficientMemory 3m50s kubelet, kind-worker2 ... Normal NodeHasNoDiskPressure 3m50s kubelet, kind-worker2 ... Normal NodeHasSufficientPID 3m50s kubelet, kind-worker2 ... Normal Starting 3m49s kube-proxy, kind-worker2 ...