Node Conditions
Overview
Node Conditions - node conditions that can be used to determine whether the node is healthy and ready to accept pods. Conditions are displayed on node page and in kubectl describe node.
Healthy node states
| State | Description | Healthy Status |
|---|---|---|
| NetworkUnavailable | Cilium/CNI is not running on the node | false |
| MemoryPressure | Kubelet reports low memory | false |
| DiskPressure | Kubelet reports low disk space | false |
| PIDPressure | Too many processes (PID) on node | false |
| Ready | The node is ready to accept pods | true |
Additional conditions (Node Problem Detector)
When Node Problem Detector (NPD) is installed, additional conditions may be displayed:
| State | Description | Healthy Status |
|---|---|---|
| KernelDeadlock | Linux kernel locked | false |
| CNIProblem | CNI plugin does not work correctly | false |
| DiskPressureContainer | Not enough space for containers | false |
| KubeletUnhealthy | Problems with kubelet | false |
| CorruptDockerOverlay2 | Storage driver corruption | false |
| ReadOnlyContainer | Read-only container file system | false |
| KubeProxyUnhealthy | Problems with kube-proxy | false |
Automatic Taints under conditions
Under certain conditions, Kubernetes automatically adds Taints to the node:
| Taint | Description | Effect |
|---|---|---|
node.kubernetes.io/not-ready | Ready=False | NoExecute |
node.kubernetes.io/unreachable | Ready=Unknown | NoExecute |
node.kubernetes.io/memory-pressure | Out of memory | NoSchedule |
node.kubernetes.io/disk-pressure | Disk shortage | NoSchedule |
node.kubernetes.io/pid-pressure | PID Limit | NoSchedule |
node.kubernetes.io/network-unavailable | Network unavailable | NoSchedule |
node.kubernetes.io/unschedulable | The node is not subject to scheduling (cordon) | NoSchedule |
node.cloudprovider.kubernetes.io/uninitialized | Node with cloud provider before cloud-controller-manager initialization | NoSchedule |
Read more about built-in taints in Taints and Tolerations.
Where to watch
- GUI: Administration → Manage nodes → click on a node → “Node” tab → “Status” block.
- CLI:
kubectl describe node <name>— Conditions section.