Calico is a Kubernetes container network interface (CNI) plugin that provides pod connectivity and supports network-policy enforcement. It runs as cluster networking components, configures pod interfaces, addresses, routes, and related networking behavior as pods are created or removed. section 2.3.2 section 9.3.5
Use these checks when identifying or troubleshooting Calico-related networking:
- Inspect kube-system pods with kubectl get pods -n kube-system to identify networking components and their readiness. section 2.3.2
- Remember that the CNI determines how pods communicate across nodes and may implement network policies. section 2.3.2
- Distinguish Calico from Flannel during exam tasks: Calico supports network policies, whereas Flannel does not. section 9.3.5
- Treat CNI installation, replacement, and troubleshooting as practical administrator competencies. section 2.3.2
Verify networking components
Run kubectl get pods -n kube-system and inspect the resulting component list. A representative cluster can show calico-kube-controllers and canal pods alongside CoreDNS and other system components; use readiness and status fields to identify obvious failures. section 2.3.2
$ kubectl get pods -n kube-system NAME READY STATUS RESTARTS AGE calico-kube-controllers-fdf5f5495-7lzbl 1/1 Running 2 (43m ago) 9d canal-vmgsc 2/2 Running 2 (43m ago) 9d canal-xntjt 2/2 Running 2 (43m ago) 9d coredns-7695687499-27bvx 1/1 Running 1 (43m ago) 9d coredns-7695687499-wfcnf 1/1 Running 1 (43m ago) 9d etcd-controlplane 1/1 Running 3 (43m ago) 9d kube-apiserver-controlplane 1/1 Running 2 (43m ago) 9d kube-controller-manager-controlplane 1/1 Running 2 (43m ago) 9d kube-proxy-nhwwx 1/1 Running 1 (43m ago) 9d kube-proxy-nlw5b 1/1 Running 2 (43m ago) 9d kube-scheduler-controlplane 1/1 Running 2 (43m ago) 9d
Inspect the representative kube-system listing to practice recognizing Calico-related pods and checking their READY, STATUS, RESTARTS, and AGE fields. section 2.3.2
