Monitoring-logs-checking

Monitoring cluster:
---Heapster---
Its is a cluster wide aggregator for monitoring and event data.
Heapster run as pod inside the cluster.
Heapster pod discover all the nodes in the cluster & query usage information from node kubelet & kubelete fetches data from cAdvisor,
then the data sent to storage backend for visulization process, in that we can use influxdb using grafana.

kubelet/cAdvisor on the node---> Heapster runs on single node with Kubelet/Cadvisor(communicates with master)---->storage Backend(stores data from Heapster)

cAdvisor is an container resource usage and performance analysis agent.

The Default dashboard of Kubernete contains an example dashboard that monitors resorces usage of cluster and the pods inside of it,the dashboard can be fully customized and expanded.


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How to check logs in Kubernetes

kubectl logs <pod-name>

you can go inside the kubernetes path.

cd /var/log/containers
@master:/var/log/containers# ls
calico-kube-controllers-74b4db5cc9-m4lgr_kube-system_calico-kube-controllers-27d29e7442634c2dc9f22ee7c.log
calico-kube-controllers-74b4db5cc9-m4lgr_kube-system_calico798ef0389adf0bd96b05b82d78da472d8c53b89310.log
calico-node-mc2pq_kube-system_calico-node-624de0ee1ad23ce81df5d70b1564d7bfa60deaa71295d61adf7b.log
calico-node-mc2pq_kube-system_calico-node-d369038cfe0431004319d05cfb97a8f780b2fb1501cd5d15c3ffb0c7436.log
calico-node-mc2pq_kube-system_install-cni-370e3f176c57d80be556a8ea420b429b62fc0503160a5917e6d2d1df.log
calico-node-mc2pq_kube-system_upgrade-ipam-d8ec593b91744b47058652049f01c8a637a5ecbe0683b0204663f947b.log
coredns-5c98db65d4-grz2m_kube-system_coredns-364beee14f9c371b5bef848f187aa7e8de493bb123a9fe7ae130ff4e42.log


tail -f calico-kube-controllers-74b4db5cc9-m4lgr_kube-system_calico-kube-controllers-20ee7c.log