Monitor Cluster Components - Kubernetes

 Let us deploy metrics-server to monitor the PODs and Nodes. Pull the git repository for the deployment files. https://github.com/kodekloudhub/kubernetes-metrics-server.git

-master $ git clone https://github.com/kodekloudhub/kubernetes-metrics-server.git

Cloning into 'kubernetes-metrics-server'...

remote: Enumerating objects: 3, done.

remote: Counting objects: 100% (3/3), done.

remote: Compressing objects: 100% (3/3), done.

remote: Total 15 (delta 0), reused 0 (delta 0), pack-reused 12

Unpacking objects: 100% (15/15), done.

master $

master $

master $ ls -ltr

total 8

drwxr-xr-x 4 root root 4096 Jul  8 08:30 go

drwxr-xr-x 3 root root 4096 Sep 25 02:36 kubernetes-metrics-server

Deploy the metrics-server by creating all the components downloaded. Run the 'kubectl create -f .' command from within the downloaded repository.

master $ cd kubernetes-metrics-server/

master $ ls -ltr

total 32

-rw-r--r-- 1 root root 612 Sep 25 02:36 resource-reader.yaml

-rw-r--r-- 1 root root 219 Sep 25 02:36 README.md

-rw-r--r-- 1 root root 249 Sep 25 02:36 metrics-server-service.yaml

-rw-r--r-- 1 root root 976 Sep 25 02:36 metrics-server-deployment.yaml

-rw-r--r-- 1 root root 298 Sep 25 02:36 metrics-apiservice.yaml

-rw-r--r-- 1 root root 329 Sep 25 02:36 auth-reader.yaml

-rw-r--r-- 1 root root 308 Sep 25 02:36 auth-delegator.yaml

-rw-r--r-- 1 root root 384 Sep 25 02:36 aggregated-metrics-reader.yaml

master $ kubectl create -f resource-reader.yaml

clusterrole.rbac.authorization.k8s.io/system:metrics-server created

clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server created

master $ kubectl create -f metrics-server-service.yaml

service/metrics-server created

master $ kubectl create -f metrics-server-deployment.yaml

serviceaccount/metrics-server created

deployment.apps/metrics-server created

master $ kubectl create -f metrics-apiservice.yaml

apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io created

master $ kubectl create -f auth-reader.yaml

rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created

master $ kubectl create -f auth-delegator.yaml

clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created

master $ kubectl create -f aggregated-metrics-reader.yaml

clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created

Instead of going over each individual and executing kubectl create -f <filename>, kubectl create -f  . within the directory works as well !

It takes a few minutes for the metrics server to start gathering data.

Run the 'kubectl top node' command and wait for a valid output.

master $ kubectl top node

NAME     CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%

master   109m         5%     938Mi           49%

node01   2000m        100%   563Mi           14%

Identify the node that consumes the most CPU.

--  From the above command itself, the answer is node01.

Identify the node that consumes the most Memory.

-- From the above command, (kubectl top node), the answer is master.

Identify the POD that consumes the most Memory.

master $ kubectl top pod

NAME       CPU(cores)   MEMORY(bytes)

elephant   13m          50Mi

lion       956m         1Mi

rabbit     976m         1Mi

--- The answer is elephant

Identify the POD that consumes the most CPU.

--The answer is rabbit