Scaling the Deployment using kubectl

In this tutorial, you’ll learn how to scale an Azure Kubernetes Service (AKS) deployment and understand the per-node pod limit enforced by Azure CNI. We’ll cover:

Inspecting your current Deployment and Service
Scaling the Deployment to 5 replicas
Hitting the 30-pod per-node limit
Examining Namespaces and system pods

1. Inspect the current Deployment and Service

Before scaling, verify your application’s replica count and external endpoint.

# Check the Deployment replicas
kubectl get deployments
# Output example:
# NAME            READY   UP-TO-DATE   AVAILABLE   AGE
# Find the LoadBalancer’s public IP
kubectl get service
# NAME            TYPE           CLUSTER-IP      EXTERNAL-IP     PORT(S)         AGE
# kodekloudapp    LoadBalancer   10.0.199.121    20.247.251.108  80:30895/TCP    73m
# kubernetes      ClusterIP      10.0.0.1        <none>          443/TCP         124m

2. Scale to 5 replicas

Increase your Deployment to five pods:

kubectl scale deployment kodekloudapp --replicas=5
kubectl get deployment kodekloudapp
# NAME            READY   UP-TO-DATE   AVAILABLE   AGE
# kodekloudapp    5/5     5            5           76m

Validate load balancing

Open three incognito browser windows and navigate to your Service’s public IP. You should see traffic routed to different pods:

The image shows three browser windows displaying the "KodeKloudApp" homepage with a welcome message, system name, and IP address highlighted in yellow. Each window has a different system name and IP address.

3. Scale to the pod limit (30 replicas)

When you created the AKS cluster, you configured Azure CNI with a maximum of 30 pods per node. Let’s push the Deployment to that limit:

kubectl scale deployment kodekloudapp --replicas=30
kubectl get deployment kodekloudapp
# NAME            READY   UP-TO-DATE   AVAILABLE   AGE
# kodekloudapp    16/30   30           16          78m

Only 16 pods are running; the rest remain Pending:

kubectl get pods
# NAME                           READY   STATUS    RESTARTS   AGE
# kodekloudapp-677fc758c5-5k92g  0/1     Pending   0          57s
# kodekloudapp-677fc758c5-bbp84  0/1     Pending   0          57s
# ...

Filter non-running pods

List pods that aren’t in the Running phase:

kubectl get pods --field-selector=status.phase!=Running

Inspect pod scheduling events

Describe one pending pod to see why it isn’t scheduled:

kubectl describe pod kodekloudapp-677fc758c5-5k92g

In the Events section you’ll find:

Warning  FailedScheduling   2m     default-scheduler   0/1 nodes are available: 1 Too many pods.
Normal   NotTriggerScaleUp  110s   cluster-autoscaler  max node group size reached

4. Namespaces and system pods

AKS uses several namespaces to isolate workloads. System pods in kube-system count toward your per-node limit.

kubectl get namespaces
# NAME              STATUS   AGE
# default           Active   129m
# kube-node-lease   Active   129m
# kube-public       Active   129m
# kube-system       Active   129m

Namespace overview

Namespace	Purpose	Pod Count
default	User applications	16
kube-node-lease	Node heartbeat leases	0
kube-public	Public config and resources	0
kube-system	Core cluster services	12+

kubectl get pods --namespace kube-system
# NAME                                               READY   STATUS    RESTARTS   AGE
# ama-logs-rs-7f8bcb7c6f-5dlqq                       1/1     Running   0          131m
# coredns-59b6bf8b4f-lwt4c                           1/1     Running   0          131m
# metrics-server-7d74d8758-wfsdd                     2/2     Running   0          130m
# ...

Azure CNI assigns IPs from your VNet based on the --max-pods setting at cluster creation. You cannot change this limit post-creation.

Introduction

Just Enough Azure for AKS

Building and containerizing sample application

Working with AKS

Networking in AKS

AKS Security

CICD Workflow for AKS

Observability

Close out

Scaling the Deployment using kubectl

1. Inspect the current Deployment and Service

2. Scale to 5 replicas

Validate load balancing

3. Scale to the pod limit (30 replicas)

Filter non-running pods

Inspect pod scheduling events

4. Namespaces and system pods

Namespace overview

Next steps

Links and References

Watch Video

Introduction

Just Enough Azure for AKS

Building and containerizing sample application

Working with AKS

Networking in AKS

AKS Security

CICD Workflow for AKS

Observability

Close out

​1. Inspect the current Deployment and Service

​2. Scale to 5 replicas

​Validate load balancing

​3. Scale to the pod limit (30 replicas)

​Filter non-running pods

​Inspect pod scheduling events

​4. Namespaces and system pods

​Namespace overview

​Next steps

​Links and References

Watch Video

1. Inspect the current Deployment and Service

2. Scale to 5 replicas

Validate load balancing

3. Scale to the pod limit (30 replicas)

Filter non-running pods

Inspect pod scheduling events

4. Namespaces and system pods

Namespace overview

Next steps

Links and References