See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1 . Create a NetworkPolicy Resource: Define a 'NetworkPolicy' resource using a YAML file. The
'NetworkPolicy' resource will contain the rules for network traffic access to the pods. You can use 'kubectl create -f networkpolicy.yaml' to create the NetworkPolicy resource.

2. Set 'podSelectoo: Use the podSelector' field to identify the pods that will be affected by the policy. In this example, we are targeting pods with the label 'app: sensitive-app'. 3. Define 'ingress' and 'egress' Rules: Use the 'ingress' and 'egress' sections to define the rules for incoming and outgoing traffic. 'ingress': This section specifies which pods or services are allowed to send traffic to the pods targeted by the 'NetworkPolicy'. Here, we are allowing traffic from pods labeled app: trusted-service'. 'egress': This section specifies which destinations the pods targeted by the NetworkPolicy are allowed to send traffic to. In this example, we are allowing egress traffic to the IP address range 10.0.0.0/16. 4. Implement the "NetworkPolicy': Apply the YAML file using 'kubectl apply -f networkpolicy.yaml'. Once applied, the NetworkPolicy will be enforced, blocking any traffic that does not meet the specified rules.

See the solution below.
Explanation
solution

SOLUTION:
[student@node-1] > ssh ek8s
kubectl cordon k8s-master
kubectl drain k8s-master --delete-local-data --ignore-daemonsets --force apt-get install kubeadm=1.20.1-00 kubelet=1.20.1-00 kubectl=1.20.1-00 --disableexcludes=kubernetes kubeadm upgrade apply 1.20.1 --etcd-upgrade=false systemctl daemon-reload systemctl restart kubelet kubectl uncordon k8s-master

See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Use a Database with High Availability:
- Select a database system that supports high availability, such as MySQL with Galera or PostgreSQL with Patroni. These database systems can replicate data across multiple nodes, providing fault tolerance and scalability.
2. Deploy the Database as a StatefulSet:
- Create a StatefulSet for your database deployment, ensuring that each pod is assigned a unique name and volume claim. This will ensure that the database data is preserved even if pods are restarted or deleted.
3. Implement Persistent Volumes and Claims:
- Define PersistentVolumeClaims (PVCs) for each database node, requesting a storage class that provides the desired performance and resilience.
- Create corresponding PersistentVolumes (PVs) to back these PVCs, ensuring sufficient capacity and appropriate access modes.
4. Configure Microservice Pods to Access the Database:
- Configure each microservice pod to access the database using the StatefulSet's service name or a dedicated database service.
5. Utilize a Service Mesh:
- Consider deploying a service mesh like Istio to manage communication between microservices and the database. A service mesh provides features like load balancing, service discovery, and security, simplifying communication management.
6. Implement Monitoring and Alerting:
- Monitor the health and performance of both the database and microservices to quickly detect and resolve any issues. Configure alerts to notify you of critical events or failures.
7. Scale the Database as Needed:
- Use horizontal pod autoscaling (HPA) to automatically scale the database deployment based on its load. This ensures that the database can handle increasing traffic.

Solution:
#network.yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: allow-port-from-namespace
namespace: internal
spec:
podSelector:
matchLabels: {
}
policyTypes:
- Ingress
ingress:
- from:
- podSelector: {
}
ports:
- protocol: TCP
port: 8080
#spec.podSelector namespace pod
kubectl create -f network.yaml