DevOps Real Time Troubleshooting’s

1. Issue: Jenkins Master Fails to Start

o Resolution: Check Jenkins logs (/var/log/jenkins/jenkins.log). Look for any error messages indicating startup failures. Common issues include port conflicts, insufficient permissions, or corrupted configurations. Resolve these issues and restart Jenkins.

2. Issue: Out of Memory Error

o Resolution: Increase the Java heap space allocated to Jenkins. Edit the Jenkins startup script or configuration file to set the JAVA_ARGS parameter with a higher heap size, e.g., -Xmx2g. Monitor system resources to ensure sufficient RAM is available.

3. Issue: Plugin Compatibility

o Resolution: Check Jenkins plugin versions for compatibility with the Jenkins master version. Outdated or incompatible plugins can cause crashes. Update plugins to versions compatible with your Jenkins master.

4. Issue: Disk Space Exhaustion

o Resolution: Inspect disk space on the server hosting Jenkins. Jenkins may crash if it runs out of disk space. Clean up unnecessary files, logs, and artifacts. Consider expanding the disk space if needed.

5. Issue: Corrupted Configuration Files

o Resolution: Review Jenkins configuration files, such as config.xml. Manually inspect or restore from a backup if corruption is detected. Ensure proper syntax and configuration settings.

6. Issue: Database Connection Problems

o Resolution: If Jenkins uses an external database, verify the database connection settings in Jenkins configurations. Check the database server for issues. Repair or reconfigure the database connection settings in Jenkins if necessary.

7. Issue: Java Compatibility

o Resolution: Ensure Jenkins is using a supported version of Java. Check the Java version compatibility with the Jenkins version. Update Java if needed and restart Jenkins.

8. Issue: Permission Problems

o Resolution: Verify that the Jenkins process has the necessary permissions to access its home directory and required resources. Ensure proper ownership and permissions for Jenkins files and directories.

9. Issue: Overloaded Jenkins Master

o Resolution: Analyze Jenkins load and resource usage. If the Jenkins master is overloaded with jobs, consider distributing the workload by using Jenkins agents. Scale your Jenkins infrastructure horizontally if needed.

Roles and Responsibilities for Kubernetes Cluster Management:

1. Cluster Administrator:

o Responsible for overall cluster health and performance.

o Manages node resources and ensures proper scaling.

o Implements security policies and access controls.

2. Deployment Engineer:

o Handles application deployment on Kubernetes clusters.

o Ensures proper configuration of pods, services, and other resources.

o Monitors and troubleshoots application issues.

3. Security Specialist:

o Implements and monitors security measures for the cluster.

o Manages network policies, RBAC (Role-Based Access Control), and secrets.

o Conducts regular security audits.

4. Monitoring and Logging Expert:

o Implements monitoring tools to track cluster performance.

o Configures logging for cluster and application components.

o Analyzes logs and metrics to identify issues.

5. Networking Specialist:

o Manages cluster networking, including services, ingress, and egress.

o Resolves network-related issues and ensures proper communication between pods.

o Configures and maintains network policies.

6. Storage Administrator:

o Handles storage configuration for persistent data in Kubernetes.

o Manages storage classes, persistent volumes, and persistent volume claims.

o Ensures data persistence and availability.

7. Backup and Recovery Specialist:

o Implements backup strategies for critical data and configurations.

o Designs and tests recovery procedures in case of data loss or cluster failure.

o Monitors backup health and performs periodic recovery drills.

8. Upgradation and Patching Coordinator:

o Plans and executes Kubernetes version upgrades.

o Ensures timely application of security patches.

o Tests upgrades in a controlled environment before production.

9. Capacity Planner:

o Monitors resource utilization and forecasts capacity requirements.

o Plans for scaling operations based on usage patterns.

o Optimizes resource allocation for cost efficiency.

10. Compliance Manager:

o Ensures cluster compliance with organizational and regulatory policies.

o Conducts audits to verify adherence to security and operational standards.

o Implements corrective actions for any compliance violations.

Real-Time Troubleshooting for Kubernetes Cluster

1. Issue: Pod CrashLoopBackOff

o Resolution: Check pod logs for error messages, review pod configuration, and fix any misconfigurations. Verify resource constraints and adjust accordingly.

2. Issue: Network Communication Failure Between Pods

o Resolution: Examine network policies, check for firewall rules, and ensure correct service and pod configurations. Use tools like traceroute to identify network issues.

3. Issue: Node Resource Exhaustion

o Resolution: Monitor node resources using tools like Prometheus. Scale nodes or adjust resource requests/limits for pods. Identify and optimize resource-hungry applications.

4. Issue: Unauthorized Access

o Resolution: Review RBAC settings, ensure proper user roles, and update access controls. Implement network policies to restrict unauthorized access.

5. Issue: Persistent Volume Mount Failures

o Resolution: Check persistent volume and persistent volume claim configurations. Verify storage class availability, fix storage backend issues, and ensure correct access modes.

6. Issue: Ingress Misconfiguration

o Resolution: Validate Ingress YAML, check backend service configurations, and ensure DNS resolution. Use kubectl describe to inspect Ingress objects for errors.

7. Issue: Slow Application Performance

o Resolution: Analyze application and cluster metrics using tools like Grafana. Optimize application code, adjust resource limits, and scale if necessary.

8. Issue: Node Not Ready

o Resolution: Investigate node status using kubectl get nodes. Check system logs for any issues. Resolve networking problems, disk space issues, or other system-level problems.

9. Issue: Image Pull Errors

o Resolution: Verify image availability, check registry credentials, and ensure correct image names in pod specifications. Troubleshoot network connectivity to the image registry.

10. Issue: Cluster-wide Outage

o Resolution: Examine system-wide issues such as etcd failures, control plane problems, or network partitioning. Use tools like kubectl get events and logs to identify root causes. Implement disaster recovery procedures if needed.

AWS Real Time Troubleshooting’s

1. EC2: Instance Unreachable

o Symptoms: Unable to connect to an EC2 instance.

o Resolution: Check security group rules and Network ACLs to ensure correct inbound and outbound traffic. Verify the instance state and system logs for any issues. Update security groups if necessary.

2. Auto Scaling: Scaling Issues

o Symptoms: Auto Scaling fails to launch or terminate instances.

o Resolution: Review Auto Scaling group configuration, launch configurations, and health checks. Check instance termination protection settings. Investigate CloudWatch alarms for triggers and adjust policies accordingly.

3. Load Balancer: Unhealthy Instances

o Symptoms: Load balancer reports instances as unhealthy.

o Resolution: Inspect CloudWatch metrics for instances, troubleshoot application health checks, and ensure instances are registered with the correct load balancer. Check security group settings and troubleshoot application health.

4. Route 53: DNS Resolution Issues

o Symptoms: Domain not resolving or pointing to the wrong IP address.

o Resolution: Verify Route 53 records for accuracy. Check DNS propagation and TTL settings. Confirm the health of associated resources (e.g., Load Balancer, EC2 instances). Investigate any issues reported in Route 53 health checks.

5. CloudWatch: Alarm Triggering Incorrectly

o Symptoms: CloudWatch alarms triggering when they shouldn’t or not triggering when expected.

o Resolution: Review alarm configurations, thresholds, and evaluation periods. Check associated metrics for accuracy. Verify the underlying issue causing the alarm condition.

6. SSL: Certificate Expiry

o Symptoms: SSL certificate expired or causing browser warnings.

o Resolution: Renew or replace the SSL certificate. Update the certificate in the associated AWS services (e.g., Load Balancer, CloudFront). Monitor certificate expiry using AWS Certificate Manager (ACM) or other tools.

7. Cloud Front: Content Not Updating

o Symptoms: Changes in the origin not reflected in CloudFront distribution.

o Resolution: Invalidate CloudFront cache for updated content. Check CloudFront distribution settings, origin configurations, and TTL settings. Ensure that the origin is serving the latest content.

8. Elastic Cache: Cache Node Issues

o Symptoms: High latency or cache node failures in Elastic Cache.

o Resolution: Monitor CloudWatch metrics for Elastic Cache. Investigate and resolve issues such as memory pressure, evictions, or network problems. Consider scaling the cache cluster if needed.

9. RDS: Database Performance Degradation

o Symptoms: Slow queries or high database latency.

o Resolution: Analyze CloudWatch metrics for RDS. Optimize database queries, adjust instance size, or consider scaling read replicas. Monitor storage capacity and perform database maintenance tasks.

10. IAM User: Access Denied

o Symptoms: IAM user unable to perform expected actions.

o Resolution: Review IAM user policies and roles. Ensure the user has the necessary permissions for the intended actions. Check for any explicit "Deny" policies that might override "Allow" policies.

11. Deployment: Application Rollback

o Symptoms: Deployment of an application version introduces issues.

o Resolution: Implement a rollback mechanism in your deployment strategy. Investigate logs and metrics to identify the problematic version. Rollback to the previous stable version and analyze the root cause of the issue before attempting a re-deployment.

12. CloudFormation: Stack Creation Failure

o Symptoms: CloudFormation stack creation fails.

o Resolution: Check CloudFormation events and logs for error messages. Validate the template syntax. Review IAM roles and permissions. Identify and resolve resource dependencies. Use AWS CloudFormation StackSets for multiple accounts/regions.