How-to Guides on Advanced Beginner

Pod Troubleshooting

d8lzz1gpw@mozmail.com (kimbenji) — Fri, 16 Jan 2026 00:00:00 +0000

Objective: Identify and resolve issues when Pods fail to start or terminate abnormally Estimated Time: 30 minutes

Scope of This Guide
Covers: Pod startup failures, CrashLoopBackOff, ImagePullBackOff, Readiness failures

Does not cover: Network connectivity issues (see Network Troubleshooting), performance degradation due to resource constraints (see Resource Optimization)

Before You Begin#

Verify the following prerequisites.

1. Verify kubectl Installation and Version#

kubectl version --client

Success output:

Client Version: v1.28.0

Version Compatibility
kubectl version must be within ±1 minor version of cluster version. Example: Cluster 1.27 → kubectl 1.26~1.28 supported

2. Verify Cluster Access#

kubectl cluster-info

Success output:

Resource Optimization

d8lzz1gpw@mozmail.com (kimbenji) — Fri, 16 Jan 2026 00:00:00 +0000

Objective: Find appropriate CPU/memory settings to improve resource efficiency Estimated Time: 45 minutes

Scope of This Guide
Covers: Measuring resource usage, determining appropriate requests/limits values, resolving throttling/OOM

Does not cover: Auto-scaling (see Scaling), Pod startup issues (see Pod Troubleshooting)

Before You Begin#

Verify the following prerequisites.

1. Verify kubectl Installation and Version#

kubectl version --client

Success output:

Client Version: v1.28.0

2. Verify Metrics Server Installation#

kubectl top nodes

Success output:

NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
node-1 250m 12% 1024Mi 50%

If you get an error, install Metrics Server.

Network Troubleshooting

d8lzz1gpw@mozmail.com (kimbenji) — Fri, 16 Jan 2026 00:00:00 +0000

Objective: Identify and resolve issues when Service or Ingress fails to connect Estimated Time: 30 minutes

Scope of This Guide
Covers: Service connectivity issues, DNS issues, Ingress routing issues

Does not cover: Pod startup issues (see Pod Troubleshooting), external network firewall configuration

Before You Begin#

Verify the following prerequisites.

1. Verify kubectl Installation and Cluster Access#

kubectl cluster-info

Success output:

Kubernetes control plane is running at https://xxx.xxx.xxx.xxx
CoreDNS is running at https://xxx.xxx.xxx.xxx/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy

2. Verify Pod Status#

Verify the target Pods you want to connect to are in Running status.

Log Collection & Analysis

d8lzz1gpw@mozmail.com (kimbenji) — Fri, 16 Jan 2026 00:00:00 +0000

Objective: Effectively collect and analyze logs to diagnose problems Estimated Time: 25 minutes

Scope of This Guide
Covers: kubectl logs usage, multi-container logs, log filtering, stern tool

Does not cover: Central logging system (ELK, Loki) setup, long-term log retention

Before You Begin#

Verify the following prerequisites.

1. Verify kubectl Installation and Cluster Access#

kubectl cluster-info

Success output:

Kubernetes control plane is running at https://xxx.xxx.xxx.xxx

2. Verify Log Access Permissions#

kubectl auth can-i get pods/log

Success output: