kubectl logs for debugging in Kubernetes - Step-by-Step Execution

Process Flow - kubectl logs for debugging

Start: Identify Pod

↓

Run kubectl logs <pod-name>

↓

Fetch logs from Pod's container

↓

Display logs in terminal

↓

Analyze logs for errors or info

↓

Decide next step: Fix issue or get more logs

↓

Use options like -c, --since, --tail

↓

End

This flow shows how to use kubectl logs command to fetch and analyze logs from a Kubernetes pod for debugging.

Execution Sample

Kubernetes

kubectl logs my-pod
kubectl logs my-pod -c my-container
kubectl logs my-pod --since=1h
kubectl logs my-pod --tail=50

These commands fetch logs from a pod, optionally specifying container, time range, or number of lines.

Process Table

Step	Command Run	Action	Result/Output
1	kubectl logs my-pod	Fetch logs from default container in pod 'my-pod'	Logs displayed in terminal from pod's default container
2	kubectl logs my-pod -c my-container	Fetch logs from container 'my-container' in pod 'my-pod'	Logs displayed for specified container
3	kubectl logs my-pod --since=1h	Fetch logs from last 1 hour	Logs from last 1 hour shown
4	kubectl logs my-pod --tail=50	Fetch last 50 lines of logs	Only last 50 log lines displayed
5	kubectl logs unknown-pod	Try fetching logs from non-existent pod	Error: pod not found
6	kubectl logs my-pod --follow	Stream logs live	Logs stream continuously until stopped
7	Exit	No more commands	End of debugging session

💡 User stops after viewing logs or encounters error like pod not found

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5	After Step 6	Final
pod-name	my-pod	my-pod	my-pod	my-pod	my-pod	unknown-pod	my-pod	my-pod
container-name	default	default	my-container	my-container	default	default	default	default
logs-output	empty	logs from default container	logs from my-container	logs last 1 hour	last 50 lines logs	error: pod not found	streaming logs	streaming logs or stopped

Key Moments - 3 Insights

Why do I get an error when running kubectl logs on a pod?

If the pod name is wrong or the pod is not running, kubectl logs shows an error. See step 5 in execution_table where 'unknown-pod' causes 'pod not found' error.

How do I get logs from a specific container in a pod with multiple containers?

Use the -c option with the container name. Step 2 shows 'kubectl logs my-pod -c my-container' fetching logs from the specified container.

How can I see only recent logs or limit the amount of logs?

Use options like --since to get logs from a time range or --tail to limit lines. Steps 3 and 4 demonstrate these options.

Visual Quiz - 3 Questions

Look at the execution_table, what output do you get when running 'kubectl logs my-pod --tail=50'?

A Logs from the last 1 hour

B Error: pod not found

C Logs from the last 50 lines

D Streaming logs continuously

💡 Hint

Check step 4 in the execution_table for the command with --tail=50

At which step does the command fail due to a non-existent pod?

A Step 5

B Step 3

C Step 2

D Step 6

💡 Hint

Look for the error message 'pod not found' in the execution_table

If you want to see logs from a specific container, which command would you use?

A kubectl logs my-pod --since=1h

B kubectl logs my-pod -c my-container

C kubectl logs my-pod --tail=50

D kubectl logs unknown-pod

💡 Hint

Refer to step 2 in the execution_table where container is specified with -c

Concept Snapshot

kubectl logs <pod-name> - Fetch logs from a pod's default container
Use -c <container-name> to specify container in multi-container pods
Options --since and --tail limit logs by time or lines
--follow streams logs live for real-time debugging
Errors occur if pod name is wrong or pod is not running

Full Transcript

This visual execution shows how to use the kubectl logs command to debug Kubernetes pods. First, identify the pod name. Then run 'kubectl logs <pod-name>' to fetch logs from the default container. Use -c to specify a container if there are multiple. Options like --since and --tail help limit logs by time or number of lines. If the pod name is incorrect, an error appears. You can also stream logs live with --follow. This step-by-step trace helps beginners see how commands fetch logs and handle errors.