Log Aggregation and Streaming

Beginner5 min

Stream and aggregate logs from pods, deployments, and multiple containers using kubectl and label selectors.

Prerequisites

-kubectl configured

Steps

Stream logs from a pod

Follow log output from a specific pod in real time.

$ kubectl logs -f <pod-name>

Stream logs from all pods in a deployment

Follow logs from every pod matching a label selector.

$ kubectl logs -f -l app=myapp --all-containers --max-log-requests=10

The --max-log-requests flag limits concurrent log streams. Increase it for deployments with many replicas.

View logs from a previous container instance

See logs from a container that crashed and was restarted.

$ kubectl logs <pod-name> --previous

This is essential for debugging CrashLoopBackOff pods since the current container may not have useful output yet.

Filter logs by time range

Show logs from a specific time window.

$ kubectl logs <pod-name> --since=1h --timestamps

Full Script

full-script.sh

#!/bin/bash
# Log Aggregation and Streaming
set -euo pipefail

SELECTOR=${1:?"Usage: $0 <label-selector> [namespace]"}
NS=${2:-"default"}

echo "=== Pods matching selector: $SELECTOR ==="
kubectl get pods -n "$NS" -l "$SELECTOR" -o wide

echo ""
echo "=== Recent logs (last 50 lines per pod) ==="
kubectl logs -n "$NS" -l "$SELECTOR" --all-containers --tail=50 --timestamps

echo ""
echo "=== Streaming Commands ==="
echo "Follow all:    kubectl logs -f -n $NS -l $SELECTOR --all-containers"
echo "Since 1h:      kubectl logs -n $NS -l $SELECTOR --since=1h"
echo "Previous:      kubectl logs -n $NS <pod-name> --previous"

FAQ

Discussion

Loading comments...

#!/bin/bash # Log Aggregation and Streaming set -euo pipefail SELECTOR=${1:?"Usage: $0 <label-selector> [namespace]"} NS=${2:-"default"} echo "=== Pods matching selector: $SELECTOR ===" kubectl get pods -n "$NS" -l "$SELECTOR" -o wide echo "" echo "=== Recent logs (last 50 lines per pod) ===" kubectl logs -n "$NS" -l "$SELECTOR" --all-containers --tail=50 --timestamps echo "" echo "=== Streaming Commands ===" echo "Follow all: kubectl logs -f -n $NS -l $SELECTOR --all-containers" echo "Since 1h: kubectl logs -n $NS -l $SELECTOR --since=1h" echo "Previous: kubectl logs -n $NS <pod-name> --previous"