bash java thread dump for all pods in a kubernetes deployment

tdump-pods

#!/bin/bash

# get java thread dump report for each pod in a deployment

if [ "$#" -ne 2 ]; then
  echo "Usage: $0 DEPLOYMENT_NAME CONTAINER_NAME"
  exit 1
fi

DEPLOYMENT_NAME="$1"
CONTAINER_NAME="$2"

# Get list of pods
pods=$(kubectl get pods -l app=$DEPLOYMENT_NAME -o jsonpath="{.items[*].metadata.name}")

for pod in $pods; do
    echo "Capturing thread dump for pod: $pod"

    # Start capturing logs in the background and filter for the thread dump
    (
      stdbuf -oL kubectl logs -f --tail 1 $pod $CONTAINER_NAME | 
      awk '/Full thread dump OpenJDK/{flag=1}/^Heap/{heap=1}/^$/{if(heap) exit}flag' > "${pod}.tdump"
    ) &

    # Get the PID of the Java process
    JAVA_PID=$(kubectl exec $pod -- ps -ef | grep java | grep -v grep | grep -v "sh -c java" | awk '{print $2}')
    
    # Check if JAVA_PID was successfully retrieved
    if [ -z "$JAVA_PID" ]; then
        echo "Error: Could not identify Java PID for pod $pod. Ensure Java is running in the container."
        exit 1
    fi

    echo "Identified Java PID as: $JAVA_PID"

    # Execute a kill -3 to generate a thread dump
    kubectl exec $pod -- kill -3 $JAVA_PID

    # Wait a bit for the thread dump to be captured
    sleep 2

done

echo "Completed capturing thread dumps for pods in deployment: $DEPLOYMENT_NAME"