Karthik Prasad kprasad99

How to take Thread Dump for Java Application in Kubernetes.

Get the container id of the pod.

$ kubectl get po <pod-id>  -o=jsonpath='{.status.containerStatuses[0].containerID}{"\n"}' | awk '{print substr($0, 10, 12);}'

Note	In my case there is only one container, if there are mulitple container, you can use selectors.

The Docker Compose binary cam be downloaded from the Compose repository release page on GitHub.

Install following dependency packages

$ sudo apt update && sudo apt install -y py-pip python-dev libffi-dev openssl-dev gcc libc-dev make

Download zookeeper distribution

wget http://apachemirror.wuchna.com/zookeeper/zookeeper-3.4.14/zookeeper-3.4.14.tar.gz

To list Installed plugins

.Linux

code --list-extensions | xargs -L 1 echo code --install-extension

.Windows (PowerShell, e. g. using VSCode's integrated Terminal):

A step by step description of bringing up kubernetes cluster using VirtualBox 6.0 with ubuntu 18.04 server.

Create two VMs k8s-master and k8s-s1 as shown in below diagram.

Below are the steps to install docker in ubuntu 18.04

$ sudo apt update ; sudo apt upgrade

	# reference https://stackoverflow.com/questions/53669151/java-11-application-as-lightweight-docker-image

	FROM alpine:latest as builder

	RUN apk --no-cache add openjdk11-jdk openjdk11-jmods

	ENV JAVA_MINIMAL="/opt/java-minimal"

	# build minimal JRE
	RUN /usr/lib/jvm/java-11-openjdk/bin/jlink \

	version: '3.7'

	services:
	zoo1:
	image: zookeeper:3.4.14
	restart: always
	hostname: zoo1
	volumes:
	- "/opt/docker-volumes/zoo1/data:/data"
	- "/opt/docker-volumes/zoo1/datalog:/datalog"

	apiVersion: kubeadm.k8s.io/v1beta2
	bootstrapTokens:
	- groups:
	- system:bootstrappers:kubeadm:default-node-token
	token: abcdef.0123456789abcdef
	ttl: 24h0m0s
	usages:
	- signing
	- authentication
	kind: InitConfiguration

	# Sample ``local.conf`` for user-configurable variables in ``stack.sh``

	# NOTE: Copy this file to the root DevStack directory for it to work properly.

	# ``local.conf`` is a user-maintained settings file that is sourced from ``stackrc``.
	# This gives it the ability to override any variables set in ``stackrc``.
	# Also, most of the settings in ``stack.sh`` are written to only be set if no
	# value has already been set; this lets ``local.conf`` effectively override the
	# default values.