Archives for November 2021

Remove Oracle Java

November 30, 2021

Here’s a script that removes Oracle Java on your system. Installs OpenJDK Hotspot as a replacement.

#!/bin/bash
# set env
oracle_jre_version="jdk1.8.0_172"
open_jre_version="java-1.8.0-openjdk"
# REMOVE LINKS
deljdk () {
	sudo update-alternatives --remove "java" "/usr/lib/jvm/$oracle_jre_version/bin/java"
	sudo update-alternatives --remove "javac" "/usr/lib/jvm/$oracle_jre_version/bin/javac"
	sudo update-alternatives --remove "javaws" "/usr/lib/jvm/$oracle_jre_version/bin/javaws"
}
# REMOVE RPM
delrpm () {
	jdk=$(rpm -qa | grep jdk-1.7)
	rpm -e $jdk
	jdk=$(rpm -qa | grep jdk1.8)
	rpm -e $jdk
	sudo rm -rf /usr/java/jdk*
}
# REMOVE SYMBOLIC LINKS
delsym () {
	rm /usr/java/default /usr/java/latest
	rm /usr/lib/mozilla/plugins/libnpjp2.so
	rm /usr/lib/mozilla/plugins/libnpjp2.so
}
# INSTALL OPENJDK
addjdk () {
	cd /usr/java
	rm -f /usr/java/OpenJDK8U-jdk_x64_linux_hotspot_8u302b08.tar.gz
	wget --no-check-certificate https://10.49.39.125/download/OpenJDK8U-jdk_x64_linux_hotspot_8u302b08.tar.gz
	tar xzf OpenJDK8U-jdk_x64_linux_hotspot_8u302b08.tar.gz
	chown -R username:username /usr/java/jdk8u302-b08
}
# ADD PATH
addpath () {
	sed -i '/jdk8u302-b08/d' /home/username/.zshrc
	sed -i '/jdk8u302-b08/d' /home/username/.profile
	echo 'export PATH=/usr/java/jdk8u302-b08/bin:$PATH' | tee -a ~/.bashrc
	echo 'export PATH=/usr/java/jdk8u302-b08/bin:$PATH' | tee -a /home/username/.zshrc
	echo 'export PATH=/usr/java/jdk8u302-b08/bin:$PATH' | tee -a /home/username/.profile
	chown username:username /home/username/.zshrc
	chown username:username /home/username/.profile
}
deljdk
delrpm
delsym
addjdk
addpath

Git Clone Multiple Accounts

November 28, 2021

How to clone repositories with multiple Github accounts.

git clone git@github.com-yourgitaccount:yourgitaccount/myrepo.git

GCP Spot Instance

November 25, 2021

You can save anywhere from 60-91% using a spot instance. The downside is, the instance can be preempted anytime.

Create a spot instance.

gcloud beta compute instances create spot-example \
--provisioning-model=SPOT \
--instance-termination-action=STOP \
--image-project=ubuntu-os-cloud \
--image-family=ubuntu-2004-lts \
--machine-type=e2-micro \
--project=your-project-id \
--zone=us-central1-a

Delete instance.

gcloud compute instances delete spot-example \
--project=your-project-id \
--zone=us-central1-a

Terraform AWS Security Group

November 15, 2021

How to create a security group in AWS via Terraform.

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
    }
  }
}
 
provider "aws" {
  profile = "default"
  region  = "us-east-1"
}
 
resource "aws_security_group" "my_sg" {
  vpc_id       = "vpc-xxxxxxxxxxxxxxxxx"
  name         = "My Security Group"
  description  = "My Security Group"
  ingress {
	from_port   = 8088
	to_port     = 8088
        protocol    = "tcp"
        cidr_blocks = ["0.0.0.0/0"]
  }
  egress {
        from_port   = 0
        to_port     = 0
        protocol    = "-1"
        cidr_blocks = ["0.0.0.0/0"]
  }
  tags = {
        Name = "My Security Group"
  }  
}

Terraform AWS S3

November 15, 2021

How to create S3 bucket via Terraform.

erraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
    }
  }
}
 
provider "aws" {
  profile = "default"
  region  = "us-east-1"
}
 
resource "aws_s3_bucket" "bucket" {
  bucket = "my-ulysses-bucket"
  acl    = "private"
 
  tags = {
    Name        = "My Ulysses bucket"
    Environment = "Dev"
  }
}
 
resource "aws_s3_bucket_public_access_block" "example" {
  bucket = aws_s3_bucket.bucket.id
  block_public_acls = true
  block_public_policy = true
  ignore_public_acls = true
  restrict_public_buckets = true
}

Wiki SSL Certificate Location

November 12, 2021

Here’s where the Wiki keeps its SSL certificate keys.

/etc/pki/tls/certs/yourdomain.crt
/etc/pki/tls/private/yourdomain.key

In some cases, SSL needs to be converted so it doesn’t prompt you for a password if you restart Apache.

Conversion

openssl rsa -in /etc/pki/tls/private/yourdomain.key.new -out /etc/pki/tls/private/yourdomain.key.new_no_pass

Github SSH Keys Setup

November 11, 2021

Here’s how to setup your SSH keys to work with Github.

Generate a key using ed25519 public-key signature system.

ssh-keygen -t ed25519

It creates a id_ed25519.pub file.

Go to Github.com and open up Settings > SSH & GPG keys.

Click New SSH key. Give a title and paste your pub key. Authorize.