System Stuff

6

Quickly deploy elasticsearch with docker

Posted on by jlim0930

UPDATE: there is a new version that was released in March 2022 and you can read about it here I needed a way to quickly stand up various versions of elasticsearch for testing. Sometimes just 1 instance was needed and at other time a small cluster and configure it with TLS and security settings. I spent way too much time installing and reinstalling the software on my vm and knew that this will not work well for me. So I set out to look for a light weight, portable, fast, re-produce-able solution that I can quickly stand up and delete… Continue Reading →

1

kafka – stand up a test instance with SSL for testing

Posted on by jlim0930

I had a need to stand up a Kafka instance with SSL to test SSL handshakes. Today was the first time looking at Kafka so needless to say I was a bit lost. 🙁 Started out looking up various projects and found some interesting things that enabled me to setup a instance of kafka using docker containers with SSL. Requirements: git, docker, docker-compose installed on your server. Clone wurstmeister/kafka repo Get confluent’s kafka-generate-ssl.sh script, run it and follow all the instructions. Please make sure to remember the passphrase and the truststore/keystore passwords. This will generate the following Create “certs” directory… Continue Reading →

0

wildcard certificates

Posted on by jlim0930

How to create wildcard certificate the right way to use for home so that you wouldn’t get the not trusted thingy for your site. Use my script on https://github.com/jlim0930/scripts/blob/master/wildcard.sh to generate the CA,CA key, & the certificate. Use the certificate to encrypt your devices and sites like synology,esxi,others and import the CA into your computer so that it will verify the cert! enjoy!

2

Kubernetes 101 & 102

Posted on by jlim0930

Lets dive into kubernetes(will refer to it as k8s from here on out). What is k8s? according to wikipedia: Kubernetes (commonly stylized as k8s) is an open-source container-orchestration system for automating application deployment, scaling, and management. It was originally designed by Google and is now maintained by the Cloud Native Computing Foundation. It aims to provide a “platform for automating deployment, scaling, and operations of application containers across clusters of hosts”. It works with a range of container tools, including Docker. Many cloud services offer a Kubernetes-based platform or infrastructure as a service (PaaS or IaaS) on which Kubernetes can… Continue Reading →

0

grub2 tips and tricks – CentOS/RHEL based

Posted on by jlim0930

grub2 is vastly different from grub. Will post some tips and tricks.. list the current kernels on the OS # egrep ^menuentry /etc/grub2.cfg | cut -f 2 -d \’ Linux Server, with Linux 3.10.0-123.el7.x86_64 Linux Server, with Linux 3.10.0-123.4.4.el7.x86_64 Linux Server, with Linux 0-rescue-d3e0313c0f6d48a0bb72495d2x32r1 if your wanting to change the defautl kernel that the system boots into grub2-set-default # where the # is the line number starting with 0 if your just wanting to boot into a version of kernel just 1 time you can do grub2-reboot # where the # is the line number starting with 0 or if… Continue Reading →

1

RHEL/Centos 6.x software raid LIVE! both LVM and standard partitions with grub

Posted on by jlim0930

It seems that there are still many machines out in the world today that have a need for software raid to protect its data. Recently I’ve been working on some POS machines which can house 2 drives but does not have any type of raid option for protection. This post will walk through creating a software raid1 and also talk about even changing partition sizes and also deal with those systems that have LVM instead of standard partitions. (I am a big fan of LVM and use it as much as possible even on small drives.) This post is a… Continue Reading →

2

RHEL/CentOS7 create custom cdrom

Posted on by jlim0930

Once in a while you will need to install a system thats not on the network and instead of manually installing it you want it automated with a kickstart file. For most hosts you can create a floppy image with the kickstart file and mount it however on most Dell servers due to the way it handles the device names it can be tricky and this is where a custom cdrom can help. – download the dvd iso – mount the iso.. mkdir dvd; mount -o loop rhel-server-7.2-dvd.iso ./dvd – create a temp directory and copy over the files.. mkdir… Continue Reading →

0

use fail2ban to block wordpress login attempts

Posted on by jlim0930

Today while monitoring traffic on my server I noticed that there was 1 IP from UK that is keep accessing my server and generating noticeable amount of traffic. I did a quick IP lookup and netstat to find that the IP was accessing port 80 on my server. I then went to the httpd logs and searched for the IP and wala! it is trying to log into my wordpress site attempt after attempt. Since I already have fail2ban running on my server I decided to look into using fail2ban to ban lots of failed attempts looking at my logs… Continue Reading →

0

Linux cleanup before turning images into templates for virtual environments

Posted on by jlim0930

After the OS is installed and prepped there are some cleanup steps needed before turning it into a template. Remove old kernels Remove yum cache Clean out log files Remove device persistencies Clean up MAC and UUID Clean up history and keys I made a sample script that will automate the process. Instead of hosting the script here I’ve moved it to my github.

0

all things subscription-manager

Posted on by jlim0930

Register and auto subscribe in one step # subscription-manger register –username –password –auth-attach Register first then attach a subscription in the customer portal # subscription-manger register Attach a subscription from any available that match the system # subscription-manager attach –auth Register with a specific pool # subscription-manager attach –pool= Get pool id # subscription-manager list –available –all Check your enabled subscriptions # subscription-manger list Status of consumed subscriptions # subscription-manager list -consumed Unregister system # subscription-manager remove –all # subscription-manager unregister # subscription-manager clean list all provided repos # subscription-manager repos –list enable/disable repos # subscription-manager repos –enable or –disalbe