centos

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Google Cloud scripts

Posted on by jlim0930

At work we use google cloud as our lab to stand up and take down instances. As I work, I noticed that I usually stand up the same type of instance and run the same post install all the time so instead of doing this manually I decided to create a script for the compute instance and another for the kubernetes cluster. Compute Instance gcp.sh – script to automate creating and deletion of compute instance script is located: https://github.com/jlim0930/scripts/blob/master/gcp.sh edit gcp_name & gcp_project to match your environment. Also zone and region as needed – The script will stand up a… Continue Reading →

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Install and configure a database and a webserver – Migrated to a new server 2 of 4

Posted on by jlim0930

This is the second section in the 4 part series of migrating my server Install and configure the host machine Install and configure a database and webserver – we are here Install and configure a mailserver Install and configure vaultwarden Tie everything back to 1. for backups, misc, etc Dockerized services I will configure a database and a webserver(mainly wordpress container) to listen internally only and not exposed to the outside network. I will also configure a nginx-proxy and letsencrypt to provide the access from the world to the wordpress site and to generate the letsencrypt certificate. Wanted to note… Continue Reading →

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Linux basic install – Migrated to a new server 1 of 4

Posted on by jlim0930

Migrated to a new server! For the past 20 years I been running various linux server to host my websites and mail. It evolved over time and the very last server was installed about 5 years ago. I decided that a new server was in order and decided to redesign some things and now here we are. Just some personal notes on how the new server is configured and setup. You can follow my steps or make changes but if you do anything thats better or noteworthy please let me know! This will be a multi-part article so that I… Continue Reading →

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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 →

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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 →

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RHEL/Centos 7.x software raid LIVE! both LVM and standard partitions with grub2

Posted on by jlim0930

Before getting started please read my previous post for RHEL/CentOS 6.x systems here. grub2 is vastly different than grub and I did not find any good solution of doing this on a live machine so lets get started. The setup will be the same as the previous post. make sure that the 2nd disk is added and now clone the partitions. You can also create partitions manually if you like or if you want to change the sizes of the partitions. [root@cent7 ~]# cat /proc/partitions major minor #blocks name 8 0 8388608 sda 8 1 1048576 sda1 8 2 7339008… Continue Reading →

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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 →

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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 →

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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 →

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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.