linux

3

ESXi on old hardware Error 10 – Out of resources failed to malloc MMIO

Posted on by jlim0930

At home I use a old Dell Precision T5600. It has 16 cores total with 128GB of memory and while old its still good for running multiple workloads via ESXi. In the 6.x days I had no issues with ESXi, however with 7.0 I now get the CPU is unsupported as well as many other warnings. However I was able to run 7.0 Update 2 build 17867351 without issues. When I first installed ESXi I used BIOS to install and to run it since it never worked with EFI and at the time I did not bother to figure out… Continue Reading →

3

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 →

2

minikube wrapper – kubernetes

Posted on by jlim0930

What is minikube? Minikube was developed to allow users to run Kubernetes LOCALLY. When you run minikube it will launch a minikube host as a container/VM depending on the driver and runs a single-node k8s cluster. Why minikube? Previously whenever I needed to test anything in the kubernetes environment I would stand up a full suite of servers 4 actually, 3 workers and 1 master node on a VM and it was very time-consuming to set up and use and also resource-intensive for my tiny home lab. I needed a way to create an environment fast and make it re-producible… 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

Colourful ! systemd vs sysVinit Linux Cheatsheet

Posted on by jlim0930

systemd is the new init system, started with Fedora and now started adopted in many distributions like redhat, suse and centos. This long period we all been using traditional SysV init scripts usually residing in /etc/rc.d/init.d/ directory. These scripts invokes daemon binary which will then forks a background process. Even though shell scripts very are flexible buts other tasks like supervising processes and parallized execution ordering will be very hard to implement. With the introduction of systemd new-style daemons which makes easier to supervise and control them at runtime and simplifies their implementation. systemctl command is a very good initiative… Continue Reading →

0

mount qcow2 with libguestfs

Posted on by jlim0930

sometimes you have multiple qcow2 files sitting around from older upgrades and OS’s that you just need to grab a file or a config from and dont want to bother with booting it up. there is a way to mount the filesystem using libguestfs which can save time! This works with LVM and non LVM qcow2 files and also even if you dont know how the qcow2 partitions are laid out you can feed it a bogus partition and it will list it for you. # guestmount -a rhel5.qcow2 -m /dev/sdzz1 /mnt libguestfs: error: mount_options: mount_options_stub: /dev/sdzz1: No such file… Continue Reading →

0

mysql changing to utf8 and converting DB to utf8

Posted on by jlim0930

by default mysql is installed as latin1 and sometimes it causes problems when your data is not always latin1. Follow the steps to change mysql to utf and also convert existing databases to UTF8 #1 backup your databases and convert it to UTF8 mysqldump -uusername -ppassword -c -e –default-character-set=utf8 –single-transaction –skip-set-charset –add-drop-database -B dbname -r dbname.utf8.dump.sql do this for each of your databases. #2 shutdown mysql service mysqld stop #3 edit /etc/my.cnf ADD to [mysqld] section # init_connect=’SET collation_connection = utf8_unicode_ci’ init_connect=’SET NAMES utf8′ character-set-server=utf8 collation-server=utf8_unicode_ci skip-character-set-client-handshake also [client] default-character-set=utf8 #4 restart mysqld service mysqld start #5 import your databases… Continue Reading →

0

wget stuff

Posted on by jlim0930

Many times when downloading via command line large files you might want to run it in the background and forget about it. you can run this is screen however its also good to use wget options. one quicky is to do wget -bqc url -b is to background as soon as starting -c is to resume broken downloads -q is to quiet wget

0

VirtualBox – how to create and share disks to setup/test clusters

Posted on by jlim0930

Once in a while you will want to setup clusters with shared disks to test and play around with various clusters. while this is easy to do in kvm/xen/etc its not so easy with virtualbox. There is a way via command line tools to create disks and attaching it so that it is shared. For me I have windows 7 64bit and I am running virtualbox 64bit 4.xxxxx. It is most likely easier if you include the path for “c:Program FilesOracleVirtualBox” however if you do not its ok. We will need to run the command VBoxManage or “c:Program FilesOracleVirtualBoxVBoxManage.exe” if… Continue Reading →

0

How to rollback YUM UPDATES

Posted on by jlim0930

Once in a while you might have problems after running “yum update.” There is an intermediate solution by rollback feature included in YUM. THIS OPTION IS NOT ENABLED BY DEFAULT. 1. To enable rollback edit /etc/yum.conf and add tsflags=repackage 2. Add the following line into /etc/rpm/macros file if it doesn’t exist and add %_repackage_all_erasures 1 now you are all set and can use the following examples to rollback rpm -Uvh –rollback ’22:00′ rpm -Uvh –rollback ‘3 hours ago’ rpm -Uvh –rollback ‘june 13’ rpm -Uvh –rollback ‘yesterday’ All previous repackaged software will be stored onto /var/spool/repackage