Uly.me

cloud engineer

Archives for January 2019

xfs vs ext 2/3/4

When resizing disks, here are the commands for each respected file system.

For xfs:

xfs_growfs /dev/vgname/lgname

For ext 2/3/4:

resize2fs /dev/vgname/lgname

Extend LVM volume

Extending a LVM logical volume can be tricky. Extending a physical volume especially a boot drive is even more challenging. To make things simple, you can just easily add a new physical disk to your physical volume group. Here are the steps:

# add disk to your instance. 
fdisk /dev/sdh
pvcreate /dev/sdh1
vgextend system /dev/sdh1
lvextend -l +100%FREE /dev/system/opt
resize2fs /dev/system/opt

The fdisk command requires a few steps inside such as creating a new partition, changing the partition to type to “8e” which is Linux LVM, and then writing your changes to disk.

The rest are pretty much self explanatory. It’s about creating a physical volume, extending the volume group, extending the logical volume, and then finally resizing the file system.

Apps to Install on Linux Mint

I recently started using Linux Mint again. Although it contains many excellent apps, there are a few things that are missing. So, here’s a list of programs that I have installed ✅ or will be installing on Linux Mint in the near future.

  • ✅ sublime text 3
  • ✅ lastpass
  • ✅ discord
  • ✅ aws cli
  • ✅ ffmpeg
  • ✅ handbrake
  • ✅ git
  • ✅ vim
  • ✅ emacs
  • ✅ tor
  • ✅ slack
  • ✅ docker
  • virtualbox

Samba 4 Domain Controller

Starting with version 4, Samba can now run as a domain controller. It can support Windows and Linux clients. You can compile it from source or install it via package managers such as rpm, yum and apt. You can always use it as a standard shared drive and even use it as a print server.

SSL Certificates Explained

If you’re confused about the different formats and files that the Certificate Manager will accept in AWS, this site explains it fairly well. The Certificate Manager contains 3 fields during the import process. Certificate body, Certificate private key, and Certificate chain.

  • Server certificate > Intermediate certificate > Root certificate
  • Private RSA Key
  • Chain consists of Root and Intermediate

Gutenberg Youtube Embed

The Gutenberg Youtube embed lacks a few things. The alignment doesn’t seem to be working, at least in the theme I’m using. I’m using Generate-Pro, a Genesis child theme. By default, it’s left-aligned. I have to add this div to make it centered.

<div style="text-align:center">
</div>

If you want right aligned, use this div.

<div style="text-align:right">
</div>

Regex Match

Regex is really cool. You can do amazing things with it, but if you’re starting new, it’s quite daunting task. If you ever find one that works, you better hang on to it for dear life. Here’s one that I know is working. It reads data from a file, and compares and matches a variable to a certain pattern. In the example below, the variable I’m searching for, must contain a string with the following characters “server-w.” They also must be followed by at least one number or a set of numbers.

cat filename | while read LINE; do
  if [[ $LINE =~ server-w-*.[0-9] ]]; then
     echo "Do not backup $LINE"
  else
     echo "Backup $LINE"
  fi
done

If you need help with Regex, check out a couple of sites below that allows you to test your regex skills. Regex and RegExr.