Linux on Logan's Nest

WireGuard Setup

Fri, 14 Mar 2025 00:00:00 +0000

I spent some time figuring out how WireGuard works and found the guidelines, including the official ones, to be rather complex. So, I’m jotting down my learnings here.

If you can’t be bothered with all the key and config files, https://www.wireguardconfig.com/ provides one click setup for that with QR code.

Extract TLD from string by bash

Fri, 25 Jun 2021 00:00:00 +0000

Faced this interesting use case when I need to extract TLD from the provided hostname string.

Realised simply slicing two bits from the last won’t cut when the hostname comes with mixed .com and .co.uk

Amazon SES with Postfix in Ubuntu

Fri, 15 May 2020 00:00:00 +0000

Was looking at https://docs.aws.amazon.com/ses/latest/DeveloperGuide/postfix.html but it’s not really working as it’s missing some key commands.

Install packages apt install -y postfix libsasl2-modules\ select ’no configuration'

Config files

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cp /usr/share/postfix/main.cf.debian /etc/postfix/main.cf

in /etc/postfix/main.cf

Lets Encrypt nginx SSL certificate renewal via cron

Wed, 18 Nov 2015 00:00:00 +0000

Add below as a cron entry.

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#!/bin/bash
/path/letsencrypt/letsencrypt-auto --server https://acme-v01.api.letsencrypt.org/directory --renew-by-default -a webroot --webroot-path /webroot/ --email youremail --text --agree-tos --agree-dev-preview -d 7979.us -d www.7979.us auth
/etc/init.d/nginx reload

Then configure nginx SSL like below.

rpmlib(FileDigests) / rpmlib(PayloadIsXz) is needed

Wed, 06 May 2015 00:00:00 +0000

This means you are attemping to install a RPM created in CentOS6+ from CentOS5.

For backward compatibility, rebuild rpm like: rpmrebuild -e -p xyz.rpm

Then add below: %define _binary_filedigest_algorithm 1 %define _binary_payload w9.gzdio

gnu parallel

Wed, 29 Apr 2015 00:00:00 +0000

So I was testing this today and this is the message I saw when I ran it:

`Academic tradition requires you to cite works you base your article on. When using programs that use GNU Parallel to process data for publication please cite:

Disable msi with minimal interruption

Mon, 14 Oct 2013 00:00:00 +0000

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ifconfig eth0 down
rmmod bnx2
modprobe bnx2 disable_msi=1
ifconfig eth0 up
route add -net default netmask 0.0.0.0 gw [default gw here] eth0

For bonding interface:

3TB partition support in Linux

Tue, 31 Jul 2012 00:00:00 +0000

Make a GPT partition:

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parted /dev/sda
mklabel gpt
unit TB
mkpart primary 0 -0
quit

Format with 1% root reservation:

mkfs.ext4 -m1 /dev/sda1

Note: HP Array controller may require firmware update for 3TB disk support.

How to increase VM disk size without re-deploy the machine

Fri, 13 Jul 2012 00:00:00 +0000

Ref: http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&docType=kc&docTypeID=DT_KB_1_1&externalId=1006371

[root@demo ~]# fdisk /dev/sda

-Create a primary partition-

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[root@demo ~]# fdisk -l

Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 64 1306 9972736 8e Linux LVM
/dev/sda3 1306 6527 41942367+ 83 Linux

[root@demo ~]# pvcreate /dev/sda3
[root@demo ~]# vgextend vg_demo /dev/sda3

[root@demo ~]# vgdisplay vg_demo | grep Free
Free PE / Size 10239 / 40.00 GiB

[root@demo ~]# lvextend -L+40.00G /dev/vg_demo/lv_root

[root@demo ~]# resize2fs /dev/vg_demo/lv_root

Note: I wouldn’t do this for any production system as it looks pretty inefficient way to extend volume size.

Fix Hadoop leap second bug without rebooting

Tue, 03 Jul 2012 00:00:00 +0000

Source: http://blog.wpkg.org/2012/07/01/java-leap-second-bug-30-june-1-july-2012-fix/

Applied our hadoop node having CPU usage issue. (CentOS)

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service ntpd stop
date `date +”%m%d%H%M%C%y.%S”`
service ntpd start

Works like a charm!

Facebook scribe with hdfs

Fri, 17 Feb 2012 00:00:00 +0000

packages:
libevent
hadoop-0.20-libhdfs
JDK for hdfs support

Boost
http://sourceforge.net/projects/boost/
./bootstrap.sh
./bjam
./bjam install

thrift
download form http://thrift.apache.org/download/
./configure
make
make install

fb303
it’s in /contrib/fb303

./bootstrap.sh
./configure CPPFLAGS="-DHAVE_INTTYPES_H -DHAVE_NETINET_IN_H"
(To avoid compile error, recompile thrift with this option if it doesn’t work)
make
make install