Linux – Klim Server Blog

Replace defective HDD on CentOS 6 (mbr)

Prologue: sda old but works, sdc defective. I will replace sdc.

First of all, mark disk sdc as defective and remove from raid.

mdadm --manage /dev/md0 --fail /dev/sdc2
mdadm --manage /dev/md1 --fail /dev/sdc1
mdadm --manage /dev/md2 --fail /dev/sdc3
mdadm /dev/md0 -r /dev/sdc2
mdadm /dev/md1 -r /dev/sdc1
mdadm /dev/md2 -r /dev/sdc3

Physically replace disk and copy partition table to new one.

Postfix as Yandex Relay

In that quickie article we will setup Postfix as yandex relay that servers only local mail (emails for root) on AlmaLinux 8.

dnf install postfix mailx cyrus-sasl-plain

UFW for antizapret

Couple UFW rules for antizapret node

ufw default deny incoming
ufw default allow outgoing
ufw allow ssh / ufw allow from 203.0.113.4 to any port 22
ufw allow 1194
ufw route allow proto tcp from any to any port 1194
ufw route allow proto udp from any to any port 1194
ufw allow in on lxdbr0
ufw route allow in on lxdbr0

ufw enable

Nginx as CDN POP

This released on ubuntu with packages nginx and nginx-extras (some modules used additionally that not avail on Alma packages, that’s why ubuntu).

We will store cached files in /cdncache and logs in /var/log/nginx/cdnlogs.

Our CDN URL is yourcdn1.domain.name for site1.dev and yourcdn2.domain.name for site2.dev

We will server static files (mp4,jpg,png,gif,jpeg,js,ico,html,htm,webp,css,mp3,wav,swf,mov,doc,pdf,xls,ppt,docx,pptx,xlsx,ttf,woff,woff2), accept only GET queries and disallow listing for /.

Upgrading all packages on OpenWRT

More difficult than on Centos, yeah? 🙂

opkg list-upgradable | cut -f 1 -d ' ' | xargs opkg upgrade

Ivacy VPN strongswan settings for android (and may be iOS)

Hey. I just tried to find out how to setup Ivacy on my android phone but not with OpenVPN or stock Ivacy app.

As we now strongswan app is more battery-friendly. So we should use strongswan. You hear? Use strongswan if its possible.

But googling not give me anything. I asked support and receive half of truth. But figure out the rest by myself. So lets go.

How to install guacamole 1.0.0 on Centos 7 box

Hey. Guacamole – really good app that allow you to connect to PC in your net via RDP/SSH/Telnet/VNC. Lets install it.

yum install cairo-devel libjpeg-devel libpng-devel uuid-devel freerdp-devel pango-devel libssh2-devel libssh-dev tomcat libvncserver-devel libtelnet-devel tomcat-admin-webapps tomcat-webapps gcc terminus-fonts

You can’t upgrade from Centos6 to Centos7

Via redhat-upgrade-tool ?

A lot of articles. And a lot of comments that tool is broken. 🙁

RAMDISK: incomplete write, kernel panic on centos

Today from early morning I was called by my colleague who said that his centos6 box can’t boot after reboot. After grub screen centos show that error:

RAMDISK: incomplete write (6257 != 32768)
write error
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
Pid: 1, comm: swapper not tainted %kernel_ver% #1
Call trace:

Let fix that.

Upgrading MariaDB on Centos7

Hey. I’m already has mariadb installed but it was 5.x version. Today actual version 10.3.x. Lets upgrade!

yum remove mariadb-server mariadb-libs