CentOS 7 on Hyper-V 2016

CentOS 7 minimal installs happily on Windows Server Hyper-V 2016. Do not forget to run
nmcli
nmtui

to active network connection, as by default it is not active.

Linux Integration Services 3.5

Linux Integration Services 3.5 Announcement http://blogs.technet.com/b/virtualization/archive/2014/01/02/linux-integration-services-3-5-announcement.aspx

dd-wrt NAT with several subnets behind

If you have a complex lab at home and you would like to setup dd-wrt routing do not forget to enable nat for all subnets, as by default dd-wrt will only take care of the one directly connected.
Here is example of my script that adds 10.10.10.0 subnet to the internet nat, script also contains openvpn related commands:
iptables -I INPUT 1 -p udp --dport 1194 -j ACCEPT
iptables -I FORWARD 1 --source 192.168.66.0/24 -j ACCEPT
iptables -I FORWARD -i br0 -o tun0 -j ACCEPT
iptables -I FORWARD -i tun0 -o br0 -j ACCEPT
iptables -t nat -I POSTROUTING -o `get_wanface` --source 10.10.10.0/24 -j SNAT --to `nvram get wan_ipaddr`

CentOS cluster

Detailed video walkthrough of creation of  a cluster on CentOS (RedHat) nodes

http://youtu.be/FP2_MxXGibY

note that you can not use cluster fencing on hyper-v guests, so for your lab use KVM or VMWare or Xen - read more at https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/High_Availability_Add-On_Overview/s1-virt-guestcluster.html.

CentOS switching to Oracle Linux

According to Oracle by switching from CentOS to Oracle Linux you shorten delays on RHEL sources recompilation which sometimes can be vital in critical enterprise environments. Oracle Linux claims 100% compatibility with CentOS. Another advantage is that Enterprise customers can optionally buy a support from Oracle. Otherwise it is as free as CentOS.

to switch use command:

curl -O https://linux.oracle.com/switch/centos2ol.sh 
sh centos2ol.sh

break out from PRISM

Diificult to walk away from NSA surveillance, but possible:

http://prism-break.org/

As usual the answer is in the domain of open source.

CentOS 6.4 comes with native support for Hyper-V

CentOS 6.4 comes with Linux integration Services build-in.
"Microsoft Hyper-V drivers have been added to allow CentOS to be more efficient as a Virtual Machine when installed on Microsoft Hyper-V server."
http://wiki.centos.org/Manuals/ReleaseNotes/CentOS6.4
Bravo. Will FreeBSD 9.x follow?

The linux kernel 2.6.32 has the hyper-v support and other distributions such as Ubuntu should also be compatible.

A book for all NGINX fans

http://www.packtpub.com/mastering-nginx-guide-for-novice-and-advanced-user/book

for those who is not familiar with NGINX, think about Apache that 10 times faster!

NGINX is growing....

Nginx overtakes Microsoft as No. 2 Web server after Apache:
http://www.infoworld.com/t/application-servers/nginx-overtakes-microsoft-no-2-web-server-183079?utm_source=twitterfeed&utm_medium=twitter

CentOS 5 time zone issue

It is a second time that I'm having issue with timezone. Even if all settings are ok it shows wrong timezone.

The siolution is

yum reinstall tzdata

CentOS 5 life cycle

CentOS 5 (RHEL5) will be safe to use until 2017: refer to upstream life cycle info: https://access.redhat.com/support/policy/updates/errata/

VDI broker

Trying out free VDI broker

CentOS 6 eth0

Before you install new CentOS please review FAQ and do not forget:

"at install time where, after the installer asks for your language and keyboard and Basic or other storage devices, it runs "Examining Devices" then it presents a screen "Please name this computer..." On this screen is a button labeled "Configure Networking". Clicking that button will launch NetworkManager. Select the Ethernet connection which is probably listed as "System eth0" and edit the settings. If you select the check box by "Connect Automatically" networking will start on boot in the future."

Otherwise there will be no network unless you disable Netowkr Manager in the config...

CentOS kernet update under hyper-v

Microsoft Hyper-v integration tool conflicts with CentOS kernel upgrade. Please refer here for a workaround. Unfortunaltely to be repeated everytime you update kernel.

Arpwatch ethercodes update on EasyIDS (CentOS5)

You can update old arpwatch ethrcode.dat file from debian; download source from http://packages.ubuntu.com/maverick/i386/arpwatch/download

Extract ethercodes.dat with 7zip and place in /var/arpwatch

Now as example it will recognise Iphones...

EasyIDS date is wrong

I found that EasyIDS (CentOS 5.5) shows a wrong local date/time - 2 hours difference.

I was able to correct it by

ln -sf /usr/share/zoneinfo/Europe/Zurich localtime

command.

Gigabit

Spent few moments trying to figure out why server's giga NIC sets to 100MB only... Twicked cisco switch port, restarted interface few times, even tried different distro - ubuntu instead of centos - result zero! Finally went and changed a patch cable - surprise-surpise: 1GB! IT is used to blame OS or driver, but HW is equally important...

Linux from USB

A reminder - there is a great tool UNETBOOTIN that allows to create USB bootable for many distros - Ubuntu, Suse, FreeBSD, etc.

Partition manager

Try Gparted LiveCD, it's working perfectly! Just now I resized partition on HP DL360G4 server. The sequence:

1) download ISO image and burn on CDRW
2) Map CD remotely to a server using Virtual Media ILO feature
3) Reboot, GParted recognized all HW without any problem (!).
4) Resize, chkdsk, enjoy!