Centos7-RHEL9

Development

To make life super easy for the first cut of something

Disable firewall

service firewalld stop
systemctl disable firewalld

Disable SELinux

 /etc/selinux/config
 SELINUX=enforcing  --> permissive
 Reboot

Interfaces

 vi /etc/sysconfig/network-scripts/ifcfg-eth0

VM interfaces

VMWare interfaces are created in the following order

• ens192
• ens224
• ens256
• ens161

Static Routes

Temporary ip route add 172.16.5.0/24 via 10.0.0.101 dev eth0 ip route delete 192.168.0.0/16 dev ens256 scope link metric 1005

/etc/sysconfig/network-scripts/route-eth0

 172.16.5.0/24 via 10.0.0.101 dev eth0

Remember to bounce the interface after

ifdown eth0
ifup eth0

Dummy Interface

$ cat /etc/modules-load.d/dummy.conf
# Load dummy.ko at boot
dummy
$ cat /etc/modprobe.d/dummy.conf 
install dummy /sbin/modprobe --ignore-install dummy; /sbin/ip link set name ethdummy1 dev dummy0
$ cat /etc/sysconfig/network-scripts/ifcfg-ethdummy1
NAME=ethdummy1
DEVICE=ethdummy1
MACADDR=00:22:22:ff:ff:ff
IPADDR=10.10.10.1
NETMASK=255.255.255.0
ONBOOT=yes
TYPE=Ethernet
NM_CONTROLLED=no

Screen

Terminal multiplexer. https://linuxize.com/post/how-to-use-linux-screen/

Start a 'window' screen or to give the session a name screen -S 'hello_world' To exit exit [enter] To detach from the session ctrl + a , d)

Show windows/terminals screen -ls Re-attach screen -r [number or sesssion_name]

Scrollback start with -h [numlines] to access - use copy mode ctrl-A, Esacpe , [then up/down], Escape to return.

Locale Problems

This is an issue with Mobaxterm/WSL/Ubuntu not centos which sets the locale as C.UTF-8, but here is a work around - add the following to your .bashrc file (seriously, there is something wrong with mobaxterm and this was the only fix (read: crude workaround)

export LANGUAGE=en_US.UTF-8
export LANG=en_US.UTF-8
export LC_ALL=en_US.UTF-8
export LC_CTYPE=en_US.UTF-8

Appears mobaxterm is built from cygwin sources which defaults to C.UTF-8 (which is an extended char set of en_US.UTF-8) - however some centos boxes do not know about the C variant so complain.

Normal fix (that Mobaxterm seems to ignore and set to C.UTF.8)

sudo locale-gen en_US.UTF-8
sudo update-locale LANG=en_US.UTF-8

Packages

Remember to stop the service first :)

 systemctl stop httpd

Add a specific package version

Show what versions are available

 yum list httpd --showduplicates
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.xnet.co.nz
 * centos-sclo-rh: mirror.xnet.co.nz
 * centos-sclo-sclo: mirror.xnet.co.nz
 * epel: mirror.xnet.co.nz
 * extras: mirror.xnet.co.nz
 * remi-php73: mirrors.mediatemple.net
 * remi-safe: mirrors.mediatemple.net
 * updates: mirror.xnet.co.nz
Available Packages
httpd.x86_64                                                                              2.4.6-90.el7.centos                                                                               base
httpd.x86_64                                                                              2.4.41-4.codeit.el7          

To install a particular one

sudo yum install httpd-2.4.6-90.el7.centos