I have servers running CentOS, but all of them are on release 6. I haven’t found the reason to use 7. So today out of curiosity, I decided to try out the new CentOS 7. I read that there are quite a number of changes over CentOS 6 or rather it’s a departure from the traditional architecture we are all used to.
The init Scripts – They are now managed by systemd. Actually that feels a lot like the launchctl in OS X and systemctl in Solaris. Sidenote, my adventure with Solaris ended when Oracle killed OpenSolaris. I haven’t had the environment to put the derivatives (Illumos) to work again.
The documentation are found here – MANAGING SERVICES WITH SYSTEMD.
Managing the network – This one is an overhaul too. Looks like everything is managed by Network Manager now. The command line to configure the network is nmcli. There is a ncurses GUI for this which looks like the old system-config-network-tui. The replacement for it now is nmtui.
The next very important thing – ifconfig. Missing! The new replacement command is ip addr. There are a lot of other things that you can do with the ip command. The ip command has been around for many years. RedHat / CentOS has finally decided to make this de facto.
For firewall, iptables is now managed by firewalld. The command line to configure the firewall is firewall-cmd. There’s also a GUI available. I haven’t played with this, but it looks like RedHat is turning firewalld into a full featured firewall, most likely in the direction of Network Function Virtualisation. Personally, I do have a vision of the whole network infrastructure running virtual routers, switches, firewalls and load balancers etc.
Changing hostname now is hostnamectl set-hostname and setting timezone is timedatectl.
These are the basic things to get the server up and running. I’m preparing these servers for a setup with Foreman to manage blade servers. Stay tuned for that. :)