Monday, 21 September 2015

CentOS 7

Having started an install for CentOS 7, this is my first time working with the Red Hat Enterprise Linux 7 based system and they've done a few things I'll have to learn.

Goodbye, Sys V init! What an era there's been with init scripts. The newer "systemd" system and service manager replaces the init system along with RedHat's chkconfig and similar tools. The "systemctl" command is kindof similar to "chkconfig", but takes the command name first and the new style service name second:


# systemctl status nfs-server.service

Overview of systemd for RHEL 7
https://access.redhat.com/articles/754933

The other is the new "firewalld" which provides more of set of front-ends to iptables. The command-line tool, firewalld-cmd, can generate the settings changes like to open ports. As the RedHat docs say, this mechanism can load firewall rule changes instead of dumping the whole rule set so you keep open connections and stats.

# firewall-cmd --zone=public --add-port=80/tcp --permanent
# firewall-cmd --reload

Using Firewalls
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Security_Guide/sec-Using_Firewalls.html

I'm sure there's more but mostly cosmetic like how the installer works, which packages are bundled or not (like bind-utils not included in a base install? interesting). Sometimes hard to figure out what to do in a new system when there's big changes that aren't just drop-in replacements for older tools.

Ciao,
Arch

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