WorkingWithRHEL7

Getting rid of firewalld and coming back to iptables

Here are the magic commands :

systemctl stop firewalld
systemctl disable firewalld
yum remove firewalld
yum install iptables-services
systemctl enable iptables.service
systemctl enable ip6tables.service

Don't forget to configure SSH with system-config-firewall-tui. And after that :

systemctl start iptables.service
systemctl start ip6tables.service

Replacing NetworkManager by network

First, check if there is the GATEWAY parameter in the ifcfg-ethX of the NIC. (GATEWAY0 is not working without NM) Then, type these commands :

systemctl stop NetworkManager
systemctl disable NetworkManager

And now, we can restart network :

service network restart

Adoption of Predictable Network Interface Names

Names of NICs will change. To prepare yourself to the new naming rules, please read these documents :

• http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/
• http://blog.laimbock.com/2014/11/22/systemd-understanding-predictable-network-interface-names/

Default filesystem : xfs

RHEL7 adopts XFS as the default filesystem. It might generates troubles with our Quattor scdb -> check our filesystem layout templates.

Transition from SysVinit to Systemd

I find this link useful.

Here are some useful commands :

List types of unit

systemctl -t help

List units of a certain type

systemctl list-units --type=[unit_name]

List of services

systemctl list-units --type=service

Check status of services

systemctl status [service_name]

If you want something more concise info :

systemctl is-enabled [service_name]
systemctl is-active [service_name]

Stop/start/restart service

systemctl start [service_name]
systemctl stop [service_name]
systemctl restart [service_name]

Enable/disable at boot time

systemctl enable [service_name]
systemctl disable [service_name]

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