RHEL7 post-installation

this is obsolete doc -- see http://doc.nethence.com/ instead

http://pbraun.nethence.com/unix/sysutils_linux/redhat.html

http://pbraun.nethence.com/unix/sysutils_linux/redhat-networking.html

http://pbraun.nethence.com/unix/sysutils_linux/redhat_rhel6.html

http://pbraun.nethence.com/unix/sysutils_linux/redhat_rhel7.html

http://pbraun.nethence.com/unix/sysutils_linux/systemd.html

Getting access remotely

Get a temporary IP just to login remotely,

ifconfig -a

ip addr

ip link

dhclient ens192

Network setup

Choice 1) with freaking NetworkManager

nmtui

TYPE=Ethernet

NAME=eno16780032

DEVICE=eno16780032

BOOTPROTO=static

IPADDR=x.x.x.x

NETMASK=255.255.x.x

GATEWAY=x.x.x.x

DEFROUTE=yes

ONBOOT=yes

DNS1=x.x.x.x

DNS2=x.x.x.x

DOMAIN=domain.tld

Choice 2) without NetworkManager

Stop and disable the freaking NetworkManager and switch back to classic networking,

systemctl stop NetworkManager

systemctl disable NetworkManager

chkconfig --list | grep network

#chkconfig network on

Refs.

https://dingyichen.wordpress.com/2014/08/06/fedora-and-rhel-configure-static-ip-and-disable-networkmanager/

https://ask.fedoraproject.org/en/question/9585/disable-network-manager-and-use-the-simple-network-service/

Configure the network,

vi /etc/hosts

10.0.0.X     short short.fqdn long long.fqdn

vi /etc/sysconfig/network

GATEWAY=10.0.0.X

vi /etc/sysconfig/network-scripts/ifcfg-ens192

DEVICE=ens192

BOOTPROTO=static

IPADDR=10.0.0.X

NETMASK=255.255.X.X

ONBOOT=yes

vi /etc/resolv.conf

domain example.local

#search example.local

nameserver DNS_IP_1

nameserver DNS_IP_2

3) common network setup in both situations

Configure the hostname,

vi /etc/hostname

#nmcli general hostname host.example.net

#systemctl status systemd-hostnamed

#systemctl restart systemd-hostnamed

service network restart

and check,

hostname --short; hostname --long

Ref. http://www.itzgeek.com/how-tos/linux/centos-how-tos/change-hostname-in-centos-7-rhel-7.html

Eventually get rid of the virbr0 interface,

virsh net-destroy default

virsh net-autostart default --disable

virsh net-undefine default

chkconfig libvirtd off #rhel5-6

systemctl disable libvirtd.service #rhel7

Ref. What is the interface virbr0 for and how do I disable it?: https://access.redhat.com/solutions/27195

Post-installation

Disable the graphical interface,

telinit 3

runlevel

note. runlevel should return 3 on the last digit

systemctl get-default

systemctl set-default multi-user.target

check with,

systemctl status multi-user.target

systemctl status graphical.target

systemctl list-unit-files | grep multi-user

systemctl list-unit-files | grep graphical.target

ls -l /etc/systemd/system/default.target

Eventually put your SSH public key in place,

cd /root/

mkdir .ssh/

vi authorized_keys

Subscribe to RHN,

subscription-manager register --username RH_USERNAME --password RH_PASSWORD --auto-attach

ref. How to register and subscribe a system to the Red Hat Customer Portal using Red Hat Subscription-Manager. https://access.redhat.com/solutions/253273

or point to a repo,

cd /etc/yum.repos.d/

mkdir .trash/

mv * .trash/

cat > srvinstall.repo <<EOF

[rhel7]

name=srvinstall install server

baseurl=http://srvinstall/RHEL7/

enabled=1

gpgcheck=1

gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release

EOF

and install vmware tools if it's a VM,

yum install open-vm-tools

Ref. http://partnerweb.vmware.com/GOSIG/CentOS_7.html

If it is a VM, check that vmware tools is enabled,

vmware-checkvm

systemctl list-unit-files | grep tools

systemctl status vmtoolsd

systemctl enable vmtoolsd

systemctl start vmtoolsd

Prevent sysstat to spam your logs,

cd /etc/

mkdir cron.trash/

mv cron.d/sysstat cron.trash/

Note. alternatively,

cp /etc/systemd/system.conf /etc/systemd/system.conf.dist

vi /etc/systemd/system.conf

#LogLevel=info

LogLevel=notice

systemctl restart rsyslog

Disable SELinux,

getenforce

setenforce 0

vi /etc/sysconfig/selinux

SELINUX=permissive

Disable the firewall,

systemctl status firewalld

systemctl stop firewalld

systemctl disable firewalld

Re-enable the firewall,

systemctl status firewalld

systemctl enable firewalld

systemctl start firewalld

vi /etc/sysconfig/selinux

System firewall -- with firewalld

Allow some port

firewall-cmd --get-active-zones

firewall-cmd --zone=public --add-port=PORT_NUM/tcp --permanent

firewall-cmd --zone=public --add-port=PORT_NUM/udp --permanent

firewall-cmd --reload

remove the port,

firewall-cmd --zone=public --remove-port=PORT_NUM/udp --permanent

firewall-cmd --reload

System firewall -- with iptables

Switch back to iptables,

yum install iptables-service

systemctp stop firewalld

systemctl disable firewalld

#systemctl mask firewalld (stronger)

systemctl start iptables

systemctl start ip6tables

systemctl enable iptables

systemctl enable ip6tables

ls -l /etc/sysconfig/iptables

#iptables-save > /etc/sysconfig/iptables

Ref. RHEL7: How to disable Firewalld and use Iptables instead.: http://www.certdepot.net/rhel7-disable-firewalld-use-iptables/

Change the system firewall rules,

cd /etc/sysconfig/

cp iptables iptables.`date +%s`

service iptables save

#iptables-save > iptables

cp iptables iptables.`date +%s`

vi iptables

apply,

iptables-restore < iptables

and check,

iptables -n -L

Miscellaneous

If you need to recover the root password, after the remount and passwd, do not forget to relabel the filesystem (SElinux),

touch /.autorelabel

Refs.

Single User Mode: Resetting/Recovering Forgotten Root User Account Password in RHEL/CentOS 7: http://www.tecmint.com/reset-forgotten-root-password-in-centos-7-rhel-7/

24.9. TERMINAL MENU EDITING DURING BOOT: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/sec-Terminal_Menu_Editing_During_Boot.html#sec-Changing_and_Resetting_the_Root_Password

The joy of SELinux relabelling.: http://danwalsh.livejournal.com/38157.html