ОС CentOS, список персональных граблей.

1) После установки "чистой" ОС и обновления пакетов до актуального состояния нам могут понадобиться пакеты из сторонних репозиториев, пример: htop, его в стандартных репо просто нет.
Ниже буду писать список репозиториев, принесших пользу лично мне.

Fedoraproject Epel x86_64
для версии 6, для 7 версии.
для подключения к своей системе устанавливаем RPM epel-release.

(В случае возникновения Error: Cannot retrieve metalink for repository: epel. Please verify its path and try again)

Фикс простой:

vim /etc/yum.repos.d/epel.repo

И на строке mirrorlist=https заменяем на http. 

RepoForge (ex. RPMForge)


RPMfusion.org

2) Смена timezone на работающем сервере:
 cp /usr/share/zoneinfo/Europe/moscow /etc/localtime

3)  dot1q vlan на сетевых интерфейсах (from redhat customer portal)

modprobe 8021q 

 Configure your physical interface in /etc/sysconfig/network-scripts/ifcfg-ethX, where X is a unique number corresponding to a specific interface, as follows:

DEVICE=ethX
TYPE=Ethernet
BOOTPROTO=none
ONBOOT=yes

 Configure the VLAN interface configuration in /etc/sysconfig/network-scripts. The configuration filename should be the physical interface plus a . character plus the VLAN ID number. For example, if the VLAN ID is 192, and the physical interface is eth0, then the configuration filename should be ifcfg-eth0.192:

DEVICE=ethX.192
BOOTPROTO=none
ONBOOT=yes
IPADDR=192.168.1.1
NETMASK=255.255.255.0
USERCTL=no
NETWORK=192.168.1.0
VLAN=yes

If there is a need to configure a second VLAN, with for example, VLAN ID 193, on the same interface, eth0 , add a new file with the name eth0.193 with the VLAN configuration details.
 Restart the networking service, in order for the changes to take effect, as follows:

service network restart

5) Использование Http proxy  в yum и консоли (from centos docs):

To enable all yum operations to use a proxy server, specify the proxy server details in /etc/yum.conf. The proxy setting must specify the proxy server as a complete URL, including the TCP port number. If your proxy server requires a username and password, specify these by adding proxy_username and proxy_password settings.
The settings below enable yum to use the proxy server mycache.mydomain.com, connecting to port 3128, with the username yum-user and the password qwerty.

# The proxy server - proxy server:port number
proxy=http://mycache.mydomain.com:3128
# The account details for yum connections
proxy_username=yum-user
proxy_password=qwerty

 To enable proxy access for a specific user, add the lines in the example box below to the user's shell profile. For the default bash shell, the profile is the file ~/.bash_profile. The settings below enable yum to use the proxy server mycache.mydomain.com, connecting to port 3128.

# The Web proxy server used by this account
http_proxy="http://mycache.mydomain.com:3128"
export http_proxy

6) How to install dig on CentOS

yum install bind-utils