====== Linux Hints, Top Tips, and FAQs ======

Here are some of the Linux hints and documentation that seems to be woefully lacking or just mis-leading on the greater wider Internet.

===== Setting iDRAC8 Server info =====

This applies to Dell servers of course. First off, install ''ipmitools'':

''apt-get update; apt-get install ipmitools''

To find out the options available in ''ipmitools'', run:

''ipmitools help''

and there is a manpage available too.

To set the iDRAC8 System Host Name, you want:

''ipmitools mc setsysinfo system_name HOSTNAME''

To set the iDRAC8 Operating System, you want:

''ipmitools mc setsysinfo os_name OSNAME''

To set the iDRAC8 Operating System Version, you want:

''ipmitools mc setsysinfo delloem_os_version OSVERSION''

And that's it - after that, if you refresh the iDRAC8 Server Overview screen you will see the changes you made.

===== Ubuntu LACP with Cisco Catalyst Switches =====

This will of course depend on the switch model you are using and the IOS version, but I've documented here what works in the installations I've been assisting with.

==== Ubuntu LACP Configuration ====

This example shows the ''/etc/network/interfaces'' configuration using two ethernet interfaces on a server to be combined to form a LAG, and using LACP. Here I'm using VLAN 3, 5 and 7 on the server, and they are being passed by the LAG from the switch the server is connected to. VLAN 3 is for server management access, whereas VLAN 5 and 7 are passed on to virtual machines within the server.

<code>
source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

auto eno1
iface eno1 inet manual
        bond-master bond0

auto eno2
iface eno2 inet manual
        bond-master bond0

auto bond0
iface bond0 inet manual
        bond-mode 802.3ad
        bond-miimon 100
        bond-lacp-rate 1
        bond-slaves eno1 eno2

auto bond0.3
iface bond0.3 inet manual
        vlan-raw-device bond0

auto bond0.5
iface bond0.5 inet manual
        vlan-raw-device bond0

auto bond0.7
iface bond0.7 inet manual
        vlan-raw-device bond0
        
auto br0
iface br0 inet static
        address 192.168.1.2
        netmask 255.255.255.0
        gateway 192.168.1.254
        bridge_ports bond0.3
        bridge_stp off
        bridge_fd 0

auto br1
iface br1 inet manual
        bridge_ports bond0.5
        bridge_stp off
        bridge_fd 0

auto br2
iface br2 inet manual
        bridge_ports bond0.7
        bridge_stp off
        bridge_fd 0
</code>

==== Cisco Catalyst 2950G-48 Configuration ====

Configuration snipped for a Catalyst 2950G-48 running '12.1(22)EA13'. Note that the 2950G-48 needs the ''flowcontrol send off'' command - other switches don't seem to need this.

For security reasons, I've made the native VLAN on the trunk to be 999, rather than the default VLAN of 1. I strongly recommend never to use VLAN1 for anything.

<code>
interface Port-channel2
 description Trunk
 switchport trunk native vlan 999
 switchport mode trunk
 load-interval 30
 flowcontrol send off
!
interface FastEthernet0/1
 description LAG-PORT1
 switchport trunk native vlan 999
 switchport mode trunk
 load-interval 30
 channel-group 2 mode active
!
interface FastEthernet0/2
 description LAG-PORT2
 switchport trunk native vlan 999
 switchport mode trunk
 load-interval 30
 channel-group 2 mode active
!
</code>

With this configuration, VLAN 999 is the native VLAN (frames sent untagged), and all other VLANs (including 1) are sent tagged.

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