Category: Networking

Notes on getting Ubuntu 16.04 to work with NIS

Note – this only sets up the system to use user and group logons, not automounting home directories. I haven’t figured out how to make this work in Ubuntu 16.

Install package nis

Probably a good idea to set network address statically in /etc/network/interfaces (NetworkManager should recognise this and then leave it alone)

Probably also a good idea to check that /etc/hosts has the domain name for the system, i.e.

127.0.1.1 domain.name.machinename machinename

Add yp server to /etc/yp.conf

Edit /etc/nsswitch.conf to add nis for passwd, group and shadow. Note that compat should include nis by default.

Add a dependency to make the rpcbind service start at boot

systemctl add-wants multi-user.target rpcbind.service

(See this Debian bug report or this Ubuntu one)

Note that this is not a complete fix – it is reported that if the network does not come up fast enough things still break.

For users that need to log on to the system, create home directories

mkhomedir_helper <username>

Remember to reboot to check everything is working:

yptest

if that fails check if the bind services are running

systemctl status rpcbind
systemctl status ypbind

Raspberry Pi networking notes for connecting directly to laptop

If running normal raspbian edit the file /etc/network/interfaces to add in two blocks:

iface eth0 inet dhcp

and

iface eth0 inet static
    address 169.254.210.230
    netmask 255.255.0.0

Comment out the block not in use. For networks that have a dhcp server running use the first block, for connecting to a Windows computer via a private network use the second (If Windows connects to a network, is set to obtain an address automatically and can’t get one then it self-assigns a 169.254.x.y address). Static address can be anything of the form 169.254.x.y.

Full example file:

# For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf'

# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d

auto lo
iface lo inet loopback

auto eth0
allow-hotplug eth0

# Comment out this block when connected to laptop
#iface eth0 inet dhcp

# Comment out this block when connected to building network (or any network with dhcp)
iface eth0 inet static
   address 169.254.210.230
   netmask 255.255.0.0


allow-hotplug wlan0
iface wlan0 inet manual
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

allow-hotplug wlan1
iface wlan1 inet manual
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

Proxmox clustering and multicast (also, DNS)

After much problems with getting a new Proxmox cluster up and running two things have helped:

Putting the SAN IP addresses in the hosts file, avoiding DNS dependancies (especially when one of the systems isn’t in there yet…). This put me on track: http://blog.rhavenindustrys.com/2013/04/curious-proxmox-clustering-fix.html

Important bit:

127.0.0.1 localhost.localdomain localhost
169.254.0.1 proxmox1.local proxmox1 pvelocalhost
169.254.0.2 proxmox2.local proxmox2

10.10.5.101 proxmox1.example.com
10.10.5.102 proxmox2.example.com

This associates the short aliases with the network used by corosync, while leaving the long addresses to the outside world.

Then tried tests detailed at: https://pve.proxmox.com/wiki/Troubleshooting_multicast,_quorum_and_cluster_issues

The multicast test failed – i.e. running

omping -c 10000 -i 0.001 -F -q <list of all nodes>

on both nodes at the same time resulted in 100% loss. Fixed this by disabling IGMP snooping on the SAN VLAN. ExtremeOS command is:

disable igmp snooping <vlanname>

Hey presto, after getting the second node to join properly:

pvecm add 192.168.xxx.xxx -force

it gets quorum immediately. I suspect this issue was causing a lot of the historical issues with getting quorum to work on this switch.