From BCCD 3.0

Revision as of 17:27, 18 May 2019

Stages

Stage descriptions

BCCD goes through the following network configuration stages:

1. Live mode
   1. Initial boot:
      1. Try to obtain an IP address from a BCCD DHCP server
      2. If no BCCD DHCP servers are available, obtain an IP address from any DHCP server
   2. Head node: Upon user request, start DHCP server that will answer requests only from other BCCD systems
2. Liberated mode
   1. Initial boot:
      1. Try to obtain an IP address from a BCCD DHCP server
      2. If no BCCD DHCP servers are available, obtain an IP address from any DHCP server
   2. Diskless boot: Upon user request, start DHCP server that will answer requests from diskless BCCD systems on only a given interface

Open questions:

1. Can bccd-reset-network be rewritten to produce systemd.network configuration files via templates for each stage?
2. How do we detect that a BCCD DHCP server has not responded to a client, and obtain an address from any DHCP server?

Answered questions:

1. Should we continue using bccd-identifier or switch to using the standard vendor-class-identifier that can be provided via systemd.network? vendor-class-identifier confirmed to work. dhcpd.conf snippet:

# dhclient on live BCCD systems will set this identifier
class "bccd-nodes" {
  match if option vendor-class-identifier = "bccd-client";
}

# Anything else, including PXE boot, will not
class "pxelinux-nodes" {
  match if option vendor-class-identifier != "bccd-client";
}

1. How do we have both a static (i.e. 192.168.3.1/24) and DHCP address on one interface, with a DHCP server listening on the static (192.168.3.1/24) address? Supply an Address stanza in addition to a Network stanza with DHCP set

Stage configuration

Current testing files:

• Head node
  • eth0
    • /etc/systemd/network/10-dhcp-eth0.network

[Match]
Name=eth0

[Network]
DHCP=yes

• • • or having a DHCP and static address:

[Match]
Name=eth0

[Network]
DHCP=yes

[Address]
Address=192.168.3.1/24

• • /etc/systemd/network/20-static-eth1.network

[Match]
Name=eth1

[Network]
Address=192.168.3.1/24
DHCP=no

• Client node
  • /etc/systemd/network/10-dhcp-eth0.network

[Match]
Name=eth0

[Network]
DHCP=yes

[DHCP]
VendorClassIdentifier=bccd-client

systemd notes

systemd commands

Restart networking 

systemctl restart systemd-networkd

Networking status 

networkctl

systemd tricks

• Move /etc/network/interfaces out of the way to ensure that regular network setup doesn't occur
• Interface files need to have a numeric prefix and a .network suffix (i.e. /etc/systemd/network/10-static-eth0.network

Troubleshooting

RTNETLINK answers: File exists

If you get an error like this:

RTNETLINK answers: File exists
Failed to bring up eth1.

Try flushing that interface and replumbing it:

$ sudo ip addr flush dev eth1