3 thoughts on - CentOS 7, Networkmangler, And Hostname

• .

  Best I found using network manager is writing a script, dhclient-exit-hooks.d/hostname
  (http://askubuntu.com/questions/104918/how-to-get-hostname-from-dhcp-server). There is also a way to do that using systemd-networkd; I am not very proud to say I know how to do so though.

• Mauricio Tavares wrote:
  I’ve been digging, and found something a) confusing and b) disturbing. But first, *does* NM use any of the /etc/sysconfig/network-scripts *other*
  than the ifcfg-? Specifically, does it use ifup, ifdown, and esp. ifup-post?

  Here’s the reason: in ifup-post is the following code:
  # don’t set hostname on ppp/slip connections if [ “$2” = “boot” -a \
  “${DEVICE}” != lo -a \
  “${DEVICETYPE}” != “ppp” -a \
  “${DEVICETYPE}” != “slip” ]; then
  if need_hostname; then
  IPADDR=$(LANG=C ip -o -4 addr ls dev ${DEVICE} | awk ‘{ print $4 ;
  exit }’)
  eval $(/bin/ipcalc –silent –hostname ${IPADDR} ; echo “status=$?”)
  if [ “$status” = “0” ]; then
  set_hostname $HOSTNAME
  fi
  fi fi

  Now, that function, need_hostname, is in network-functions, and reads:
  need_hostname ()
  {
  CHECK_HOSTNAME=$(hostname)
  if [ “$CHECK_HOSTNAME” = “(none)” -o “$CHECK_HOSTNAME” = “localhost” -o \
  “$CHECK_HOSTNAME” = “localhost.localdomain” ]; then
  return 0
  else
  return 1
  fi
  }

  So it *should* be setting it… if it’s called.

  mark

• )

  My experience with NM is from ubuntu, over there if you configure an interface in the /etc/network/interfaces file (their equivalent of /etc/sysconfig/network-scripts , it *should* not try to fondle that interface any longer. That said, the network-scripts do have a

  NM_CONTROLLED=no

  option, so NM must at least check for that. I have a feeling if you set that to yes, it will ignore the rest of the file and do its own thing.

  There is also a /etc/NetworkManager/ directory which seems to imply that NM does a lot of things on its own and ignore the old network config files. https://bugzilla.gnome.org/show_bug.cgi?idf7874 and the picture in http://serverfault.com/questions/429014/what-is-the-relation-between-networkmanager-and-network-service-in-fedora-rhel-c seem to confirm that.