From 44750996be15a0a55a442fa8b61f839b2bb45941 Mon Sep 17 00:00:00 2001
From: Manuel Montecelo <mmontecelo@sipwise.com>
Date: Tue, 8 Jun 2021 18:46:39 +0200
Subject: [PATCH] TT#105151 Rename network interfaces eth*->neth*

Using "eth*" names was discouraged for many years, we've been finding
problems here and there and working around them with the help of
udev-rules (/etc/udev/rules.d/70-persistent-net.rules) to map address
interfaces according to PCIIDs, using "net.ifnames=0" as Linux kernel
boot parameter when booting in GRUB, etc.

Finally we found unsurmountable problems when moving to Debian bullseye
(mr9.5), because as we attempt to rename interfaces in some hardware
systems that we use, we got race conditions and clashes with renaming
that we could not solve in other ways.

We had different alternatives:

- Use names purely deterministic, based on PCI paths (for example
  "enp4s0f1"), MAC address or other of the alternatives, which would be
  "definitive", but given that we have a diversity of hardware and VM
  installations in customers the devices in different systems would be
  different, and the fact that it would be easier to mistype or confuse
  them makes this not ideal.

- Use names purely based on functionality, like for example "ha0",
  "ext0" or "int0".  The problem in this case is that we would have to
  find names that would satisfy everyone (and there's no time for doing
  this at this point), that different of our system types are quite
  different (e.g. Pro without bonds, Carrier with bonds and many vlans
  by default; using the same hardware), and some customers with
  different installations or needs (e.g. using VMs) have also totally
  different network configuration -- so any attempt to unify this to
  make good use of the functionality-based names would be very
  challenging.

- Finally, there's the option to use some symbolic names similar to
  traditional names like "eth0", but without being exactly this.
  Popular names in general, although there's no wide consensus, are
  names like "net0" and "lan0".

Talking with groups involved in deploying and maintaining the system,
the decision was taken to move to names not purely deterministic, and
there's no time for purely symbolic (they also didn't express much
interest on them), and prefer something more traditional that they are
already used too.  Instead of names like "net0" or "lan0", they prefer
the more direct mapping to existing interfaces like "neth0".

This is ugly or slighly discomforting to use for some, but since the
main users (among us) of these names prefer them, so be it.  It has the
advantage of having a very simple and mechanichal translation based on
the current names, which is an advantage especially at the critical time
of upgrading existing systems to the new name.

Change-Id: I4a168c7d81e40f609749f77a509d2acb72d3a9d3
---
 templates/scripts/includes/deployment.sh | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/templates/scripts/includes/deployment.sh b/templates/scripts/includes/deployment.sh
index 0566365..99a259a 100755
--- a/templates/scripts/includes/deployment.sh
+++ b/templates/scripts/includes/deployment.sh
@@ -895,7 +895,7 @@ DHCP="${DHCP}"
 EXTERNAL_DEV="${EXTERNAL_DEV}"
 GW="${GW}"
 EXTERNAL_NETMASK="${EXTERNAL_NETMASK}"
-ORIGIN_INSTALL_DEV="${INSTALL_DEV}"
+ORIGIN_INSTALL_DEV="${ORIGIN_INSTALL_DEV}"
 FALLBACKFS_SIZE="${FALLBACKFS_SIZE}"
 ROOTFS_SIZE="${ROOTFS_SIZE}"
 SWAPFILE_SIZE_MB="${SWAPFILE_SIZE_MB}"
@@ -1751,11 +1751,14 @@ IP1="${IP1:-${DEFAULT_IP1}}"
 IP2="${IP2:-${DEFAULT_IP2}}"
 IP_HA_SHARED="${IP_HA_SHARED:-${DEFAULT_IP_HA_SHARED}}"
 EXTERNAL_DEV="${EXTERNAL_DEV:-${INSTALL_DEV}}"
+EXTERNAL_DEV="n${EXTERNAL_DEV}" # rename eth*->neth*
 EXTERNAL_IP="${EXTERNAL_IP:-${INSTALL_IP}}"
 EADDR="${EXTERNAL_IP:-${EADDR}}"
 INTERNAL_NETMASK="${INTERNAL_NETMASK:-${DEFAULT_INTERNAL_NETMASK}}"
 MANAGEMENT_IP="${MANAGEMENT_IP:-${IP_HA_SHARED}}"
 INTERNAL_DEV="${INTERNAL_DEV:-${DEFAULT_INTERNAL_DEV}}"
+INTERNAL_DEV="n${INTERNAL_DEV}" # rename eth*->neth*
+ORIGIN_INSTALL_DEV="n${INSTALL_DEV}" # rename eth*->neth*
 if [[ -n "${EXT_GW}" ]]; then
   GW="${EXT_GW}"
 fi
@@ -2139,9 +2142,10 @@ for dev in ${NETWORK_DEVICES}; do
 
   pciid=$(ethtool -i "${dev}" | awk '/^bus-info: / {print $2}')
   if [[ "${pciid}" =~ ^([0-9a-fA-F:.-])+$ ]]; then
-    echo "Adding device '${dev}' with PCIID '${pciid}'"
+    dev_name_new="n${dev}"
+    echo "Adding device '${dev}' with PCIID '${pciid}', dev_name_new=${dev_name_new}"
     cat >> "${TARGET_UDEV_PERSISTENT_NET_RULES}" <<EOL
-SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", KERNELS=="${pciid}", NAME="${dev}"
+SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", KERNELS=="${pciid}", NAME="${dev_name_new}"
 EOL
   else
     echo "WARNING: could not find valid PCIID '${pciid}' for device '${dev}'"
@@ -2149,6 +2153,10 @@ EOL
   unset pciid
 done
 
+# Rename existing network devices at this time, to use the new names "neth*"
+# when creating config_deploy.inc later
+NETWORK_DEVICES="${NETWORK_DEVICES//eth/neth}"
+
 if "$NGCP_INSTALLER" ; then
   set_deploy_status "ngcp-installer"
 
@@ -2222,6 +2230,11 @@ EOT
     echo "Copying /etc/network/interfaces ..."
     cp /etc/network/interfaces "${TARGET}/etc/network/"
     sed -i '/iface lo inet dhcp/d' "${TARGET}/etc/network/interfaces"
+    echo "Renaming eth*->neth* in /etc/network/interfaces ..."
+    sed -i '/eth[0-9]/ s|eth|neth|g' "${TARGET}/etc/network/interfaces"
+    echo "Content of resulting /etc/network/interfaces:"
+    tail -v -n +0 "${TARGET}/etc/network/interfaces"
+    echo "========"
     unset method netcardconf
   else
     die "Error during installation of ngcp. Find details at: ${TARGET}/var/log/ngcp-installer.log"