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--- wiki:interface_renaming_scripts [2018/06/19 10:32] – walkeradmin
+++ wiki:interface_renaming_scripts [2023/03/09 22:35] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-Interface Renaming Scripts
+====== Interface Renaming Scripts ======
-Jun 2018
+<color darkorange>June 2018</color>
+\\
+\\
 ----
-For anyone that has used CentOS/Red Hat prior to version 7, or indeed other versions of Linux, the norm for network interface naming is to use eth0, eth1, eth2 etc.
+<color #ed1c24>Please see the end of this page for the two sripts</color>
+----
+\\
+\\
+For anyone that has used CentOS/Red Hat prior to version 7, or indeed other versions of Linux, the norm for network interface naming is to use **eth0, eth1, eth2** etc.
 \\
 \\
 CentOS 7 changed this naming convention, for two main reasons.
 . Security (knowing particular interface names is considered a security risk).
 . Deterministic Naming. While the interfaces names used have always been the same, the
-    mapping has been a bit hit and miss, and so on 10 identical servers, while the names are
+       mapping has been a bit hit and miss, and so on 10 identical servers, while the names are
-    the same, eth0 may not always be the same physical interface (like Windows it can move).
+       the same, eth0 may not always be the same physical interface (like Windows it can move).
 \\
 \\
+Here we are looking at a couple of scripts written by an engineer here at work (not by me). While these scripts can work very well, there are a couple of things to be aware off.
+\\
+\\
+Firstly the two scripts, these are:
+. store_macaddr_mapping.sh - stores server MAC addresses for use by the rename_network_interfaces.sh script.
+. rename_network_interfaces.sh - renames the interfaces using the information generated
+       by store_macaddr_mapping.sh
+\\
+=== store_macaddr_mapping.sh ===
+\\
+The store_macaddr_mapping.sh is the trickier of the two scripts. I don't know what hardware this script was written for, but for me it has been a little troublesome. But it provides a good starting point for the renaming process.
+\\
+Copy this file to the server that needs the interfaces renaming, then give the file execute rights.
+\\
+\\
+    chmod 777 store_macaddr_mapping.sh
+\\
+Now execute the file using the following syntax:
+\\
+    ./store_macaddr_mapping.sh --output network_mapping.csv
+\\
+\\
+A file network_mapping.csv will have been created. you can view this file using:
+\\
+   cat network_mapping.csv
+\\
+Here is an example of what I have:
+\\
+    enp4s0f0;00:1e:67:d1:24:0e
+    ;00:1e:67:d1:24:0f
+    ;00:1e:67:d1:24:10
+    ;00:1e:67:d1:24:11
+    ;00:1e:67:d8:b3:68
+    ;00:1e:67:d8:b3:69
+\\
+The file should contain the following:
+\\
+    interface;mac
+    interface;mac
+    interface;mac
+    interface;mac
+    etc.
+\\
+There are two issues here:
+\\
+. The interface names need to be eth0, eth1 etc.
+. The MAC Addresses are in the incorrect order, and this will break the mapping.
+\\
+Both of these are easy to fix. Firsly you can manually edit the file, so that the interface names are correct, but more importantly, you need to get the MAC address order correct.
+\\
+\\
+Use <color #ed1c24>ip link show</color> to show interfaces and MACS
+\\
+    ip link show
+: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT
+        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
+: ens513f0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT qlen 1000
+        link/ether 00:1e:67:d1:24:0e brd ff:ff:ff:ff:ff:ff
+: ens513f1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT qlen 1000
+        link/ether 00:1e:67:d1:24:0f brd ff:ff:ff:ff:ff:ff
+: ens513f2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT qlen 1000
+        link/ether 00:1e:67:d1:24:10 brd ff:ff:ff:ff:ff:ff
+: ens513f3: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT qlen 1000
+        link/ether 00:1e:67:d1:24:11 brd ff:ff:ff:ff:ff:ff
+: enp4s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT qlen 1000
+        link/ether 00:1e:67:d8:b3:68 brd ff:ff:ff:ff:ff:ff
+: enp4s0f3: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT qlen 1000
+        link/ether 00:1e:67:d8:b3:69 brd ff:ff:ff:ff:ff:ff
+\\
+From here we can see which MAC is associated with which interface (so I know that enp4s0f0 is the first interface on my server) this allows me to build the following file:
+\\
+    eth0;00:1e:67:d8:b3:68
+    eth1;00:1e:67:d8:b3:69
+    eth2;00:1e:67:d1:24:0e
+    eth3;00:1e:67:d1:24:0f
+    eth4;00:1e:67:d1:24:10
+    eth5;00:1e:67:d1:24:11
+\\
+So now the <color #ed1c24>network_mapping.csv</color> file is ready to use.
+\\
+\\
+----
+===rename_network_interfaces.sh===
+\\
+The next part is much simpler. Copy the rename_network_interfaces.sh to your server, and give it execute privileges using the following syntax:
+\\
+    chmod 777 rename_network_interfaces.sh
+\\
+Now execute the script using the following syntax:
+\\
+    ./rename_network_interfaces.sh --csv network_mapping.csv
+\\
+\\
+If successful the following output will be observed (depending on what interface scripts already existed).
+\\
+<file>
+*** Getting macaddr to register ***
+*** Using network_mapping.csv for network interface mapping ***
+        Backup of /etc/sysconfig/network-scripts/ifcfg-ens513f3 in /etc/sysconfig/network-scripts/backup/ifcfg-ens513f3
+        Backup of /etc/sysconfig/network-scripts/ifcfg-ens513f1 in /etc/sysconfig/network-scripts/backup/ifcfg-ens513f1
+        Backup of /etc/sysconfig/network-scripts/ifcfg-enp4s0f0 in /etc/sysconfig/network-scripts/backup/ifcfg-enp4s0f0
+        Backup of /etc/sysconfig/network-scripts/ifcfg-enp4s0f3 in /etc/sysconfig/network-scripts/backup/ifcfg-enp4s0f3
+        Backup of /etc/sysconfig/network-scripts/ifcfg-ens513f2 in /etc/sysconfig/network-scripts/backup/ifcfg-ens513f2
+        Backup of /etc/sysconfig/network-scripts/ifcfg-ens513f0 in /etc/sysconfig/network-scripts/backup/ifcfg-ens513f0
+        Generating file /etc/sysconfig/network-scripts/ifcfg-eth0
+        Generating file /etc/sysconfig/network-scripts/ifcfg-eth1
+        Generating file /etc/sysconfig/network-scripts/ifcfg-eth2
+        Generating file /etc/sysconfig/network-scripts/ifcfg-eth3
+        Generating file /etc/sysconfig/network-scripts/ifcfg-eth4
+        Generating file /etc/sysconfig/network-scripts/ifcfg-eth5
+</file>
+\\
+Check the /etc/sysconfig/network-scripts location to see the new files.
+\\
+Note: No configuration information is copied from the old interface scripts, so before you reboot, you need to re-add all of your IP/Netmask/Gateway/DNS information.
+\\
+\\
+Reboot the server to check the interfaces have been renamed, and the mapping is correct.
+\\
+\\
+----
+===The Scripts===
+\\
+<color #ed1c24>store_macaddr_mapping</color>
+\\
+<file>
+#!/bin/bash
+# this script is based on infos got from blog page:
+# http://ask.xmodulo.com/change-network-interface-name-centos7.html
+# exit at first error
+set -o errexit
+export IP_INTERFACES="ip addr"
+export INTERFACE_ANCHOR="state UP"
+export MACADDR_ANCHOR="link/ether"
+export OUTPUT_FILE
+function show_help() {
+cat <<- EOF
+Generate csv file with interface name; mac addr. Output file is a mandatory parameter.
+    --output                                    Output file path where mac addre mapping will be stored
+    --help|-h                                   [Optional] Display this help and exit
+EOF
+}
+while [ $# -gt 0 ] ; do
+    case $1 in
+        --output) OUTPUT_FILE="$2";shift 2;;
+        --help|-h) show_help;exit 0;;
+        *) if ! [ -z "$1" ] ; then echo "Unknown parameter $1" ; show_help ; exit 1 ; else  shift 1; fi ;;
+    esac
+done
+[ -z "$OUTPUT_FILE" ] && show_help && exit 1
+rm -f "$OUTPUT_FILE" > /dev/null 2>&1
+echo "Generating $OUTPUT_FILE"
+interface_name_list=$($IP_INTERFACES | grep "$INTERFACE_ANCHOR" | awk '{print $2}' | sed 's|:||')
+interface_name_list=($interface_name_list)
+macaddr_list=$($IP_INTERFACES | grep "$MACADDR_ANCHOR" | awk '{print $2}' | tr '[:upper:]' '[:lower:]')
+macaddr_list=($macaddr_list)
+cnt=0
+arraySize="${#macaddr_list[@]}"
+while [ "$cnt" != "$arraySize" ] ; do
+    echo "${interface_name_list[$cnt]};${macaddr_list[$cnt]}" >> "$OUTPUT_FILE"
+    cnt=$(( cnt + 1 ))
+done
+</file>
+<color #ed1c24>rename_network_interfaces.sh</color>
+\\
+<file>
+#!/bin/bash
+# this script is based on infos got from blog page:
+# http://ask.xmodulo.com/change-network-interface-name-centos7.html
+# exit at first error
+set -o errexit
+IP_INTERFACES="ip addr"
+MACADDR_ANCHOR="link/ether"
+NET_NAME_TEMPLATE="eth"
+CSV_FILE=
+NETWORK_SCRIPT_DIR="/etc/sysconfig/network-scripts"
+NETWORK_BACKUP_DIR="/etc/sysconfig/network-scripts/backup"
+NETWORK_SCRIPT_TEMPLATE='NAME="<network_name>"
+DEVICE="<network_name>"
+ONBOOT=yes
+NETBOOT=yes
+BOOTPROTO=dhcp
+TYPE=Ethernet
+# HWADDR key is mandatory to use custom interface name: do not delete it
+HWADDR=<mac_addr>
+'
+function show_help() {
+cat <<- EOF
+Update network interfaces names. A csv file with the expected mapping can be given as arg.
+    --csv                                       Csv file containing <interface name>;<mac addr> as they should be defined
+    --help|-h                                   [Optional] Display this help and exit
+EOF
+}
+while [ $# -gt 0 ] ; do
+    case $1 in
+        --csv) CSV_FILE="$2";shift 2;;
+        --help|-h) show_help;exit 0;;
+        *) if ! [ -z "$1" ] ; then echo "Unknown parameter $1" ; show_help ; exit 1 ; else  shift 1; fi ;;
+    esac
+done
+echo "*** Getting macaddr to register ***"
+macaddr_list=$($IP_INTERFACES | grep "$MACADDR_ANCHOR" | awk '{print $2}')
+if ! [ -z "$CSV_FILE" ] && [ -f "$CSV_FILE" ] ; then
+    echo "*** Using $CSV_FILE for network interface mapping ***"
+    ! [ -d "$NETWORK_BACKUP_DIR" ] && mkdir -p "$NETWORK_BACKUP_DIR"
+    for old_script_file in $(find $NETWORK_SCRIPT_DIR -maxdepth 1 -name "ifcfg-*" -a -not -name "ifcfg-lo" -a -not -name "ifcfg-*\.*"); do
+        echo -e "\tBackup of $old_script_file in $NETWORK_BACKUP_DIR/$(basename "$old_script_file")"
+        mv -f "$old_script_file" $NETWORK_BACKUP_DIR/.
+    done
+    while read interface_data
+    do
+        [ -z "$interface_data" ] && continue
+        interface_name=$(echo "$interface_data" | cut -d \; -f1)
+        mac_addr=$(echo "$interface_data" | cut -d \; -f2 | tr '[:upper:]' '[:lower:]')
+        [ -z "$interface_name" ] && continue
+        [ -z "$mac_addr" ] && continue
+        # check that given mac addr exist
+        if ! echo "$macaddr_list" | grep "$mac_addr" > /dev/null 2>&1 ; then
+            echo "Unable to find $mac_addr in available network interfaces, please review file content of $CSV_FILE"
+            exit 1
+        fi
+        echo -e "\tGenerating file $NETWORK_SCRIPT_DIR/ifcfg-$interface_name"
+        echo "$NETWORK_SCRIPT_TEMPLATE" > $NETWORK_SCRIPT_DIR/ifcfg-"$interface_name"
+        sed -i "s|<network_name>|$interface_name|g" $NETWORK_SCRIPT_DIR/ifcfg-"$interface_name"
+        sed -i "s|<mac_addr>|$mac_addr|g" $NETWORK_SCRIPT_DIR/ifcfg-"$interface_name"
+    done < "$CSV_FILE"
+else
+    echo "*** Using default naming (${NET_NAME_TEMPLATE}x) for network interface mapping ***"
+    ! [ -d "$NETWORK_BACKUP_DIR" ] && mkdir -p "$NETWORK_BACKUP_DIR"
+    cnt=0
+    for old_script_file in $(find $NETWORK_SCRIPT_DIR -maxdepth 1 -name "ifcfg-*" -a -not -name "ifcfg-lo" -a -not -name "ifcfg-*\.*"); do
+        echo -e "\tBackup of $old_script_file in $NETWORK_BACKUP_DIR/$(basename "$old_script_file")"
+        mv -f "$old_script_file" $NETWORK_BACKUP_DIR/.
+    done
+    for mac_addr in ${macaddr_list[*]}; do
+        mac_addr=$(echo "$mac_addr" | tr '[:upper:]' '[:lower:]')
+        echo -e "\tGenerating file $NETWORK_SCRIPT_DIR/ifcfg-$NET_NAME_TEMPLATE$cnt"
+        echo "$NETWORK_SCRIPT_TEMPLATE" > $NETWORK_SCRIPT_DIR/ifcfg-$NET_NAME_TEMPLATE$cnt
+        sed -i "s|<network_name>|$NET_NAME_TEMPLATE$cnt|g" $NETWORK_SCRIPT_DIR/ifcfg-$NET_NAME_TEMPLATE$cnt
+        sed -i "s|<mac_addr>|$mac_addr|g" $NETWORK_SCRIPT_DIR/ifcfg-$NET_NAME_TEMPLATE$cnt
+        cnt=$(( cnt + 1 ))
+    done
+fi
+echo "*** Please check consistency of generated files in directory $NETWORK_SCRIPT_DIR ***"
+</file>
+\\
+\\