Hyperflex SCVM may not connect to the network after we make any changes in the .VMX file and reboot.

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Updated:May 31, 2019
Document ID:214480

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    INTRODUCTION 

    With Udev and modular network drivers, the network interface numbering is not persistent across reboots by default. This is due to drivers being loaded in parallel and thus network devices show up in random order.

    Example: On a computer having two network cards made by Intel and Realtek, the network card manufactured by Intel may become eth0 and the Realtek card becomes eth1

    In some cases, after a reboot the cards get renumbered the other way around. To avoid this, Udev comes with a script and some rules to assign stable names to network cards based on their MAC address

    PROBLEM 

    Hyperflex Storage Controller VM (SCVM) may not connect to the network after changes are made in the VMX file (e.g., uuid.bios parameter) after reboot because its MAC addresses are getting jumbled up in the file 70-persistent-net.rules

    SOLUTION

    Step 1: Map the ATTR{address} Field with the NAME Field

    SSH to the SCVM

    Type cat /etc/udev/rules.d/70-persistent-net.rules

    root@SpringpathControllerABCDE01234:~# cat /etc/udev/rules.d/70-persistent-net.rules
# This file has been auto-generated during Springpath controller deployment.
SUBSYSTEM=="net" ACTION=="add" ATTR{address}=="00:50:56:8b:af:33" ATTR{dev_id}=="0x0" ATTR{type}=="1" NAME="mgmt-if"
SUBSYSTEM=="net" ACTION=="add" ATTR{address}=="00:50:56:8b:ac:45" ATTR{dev_id}=="0x0" ATTR{type}=="1" NAME="data-if"
SUBSYSTEM=="net" ACTION=="add" ATTR{address}=="00:50:56:8b:cf:00" ATTR{dev_id}=="0x0" ATTR{type}=="1" NAME="repl-if"

    Step 2: Enter the SCVM VM Settings 

    Login to vCenter 

    Locate the SCVM

    Right click it and select Edit Settings...

    Step 3a: Identify the SCVM Network Adapter MAC Addresses from vCenter settings

    In Edit Settings window, expand all network adapters and make a note of their MAC addresses

      

    Step 3b: Identify the SCVM Network Adapter MAC Addresses from SCVM shell.

       From SCVM shell issue "ifconfig -a". eth0 points to the management network interface, eth1 points to data storage network interface and eth1 points to the replication network interface. Make a note of these MAC addresses. 

    root@help:~# ifconfig -a
    eth0 Link encap:Ethernet HWaddr 00:50:56:8b:ae:b7  <<<< mgmt-if
    inet addr:10.197.252.81 Bcast:10.197.252.95 Mask:255.255.255.224
    UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
    RX packets:2919331 errors:0 dropped:77 overruns:0 frame:0
    TX packets:1186365 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:1000
    RX bytes:912923504 (912.9 MB) TX bytes:1169716469 (1.1 GB)

    eth1 Link encap:Ethernet HWaddr 00:50:56:8b:bd:41 <<<< data-if
    inet addr:10.197.252.100 Bcast:10.197.252.127 Mask:255.255.255.224
    UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
    RX packets:152529984 errors:0 dropped:416 overruns:0 frame:0
    TX packets:132458793 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:1000
    RX bytes:242676663088 (242.6 GB) TX bytes:224531042730 (224.5 GB)

    ...

    eth2 Link encap:Ethernet HWaddr 00:50:56:8b:cf:f3  <<< repl-if
    BROADCAST MULTICAST MTU:1500 Metric:1
    RX packets:1671340 errors:0 dropped:131 overruns:0 frame:0
    TX packets:3340062 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:1000
    RX bytes:164403101 (164.4 MB) TX bytes:300665525 (300.6 MB)
    ...

    Step 4: Update the 70-persistent-net.rules with the MAC Addresses from Previous Step 

    Type vi /etc/udev/rules.d/70-persistent-net.rules

    Input the MAC addresses from the previous step in the ATTR{address} section and save changes 

    root@SpringpathControllerABCDE01234:~# vi /etc/udev/rules.d/70-persistent-net.rules
# This file has been auto-generated during Springpath controller deployment.
SUBSYSTEM=="net" ACTION=="add" ATTR{address}=="00:50:56:8b:ae:b7" ATTR{dev_id}=="0x0" ATTR{type}=="1" NAME="mgmt-if"
SUBSYSTEM=="net" ACTION=="add" ATTR{address}=="00:50:56:8b:bd:41" ATTR{dev_id}=="0x0" ATTR{type}=="1" NAME="data-if"
SUBSYSTEM=="net" ACTION=="add" ATTR{address}=="00:50:56:8b:cf:f3" ATTR{dev_id}=="0x0" ATTR{type}=="1" NAME="repl-if"

    Step 5: Reboot SCVM

    Type reboot to restart the SCVM 

    Once SCVM comes back up, it should be able to connect to the network just fine

    root@SpringpathControllerABCDE01234:~# reboot
    TAC Authored

    Contributed by Cisco Engineers

    • Himanshu Sardana
      TECHNICAL CONSULTING ENGINEER
    • Yogesha MG
      TECHNICAL LEADER

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