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Mouhamadou Diaw

ODA KVM Machines : Adding a Network Interface on a Virtual Machine

In a previous blog , I was talking about virtual machines on ODA servers. Sometimes it comes that we want to add another network interface for other purpose.
In this blog I am describing the main tasks to add a second network interface card on KVM virtual machine. Let’s describe the context
I have an ODA X8-2M with appliance 19.12. This ODA contains virtual machines for the applications. The virtual machine only has one NIC used for the public connexion. The idea is to add a second network interface that will be used for the backups
-The oda server : oda-dev-01
-The virtual machine : vmserver_appli
We show the actual network configuration for the virtual machine vmserver-appli. Only eth0 is present in the VM.

[[email protected] ~]# ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0:  mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 52:54:00:e9:26:18 brd ff:ff:ff:ff:ff:ff
    inet 10.18.35.139/24 brd 10.18.35.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::f7a:d225:d568:5afa/64 scope link noprefixroute
       valid_lft forever preferred_lft forever
[[email protected] ~]#

As we can see below the eth0 is actually using the vNetwork pubnet of the physical ODA server. The pubnet is configured with the btbond1.

[[email protected] ~]# odacli list-vnetworks
Name                  Type             Interface        Bridge                Uniform   Created                  Updated
--------------------  ---------------  ---------------  --------------------  --------  -----------------------  -----------------------
pubnet                Bridged          btbond1          pubnet                NO        2021-09-27 10:55:41      2021-09-27 10:55:41
                                                                                        CEST                     CEST

[[email protected] ~]#

In the ODA there is a second configured bonding with btbond2.

[[email protected] network-scripts]# cat ifcfg-btbond2
# This file is automatically created by the ODA software.
DEVICE=btbond2
ONBOOT=yes
BOOTPROTO=none
USERCTL=no
TYPE=BOND
IPV6INIT=no
NM_CONTROLLED=no
PEERDNS=no
BONDING_OPTS="mode=active-backup miimon=100 primary=p7p3"
[[email protected] network-scripts]#

As we can see btbond2 is not used yet compared to btbond1 used for the pubnet vNetwork

[[email protected] network-scripts]# cat ifcfg-btbond1
# This file is automatically created by the ODA software.
DEVICE=btbond1
ONBOOT=yes
USERCTL=no
TYPE=BOND
IPV6INIT=no
NM_CONTROLLED=no
PEERDNS=no
BONDING_OPTS="mode=active-backup miimon=100 primary=p7p1"
BRIDGE=pubnet
[[email protected] network-scripts]#

So the idea is to create backupnet vNetwork based on btbond2. Later the backupnet vNetwork will be attached to the virtual machine.The command odacli create-vnetwork is used to create backupnet

[[email protected] network-scripts]# odacli create-vnetwork --name backupnet --bridge backupnet --type bridged --interface btbond2 --ip 10.18.45.55 --gateway 10.18.45.1 --netmask 255.255.255.128

Job details
----------------------------------------------------------------
                     ID:  f3490869-1d38-4562-928f-644e971b24cd
            Description:  vNetwork backupnet creation
                 Status:  Created
                Created:  January 20, 2022 10:39:12 AM CET
                Message:

Task Name                                Start Time                          End Time                            Status
---------------------------------------- ----------------------------------- ----------------------------------- ----------

[[email protected] network-scripts]#

We verify that the job is ok

[[email protected] network-scripts]# odacli describe-job -i f3490869-1d38-4562-928f-644e971b24cd

Job details
----------------------------------------------------------------
                     ID:  f3490869-1d38-4562-928f-644e971b24cd
            Description:  vNetwork backupnet creation
                 Status:  Success
                Created:  January 20, 2022 10:39:12 AM CET
                Message:

Task Name                                Start Time                          End Time                            Status
---------------------------------------- ----------------------------------- ----------------------------------- ----------
Validate Virtual Network doesn't exist   January 20, 2022 10:39:12 AM CET    January 20, 2022 10:39:12 AM CET    Success
Validate interface to use exists         January 20, 2022 10:39:12 AM CET    January 20, 2022 10:39:12 AM CET    Success
Validate interfaces to create not exist  January 20, 2022 10:39:12 AM CET    January 20, 2022 10:39:12 AM CET    Success
Validate interface is not default        January 20, 2022 10:39:12 AM CET    January 20, 2022 10:39:12 AM CET    Success
Create bridge from interface             January 20, 2022 10:39:12 AM CET    January 20, 2022 10:39:18 AM CET    Success
Create metadata                          January 20, 2022 10:39:18 AM CET    January 20, 2022 10:39:18 AM CET    Success
Persist metadata                         January 20, 2022 10:39:18 AM CET    January 20, 2022 10:39:18 AM CET    Success

[[email protected] network-scripts]#

And we can then list the vNetworks in the ODA

[[email protected] network-scripts]# odacli list-vnetworks
Name                  Type             Interface        Bridge                Uniform   Created                  Updated
--------------------  ---------------  ---------------  --------------------  --------  -----------------------  -----------------------
pubnet                Bridged          btbond1          pubnet                NO        2021-09-27 10:55:41      2021-09-27 10:55:41
                                                                                        CEST                     CEST
backupnet             Bridged          btbond2          backupnet             NO        2022-01-20 10:39:18 CET  2022-01-20 10:39:18 CET

[[email protected] network-scripts]#

Let’s describe the VM that I want to add a second network interface. We can see that only one vNetwork (pubnet) is attached to the VM.

[[email protected] network-scripts]# odacli describe-vm -n vmserver-appli
VM details
--------------------------------------------------------------------------------
                       ID:  14f10064-a048-419d-a850-18b1d9b2b69e
                     Name:  vmserver-appli
                  Created:  2021-10-21 14:51:50 CEST
                  Updated:  2021-10-21 14:51:50 CEST
               VM Storage:  storevms
              Description:  Web site standby
            VM image path:  /u05/app/sharedrepo/storevms/.ACFS/snaps/vm_vmserver-appli/vmserver-appli
                  VM size:  20.00 GB
                   Source:  V1009690-01.iso
                  OS Type:  NONE
               OS Variant:  NONE
        Graphics settings:  vnc,listen=127.0.0.1
             Display Port:  127.0.0.1:1

 Status
--------------------------
             Current node:  oda-dev-01
            Current state:  ONLINE
             Target state:  ONLINE

 Parameters
--------------------------
           Preferred node:  NONE
              Boot option:  NONE
               Auto start:  YES
                Fail over:  NO
             NUMA enabled:  NO

                            Config                     Live
                            -------------------------  -------------------------
                   Memory:  4.00 GB                    4.00 GB
               Max Memory:  8.00 GB                    8.00 GB
               vCPU count:  3                          3
           Max vCPU count:  6                          6
                 CPU Pool:  cpuvms                     cpuvms
        Effective CPU set:  1-9,17-25,33-41,49-57      1-9,17-25,33-41,49-57
                    vCPUs:  0:1-9,17-25,33-41,49-57    0:1-9,17-25,33-41,49-57
                            1:1-9,17-25,33-41,49-57    1:1-9,17-25,33-41,49-57
                            2:1-9,17-25,33-41,49-57    2:1-9,17-25,33-41,49-57
                   vDisks:  vdisk2webs21:vdc           vdisk2webs21:vdc
                            vdisk1webs21:vdb           vdisk1webs21:vdb
                vNetworks:  pubnet:52:54:00:e9:26:18   pubnet:52:54:00:e9:26:18

[[email protected] network-scripts]#

Again on the virtual machine only one NIC eth0 is configured

[[email protected] ~]# ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0:  mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 52:54:00:e9:26:18 brd ff:ff:ff:ff:ff:ff
    inet 10.18.35.139/24 brd 10.18.35.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::f7a:d225:d568:5afa/64 scope link noprefixroute
       valid_lft forever preferred_lft forever
[[email protected] ~]#

To add a second network interface, let’s attach the backupnet vNetwork to the VM . Just note the use both –live and –config
–live: The change is applied to the running VM instance, but does not persist after the VM stops.
–config: The change persists in the configuration of VM instance and takes effect on subsequent reboots.

[[email protected] network-scripts]# odacli modify-vm -n vmserver-appli -avn backupnet --live --config

Job details
----------------------------------------------------------------
                     ID:  8da2a4cc-528c-47d9-bcb0-4481010c73f3
            Description:  VM vmserver-appli modification
                 Status:  Created
                Created:  January 20, 2022 10:48:25 AM CET
                Message:

Task Name                                Start Time                          End Time                            Status
---------------------------------------- ----------------------------------- ----------------------------------- ----------

[[email protected] network-scripts]#

Let’s verify that the job returns SUCCESS

[[email protected] network-scripts]# odacli describe-job -i 8da2a4cc-528c-47d9-bcb0-4481010c73f3

Job details
----------------------------------------------------------------
                     ID:  8da2a4cc-528c-47d9-bcb0-4481010c73f3
            Description:  VM vmserver-appli modification
                 Status:  Success
                Created:  January 20, 2022 10:48:25 AM CET
                Message:

Task Name                                Start Time                          End Time                            Status
---------------------------------------- ----------------------------------- ----------------------------------- ----------
Validate VM exists                       January 20, 2022 10:48:25 AM CET    January 20, 2022 10:48:25 AM CET    Success
Validate network attachment pre-reqs     January 20, 2022 10:48:25 AM CET    January 20, 2022 10:48:25 AM CET    Success
Attach vNetworks                         January 20, 2022 10:48:25 AM CET    January 20, 2022 10:48:25 AM CET    Success
Save configuration in ACFS               January 20, 2022 10:48:25 AM CET    January 20, 2022 10:48:25 AM CET    Success
Save live VM configuration in ACFS       January 20, 2022 10:48:25 AM CET    January 20, 2022 10:48:26 AM CET    Success
Modify VM metadata                       January 20, 2022 10:48:26 AM CET    January 20, 2022 10:48:26 AM CET    Success
Persist metadata                         January 20, 2022 10:48:26 AM CET    January 20, 2022 10:48:26 AM CET    Success

[[email protected] network-scripts]#

Describing again the VM, we can see that the backupnet vNetwork is now attached and persistent

[[email protected] network-scripts]# odacli describe-vm -n vmserver-appli
VM details
--------------------------------------------------------------------------------
                       ID:  14f10064-a048-419d-a850-18b1d9b2b69e
                     Name:  vmserver-appli
                  Created:  2021-10-21 14:51:50 CEST
                  Updated:  2022-01-20 10:48:26 CET
               VM Storage:  storevms
              Description:  Web site standby
            VM image path:  /u05/app/sharedrepo/storevms/.ACFS/snaps/vm_vmserver-appli/vmserver-appli
                  VM size:  20.00 GB
                   Source:  V1009690-01.iso
                  OS Type:  NONE
               OS Variant:  NONE
        Graphics settings:  vnc,listen=127.0.0.1
             Display Port:  127.0.0.1:1

 Status
--------------------------
             Current node:  oda-dev-01
            Current state:  ONLINE
             Target state:  ONLINE

 Parameters
--------------------------
           Preferred node:  NONE
              Boot option:  NONE
               Auto start:  YES
                Fail over:  NO
             NUMA enabled:  NO

                            Config                     Live
                            -------------------------  -------------------------
                   Memory:  4.00 GB                    4.00 GB
               Max Memory:  8.00 GB                    8.00 GB
               vCPU count:  3                          3
           Max vCPU count:  6                          6
                 CPU Pool:  cpuvms                     cpuvms
        Effective CPU set:  1-9,17-25,33-41,49-57      1-9,17-25,33-41,49-57
                    vCPUs:  0:1-9,17-25,33-41,49-57    0:1-9,17-25,33-41,49-57
                            1:1-9,17-25,33-41,49-57    1:1-9,17-25,33-41,49-57
                            2:1-9,17-25,33-41,49-57    2:1-9,17-25,33-41,49-57
                   vDisks:  vdisk2webs21:vdc           vdisk2webs21:vdc
                            vdisk1webs21:vdb           vdisk1webs21:vdb
                vNetworks:  backupnet:52:54:00:b2:ae:94  backupnet:52:54:00:b2:ae:94
                            pubnet:52:54:00:e9:26:18   pubnet:52:54:00:e9:26:18

[[email protected] network-scripts]#

Connecting on the VM, we can see that there is a second network interface card eth1.

[[email protected] ~]# ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0:  mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 52:54:00:e9:26:18 brd ff:ff:ff:ff:ff:ff
    inet 10.18.35.139/24 brd 10.18.35.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::f7a:d225:d568:5afa/64 scope link noprefixroute
       valid_lft forever preferred_lft forever
3: eth1:  mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 52:54:00:b2:ae:94 brd ff:ff:ff:ff:ff:ff
[[email protected] ~]#

Now you can configure this second network card according to your needs

Conclusion

Hope this blog will help. Just a recommendation is to always restart VMs with odacli stop-vm after modifications, this will validate that your changes are persistent or not

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Mouhamadou Diaw
Mouhamadou Diaw

Senior Consultant