RHEL 8 New Features for Experienced Linux Administrators

Log in to serverb as the root user.

[student@workstation ~]$ ssh root@serverb

Explore the nmcli tool.

1. The nmcli tool is included in the NetworkManager package and is installed by default in Red Hat Enterprise Linux 8.

   [root@serverb ~]# nmcli --help
   ...output omitted...
   OBJECT
     g[eneral]       NetworkManager's general status and operations
     n[etworking]    overall networking control
     r[adio]         NetworkManager radio switches
     c[onnection]    NetworkManager's connections
     d[evice]        devices managed by NetworkManager
     a[gent]         NetworkManager secret agent or polkit agent
     m[onitor]       monitor NetworkManager changes

2. Explore the general network status on serverb.

   [root@serverb ~]# nmcli general status
   STATE      CONNECTIVITY  WIFI-HW  WIFI     WWAN-HW  WWAN
   connected  full          enabled  enabled  enabled  enabled

3. Verify network connectivity on serverb.

   [root@serverb ~]# nmcli networking connectivity check
   full

4. Explore the wireless options with nmcli radio.

   [root@serverb ~]# nmcli radio help
   Usage: nmcli radio { COMMAND | help }
   
   COMMAND := { all | wifi | wwan }
   
     all | wifi | wwan [ on | off ]

5. Show network device status on serverb.

   [root@serverb ~]# nmcli device status
   ens3    ethernet  connected     Wired connection 1
   ens4    ethernet  disconnected  --
   ens5    ethernet  disconnected  --
   ens6    ethernet  disconnected  --
   lo      loopback  unmanaged     --

6. Show network connection status on serverb.

   [root@serverb ~]# nmcli connection
   NAME                UUID                                  TYPE      DEVICE
   Wired connection 1  d27327cd-9e6e-45dd-b71f-4c0b99e62742  ethernet  ens3

7. Rename a network connection on serverb.

   [root@serverb ~]# nmcli connection modify "Wired connection 1" \
   > connection.id ens3
   [root@serverb ~]# nmcli connection
   NAME  UUID                                  TYPE      DEVICE
   ens3  d27327cd-9e6e-45dd-b71f-4c0b99e62742  ethernet  ens3

Configure a network interface with the nmcli tool on serverb.

1. Create an Ethernet network connection on serverb using the ens4 interface and name it ens4.

   [root@serverb ~]# nmcli connection add type ethernet ifname ens4 \
   > connection.id ens4
   Connection 'ens4' (99671499-dacd-4f87-8c09-25d9e0b7301e) successfully added.

2. Assign an IPv4 address to the ens4 network connection on serverb.

   [root@serverb ~]# nmcli connection modify ens4 ipv4.addresses 172.25.250.20/24

3. Enable manual IPv4 address assignation on interface ens4 on serverb.

   [root@serverb ~]# nmcli connection modify ens4 ipv4.method manual

4. Activate the ens4 network connection on serverb.

   [root@serverb ~]# nmcli connection up ens4
   Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/124)

5. Verify the system interface status on serverb.

   [root@serverb ~]# ip address
   ...output omitted...
   3: ens4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
       link/ether 2c:c2:60:23:34:b3 brd ff:ff:ff:ff:ff:ff
       inet 172.25.250.20/24 brd 172.25.250.255 scope global noprefixroute ens4
   ...output omitted...

6. Show network device status on serverb.

   [root@serverb ~]# nmcli device status
   DEVICE  TYPE      STATE         CONNECTION
   ens3    ethernet  connected     ens3
   ens4    ethernet  connected     ens4
   ens5    ethernet  disconnected  --
   ens6    ethernet  disconnected  --
   lo      loopback  unmanaged     --

Configure a bonded interface with nmcli tool on serverb.

1. Create an Active-Backup bonded interface, name it bond0 with ens5 and ens6 as members on serverb.

   [root@serverb ~]# nmcli connection add type bond \ 
   > ifname bond0 connection.id bond0 \
   > ipv4.method disabled ipv6.method ignore \
   > mode active-backup
   Connection 'bond0' (bf741496-bd5f-4573-a453-16dae9743bdb) successfully added.

2. Assign the network interfaces ens5 and ens6 as members of the bonded interface bond0 on serverb.

   [root@serverb ~]# nmcli connection add type ethernet \
   > ifname ens5 connection.id ens5 \
   > ipv4.method disabled ipv6.method ignore \
   > master bond0
   Connection 'ens5' (17b957ca-a691-433d-b632-5048944e3646) successfully added.
   [root@serverb ~]# nmcli connection add type ethernet \
   > ifname ens6 connection.id ens6 \
   > ipv4.method disabled ipv6.method ignore \
   > master bond0
   Connection 'ens6' (c06fc02d-3cc0-4b45-babd-b4e1895f631f) successfully added.

3. Enable manual IPv4 address assignment, and set an IPv4 address to the bonded interface bond0 on serverb.

   [root@serverb ~]# nmcli connection modify bond0 \
   > ipv4.method manual ipv4.addresses 172.25.250.21/24

4. Activate the member interfaces ens5, ens6 an the bonded interface bond0 network connections on serverb.

   [root@serverb ~]# nmcli connection up ens5
   Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/128)
   [root@serverb ~]# nmcli connection up ens6
   Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/129)
   [root@serverb ~]# nmcli connection up bond0
   Connection successfully activated (master waiting for slaves) (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/130)

5. Show the network devices status on serverb.

   [root@serverb ~]# nmcli device status
   DEVICE  TYPE      STATE      CONNECTION
   ens3    ethernet  connected  ens3
   bond0   bond      connected  bond0
   ens4    ethernet  connected  ens4
   ens5    ethernet  connected  ens5
   ens6    ethernet  connected  ens6
   lo      loopback  unmanaged  --

6. Verify the system interfaces status on serverb.

   [root@serverb ~]# ip address
   ...output omitted...
   3: ens5: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc fq_codel master bond0 state UP group default qlen 1000
       link/ether 2c:c2:60:33:e6:79 brd ff:ff:ff:ff:ff:ff
   4: ens6: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc fq_codel master bond0 state UP group default qlen 1000
       link/ether 2c:c2:60:33:e6:79 brd ff:ff:ff:ff:ff:ff
   8: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
       link/ether 2c:c2:60:33:e6:79 brd ff:ff:ff:ff:ff:ff
       inet 172.25.250.21/24 brd 172.25.250.255 scope global noprefixroute bond0
   ...output omitted...

Verify the network configurations on serverb.

1. Explore the new bonded interface bond0 properties on serverb.

   [root@serverb ~]# nmcli device show bond0
   GENERAL.DEVICE:                         bond0
   GENERAL.TYPE:                           bond
   GENERAL.HWADDR:                         2C:C2:60:33:E6:79
   GENERAL.MTU:                            1500
   GENERAL.STATE:                          100 (connected)
   GENERAL.CONNECTION:                     bond0
   GENERAL.CON-PATH:                       /org/freedesktop/NetworkManager/ActiveConnection/459
   IP4.ADDRESS[1]:                         172.25.250.21/24
   ...output omitted...

2. Explore the new Ethernet interface ens4 properties on serverb.

   [root@serverb ~]# nmcli device show ens4
   GENERAL.DEVICE:                         ens4
   GENERAL.TYPE:                           ethernet
   GENERAL.HWADDR:                         2C:C2:60:23:34:B3
   GENERAL.MTU:                            1500
   GENERAL.STATE:                          100 (connected)
   GENERAL.CONNECTION:                     ens4
   GENERAL.CON-PATH:                       /org/freedesktop/NetworkManager/ActiveConnection/124
   WIRED-PROPERTIES.CARRIER:               on
   IP4.ADDRESS[1]:                         172.25.250.20/24
   ...output omitted...

3. Log off from serverb.

   [root@serverb ~]# exit
   Connection to serverb closed.