RHEL 8 New Features for Experienced Linux Administrators

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Lab: Implementing Enhanced Networking Features

In this lab, you will configure network interfaces and devices using the web console.

Outcomes

You should be able to:

  • Review the network configurations from a system using the web console and nmcli.

  • Configure Ethernet network interfaces using the web console.

  • Configure bonded network interfaces using the web console.

Log in to workstation as student using student as the password. On workstation, run the lab net-review start command to verify that the environment is ready and prepare the system for the lab. 

[student@workstation ~]$ lab net-review start

  1. The web console is already installed on the system, but it is not activated. Enable and start the web console service on serverb.

    1. Log in to serverb as the root user. 

      [student@workstation ~]$ ssh root@serverb

    2. Use the systemctl enable cockpit.socket command to enable the web console service. 

      [root@serverb ~]# systemctl enable cockpit.socket
Created symlink /etc/systemd/system/sockets.target.wants/cockpit.socket -> /usr/lib/systemd/system/cockpit.socket.

    3. Use the systemctl start cockpit command to start the web console service. 

      [root@serverb ~]# systemctl start cockpit

    4. Log off from serverb. 

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

  2. On workstation open Firefox and log in to the web console running on serverb system as the student user with student as password.

    1. Open Firefox and go to the https://serverb.lab.example.com:9090 address.

    2. Accept the self-signed certificate by adding it as an exception.

    3. Log in as student user with student as password, mark the Reuse my password for privileged tasks check box.

      You are now logged in as a student user, with Privileged access.

  3. Configure and enable an Ethernet interface on serverb, using the web console.

    Parameter Value
    Interface ens4
    Address 172.25.250.20/24

    1. Click Networking in the left menu bar.

    2. Click on the ens4 interface, to edit IPv4 details.

    3. Click on Automatic (DHCP) link.

    4. In the new IPv4 Settings window, for the Addresses choose Manual.

    5. In the Address text box, type in 172.25.250.20 as IP Address.

    6. In the Prefix length or Netmask text box, type in the 255.255.255.0 netmask value.

    7. Click the Apply button to save the new network configuration.

      Notice that the new configuration is immediately applied, and the new IP Address is visible in the IPv4 line.

    8. Enable the network interface by toggling ON/OFF to ON.

  4. Configure a Bonded interface, on serverb, using the web console.

    Parameter Value
    Interface Name bond0
    Interface Members ens5 and ens6
    Mode Active Backup
    Address 172.25.250.21/24

    Important

    When creating Bonded/Teaming Interfaces through web console, you can potentially get those interfaces in an unmanaged state. That is caused by dhclient exhausted its timeout if there are not DHCP Server available, and those interfaces are activated by default with DHCP as Addressing method. You can get the interface back to a managed state with the nmcli tool, and try again to configure the IP settings. For example, for a bonded interface named bond0: 

    nmcli device set bond0 managed yes

    1. Click Networking in the left navigation bar.

    2. Click the Add Bond button.

    3. In the new Bond Settings window, use bond0 as Name, mark the ens5 and ens6 interfaces as Members, and ensure the selected Mode is Active-Backup. Leave the other settings options as default.

    4. Click the Apply button to save the new bonded interface.

    5. Click on the bond0 interface, to edit IPv4 details.

    6. Click on Automatic (DHCP) link.

    7. In the new IPv4 Settings window, for the Addresses choose Manual.

    8. In the Address text box, type in 172.25.250.21 as IP Address.

    9. In the Prefix length or Netmask text box, type in the 255.255.255.0 netmask value.

    10. Click the Apply button to save the new network configuration.

      Notice that the new configuration is immediately applied, and the new IP Address is visible in the IPv4 line.

  5. Review the changes with the nmcli tool, and system tools like ip, on serverb.

    1. In the web console, click on Terminal in the left navigation bar to access the terminal.

      A terminal session opens with the student user already logged in.

    2. Show the network connections status on serverb. 

      [student@serverb ~]$ nmcli connection
NAME   UUID                                  TYPE      DEVICE
bond0  491a07c3-37c4-4079-98cb-bc1931a0b1b8  bond      bond0
ens3   d27327cd-9e6e-45dd-b71f-4c0b99e62742  ethernet  ens3
ens4   7b941fb1-3f77-4a5c-9c73-bbbf9f26b8fb  ethernet  ens4
ens5   554a2f71-db4b-44db-b70a-a23e70dbba69  ethernet  ens5
ens6   3650e4c9-799c-4243-b0ad-c6006f74f453  ethernet  ens6

    3. Show the network devices status on serverb. 

      [student@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  --

    4. Verify the system interfaces status on serverb. 

      [student@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:c2:60:27:fb:cf brd ff:ff:ff:ff:ff:ff
    inet 172.25.250.20/24 brd 172.25.250.255 scope global noprefixroute ens4
...output omitted...
4: ens5: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc fq_codel master bond0 state UP group default qlen 1000
    link/ether 2c:c2:60:22:6b:41 brd ff:ff:ff:ff:ff:ff
5: ens6: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc fq_codel master bond0 state UP group default qlen 1000
    link/ether 2c:c2:60:22:6b:41 brd ff:ff:ff:ff:ff:ff
15: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 2c:c2:60:22:6b:41 brd ff:ff:ff:ff:ff:ff
    inet 172.25.250.21/24 brd 172.25.250.255 scope global noprefixroute bond0
...output omitted...

    5. Log out of the web console on serverb.

Finish

From workstation, run lab net-review finish to clean up any resources created for this exercise. 

[student@workstation ~]$ lab net-review finish

This concludes the guided exercise.

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Revision: rh354-8.0-0e36520