Red Hat System Administration I

Instructions

1. Log in to servera as the student user and switch to root user.

   [student@workstation ~]$ ssh student@servera
   ...output omitted...
   [student@testa ~]$ sudo -i
   [sudo] password for student: student
   [root@testa ~]#

2. View the current hostname settings.

   1. Display the current hostname.

      [root@testa ~]# hostname
      testa

   2. Display the hostname status. The persistent, locally configured hostname is displayed in the Static hostname field. The current runtime hostname, which is obtained from DHCP or DNS network services, is displayed in the Transient hostname field.

      [root@testa ~]# hostnamectl status
         Static hostname: servera.lab.example.com
      Transient hostname: testa
               Icon name: computer-vm
                 Chassis: vm 🖴
              Machine ID: ace63d6701c2489ab9c0960c0f1afe1d
                 Boot ID: 03bf1d5518bd43b4a25cfe9a18d5a46a
          Virtualization: kvm
        Operating System: Red Hat Enterprise Linux 9.0 (Plow)
             CPE OS Name: cpe:/o:redhat:enterprise_linux:9::baseos
                  Kernel: Linux 5.14.0-70.13.1.el9_0.x86_64
            Architecture: x86-64
         Hardware Vendor: Red Hat
          Hardware Model: OpenStack Compute

3. Set a static hostname to match the current static hostname.

   1. Change the hostname and the hostname configuration file.

      [root@testa ~]# hostnamectl hostname \
      servera.lab.example.com

   2. View the content of the /etc/hostname file, which provides the hostname at network start.

      [root@testa ~]# cat /etc/hostname
      servera.lab.example.com

   3. Log out and log in to servera as the student user. Switch to the root user to change the command prompt to show the updated hostname.

      [root@testa ~]# exit
      logout
      [student@testa ~]$ exit
      logout
      Connection to servera closed.
      [student@workstation ~]$ ssh student@servera
      ...output omitted...
      [student@servera ~]$ sudo -i
      [sudo] password for student: student
      [root@servera ~]#

   4. Display the hostname status. The transient hostname is not shown, now that a static hostname is configured.

      [root@servera ~]# hostnamectl status
       Static hostname: servera.lab.example.com
             Icon name: computer-vm
               Chassis: vm
            Machine ID: 63b272eae8d5443ca7aaa5593479b25f
               Boot ID: ef299e0e957041ee81d0617fc98ce5ef
        Virtualization: kvm
      Operating System: Red Hat Enterprise Linux 9.0 (Plow)
           CPE OS Name: cpe:/o:redhat:enterprise_linux:9::baseos
                Kernel: Linux 5.14.0-70.el9.x86_64
          Architecture: x86-64
       Hardware Vendor: Red Hat
        Hardware Model: OpenStack Compute

4. Temporarily change the hostname to testname.

   1. Change the hostname.

      [root@servera ~]# hostname testname

   2. Display the current hostname.

      [root@servera ~]# hostname
      testname

   3. View the content of the /etc/hostname file, which provides the hostname at network start.

      [root@servera ~]# cat /etc/hostname
      servera.lab.example.com

   4. Reboot the system.

      [root@servera ~]# systemctl reboot
      Connection to servera closed by remote host.
      Connection to servera closed.
      [student@workstation ~]$

   5. Log in to servera as the student user and switch to the root user.

      [student@workstation ~]$ ssh student@servera
      ...output omitted...
      [student@servera ~]$ sudo -i
      [sudo] password for student: student
      [root@servera ~]#

   6. Display the current hostname.

      [root@servera ~]# hostname
      servera.lab.example.com

5. Add class as a local nickname for the classroom server, and ensure that you can ping the server with that nickname.

   1. Look up the IP address of the classroom.example.com server.

      [root@servera ~]# host classroom.example.com
      classroom.example.com has address 172.25.254.254

   2. Update the /etc/hosts file to add the class server to access the 172.25.254.254 IP address. The following example shows the expected content of the /etc/hosts file.

      [root@servera ~]# vim /etc/hosts
      127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
      ::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
      172.25.254.254 classroom.example.com classroom class

   3. Look up the IP address of the class server.

      [root@servera ~]# host class
      Host class not found: 3(NXDOMAIN)
      [root@servera ~]# getent hosts class
      172.25.254.254  classroom.example.com classroom class

   4. Use the ping command to send packets to the class server.

      [root@servera ~]# ping -c3 class
      PING classroom.example.com (172.25.254.254) 56(84) bytes of data.
      64 bytes from classroom.example.com (172.25.254.254): icmp_seq=1 ttl=63 time=1.21 ms
      64 bytes from classroom.example.com (172.25.254.254): icmp_seq=2 ttl=63 time=0.688 ms
      64 bytes from classroom.example.com (172.25.254.254): icmp_seq=3 ttl=63 time=0.559 ms
      
      --- classroom.example.com ping statistics ---
      3 packets transmitted, 3 received, 0% packet loss, time 2046ms
      rtt min/avg/max/mdev = 0.559/0.820/1.214/0.283 ms

   5. Return to the workstation system as the student user.

      [root@servera ~]# exit
      logout
      [student@servera ~]$ exit
      logout
      Connection to servera closed.
      [student@workstation ~]$