RHCSA Rapid Track

Use the ssh command to log in to servera as the student user. The systems are configured to use SSH keys for authentication, so a password is not required to log in to servera.

[student@workstation ~]$ ssh student@servera
...output omitted...
[student@servera ~]$ 

View the current host name settings.

1. Display the current host name.

   [student@servera ~]$ hostname
   servera.lab.example.com

2. Display the host name status.

   [student@servera ~]$ hostnamectl status
      Static hostname: n/a
   Transient hostname: servera.lab.example.com
            Icon name: computer-vm
              Chassis: vm
           Machine ID: f874df04639f474cb0a9881041f4f7d4
              Boot ID: 22ae5279f57049678eda547bdb39a19d
       Virtualization: kvm
     Operating System: Red Hat Enterprise Linux 8.2 (Ootpa)
          CPE OS Name: cpe:/o:redhat:enterprise_linux:8.2:GA
               Kernel: Linux 4.18.0-193.el8.x86_64
         Architecture: x86-64

   Note the transient hostname obtained from DHCP or mDNS.

Set a static host name to match the current transient host name.

1. Change the host name and host name configuration file.

   [student@servera ~]$ sudo hostnamectl set-hostname \
   servera.lab.example.com
   [sudo] password for student: student
   [student@servera ~]$ 

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

   servera.lab.example.com

3. Display the host name status.

   [student@servera ~]$ hostnamectl status
      Static hostname: servera.lab.example.com
            Icon name: computer-vm
              Chassis: vm
           Machine ID: f874df04639f474cb0a9881041f4f7d4
              Boot ID: 22ae5279f57049678eda547bdb39a19d
       Virtualization: kvm
     Operating System: Red Hat Enterprise Linux 8.2 (Ootpa)
          CPE OS Name: cpe:/o:redhat:enterprise_linux:8.2:GA
               Kernel: Linux 4.18.0-193.el8.x86_64
         Architecture: x86-64

   Note that the transient hostname is not shown now that a static hostname has been configured.

Temporarily change the host name.

1. Change the host name.

   [student@servera ~]$ sudo hostname testname

2. Display the current host name.

   [student@servera ~]$ hostname
   testname

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

   servera.lab.example.com

4. Reboot the system.

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

5. From workstation log in to servera as student user.

   [student@workstation ~]$ ssh student@servera
   ...output omitted...
   [student@servera ~]$ 

6. Display the current host name.

   [student@servera ~]$ hostname
   servera.lab.example.com

Add a local nickname for the classroom server.

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

   [student@servera ~]$ host classroom.example.com
   classroom.example.com has address 172.25.254.254

2. Modify /etc/hosts so that the additional name of class can be used to access the IP address 172.25.254.254.

   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
   172.25.254.254 content.example.com content
   ...content omitted...

3. Look up the IP address of class.

   [student@servera ~]$ host class
   Host class not found: 2(SERVFAIL)
   [student@servera ~]$ getent hosts class
   172.25.254.254    classroom.example.com class

4. Ping class.

   [student@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=64 time=0.397 ms
   64 bytes from classroom.example.com (172.25.254.254): icmp_seq=2 ttl=64 time=0.447 ms
   64 bytes from classroom.example.com (172.25.254.254): icmp_seq=3 ttl=64 time=0.470 ms
   
   --- classroom.example.com ping statistics ---
   3 packets transmitted, 3 received, 0% packet loss, time 2000ms
   rtt min/avg/max/mdev = 0.397/0.438/0.470/0.030 ms

5. Exit from servera.

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