Month: September 2018

by

Changing Hostname in xCAT 2.14

All activities to be triggered from Master Node 1

Step 1:

# ssh nodename

Step 2:

# /etc/sysconfig/network | Add HOSTNAME=newnodename						
# /etc/hostname | Add newnodename

exit

Step 3:
Remove Old Provision Environment

# makedns -d nodename /*Remove the nodes from DNS configuration*/
# makedhcp -d nodename /*Remove the nodes from the DHCP configuration*/

Step 4:
Change Definition

# chdef -t node -o oldnodename -n newnodename /*Change the hostname in the xCAT database*/
# chdef -t node -o newnodename bmc=oldbmcname /*Re add the bmc name in the xCAT database*/

Step 5:
Change the hostname and IP address in the /etc/hosts file

# makehosts newnodename

Step 6:

# makedns -n /*Configure the new names in DNS*/
# makedhcp -a /*Configure the new names in DHCP*/
# makeconfluentcfg /*Update Console Server*/

Step 7:
Reboot Updated Server

Step 8:
After you repeat Step – 1 to Step – 7 for all nodes On the primary management node.
Run

# pscp /etc/hosts all:/etc/

to copy the hosts file to all the nodes except the new node, because the new node need password authentication at this point.

by

SSH Login without Password

The SSH daemon validates SSH client access by Linux system verification via /etc/passwd, or by public/private key cryptography approach.

By using the public/private cryptography approach, we can do a SSH without password.

In my write-up it is for root-to-root connection. You can use it for user connections.

Steps 1: At the Host Machine

  1. Logon to the root home directory.
  2. Make sure the hidden .ssh directory has the permission 700. If not execute the command 
    # chmod 700 .ssh
  3. Change Directory to .ssh directory by executing the command 
    # cd .ssh
  4. Generate the public-private keys using the ssh-keygen command. 
    # ssh-keygen -t rsa
  5. The resulting file id_rsa and id_rsa.pub rsa type public key 
    # ssh-copy-id -i ~/.ssh/id_rsa.pub remote-host

    (ssh-copy-id appends the keys to the remote-host’s .ssh/authorized_key)

Step 2: At the Remote Machine,

  1. Test it out on the remote server 
    # ssh remote-host

References