Linux commands

Add user celladmin with su access

add below using visudo

visudo

celladmin  ALL=(ALL)       NOPASSWD: ALL


Now to  test

login as celladmin user

type

sudo -s


To set password not expire

password unexpire

chage -l celladmin

chage -I -1 -m 0 -M 99999 -E -1 celladmin


add user to sudo with no password

oracle ALL=(root)  NOPASSWD:  /bin/su - 

root account gets locked on exadata

On Exadata after failed login accounts even root account gets locked. Play with values below to increase hits

$  grep -i pam_tally2 /etc/pam.d/sshd
auth       required     pam_tally2.so deny=5 onerr=fail lock_time=600 serialize                        

$ grep -i pam_tally2 /etc/pam.d/login
auth       required     pam_tally2.so deny=5 onerr=fail lock_time=600 serialize

Meaning of options:
1) deny=5 <<<<<< user account will be locked after 5 in-correct wrong passwords
2) lock_time=600   <<<< user account will be locked for 600 seconds i.e. for next 10mins

When Input Wrong Root Password Login Exadata System, We Have To Wait For 10mins ( Doc ID 1541862.1 )

use vi editor to change it to 10 seconds

vi /etc/pam.d/sshd

auth       required     pam_tally2.so deny=5 onerr=fail lock_time=10 serialize



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To reset ssh for a user and allow logins

pam_tally2 -r -u oracle