Skip to main content

Reset root password RHEL/Rocky/CentOS 9

Unlike the earlier versions of Rethat variants, version 9 doesn't allow single user mode to change password, as maintanance mode in 9 requires root password.

Single user mode (runlevel 1) can easily be obtained by appending the word 'single' at the end of the line starting with 'linux' by editing the entry in boot menu by pressing 'e' at boot menu.


To reset the root password on the other hand, one requires to follow a specific set of commands,



  1. At the boot menu, edit rescue mode to append 'rd.break' at the end of the line starting with kernel.
  2. Boot with the edited line by pressing Ctrl+X or F10.
  3. At the new prompt starting with switch_root, type the following commands,

mount -o remount, rw /sysroot
chroot /sysroot
touch /.autorelabel
passwd <new root password>
exit
reboot

     



Labels:

Comments

Post a Comment

Popular posts from this blog

Multimaster replication with Symmetric DS

Symmetric DS is an awesome tool for trigger based replication whcih works for all major database vendors, including but not limited to PostgreSQL, MySQL, MSSQL, Oracle and many others. Symmetric-DS is a java application and can execute on any platform on whcih JRE is available including Windows and Linux. Trigger based replication, in constrast to disk based (eg. DRBD ) or transaction log file shipping based or statement based , works by registering triggers on DMLs and sending the data thus generated to remote machines. Another very popular trigger based DB replication tool is Slony . Symmetric-DS in addition to being database agnostic also supports multi-master replication (MMR). MMR usecase involves multiple database nodes, connected in a pool with DML updates coming from any of them. This is different from the normal master-slave replication, where slaves are not expected to generate any data events, and the sole authority of database is the master. MMR requirement causes d...
1 comment
Read more

PC Power supply and hacks

For posterity and myself, I'm leaving some tips and tricks of PC Power Supply Unit (PSU) whcih is an SMPS (Switched Mode Power Supply). There are a variety of uses of a +12V, +5V and +3V DC power supply like lighting up an LED strip or powering a raspberry pi. There are various colored cables in a typical ATX 12V SMPS. I'll list out the various color lines and what they mean, Sr. No Cable color Number of cables in a PSU Use 1 Green exactly one (1) Wake up signal from motherboard. Pressing PC power button makes this signal carry wake up signal to PSU to start. Green needs to be touched with the any ground to make the SMPS start. For self-starting PSUs, green needs to be connected with one black all the time. 2 Blue exactly one (1) -12V 3 Purple exactly one (1) +5V standby. When power supply is on standby mode (not on by signalling green), this line can give 1-2 A current. 4 Gray exactly one (1) Power good signal. When PSU levels has reached specificati...
3 comments
Read more

SSL cIpher suits and what they mean?

I'm sure you have wondered at all those cipher suits SSL supports and watched in wonder as to what the hell does all those weird abbreviation mean. To find out what all cipher suits your openssl installation supports try, $ openssl ciphers -v ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(256) Mac=AEAD ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AESGCM(256) Mac=AEAD ECDHE-RSA-AES256-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AES(256)  Mac=SHA384 ECDHE-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AES(256)  Mac=SHA384 ECDHE-RSA-AES256-SHA    SSLv3 Kx=ECDH     Au=RSA  Enc=AES(256)  Mac=SHA1 ECDHE-ECDSA-AES256-SHA  SSLv3 Kx=ECDH     Au=ECDSA Enc=AES(256)  Mac=SHA1 SRP-DSS-AES-256-CBC-SHA SSLv3 Kx=SRP      Au=DSS  Enc=AES(256)  Mac=SHA1 S...
Post a Comment
Read more