1 / 28

System Administration Software Management & User Management

System Administration Software Management & User Management. 1. Contents. Managing Software Managing Users Some Useful notes Security modules. 2. Managing Software. RPM YUM Non-RPM packages. 3. Managing Software. Red Hat Package Management ( RPM )

trey
Download Presentation

System Administration Software Management & User Management

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. System Administration Software Management & User Management 1

  2. Contents • Managing Software • Managing Users • Some Useful notes • Security modules 2

  3. Managing Software • RPM • YUM • Non-RPM packages 3

  4. Managing Software • Red Hat Package Management (RPM) • It was first used with Red Hat 2.0. • Improving the package management • Could ease the task of building software for different platform from a single set of source-code files. 4

  5. rpm Command • It is used to install, remove, upgrade, verify and build software archives. • RPM uses the system’s /var/lib/rpm to store various files containing information about the software installed. • The primary database of installed software is contained in the file named Packages. 5

  6. rpm Command Tasks • Installing new software. • Erasing or removing outdated or unneeded packages. • Upgrading an installed software package. • Querying to get information about a software package. • Verifying the installation or integrity of a package installation. 6

  7. Related Tags • -i install • -e erase • Check dependencies while removing a package • rpm -e samba • error: Failed dependencies: samba is needed by (installed) system-config-samba-1.2.83-1.fc12.noarch • two choices • ignore the dependency by including the rpm --nodeps option • remove the dependent package first 7

  8. Related Tags • -U upgrade • -q query • rpm -q • –ql  list options to list the files in a package • rpm -ql logrotate • -qa  display a list of all packages installed on the system • –qi  displays information about a package • rpm -qi logrotate 8

  9. Related Tags • -qf  determine which package a file belongs to. • rpm -qf /bin/more • -V verify • -vh provide a more verbose output and display of hash mark • -lpq where the package is installed • rpm -qf /bin/more util-linux-ng-2.16-10.2.fc12.i686 9

  10. Installing software from source • The installation procedure for software that comes in tar.gz and tar.bz2 packages isn't always the same, but usually it's like this: • Step 1. Unpacking • # tar xvzf package.tar.gz (or tar xvjf package.tar.bz2) 10

  11. Installing software from source • Step 2. Configuring • it's done by running the configure script. • $cd pkg • $./configure • configure just checks your system and assigns values for system-dependent variables. These values are used for generating a Makefile. The Makefile in turn is used for generating the actual binary. 11

  12. Installing software from source • Step 3. Building • build the binary, the executable program, from the source code. • $ make • Step 4. Installing • $ su • # make install 12

  13. Installing software from source • Cleaning up the mess • $ make clean • Uninstalling • #make uninstall 13

  14. Contents • Managing Software • Managing Users • Some Useful notes • Security modules 14

  15. Managing Users • Each system has two kinds of users: • Superuser (root) • Regular user • Each user has his own username, password, and permissions that can only be assigned by the user. • All users have a user ID (UID) and a group ID (GID). 15

  16. The su Command • It is necessary for regular users to run a command as if they were root. • The su means substitute user. • This command changes the UID and GID of the existing user. • The syntax for the su command is this: su option username arguments • To return to the regular users’ identity • exit 16

  17. The su Command • Use su with the –c option to run a single command with root privileges • su -c "kill -15 4982" • su -c “ls /root” • su -c “ls /home/bob” – bob read bob's home directory. 17

  18. The sudo Command • It gives to the certain users only a few superuser permissions. • The list of authorized users is kept in /etc/sudoers • Sudo will prompt for a password and then check the /etc/sudoers. 18

  19. Groups • /etc/group • The custom is to use GIDs of 500 or more for regular users and less for administrations or special program. • Groupname:password:gid:users root:x:0:root bin:x:1:root,bin,daemon test:x:500: • Special group • Allow these services to manage their own files with permissions that restrict other users from them. 20

  20. The Password File • /etc/passwd • It is the database file for all users on the system. • Username:password:uid:gid:comment:homedir:shell 21

  21. Shadow Passwords • /etc/shadow • It is considered to use the encrypted passwords found in /etc/passwd. • Only x or * appears in the passwprd field of /etc/passwd. • * in password means disable. 22

  22. Shadow Password Fields • User name : It is your login name • Password: It your encrypted password. • Last password change (lastchanged): Days since Jan 1, 1970 that password was last changed • Minimum: The minimum number of days required between password changes. • Maximum: The maximum number of days the password is valid (after that user is forced to change his/her password) 23

  23. Shadow Password Fields • Warn : The number of days before password is to expire that user is warned • Inactive : The number of days after password expires that account is disabled • Expire : days since Jan 1, 1970 that account is disabled i.e. an absolute date specifying when the login may no longer be used 24

  24. User’s Home Directory • When each user is created, a home directory is created for him (/home/<username>). • The set of files that initially are used to populated this home directory are kept in /etc/skel. 25

  25. User Management Commands • useradd • userdel • Delete a user • userdel -r username • usermod • groupadd • groupdel • groupmod • grpck • Verify the integrity of the system authentication information. 26

  26. Useradd • Useradd creates a new user • Based on the /etc/login.defs file, the system creates a home directory for the new user. • copies the contents of /etc/skel in the users home • useradd [-c comment] [-d home_dir] [-e expire_date] [-f inactive_time] [-g initial_group] [-G group[,...]] [-m [-k skeleton_dir]] [-p passwd] [-s shell] [-u uid [ -o]] login • useradd -g 500 -c "Alex Watson" alex –p 4567654 • The –D option displays default options • Use passwd to give the user a password. 27

  27. Communicating With Users • write • Send a message to a user • wall (write all) • Sends a message to the terminals of all user connected to the system. 28

  28. Some Useful Command • chmod Change file access permission chown Change file owner or group chroot Run command with special root directory crond Daemon to execute scheduled program

More Related