RH133 redhat enterprise linux system administration

RH133 Redhat Enterprise Linux System Administration Unit 1  Installation Hardware Overview  Kernel Support  Core support: CPU, Memory, Process  Management , Interrupt/Exception Handling etc.  Dynamically Loadable Kernel Modules  Device Drivers  Additional Functionality  User Mode Access to kernel facilities  System Calls and Signals  Filesystem Device Nodes  Network Interfaces  Are not accessed through a device node but instead are accessed through a “network interface” abstraction. CPU and Memory  Seven Supported Architectures: x86, Itanium2, AMD64/EM64T, S/390, zSeries, iSeries, pSeries.  CPU Support on x86  Technical support for more than 2 physical CPUs only on AS variant (may use Hyper-Threading)  Up to 32 Physical CPUs with SMP or hugemem kernel.  Memory support on x86  Technical support for more than 16 GB on AS or WS  Standard i686/athlon kernel: 4GB  SMP i686/athlon kernel: 16GB  Hugemem SMP kernel: 64GB Preparing to Install  Read the RELEASE-NOTES file on the first CD or at http://www.redhat.com  Check Hardware Compatibility  Redhat Supported Hardware List  Hardware compatible with Redhat Linux  http://hardware.redhat.com/hcl  XFree86 supported video cards.  http://xorg.freedesktop.org  http://www.x.org/wiki Multiboot systems  Redhat Enterprise Linux and the GRUB boot loader can co-exist with other operating systems, including the following:  Windows NT/2000/XP/2003  DOS, Windows 3.x/9x/ME  NetBSD, FreeBSD and other open systems.  Two major issues arise when implementing multiboot systems:  Partitioning and the boot process.  A boot loader such as System Commander or NTLDR is already on the system and will launch GRUB as a secondary boot loader. Device Node Examples  Block devices:  hd[a-t] IDE devices  sd[a-z]+ SCSI devices  fd[0-7] Standard floppy drives  md[0-31] software RAID metadisks  loop[0-15] loopback devices  ram[0-9] ramdisks  Character Devices:  tty[0-31] virtual consoles  ttyS[0-9]+ Serial ports  lp[0-3] Parallel Ports  null infinite sink ( the bit bucket)  zero infinite source of zeros  [u]random sources of random information  fb[0-31] framebuffer devices  Symbolic Links:  /dev/cdrom - - > /dev/hd[a-t], /dev/sd[a-z]+  /dev/modem - - > /dev/ttyS[0-9]+  /dev/pilot - - > /dec/ttyS[0-9]+ The RHEL Installer  First Stage Installer Images  diskboot.img – VFAT filesystem image for bootable media larger than a floppy  You will need to use the dd command to move this image to you media. For instance: dd <diskboot.img > /dev/sda  Floppy installation is no longer supported  boot.iso ISO9660 bootable CD image  Booting form boot.iso is the same as passing the askmethod argument to the installer when booting from CD 1.  You can create a bootable CD using the cdrecord command. For instance cdrecord dev=/dec/hdc boot.iso  pxeboot Directory  Pre-boot Execution Environment (PXE) provides for a diskless installation.  Read /usr/share/doc/syslinux-2.11/prelinux.doc  Second Stage Installer  Graphical or textual  Can be invoked in noprobe or Kickstart mode  Once located and loaded by the first stage, drives the remainder of the installation process. Installer Features  noprobe and Kickstart modes available  mediacheck tests media integrity  Multiple Interfaces:  Graphical  Starts X server and a GUI installer  Can be started in lowers mode.  Works with hard drive, CDROM, NFS Installation  Graphical is the default  Text  Menu-based terminal interface  Works with all installation methods (ftp and http) RHEL Installation Overview  Language, Keyboard and mouse selection  Media selection if applicable  Disk partitioning  Bootloader configuration  Network and firewall configuration  Authentication Setup  Package Selection  X server configuration [...]... in noprobe mode When started with: linux dd When no PCI devices are detected Post-Install Configuration  Setup Agent (firstboot)       Configure X window System if necessary Set date and time Register with Redhat Network and get updated RPMs Install additional RPMs or Redhat Documentation from CDROM Setup users system- config-* configuration tools Unit 2  System Initialization and Services... and selinux Sets kernel parameters in /etc/sysctl.conf Sets the system clock Loads keymaps Enables swap partitions Sets hostname Root filesystem check and remount Active RAID and LVM devices Enable disk quotas Check and mount other filesystems Cleans up stale locks and PID files System V run levels  Run level defines which services to start  Each run level has a corresponding directory   The system. .. firewall  Can allow access to arbitrary services  Security Enhanced Linux  Access control determines what actions processes can perform on what objects  Discretionary Access Control (Traditional Linux)   Users control permissions on objects Mandatory Access Control (SELinux)  System policy restricts permission which can be granted SELinux Installation Options  Installation Options:    Disabled... drives are divided into partitions  Partitions normally contain file systems      Primary, extended and logical partitions The default filesystem is ext3 Multiple partitions may be assembled into a larger virtual partitions: software RAID and LVM Filesystems are accessed via a mount point, which is a designed directory in the file system hierarchy Software RAID  Redundant Array of Inexpensive Disks... create a System V init script in  /etc/rc.d/init.d unless the service you are starting is so trivial it doesn’t warrant it Existing scripts can be used as a starting point  Virtual Consoles       Multiple independent VT100-like terminals Defined in /etc/inittab Accessed with Ctrl-Alt-F_key from an X session /dev/ttyn: virtual console n /dev/tty0: the current virtual console Default RedHat Enterprise. .. /etc/inittab        Initial run level System initialization scripts Run level specific script directories Trap certain key sequences Define UPS power fall/restore scripts Spawn gettys on virtual consoles Initialize X in run level 5 Kernel Initialization  Kernel boot time functions     Device detection Device driver initialization Mounts root filesystem read only Loads initial process (init)... larger disk size, performance Install-time RAID levels:    RAID 0: RAID 1: RAID 5: Striping (no redundancy) Mirroring Striping with distributed parity Configuring File Systems  Must select mount points, partition sizes, and file system types in the installer   Can set up manually or automatically There are many layouts which may be used    / mast include /etc, /lib, /bin, /sbin, /dev Swap space... device selected  First sector of boot device read and executed  Boot Loader Components  Boot Loader    Minimum Specifications for Linux:   1st Stage – small, resides in MBR or boot sector 2nd Stage – loaded from boot partition Label, kernel location, OS root filesystem and Location of the initial ramdisk (initrd) Minimum specification for other OS:  Boot device, label GRUB and grub.conf  GRUB... OS:  Boot device, label GRUB and grub.conf  GRUB – The Grand Unified Bootloader       Command-line interface available at boot prompt Boot from ext2/ext3, ReiserFS, JFS, FAT, minix, or FFS filesystems Support MD5 password protection /boot/grub/grub.conf Changes to grub.conf take effect immediately If MBR on /dev/had is corrupted, reinstall the first stage bootloader with:  /sbin/grub-install... Options  Installation Options:    Disabled Warn (Permissive) Active (default) (Enforcing) Package Selection  Package Selection   Universally (“Everything”) By predefined components   Defined in RedHat/ base/comps.xml Individually Validating Installation Virtual consoles during installation  Post-boot validation      dmesg and /var/log/dmesg /var/log/messages /root/install.log GRUB drops . RH133 Redhat Enterprise Linux System Administration Unit 1  Installation Hardware Overview  Kernel Support  Core. the first CD or at http://www .redhat. com  Check Hardware Compatibility  Redhat Supported Hardware List  Hardware compatible with Redhat Linux  http://hardware .redhat. com/hcl  XFree86 supported. cards.  http://xorg.freedesktop.org  http://www.x.org/wiki Multiboot systems  Redhat Enterprise Linux and the GRUB boot loader can co-exist with other operating systems, including the following:  Windows NT/2000/XP/2003  DOS,