Monday, October 27, 2008

Moving a volume group to another system

Moving a volume group to another system

It is quite easy to move a whole volume group to another system if, for example, a user department acquires a new server. To do this we use the vgexport and vgimport commands.

vgexport/vgimport is not necessary to move drives from one system to another. It is an administrative policy tool to prevent access to volumes in the time it takes to move them.

Unmount the file system

First, make sure that no users are accessing files on the active volume, then unmount it
# unmount /mnt/design/users

Mark the volume group inactive

Marking the volume group inactive removes it from the kernel and prevents any further activity on it.
# vgchange -an design
vgchange -- volume group "design" successfully deactivated


Export the volume group

It is now necessary to export the volume group. This prevents it from being accessed on the ``old'' host system and prepares it to be removed.
# vgexport design
vgexport -- volume group "design" successfully exported


When the machine is next shut down, the disk can be unplugged and then connected to it's new machine

Import the volume group


When plugged into the new system it becomes /dev/sdb so an initial pvscan shows:
# pvscan
pvscan -- reading all physical volumes (this may take a while...)
pvscan -- inactive PV "/dev/sdb1" is in EXPORTED VG "design" [996 MB / 996 MB free]
pvscan -- inactive PV "/dev/sdb2" is in EXPORTED VG "design" [996 MB / 244 MB free]
pvscan -- total: 2 [1.95 GB] / in use: 2 [1.95 GB] / in no VG: 0 [0]


We can now import the volume group (which also activates it) and mount the file system.

If you are importing on an LVM 2 system, run:
# vgimport design
Volume group "vg" successfully imported

If you are importing on an LVM 1 system, add the PVs that need to be imported:
# vgimport design /dev/sdb1 /dev/sdb2
vgimport -- doing automatic backup of volume group "design"
vgimport -- volume group "design" successfully imported and activated

Activate the volume group

You must activate the volume group before you can access it.
# vgchange -ay design

Mount the file system

# mkdir -p /mnt/design/users
# mount /dev/design/users /mnt/design/users


The file system is now available for use.

Saturday, October 25, 2008

Recover Corrupted Partition From A Bad Superblock

How can I Recover a bad superblock from a corrupted ext3 partition to get back my data? I'm getting following error:

/dev/sda2: Input/output error
mount: /dev/sda2: can't read superblock


How do I fix this error?

A. Linux ext2/3 filesystem stores superblock at different backup location so it is possible to get back data from corrupted partition.

WARNING! Make sure file system is UNMOUNTED.


If your system will give you a terminal type the following command, else boot Linux system from rescue disk (boot from 1st CD/DVD. At boot: prompt type command linux rescue).

Mount partition using alternate superblock

Find out superblock location for /dev/sda2:

# dumpe2fs /dev/sda2 | grep superblock

Sample output:
Primary superblock at 0, Group descriptors at 1-6
Backup superblock at 32768, Group descriptors at 32769-32774
Backup superblock at 98304, Group descriptors at 98305-98310
Backup superblock at 163840, Group descriptors at 163841-163846
Backup superblock at 229376, Group descriptors at 229377-229382
Backup superblock at 294912, Group descriptors at 294913-294918
Backup superblock at 819200, Group descriptors at 819201-819206
Backup superblock at 884736, Group descriptors at 884737-884742
Backup superblock at 1605632, Group descriptors at 1605633-1605638
Backup superblock at 2654208, Group descriptors at 2654209-2654214
Backup superblock at 4096000, Group descriptors at 4096001-4096006
Backup superblock at 7962624, Group descriptors at 7962625-7962630
Backup superblock at 11239424, Group descriptors at 11239425-11239430
Backup superblock at 20480000, Group descriptors at 20480001-20480006
Backup superblock at 23887872, Group descriptors at 23887873-23887878


Now check and repair a Linux file system using alternate superblock # 32768:

# fsck -b 32768 /dev/sda2


Sample output:

fsck 1.40.2 (12-Jul-2007)
e2fsck 1.40.2 (12-Jul-2007)
/dev/sda2 was not cleanly unmounted, check forced.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
Free blocks count wrong for group #241 (32254, counted=32253).
Fix? yes

Free blocks count wrong for group #362 (32254, counted=32248).
Fix? yes

Free blocks count wrong for group #368 (32254, counted=27774).
Fix? yes
..........
/dev/sda2: ***** FILE SYSTEM WAS MODIFIED *****
/dev/sda2: 59586/30539776 files (0.6% non-contiguous), 3604682/61059048 blocks


Now try to mount file system using mount command:

# mount /dev/sda2 /mnt


You can also use superblock stored at 32768 to mount partition, enter:

# mount sb={alternative-superblock} /dev/device /mnt
# mount sb=32768 /dev/sda2 /mnt


Try to browse and access file system:

# cd /mnt
# mkdir test
# ls -l
# cp file /path/to/safe/location


You should always keep backup of all important data including configuration files.

Creating a swap partition

For swap area give at least twice computer memory size, ex. +512M.
Default partition type is LINUX native, to change a Linux partition to a
swap partition with fdisk:

l # show partition
t 1 # change partition type for partition 1
Hex code: 82 # set type to Linux swap
w # write partition table

The new swap partion is set using the below listed commands to create
and enable the swap partition.

# mkswap -c /dev/hda2 size_in_blocks

# swapon /dev/hda

To enable all swap partitions:

# swapon -a

Check swap space usage with /usr/bin/top, /usr/bin/free and defined
partitions with /sbin/swapon (see Section 10.4) as follows:

$ /sbin/swapon -s

Filename Type Size Used Priority
/dev/hda5 partition 2048248 0 -1
/dev/hda6 partition 2048248 0 -2

Finally add the new swap partition to /etc/fstab:

/dev/hda14 / ext2 defaults 1 1
/dev/hda1 /boot ext2 defaults 1 2
/dev/hda13 /home ext2 defaults 1 2
/dev/cdrom /mnt/cdrom iso9660 noauto,owner,ro 0 0
/dev/hda5 swap swap defaults 0 0
/dev/hda6 swap swap defaults 0 0
/dev/fd0 /mnt/floppy ext2 noauto,owner 0 0
none /proc proc defaults 0 0
none /dev/pts devpts gid=5,mode=620 0 0
#
nodea:/fsa /fsa nfs rw,soft,bg 0 0
nodea:/fsb /fsb nfs ro,soft,bg 0 0

N.B. With RH7.x file systems in /etc/fstab are listed by label instead
of using partition number, in the above example /etc/fstab
entry /dev/hda1 for the /boot file system, is mapped to LABEL=/boot for
RH7.x.

10 boot time parameters you should know about the Linux kernel

The Linux kernel accepts boot time parameters as it starts to boot system. This is used to inform kernel about various hardware parameter. You need boot time parameters:

* Troubleshoot system
* Hardware parameters that the kernel would not able to determine on its own
* Force kernel to override the default hardware parameters in order to increase performance
* Password and other recovery operations

The kernel command line syntax

name=value1,value2,value3…

Where,
name : Keyword name, for example, init, ro, boot etc

Ten common Boot time parameters

init


This sets the initial command to be executed by the kernel. Default is to use /sbin/init, which is the parent of all processes.
To boot system without password pass /bin/bash or /bin/sh as argument to init
init=/bin/bash

single

The most common argument that is passed to the init process is the word 'single' which instructs init to boot the computer in single user mode, and not launch all the usual daemons

root=/dev/device

This argument tells the kernel what device (hard disk, floppy disk) to be used as the root filesystem while booting. For example following boot parameter use /dev/sda1 as the root file system:
root=/dev/sda1

If you copy entire partition from /dev/sda1 to /dev/sdb1 then use
root=/dev/sdb1

ro

This argument tells the kernel to mount root file system as read-only. This is done so that fsck program can check and repair a Linux file system. Please note that you should never ever run fsck on read/write file system.

rw

This argument tells the kernel to mount root file system as read and write mode.

panic=SECOND


Specify kernel behavior on panic. By default, the kernel will not reboot after a panic, but this option will cause a kernel reboot after N seconds. For example following boot parameter will force to reboot Linux after 10 seconds
panic=10

maxcpus=NUMBER

Specify maximum number of processors that an SMP kernel should make use of. For example if you have four cpus and would like to use 2 CPU then pass 2 as a number to maxcpus (useful to test different software performances and configurations).
maxcpus=2

debug

Enable kernel debugging. This option is useful for kernel hackers and developers who wish to troubleshoot problem

selinux [0|1]


Disable or enable SELinux at boot time.
Value 0 : Disable selinux
Value 1 : Enable selinux

raid=/dev/mdN

This argument tells kernel howto assembly of RAID arrays at boot time. Please note that When md is compiled into the kernel (not as module), partitions of type 0xfd are scanned and automatically assembled into RAID arrays. This autodetection may be suppressed with the kernel parameter "raid=noautodetect". As of kernel 2.6.9, only drives with a type 0 superblock can be autodetected and run at boot time.

mem=MEMEORY_SIZE

This is a classic parameter. Force usage of a specific amount of memory to be used when the kernel is not able to see the whole system memory or for test. For example:
mem=1024M

The kernel command line is a null-terminated string currently up to 255 characters long, plus the final null. A string that is too long will be automatically truncated by the kernel, a boot loader may allow a longer command line to be passed to permit future kernels to extend this limit (H. Peter Anvin ).

Other parameters

initrd /boot/initrd.img

An initrd should be loaded. the boot process will load the kernel and an initial ramdisk; then the kernel converts initrd into a "normal" ramdisk, which is mounted read-write as root device; then /linuxrc is executed; afterwards the "real" root file system is mounted, and the initrd file system is moved over to /initrd; finally the usual boot sequence (e.g. invocation of /sbin/init) is performed. initrd is used to provide/load additional modules (device driver). For example, SCSI or RAID device driver loaded using initrd.

hdX =noprobe

Do not probe for hdX drive. For example, disable hdb hard disk:
hdb=noprobe

If you disable hdb in BIOS, Linux will still detect it. This is the only way to disable hdb.

ether=irq,iobase,[ARG1,ARG2],name


Where,
ether: ETHERNET DEVICES

For example, following boot argument force probing for a second Ethernet card (NIC), as the default is to only probe for one (irq=0,iobase=0 means automatically detect them).
ether=0,0,eth1
How to begin the enter parameters mode?

You need to enter all this parameter at Grub or Lilo boot prompt. For example if you are using Grub as a boot loader, at Grub prompt press 'e' to edit command before booting.

1) Select second line
2) Again, press 'e' to edit selected command
3) Type any of above parameters.

See an example of "recovering grub boot loader password", for more information. Another option is to type above parameters in grub.conf or lilo.conf file itself.

See the complete list of Linux kernel parameters i.e. /usr/src/linux/Documentation/kernel-parameters.txt file.

Install Debian Etch on a Software Raid 1 with SATA disks

New server, S-ATA disks, the hardware RAID controller is not really supported. So we decided to use a software RAID 1 for the two disks. Here are the steps to create the RAID:

1)Boot the Debian Etch installer.

2)If the installation comes to "Partition method", use "Manual".

3)In the following menu, scroll to your first disk and hit enter: the partitionier asks you, if you want to create an empty partition table. Say "yes". (Hint: this will erase your existing data, if any.)

4)The partitioner is back in the disk overview, scroll one line downwards over the line with "FREE SPACE" and hit enter.

5)Create a partition with the size you need, but remember the size and the logical type.

6)In the "Partition settings" menu, go to "Use as" and hit enter.

7)Change the type to "physical volume for RAID".

8)Finish this partition with "Done setting up the partition".

9)Create other partitions on the same disk, if you like.

10)Now repeat all the steps from the first disk for the second disk.

11)After this, you should have at least two disks with the same partition schema and all partitions (beside swap) should be marked for RAID use.

12)Now look at the first menu entry in the partitioner menu, there is a new line: "Configure software RAID". Go into this menu.

13)Answer the question, if you like to write the changes, with "Yes".

14)Now pick "Create MD device".

15)Use RAID1 and give the number of active and spare devices (2 and 0 in our case).

16)In the following menu, select the same device number on the first and second disk and Continue.

17)Repeat this step for every two devices until you are done. Then use "Finish" from the Multidisk configuration options.

18)You are back in the partitioner menu and now you see one ore more new partitions named as "Software RAID Device". You can use this partitions like any normal partition and continue installing your system.

How to compile and install a new Linux kernel

Configure, build, and install

Be especially cautious when messing around with the kernel. Back up all of your files, and have a working bootable recovery floppy disk or CD-ROM nearby. Learn how to install a kernel on a system that doesn't matter. You've been warned. This is obviously a very short guide; only use in conjunction with a more thorough guide such as The Linux Kernel HOWTO

1. Download the latest kernel from kernel.org

The kernel comes as a 20 to 30 MB tar.gz or tar.bz2 file. It will decompress to about 200 MB and during the later compilation you will need additional space.

Example:
wget http://www.kernel.org/pub/linux/kernel/v2.4/linux-2.4.19.tar.gz
tar zxvf linux-2.4.19.tar.gz
cd linux-2.4.19


2. Configure the kernel options


This is where you select all the features you want to compile into the kernel (e.g. SCSI support, sound support, networking, etc.)

make menuconfig

* There are different ways to configure what you want compiled into the kernel; if you have an existing configuration from an older kernel, copy the old .config file to the top level of your source and use make oldconfig instead of menuconfig. This oldconfig process will carry over your previous settings, and prompt you if there are new features not covered by your earlier .config file. This is the best way to 'upgrade' your kernel, especially among relatively close version numbers. Another possibility is make xconfig for a graphical version of menuconfig, if you are running X.

3. Make dependencies

After saving your configuration above (it is stored in the ".config" file) you have to build the dependencies for your chosen configuration. This takes about 5 minutes on a 500 MHz system.

make dep


4. Make the kernel

You can now compile the actual kernel. This can take about 15 minutes to complete on a 500 MHz system.

make bzImage

The resulting kernel file is "arch/i386/boot/bzImage"

5. Make the modules

Modules are parts of the kernel that are loaded on the fly, as they are needed. They are stored in individual files (e.g. ext3.o). The more modules you have, the longer this will take to compile:

make modules

6. Install the modules

This will copy all the modules to a new directory, "/lib/modules/a.b.c" where a.b.c is the kernel version

make modules_install

* In case you want to re-compile...
If you want to re-configure the kernel from scratch and re-compile it, you must also issue a couple "make" commands that clean intermediate files. Note that "make mrproper" deletes your .config file. The complete process is:

make mrproper
make menuconfig
make dep
make clean
make bzImage
make modules
make modules_install


* Installing and booting the new kernel

For the remainder of this discussion, I will assume that you have LILO installed on your boot sector. Throughout this process, always have a working bootable recovery floppy disk, and make backups of any files you modify or replace. A good trick is to name all new files with -a.b.c (kernel version suffix) instead of overwriting files with the same name, although this is not shown in the example that follows.
On most Linux systems, the kernels are stored in the /boot directory. Copy your new kernel to that location and give it a unique name.

Example:
cp arch/i386/boot/bzImage /boot/vmlinuz-2.4.19


There is also a file called "System.map" that must be copied to the same boot directory.
cp System.map /boot
Now you are ready to tell LILO about your new kernel. Edit "/etc/lilo.conf" as per your specific needs. Typically, your new entry in the .conf file will look like this:

image = /boot/vmlinuz-2.4.19
label = "Linux 2.4.19"


Make sure the image points to your new kernel. It is recommended you keep your previous kernel in the file; this way, if the new kernel fails to boot you can still select the old kernel from the lilo prompt.
Tell lilo to read the changes and modify your boot sector:

lilo -v


Read the output carefully to make sure the kernel files have been found and the changes have been made. You can now reboot.

Summary of important files created during kernel build:
.config (kernel configuration options, for future reference)
arch/i386/boot/bzImage (actual kernel, copy to /boot/vmlinuz-a.b.c)
System.map (map file, copy to /boot/System.map)
/lib/modules/a.b.c (kernel modules)

Monday, January 21, 2008

108 names of Lord Vigneshwara




108 names of Lord Vigneshwara

Om Vinayakaya Namah
Om Vignarrajaya Namah
Om Gowri Puthraya Namah
Om Ganeshwaraya Namah
Om Skandha Grajaya Namah
Om Avyaya Namah
Om Puthaya Namah
Om Dakshaya Namah
Om Adhya Kshaya Namah
Om Dvijapriyaya Namah
Om Agnigarbha Chidhe Namah
Om Indhra Sripradhaya Namah
Om Vani Pradhaya Namah
Om Avyaya Namah
Om Sarva Sidhi Pradhaya Namah
Om Sarva Thanayaya Namah
Om Sarva Priyaya Namah
Om Sarvath Makhaya Namah
Om Srusti Kharte Namah
Om Devaya Namah
Om Anekar Chithaya Namah
Om Sivaya Namah
Om Shudhaya Namah
Om Bhudhi Priyaya Namah
Om Shanthaya Namah
Om Bramha Charine Namah
Om Gajana Naya Namah
Om Dhvai Mathuraya Namah
Om Munisthuthyaya Namah
Om Bhaktha Vignavinashanaya Namah
Om Ekadhanthaya Namah
Om Chathurbhahave Namah
Om Chaturaya Namah
Om Shakti Samyukthaya Namah
Om Lambhodharaya Namah
Om Surpakarnaya Namah
Om Haraye Namah
Om Bramha Viduthamaya Namah
Om Kalaya Namah
Om Graha Pathaye Namah
Om Kamine Namah
Om SOmasuryag Nilochanaya Namah
Om Pashajku Sadharaya Namah
Om Chandhaya Namah
Om Gunatithaya Namah
Om Niranjanaya Namah
Om Akalmashaya Namah
Om Swayamsidhiya Namah
Om Sidharchita Padamboojaya Namah
Om Bhijapura Phalasakthaya Namah
Om Varadhaya Namah
Om Shashwa Thaya Namah
Om Kruthine Namah
Om Vidwath Priyaya Namah
Om Vitabhayaya Namah
Om Gadhine Namah
Om Chakrine Namah
Om Ekshu Chapadhruthe Namah
Om Sridhaya Namah
Om Ajaya Namah
Om Utphala Karaya Namah
Om Sripathaye Namah
Om Stuti Harshithaya Namah
Om Kuladhribethre Namah
Om Jathilayaya Namah
Om Kalikalmasha Nashanaya Namah
Om Chandhra Chudamaniye Namah
Om Kanthaya Namah
Om Papaharine Namah
Om Samahithaya Namah
Om Aashrithaya Namah
Om Srikaraya Namah
Om Soumyaya Namah
Om Bhaktha Vamchita Dhayakayaya Namah
Om Shanthaya Namah
Om Kaivalya Sukhadhaya Namah
Om Sachida Nandha Vigrahaya Namah
Om Gynanine Namah
Om Dayayuthaya Namah
Om Danthaya Namah
Om Bramha Dvesha Vivarjithaya Namah
Om Pramatta Daithya Bhayadhaya Na

Sunday, January 20, 2008

Linux

All candidates who attend any Redhat exam sign a confidentiality agreement.
If they disclose any information they can loose thier certification status or even face
legal action.

I will monitor this forum and will report anyone disclosing specific information on
any Redhat exam to Redhat!

This is for the protection of this forum and future/current candidates.

What follows is the official exam prep guide for RHCT/RHCE




RHCE and RHCT Exam Preparation Guide
Overview

Download the training catalog

This guide provides information candidates may use in preparing to take the RHCT or RHCE exam. Red Hat is not responsible for the content or accuracy of other guides, books, online resources, or any other information provided by organizations or individuals other than Red Hat Global Learning Services. Red Hat reserves the right to change this Guide when appropriate, and candidates who have enrolled in forthcoming classes or exams are advised to check this guide periodically for changes.

The Red Hat Certified Engineer (RHCE) and Red Hat Certified Technician (RHCT) exams are performance-based evaluations of Red Hat Enterprise Linux system administration skills and knowledge. Candidates perform a number of routine system administration tasks and are evaluated on whether they have met specific objective criteria. Performance-based testing means that candidates must perform tasks similar to what they must perform on the job.

Prospective employers of RHCEs and RHCTs should verify any and all claims by people claiming to hold one of these certificates by requesting their certificate number and verifying it here.

Only Red Hat and Red Hat Certified Training Partners administer the RHCE and RHCT exams. Prospective candidates should exercise due diligence when purchasing a seat in an RHCE or RHCT exam from a provider other than Red Hat itself. They should verify that the provider is, in fact, an authorized training partner in good standing. Please notify greymarket@redhat.com about organizations that purport to offer the RHCE or RHCT exams, but who are not Red Hat Certified Training Partners.

Official scores for the RHCE and RHCT exams come exclusively from Red Hat Certification Central. Red Hat does not authorize examiners or training partners to report results to candidates directly. Scores on the exam are usually reported within three (3) US business days.

Exam results are reported as section scores. Red Hat does not report performance on individual items, nor will it provide additional information upon request.
Preparation for the RHCT and RHCE Exams

Red Hat encourages all candidates for RHCT and RHCE to consider taking one or more of its official training courses to help prepare for the RHCE or RHCT exam. Attendance in these classes is not required, and one can choose to take just an exam. Many successful candidates who have come to class already possessing substantial skills and knowledge have reported that the class made a positive difference for them.

To help you determine the best courses to take, Red Hat provides online skills assessment.

While attending Red Hat's classes can be an important part of one's preparation to take the RHCE or RHCT exam, attending class does not guarantee success on the exam. Previous experience, practice, and native aptitude are also important determinants of success.

Many books and other resources on system administration for Red Hat's OS products are available. Red Hat does not officially endorse any as preparation guides for the RHCT or RHCE exams. Nevertheless, you may find additional reading deepens understanding and can prove helpful.
Components of the RHCE and RHCT Exams

The RHCT exam is a subset of the RHCE exam, and is organized as follows:

* Troubleshooting and System Maintenance — 1 hour
* Installation and Configuration — 2 hours

In order to earn RHCT, one must successfully complete all the requirements in Troubleshooting and System Maintenance, and must achieve a score of 70 or higher on Installation and Configuration.

For RHCE exams given on Red Hat Enterprise Linux 3 and higher, the exam is organized as follows:

* Troubleshooting and System Maintenance — 2.5 hours
* Installation and Configuration — 3.0 hours

In order to earn RHCE, one must successfully complete all the RHCT-level Troubleshooting and System Maintenance requirements, and successfully complete enough additional RHCE items to earn a score of 80 or higher overall on the section.

In addition, one must score 70 or higher on the RHCT items of Installation and Configuration, and 70 or higher on the RHCE components of that section. We describe the skills associated with RHCT and RHCE below.
Study Points for the RHCE Exam
Prerequisite skills for RHCT and RHCE

Candidates should possess the following skills, as they may be necessary in order to fulfill requirements of the RHCT and RHCE exams:

* use standard command line tools (e.g., ls, cp, mv, rm, tail, cat, etc.) to create, remove, view, and investigate files and directories
* use grep, sed, and awk to process text streams and files
* use a terminal-based text editor, such as vim or nano, to modify text files
* use input/output redirection
* understand basic principles of TCP/IP networking, including IP addresses, netmasks, and gateways for IPv4 and IPv6
* use su to switch user accounts
* use passwd to set passwords
* use tar, gzip, and bzip2
* configure an email client on Red Hat Enterprise Linux
* use text and/or graphical browser to access HTTP/HTTPS URLs
* use lftp to access FTP URLs

RHCT skills
Troubleshooting and System Maintenance

RHCTs should be able to:

* boot systems into different run levels for troubleshooting and system maintenance
* diagnose and correct misconfigured networking
* diagnose and correct hostname resolution problems
* configure the X Window System and a desktop environment
* add new partitions, filesystems, and swap to existing systems
* use standard command-line tools to analyze problems and configure system

Installation and Configuration

RHCTs must be able to:

* perform network OS installation
* implement a custom partitioning scheme
* configure printing
* configure the scheduling of tasks using cron and at
* attach system to a network directory service, such as NIS or LDAP
* configure autofs
* add and manage users, groups, quotas, and File Access Control Lists
* configure filesystem permissions for collaboration
* install and update packages using rpm
* properly update the kernel package
* configure the system to update/install packages from remote repositories using yum or pup
* modify the system bootloader
* implement software RAID at install-time and run-time
* use /proc/sys and sysctl to modify and set kernel run-time parameters
* use scripting to automate system maintenance tasks

RHCE skills
Troubleshooting and System Maintenance

RHCEs must demonstrate the RHCT skills listed above, and should be able to:

* use the rescue environment provided by first installation CD
* diagnose and correct boot failures arising from bootloader, module, and filesystem errors
* diagnose and correct problems with network services (see Installation and Configuration below for a list of these services)
* add, remove, and resize logical volumes
* diagnose and correct networking services problems where SELinux contexts are interfering with proper operation.

Installation and Configuration

RHCEs must demonstrate the RHCT-level skills listed above, and they must be capable of configuring the following network services:

* HTTP/HTTPS
* SMB
* NFS
* FTP
* Web proxy
* SMTP
* IMAP, IMAPS, and POP3
* SSH
* DNS (caching name server, slave name server)
* NTP

For each of these services, RHCEs must be able to:

* install the packages needed to provide the service
* configure SELinux to support the service
* configure the service to start when the system is booted
* configure the service for basic operation
* Configure host-based and user-based security for the service

RHCEs must also be able to:

* configure hands-free installation using Kickstart
* implement logical volumes at install-time
* use iptables to implement packet filtering and/or NAT
* use PAM to implement user-level restrictions

Red Hat Courses Covering These Skills

* RH033 Red Hat Linux Essentials covers prerequisite skills, with the exception of TCP/IP fundamentals. The Network Essentials series covers TCP/IP fundamentals
* RH133 Red Hat Linux System Administration covers RHCT-level skills.
* RH253 Red Hat Linux Networking Services and Security covers RHCE-specific skills in networking services and security. Attendees should attend RH133 first.
* Red Hat RHCE Fast Track Course condenses material from RH133 and RH253. Only experienced Linux and UNIX system administrators with background in networking services should attend

Cute Babies