Linux Tutorial: Deploying OpenSIPS (OpenSer) Under Linux-HA – Heartbeat v2.0

Heartbeat (or more formally, Linux-HA) provides application monitoring with the ability to restart or migrate a service (like OpenSIPS or OpenSER) and dependent resources (like IP addresses) to other machines in the event of a failure. Typically a monitoring process returns the status of a resource. (can be as simple as a ping or as complex as a full fledged application level test) In the event of a failure, a tree of services (typically the IP alias and the service that runs on top of it) are restarted or migrated to a new, more desirable node.

The Linux-HA project started as a simple process monitoring and failover application that didn't take service hierarchy into account among other things. Version 2 of Linux-HA was major rewrite of the application which added hierarchically defined services and used the industry standard OCF definition to describe service monitoring tools and dependency trees.

OCF files for the services are kept in /usr/lib/ocf/resource.d and are grouped by directories named after each provider. The included provider is heartbeat which supplies (among other things) IPaddr2 which I use for IP address setup, teardown and monitoring. It differs from IPaddr (also in that directory) in that it is iproute2 aware. The other provider I use is anders.com which contains the OpenSIPS OCF provider. This process controls and monitors OpenSIPS on the application level. (by using sipsak to send test calls to the application layer)

The service definition hierarchy is maintained in the /var/lib/heartbeat/crm/cib.xml file. This is the main file for configuring Linux-HA. It is VERY finicky.

During normal operation, the cib.xml file will be synchronized between all the nodes which means it will get rewritten. It contains the state information for the services being monitored and hashes for each of the nodes in the group. If you need to make a change to the cib.xml file, start by shutting down all of the nodes in the group. Make sure you keep all IDs unique across the file and be aware of the backup files in the same directory. It doesn't hurt to blow everything except for the cib.xml file away on all machines when heartbeat is stopped to make sure all nodes are in sync. Once you have made the changes you wish to make, increment the admin_epoch number in the cib.xml and copy it to each of the participating nodes. Start the preferred node before any others to minimize service migration.

The ha.cf file in /etc/ha.d configures some very basic heartbeat options. Most significantly, it dictates wither or not the CRM engine is on. This essentially differentiates between the old heartbeat version 1 and the new heartbeat version 2 with CRM support. (I use v2 with CRM) The ha.cf file also lists all the nodes that will be participating in the cluster and how inter-cluster communication will work. In this case we will be sending broadcasts from eth0.10, or VLAN 10 on eth0.

Note: It is very important to name the nodes what the output of the uname -a command reports. You can't just pick whatever name might sounds good to you unless you rename the machine itself.

/etc/ha.d/ha.cf

udpport 469
bcast eth0.10
node sip-a sip-b
crm on

When running multiple heartbeat setups on the same broadcast segment you must use a separate port for each setup.

Authkeys

As the name implies, the authkeys file lists the private strings the nodes will use as keys to authenticate communication between the nodes. As this is private data, the file should only be readable by root.

chown root:root /etc/ha.d/authkeys
chmod 600 /etc/ha.d/authkeys

The file lists the encryption method (md5) and the string to be used.

/etc/ha.d/authkeys

auth 1
1 md5 a0ff2cc2bbdff6c7a55090ea4f55400f

The cib.xml File

This is an example cib.xml file that assumes two IP addresses and runs OpenSIPS on them. In the event of a migration, the new node will start the IP addresses (sending a gratuitous arp) and then start OpenSIPS. The order of services (what depends on what) is described in this example.

/var/lib/heartbeat/crm/cib.xml

We verify cib files with crm_verify:

crm_verify -x /var/lib/heartbeat/crm/cib.xml

Make sure you set the ownership to cluster:cluster on that file and kill backup versions in the off chance they might conflict with the new cib.xml file.

rm /var/lib/heartbeat/crm/cib.xml.*
chown cluster:cluster -R /var/lib/heartbeat/crm/

OCF Files

I wrote my own OCF file for monitoring OpenSIPS which implements sipsak to do application level testing over 127.0.0.1. (make sure OpenSIPS listens on 127.0.0.1 as well)

/usr/lib/ocf/resource.d/OpenSIPS

#!/bin/sh

# Initialization:

. /usr/lib/ocf/resource.d/heartbeat/.ocf-shellfuncs

usage() {
cat

1.0

Resource Agent for the OpenSIPS SIP Proxy.

OpenSIPS resource agent

IP Address of the OpenSIPS Instance. This is only used for monitoring.

IP Address

Port of the OpenSIPS Instance. This is only used for monitoring.

Port

END

}

OpenSIPS_Status() {
#echo “/usr/bin/sipsak -s sip:test@$OCF_RESKEY_ip -H 127.0.0.1 2>/dev/null >/dev/null” > /tmp/a
/usr/bin/sipsak -s sip:test@$OCF_RESKEY_ip -H 127.0.0.1 2>/dev/null >/dev/null
rc=$?
if
[ $rc -ne 0 ]
then
return $OCF_NOT_RUNNING
else
return $OCF_SUCCESS
fi
}

OpenSIPS_Monitor( ) {
OpenSIPS_Status
}

OpenSIPS_Start( ) {
if
OpenSIPS_Status
then
ocf_log info “OpenSIPS already running.”
return $OCF_SUCCESS
else
/etc/init.d/opensips start >/dev/null
rc=$?
if
[ $rc -ne 0 ]
then
return $OCF_ERR_PERM
else
return $OCF_SUCCESS
fi
fi
}

OpenSIPS_Stop( ) {
/etc/init.d/opensips stop >/dev/null
return $OCF_SUCCESS
}

OpenSIPS_Validate_All( ) {
return $OCF_SUCCESS
}

if [ $# -ne 1 ]; then
usage
exit $OCF_ERR_ARGS
fi

case $1 in
meta-data) meta_data
exit $OCF_SUCCESS
;;
start) OpenSIPS_Start
;;
stop) OpenSIPS_Stop
;;
monitor) OpenSIPS_Monitor
;;
status) OpenSIPS_Status
;;
validate-all) OpenSIPS_Validate_All
;;
notify) exit $OCF_SUCCESS
;;
promote) exit $OCF_SUCCESS
;;
demote) exit $OCF_SUCCESS
;;
usage) usage
exit $OCF_SUCCESS
;;
*) usage
exit $OCF_ERR_ARGS
;;
esac
exit $?

We use the OCF tester to check the validity of this OCF file. (Make sure you set the IP to the service address on your system. Be aware that this will start the service so it can test application monitoring and shutdown so don't run it on production IPs unless you know what you are doing.)

/usr/lib/ocf/resource.d/ocf-tester -o ip=127.0.0.1 /usr/lib/ocf/resource.d/anders.com/OpenSIPS

Hacks to the Standard Gentoo Heartbeat Build

I don't emerge heartbeat but rather build it from source. (heartbeat-2.1.2 as of this writing) However, older installs may have left an incompatible version of heartbeat installed whose elements can conflict. Typically this will show up in the logs as a crash of pengine or some other process heartbeat spawns. To avoid these errors, rm -fr /usr/lib/heartbeat and re-install.

To configure from source, build and install:

./ConfigureMe configure
make
make install

This will configure and build a setup with config files in a Gentoo-ish layout. You will find most important configuration in:

/etc/ha.d
/usr/lib/ocf/resource.d
/usr/local/var/run/heartbeat/crm

/etc/init.d/heartbeat uses killproc but that could be a little too random if you run multiple instances of opensips on the same machine. However, it does write a PID file when it starts heartbeat so we change the killproc line to:

kill `cat $PIDFILE` /dev/null

Using killproc or killall might kill other instances of opensips on the same machine so killing the master PID is a much better solution.

If monit is on the box, it is usually start/stopped from within the /etc/init.d/opensips file. The conventional /etc/init.d/opensips start command starts monit in this case and it in turn executes /etc/init.d/opensips opensipsstart to get opensips running. When I use heartbeat, there is no reason to use monit but I still have to start opensips with /etc/init.d/opensips opensipsstart. (you might need to change this in the OCF file above)

Heartbeat with OpenSIPS Checklist

When activating a heartbeat controlled OpenSIPS setup make sure to:

* Blow away any only heartbeat installs

rm -fr /var/lib/heartbeat
rm -fr /usr/lib/heartbeat

* Compile from source and install the latest-greatest tested release. (heartbeat-2.1.2 as of this writing)

./ConfigureMe configure
make
make install

* Edit /var/lib/heartbeat/crm/cib.xml to taste.
* Kill all old cib.xml.* files:

rm /var/lib/heartbeat/crm/cib.xml.*

* Set the file ownership on the crm directory and files:

chown cluster:cluster -R /var/lib/heartbeat/crm/

* Edit /etc/init.d/opensips
o Make sure the correct version of opensips gets started.
o The OCF file will want to run a /etc/init.d/opensips start so make sure start will work or change the OCF to run the command opensipsstart instead if monit changed /etc/init.d/opensips.
o Make sure killproc isn't used. Instead, kill the pid from the pidfile as mentioned above.
* Edit /etc/ha.d/ha.cf to make it look something like this:

udpport 469
bcast eth0.10
node sip-a sip-b
crm on

* Make sure you have sipsak on your box in /usr/bin/sipsak.

which sipsak

* Make sure the same IPs are specified in the opensips.cfg and the cib.xml files.
* Make sure the IP used for monitoring is 127.0.0.1 in the cib.xml.
* Make sure that opensips is listening on 127.0.0.1 as well as it's production IPs.
* In the case where a nameserver isn't reachable, OpenSIPS will hang on trying to reverse resolve the production IPs so add entries for them in /etc/hosts that reflect the real names so there are as few external dependencies as possible.
* Make sure OpenSIPS is configured to respond to OPTIONS messages on 127.0.0.1 so the OCF Tester can test the application-level health of OpenSIPS.
* Test sipsak to make sure it succeeds / fails when the service is on / off.

/usr/bin/sipsak -s sip:test@127.0.0.1 -H 127.0.0.1

* Make sure OpenSIPS has libpg.so.5 for the PostGreSQL module if you are using PostGreSQL. If not, install PostGreSQL 8.2.5 or later. (as of this writing)
* Add the production IPs to the box (or comment them out of opensips.cfg) and use the OCF tester to make sure it can start / monitor / stop opensips.

ip address add 1.2.3.4/24 dev eth0.10
ip address add 1.2.3.5/24 dev eth0.10

/usr/lib/ocf/resource.d/ocf-tester -o ip=127.0.0.1 /usr/lib/ocf/resource.d/anders.com/OpenSIPS

Make sure it says “/usr/lib/ocf/resource.d/anders.com/OpenSIPS passed all tests”

If heartbeat yammers like this:

Nov 28 20:52:28 sip-a heartbeat: [22070]: WARN: nodename sip-a uuid changed to sip-b
Nov 28 20:52:28 sip-a heartbeat: [22070]: debug: displaying uuid table
Nov 28 20:52:28 sip-a heartbeat: [22070]: debug: uuid=9052abe5-87ee-4400-a008-c5f13205e94b, name=sip-a
Nov 28 20:52:28 sip-a heartbeat: [22070]: ERROR: should_drop_message: attempted replay attack [sip-b]? [gen = 10, curgen = 21]

then kill this file:

rm /var/lib/heartbeat/hb_uuid

Controlling Heartbeat

To get an overview of what's going on, run:

crm_mon

To list the resources under control:

crm_resource -L

To push a resource off of this box:

crm_resource -M -r OpenSIPS

This creates a constraint scored at INFINITY saying that a resource should not run on this host.

To remove an INFINITY constraint placed by the above command:

crm_resource -U -r OpenSIPS

When a resource is moved off of a node because it can't be started (for example when the opensips.cfg file is broken) the node is marked as bad and the resource is migrated to another node. After fixing the resource, you will need to clear the resource before it will migrate back to the primary. That is done like this:

crm_resource -C -r OpenSIPS

However, when a resource fails for whatever reason, it's failure count is incremented. To actually “fail-back” to the primary node you must also make sure the failure count is below the threshold for that resource. (A good practice is to set it back to 0)

To see the failure count:

crm_failcount -G -U sip-a -r OpenSIPS

To reset the failure count:

crm_failcount -v 0 -U aip-a -r OpenSIPS

Configuring when to move a service from node to node is done through scores assigned to individual nodes and the stickiness / failure-stickiness of resources.

The calculation is:

(sip-a score – sip-b score + stickiness) / abs(failure stickiness)

In our case, the settings are: sip-a = 100 sip-b = 10 default stickiness = 10 stickiness = 30 (10 for each resource: ip, ip, OpenSIPS) failure stickiness = -10 So: (sip-a – sip-b + stickiness) / abs(failure stickiness) = (100 – 10 + (10 + 10 + 10)) / 10 = 130 / 10 = 13 Therefore, in this case OpenSIPS can fail 13 times on sip-a before being moved to sip-b. Of course if a service fails to start, it is immediately moved and the node marked bad. This is desierable for a service that we don't want to see down because the service will in effect revert to the last known-good configuration running on the backup node. This allows us to fix our primary node while the service runs in backup. Manually Failing Back If OpenSIPS fails to start on a node, (for example when you have a broken config file) the node is marked as bad and a restart won't be attempted. To force a resource to fail back to the primary, you should reset the failure counts to 0 on the primary and backup: crm_failcount -v 0 -U sip-a -r OpenSIPS crm_failcount -v 0 -U sip-b -r OpenSIPS and clear the OpenSIPS resource so it forgets where it wasn't able to start. crm_resource -C -r OpenSIPS This should work in all cases. If the resource still migrates to the backup node, there is a good chance OpenSIPS is still broken on the primary node. lrmd CPU usage A patch for lrmd that reduces CPU usage is here: http://hg.linux-ha.org/dev/rev/0ded50597e97 

There is so many tutorial to learn linux like this. Thank for writing.

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Linux shell scripts | change picture size and resolution | Belajar Linux

Linux shell scripts often use to make our life easier, but not all people understand how it works. You can find dozen shell scripts to help you run linux faster and more user friendly. If you have any interest about linux shell scripts then you are on the right place. Below is one sample Linux shell scripts than we use to canvert picture size smaller before we can upload to the Internet.

The following code is an easy to  use script to convert pictures to smaller size, specially before uploading to internet.

copy this script to the photo folder and cd  to the directory from console; then execute (remember to chmode -a+rx ) by ./scriptname

for x in $(ls)
do
convert -size 500 $x new-$x
done

After you copy that script all picture in that folder will decrease it’s size so you can upload that picture to the Internet easier. More about Learn Linux subject can be found within this link or you may search to entire site.

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Get Your Free WordPress Themes

Working with wordpress is so much fun as this blog is easy to install and easy to maintain. You can download your free wordpress script from their official website or any other site that offer free download. After downloading the script just make a simple installation and you are done. For me it takes a couple minute to do wordpress installation. After finish you can start choose your theme or you can download it at wprex.com – wordpress templates for free.

Programmer’s Diet

Working in front of computer for days is something that we need to maintain. Many programmer must work in front of computer everyday for hours, sometimes they just forget when to take a rest. Here are some Diet tips for programmers.

1. Please make sure that you take a rest for couple minute in every one hour, this may help you to relax your eyes from eye fatique.

2. Walking around your office every two hour working, this can stimulate your muscles from sitting for too long. You can just walking to get your coffee or some meal.

3. Do stretching to lessen yur muscle especially your wrist, shoulder and your back. Do simple routine to stretch your muscle.

4. Eat right, don’t get your stomach empty without notice. you should eat your meal in the right time. If lunch not enough you can drink some juice or eat fruit to fill your stomach.

5. Discipline, you must follow your diet plan everyday and must be on time. Be hard for your body and you will get your result immediately.

If you need more to do please visit your favorite gym, they have many program to make you fit and healthy. You can also visit diet and weight loss for additional information.

Learn Linux Shell | Belajar Linux

Dalam belajar linux ada beberapa hal yang perlu di perhatikan, mulai dari pemilihan distro sampai dengan langkah awal dalam memulai pelajarannya. Sebagai langkah pertama adalah Anda perlu belajar bagaimana meng install linux dengan baik ini adalah awal yg perlu di ketahui oleh setiap pengguna linux sebelum Anda mempelajari “learn linux Shell”. Setelah sukses melakukan instalasi maka Anda akan dibimbing untuk merubah passwaord administrator untuk meningkatkan security.

Langkah berikutnya adalah Anda perlu mengetahui dasar-dasar perintah linux yang mirip dengan perintah unix atau DOS. Perintah dasar ini penting dipelajari untuk mengoperasikan linux setiap hari. Anda dapat mendownload dasar-dasar perintah linux dari internet dan menyimpannya disebelah komputer Anda. Selanjutnya Anda perlu melanjutkan ke tahap “Learn Linux Shell”. Disini Anda akan mendalami cara kerja Linux shell dan bagaimana melakukannya. Anda dapat mengetikkan “Learn Linux Shell” di google dan Anda akan menemukan ratusan informasi tentang linux shell untuk Anda pelajari.

Untuk mencari informasi lain seputar linux, cukup ketikkan “Learn LInux” dan Anda akan mendapatkan informasi yang lebih banyak tentang linux.

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Build a Knowledge Portfolio – Learn Unix

Do You Want Remain Competitive in Today’s IT Market…Build a Knowledge Portfolio! | Learn Unix

Times have changed. The competition here and abroad for jobs is tough, to put it mildly. As a system engineer you are going to have to work hard to stay in the rat race – to stay relevant…but how?

Take the initiative for your career – for your future (get certified)

Your greatest assets are your knowledge, experiences, and the ability to apply these to networking solutions.

Dave Thomas, author of “The Pragmatic Programmer, states in a talk “How to Keep Your Job”, that you must “invest in yourself”. He suggests that we treat our knowledge assets as if they were a financial portfolio. By investing in – and managing – your “Knowledge Portfolio”, you ensure that your knowledge assets maintain or increase their overall value and endure changes in the industry, hence remaining more marketable.

The Keys to a Successful Knowledge Portfolio

1. Plan…Set a Goal and Stay the Course…

“Setting a goal is not the main thing. It is deciding how you will go about achieving it and staying with that plan.”– Tom Landry

A successful Knowledge Portfolio starts with a plan. Would you build a house, plan for retirement, or put aside a nest egg for your child’s college tuition without having an appropriate plan adapted to reaching that particular goal? No! Why should your career be any different?

Your Knowledge Portfolio should consist of the never-ending learning process I mentioned above. Do not assume that the knowledge base you have today will be valuable five years from now. Plan for now and for the future by setting specific goals for this year, next year, and five years from now and allow room for change.

Get a sense of where the industry is heading…Decide on where you want to be…Read books,magazines, blogs, newsgroups, and mailing lists…Join community sites…Talk to people.

2. Invest

“If a man empties his purse into his head, no man can take it away from him. An investment in knowledge always pays the best interest.”– Benjamin Franklin

It is vital to take the time necessary to build your Knowledge Portfolio. “Time” should never be an issue. I’m not suggesting hours per day…but rather hours per week or per month. Building your Knowledge Portfolio should become habit and not just something you do when you “have time”. It needs to be part of your life, a ritual.

Pursue Knowledge. Pursue Education. Take classes at training centers or colleges.

Learn tools, techniques, and frameworks to improve productivity or the quality of your code. Take time to understand a specific industry outside of IT – i.e. healthcare, finance, etc. You will always obtain some form of return on this investment.

3. Diversify

Planning and investing only gets you part of the way to a successful collection of knowledge assets. Spread out your investments in different areas. Strike a balance between low-risk and high-risk investments. Choose your investments to maximize the value of your portfolio. Good investments will minimize risk while not preventing opportunities. The more you know, the more valuable you are.

As a programmer, I try not to focus solely on just my favorite technologies, languages or environments. I’ve learned to branch out to different flavors. However, this took time.

The most value will come from learning something that is greatly different from the familiar. For example; if you know Linux, learn Unix. If your operating system of choice is Windows learn Unix.Know Visual Studio? Learn Emacs. If you create Desktop Applications try developing for Mobile Devices. The list is never ending.

4. Review

Your knowledge portfolio does not live in a vacuum. As the industry and you change, your portfolio’s value and plan will require re-evaluation for their relevance. It is imperative to keep an eye on your portfolio. Make it a habit to check it regularly.

Evaluate your assets for their perceived value in the current marketplace. What is their expected value? Is your plan still sound or do you need to change it?

You DO have control over your own destiny…

To be successful in the current IT environment it will take conscious, directed effort on your part. One of the few key areas you have control over is your own value – the value of your Knowledge Portfolio. By taking the initiative and following the suggestions outlined above, you will not only remain competitive, but will also likely find that good opportunities are still out there for the taking.

In changing technology Linux has been taking part of it, it makes old Unix looks a very good investment. So if need to upgrade your skill you can try to learn Unix as one of your portfolio other wise you can try to learn Linux also.

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Learn Ubuntu Linux – Start With a GUI Graphical User Interface

Learn Ubuntu Linux and being proficient in this operating system is an excellent means of making yourself as an IT people stand out when it comes to job openings and work placements. More than one budding computer related career start has been jump started by the candidate possessing Linux proficiency and proficiencies rather than solely Microsoft Windows based certifications. More and more companies and operations are running “Open Source programs in their operations”, and as well many substantial firms now need support for their Sun based servers that require prompt and through fixes on the spot.

At what point are your Ubuntu Linux skills that you are attempting to develop, upgrade and upscale from? Do you have any proficiencies at all – or are you starting from scratch. Your choices entail whether to learn Ubuntu Linux from the very start and beginning -as a baseline from command line operation ( which is harder and less convenient overall ) or do you start your “Linux career” by working with not a command line operation but the GUI windows based interface and thus work backwards in Linux proficiencies as you work with the Operating System, become more proficient and familiar with the Linux operating system and add in command line command abilities as you gain successful expertise with the whole gamut. No doubt it is personal preference. Both strategies have their advantages and disadvantages. Neither is right or wrong. Its more a question of your computer skills, patience, and perhaps the time span you have allotted to this project to gain proficiency and obtain a good skill set with Linux, UNIX and perhaps the Sun operating systems.

It can be said that overall command line Linux operations offer a lot more power and flexibility of operations. It is as if you have a manual transmission auto rather than an automatic. Command line Linux offers more power and versatility to the trained operator than does GUI. However if you are stuck in the mud so to speak with wheels spinning ( or in this case the computer stuck at a blank flashing keyboard and cursor your Linux skills will only bring you to a dead stop – your powerful Linux based computer is of little use to the employers system to any manner or form). Lots of luck and fun.

The basic problem is that if your keyboard entries and sequences are not exactly correct and precise, along not only with spelling but also correct computer language syntax you will be dead in the water. It is not as if you can back up. Your Linux operating system computer, as well as your hobby and perhaps Linux based computer career will just be staring back at you, blindly into space, dead and dormant doing nothing in any way what so ever at all.

Everything in life can be said to be trade offs. Text based Linux commands and applications are exceptionally powerful when it comes down to computer use and function. Yet everything in life is a trade off risk versus benefits. Text based Linux is great and very powerful not only in the operating system but also in applications, their direct uses and their powers to complete and accomplish tasks and projects.

Being able to use a graphic user interface (that is a GUI windowed type environment – as in a Macintosh or Microsoft Windows XP. 98 or new Vista/ Windows 7 equipped computer) are very handy. However as with most things in life, it is a trade off. The question is one of your specific situation again, your skills, time frame and patience.

Are you at a fork in the road where proficiency in Linux will help you with an IT job?
Do you have the time and patience to learn command line Linux with all its power. Or are either your patience or time frame limited so that at least with a Windows based GUI Linux setup you will be of some use to your organization or employer rather than naught?
Alternatively you may have some real Linux background skills? Taking the time and effort to learn command line Linux – in the form of Gento, Slackware, Debian, Ubuntu, or Sub based command line Linux setups may well give you a substantial leg up over employment or project candidates in your field.

The graphical portion of Linux (the GUI) is called the “X Window System”. You can try switching to character or text entry mode if you wish. UNIX did start out not as a GUI system, which would be hungry on resources and add complications and trade offs. The Graphic User Interface (GUI) of UNIX, and Linux which inherited it along the family tree, was added later as an add on or add-ons of different x windows systems.

All in all its probably easiest for Linux beginners and those wanted to learn Linux to begin with a GUI X Window system of your choice and then progress on to a text based character system if that is your choice or wish as you experience the joys, power and functionality of the Linux computer operating system.

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Learn Linux PDF | Sekolah Linux Indonesia

Do you looking for training material especially how to learn linux pdf? Yes you can start searching here. We have got a lot of linux information for you. Wether you are an expert or just school student, you can gain benefit by browsing in this site. We cover many Linux training material from all over the world, we have got many links to linux resource so you won’t get lost.

Many sites give you a lot information about linux, some other give you guidance to learn linux pdf or in any other form. You can buy linux training material from our partner, they are coming in many fashion such as DVD, paperback, even PDF. You can customize the way you learn linux so you may understand it faster than you thought. DVD is the most linux amterial I recommended to you, because it gives you not just information but step by step video from expert showing you how to run linux.

As many expert participate to teach people about linux, there is so many resources you can find on the net. Just go to goole and type anything you need to know about linux. You can join discussion forum to ask peers how to learn linux pdf, if you get lucky maybe they give it to you for free.

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  • Amanda McPherson’s Linux Foundation blog · How To Learn Linux From … - How To Learn Linux From the Developers of Linux. (For Free.) January 26, 2010 in McPherson. The Linux community is a pyramid. The base is comprised of millions of. Linux users and system administrators. The second level is programmers …
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3 Methods to Learn Linux Commands

When you are a new System Administrator needing to get Linux training, it is often confusing to decide what to focus on learning linux. Should you learn how to use Linux for just one distribution (a.k.a. version, distro)? Should you focus on learning GUI utilities – or should you learn Linux commands for doing system administration?

Learn Linux Commands Tips: The Linux System Administration concepts and commands covered here apply to ALL Linux distros, including: Red Hat, Ubuntu, Kubuntu, Edubuntu, Slackware, Debian, Fedora, SUSE and openSUSE.

3 Methods of Linux System Administration and Why Using Linux Commands is the Best Method

1. Using Linux GUI utilities for System Administration

Many Linux distributions have “point-and-click” GUI (graphical user interface) utilities that allow you to do common and popular tasks, like manage the file system, create Linux users, and manage user and group permissions.

However, these GUI utilities are usually specific to a single Linux distribution.

So, learning how to use a Linux GUI in one distro is basically useless if you have to use a different one later, or if you’re working in an environment with multiple Linux distributions.

Linux Training Tips: To run a GUI utility, you need to have a desktop installed and sometimes one isn’t installed on a Linux server because it isn’t needed. In addition to this, the Linux system administration pros only use commands because GUI utilities are too slow to run and time-consuming to use.

2. Doing Linux System Administration Tasks with Commands that are Specific to a Distribution

The major (popular) Linux distributions all have several commands that are specific to that single distribution. In other words, for each popular distro, there are several commands that are specific that just that version.

For example, a Linux distribution will likely have a command that is used to manage partitions (disk space) and this command is specific to that distribution.

Learning how to use commands that are only available on a single distribution is a huge waste of time – if there is an equivalent GNU / Linux command – and there almost always is.

For example, the Linux fdisk command is a GNU command that is used to manage the partitions on a system and this command exists on all distributions.

So, rather than learn a command that is specific to a single Linux distribution, learn the GNU commands because these commands are common to all distributions.

3. Using Linux Commands that are Common to All Distributions – The GNU Commands

The GNU commands are the most popular Linux commands – and they are common to all distributions.

Linux Training Tips: Linux distributions are rising and falling in popularity all the time.

If you just learn how to use Linux by running the GUI utilities in one distro, and then you stop using that distro, then you have to learn all the GUI utilities of the next distro. If you learn how to use commands, then you learn how to use Linux for all distros!

How can you tell which commands are the GNU / Linux commands?

Get an excellent set of videos that shows you the popular GNU commands and then try these Linux commands yourself. Then you can learn Linux the easy way – by watching it and then working with it! Good luck.

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Learn Linux Command Line | Belajar Linux

Banyak cara untuk belajar linux, Anda cukup mengetikkan keyword ” learn linux command line ” maka Anda akan di sajikan ratusan halaman web yang akan memberikan informasi seputar Linux command line. Dengan memanfaatkan internet Anda dengan mudah menemukan beragam informasi yang Anda inginkan.

Keyword “Learn Linux Command Line” akan mengantar Anda ke ratusan hingga ribuan tips and tricks tentang bagaimana mengoperasikan linux. Hanya dengan sebuah browser dan mesin pencari Anda sudah bisa mempelajari hal-hal baru dengan cepat dan murah. Bersahabatlah dengan mesin pencari maka dunia ada di tangan Anda. Linux command line atau sering disebut CLI (command line instruction) adalah daftar perintah yang dapat digunakan untukmengoperasikan linux.

Perintah ini penting untuk di ingat agar user dapat mengoperasikan Linux dengan mudah. Beberapa perintah yang perlu di ingat adalah perintah dasar atau perintah yang paling sering digunakan sehari-harinya. Perintah ini perlu di catat dan diletakkan disisi meja kerja agar mudah ditemukan saat Anda membutuhkannya.

Untuk info selanjutnya silahkan lihat keyword “learn linux“, maka Anda akan mendapati pelajaran tentang linux yang lebih luas lagi. Anda akan menemukan semua hal tentang linux dan Anda dapat belajar linux dengan mudah dan murah.

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