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Phil explains how to use the old telephone tones to wane off telemarketers!
Posted on: April 1st, 2012 by Famous Phil
About a month ago, I was asked to write a review of UCertify’s services (their website is located at www.ucertify.com). UCertify is a certification test preparation service for taking various information technology related certification tests.
The IT industry in past years has become highly standardized and this means that many certification tests have evolved to enable people to prove that their skills are at par. Certifications tend to provide a higher probability that the person who passed will obtain a better job and will be able to perform at the job’s expectations. Certifications tend to require renewal every 5-10 years as well to ensure that the person who is certified remains knowledgeable in the ever evolving technology that surrounds them.
I might as well add in that I am not certified in anything at this point in time, but I have a computer science degree (BS and MS) from an accredited university. I tend to do IT work solely as a hobby, since my true abilities are in programming, and the theory around programming and how computers work. The difference between IT and CS is simply the amount of math and theory that you have to learn about. IT is basically really simplified practical computer science if you ask me.
Now for an actual review of UCertify. They were kind enough to provide me with a full access license to their Windows Exam (MCTS) Preparation Kit. I had to download a 15MB program that installed itself to my computer and then provided me with a nice user interface to begin learning the components of the exam. The interface was very simple and easy to understand, it was broken into a learning mode (which starts at the basics and advances) and a test mode. In learning mode, you’re simply learning about what general windows administrators need to know, there are also several quiz questions to verify that you understand what you read. In test mode, you can answer several questions and attempt to meet a goal (like a passing score for example).
I only went through a very small subset of both sections, but I was surprised to see some material that I wasn’t entirely familiar with (although I’ve heard of it), with this said, I’d strongly recommend the service as a whole for someone who needs to get certified. Certification exams assume that you will need to know everything at some point, so they test for just about everything. Unfortunately, many uncertified professionals are only exposed to what they need to know, so sometimes it can take a few minutes for someone such as me to arrive at the same conclusion that a certified person might already know. In any event, certification in the relevant field almost always guarantees that a candidate can get a specified job before someone who is uncertified for the same position.
I’d like to thank Manjari from UCertify for contacting me about this service, if you have any questions about their service, I’d suggest you email him directly at manjari [at/@] ucertify [./dot] com. I learned a little from what I have done with the service and who knows, it might even help me in the future. Hopefully this can be useful for some of my readers out there. Finally, for all of the skeptics out there, I wasn’t paid to write this review although I did get temporary free access to the windows certification prepkit to review it.
Tags: certification, prepkit, ucertify
Posted in Hosting / Server Administration, Technology
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Posted on: February 20th, 2012 by Famous Phil
About a month ago, I covered using MySQL in both PHP and Python briefly by posting two simple classes (code samples), you may view that post here. Typically, I’m a more advanced user that has a lot of skills in systems administration, and unfortunately, I kind of overlooked how to get the functionality that my code exploits working correctly, so I’m going to take a step back (after a few private emailed questions) to explain how to get MySQL working with both PHP and Python in CentOS 6, which is my operating system of choice for serving PHP and Python applications.
I guess that I’ll start with PHP since it’s by far easier to get working. Assuming that you’re using Yum (the default CentOS package manager), installing the package php-mysql (yum install php-mysql) should be sufficient in making all of the MySQL functionality work in PHP. The Ubuntu package manager, apt-get, should have a similar installation package. Any LAMP installation should install this package automatically (including Debian, Ubuntu, Suse, etc). If you’re installing by source, you’ll need to install MySQL first (by source I’d assume), then compile PHP and Apache (or your web server of choice). When compiling PHP from source, you’ll need the argument “—with-mysql” passed in as a parameter to the configure script. I’ve linked the PHP Source Code for your convenience if you wish to go the source route (which I wouldn’t recommend personally).
Next up is Python’s MySQL connectivity. Once again, you’re going to need at least the MySQL client installed on your local machine along with Python. In CentOS (6, probably 5 and 4 also), you can do a “yum install mysql-client” to get MySQL’s client on the system. I use the library called mysql-python. MySQL for Python is linked for your convenience. To install this library, visit the site (linked previously) and download the tar.gz file (currently MySQL-python-1.2.3.tar.gz), once you have that on the server, extract it using (tar xzf MySQL-python-1.2.3.tar.gz). Inside the extracted archive, you’ll find several files, including a setup.py. As root, simply run this executable with the install parameter: “python setup.py install”. This will install the Python-MySQL library and my sample singleton class should now work. As a tip, many Python related libraries use the setup.py executable in the same format.
I’m sure that I missed a lot of details, but this was merely to answer a few questions that I received through email, mostly about the Python-MySQL library. Hopefully this post helps resolve these questions.
Tags: CentOS, mysql-python, php-mysql
Posted in Hosting / Server Administration, Programming
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Posted on: November 21st, 2011 by Famous Phil
Most of the Matthouse infrastructure is running on old Celeron processors and limited RAM, you may laugh at me, but that hardware has been very reliable and has lasted Matthouse for the better part of 3 years, and some of it may continue to power Matthouse well into the future! But there are some applications out there that require a little more juice to run well, and (unfortunately) Exchange falls into this category. I say it is unfortunate since the Exchange server hosts a handful (< 10) mailboxes, yet it costs quite a bit to maintain compared to other Mail Transfer Agents (MTA). So anyways, this blog is dedicated to the procedure that I took to migrate Exchange over to brand new, shiny, fast hardware.
First, I had Server 2008 R2 Datacenter as my operating system on both the existing server (denoted double) and the new server (denoted ruby). The servers could clearly communicate with each other within the same datacenter as well so that file / data transfers could be effective. The first thing to adding any server is to give the new server a name and know its network configuration details ahead of time. I’m not going to go into details about how to install Windows, since it’s pretty simple. Just make sure that you have the correct drivers installed for your server after the installation completes.
Note about installing Windows: just so that you don’t run into any issues with your system, make sure that your primary hard drive is attached to the first port for your motherboard’s interface, in my case, the first hard drive was connected to SATA 0. If you don’t do this, you’ll run into a lot of problems and waste a lot of time (like I did!). In addition, make sure that your BIOS has AHCI enabled prior to installing Windows, this also caused problems in my scenario. Once Windows is installed, make sure that you can disable write caching on your hard disk without the operating system freezing (in computer management, under storage, right click the disk and optimize for quick removal). If you followed the above, this shouldn’t cause Windows to hang, and will prevent Active Directory from incapacitating your system during the restart phase of the installation. In addition, this is a good time to name your computer, join it to some default workgroup, add remote administration features, and change the time zone / clock settings.
Before continuing, I’d also recommend disabling Internet Explorer’s advanced security features; this is done by going to the computer management main screen and scrolling down, finding IE ESC and turning it off (acknowledging all of the warnings). If you keep them on, you’ll find yourself doing way too much work to download necessary applications, etc. These features are only useful if you plan on doing general web surfing on the server (which I would not recommend for security reasons). I also activated windows, ran all the necessary windows updates (several reboots and optional updates as well). After this all has been done, I ended up rebooting the machine a final time.
At this point, I installed several applications (using IE to get Google Chrome initially).
- Google Chrome (http://chrome.google.com) for web surfing / downloading the rest of these
- Adblock plus for chrome (http://adblockplus.org/en/) to block malware / ads
- 7zip (http://www.7-zip.org/download.html) for good archive file support
- Microsoft Security Essentials (http://windows.microsoft.com/en-US/windows/products/security-essentials), Windows 7 version works fine, this is a quick, safe, free antivirus solution for all of those who hate Symantec’s ability to slow down the entire system (hey, that’s me!) This is also good for desktop users! I would recommend disabling the scheduled Sunday scan since real-time protection is sufficient in my case.
- Magic ISO (http://www.magiciso.com/tutorials/miso-magicdisc-overview.htm) to mount ISO images (including the Exchange 2010 ISO if you downloaded it from MSDN like I did).
- Office Filter Packs which are a prerequisite for Exchange 2010 (http://www.microsoft.com/download/en/details.aspx?id=17062) Read the rest of this entry »
Tags: active directory, exchange, exchange 2010, migration, owa, Transfer, upgrade, windows
Posted in Hosting / Server Administration, Technology
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Posted on: August 22nd, 2011 by Famous Phil
Anymore, it seems like posting here is a seldom activity because I don’t often deal with server administration issues any longer (although I am working on changing that 
). Today, I was asked to reset the password on a Mac Server because the user didn’t remember the password. Personally, I don’t know how a server oriented password can be lost, but whatever, I guess I’ve seen it all now 
Mac, like Linux and its BSD roots, has a flaw when you have physical access to the machine. Basically, passwords are stored as password hashes in a simple file on the server. To change the password of any user account, you basically have to gain write access to the said password (or shadow) file and change the hash to something that matches the new desired password. Typically, this is very easy to do for any kind of Linux or BSD operating system. For all of you Windows fans, Windows stores the passwords encrypted in SAM files (if I recall correctly), and there are also password reset disks available that you boot from and overwrite the administrator account password with your own password. Once again, resetting a password is very easy to do to gain access to a machine provided you have physical access. One tiny exception to this rule on every platform, if the encryption feature is enabled on a user account (provided it exists), the files that were encrypted will never be readable again if you change the password using this method.
Since this is resetting the password of a Mac, I’m only going to cover the Mac OS. Mac, like Linux and BSD, has something called single user mode which is basically a recovery environment built into the operating system. When something doesn’t work properly, this environment typically boots and gives the local user (on the console) a command prompt that is running as the root user (or superuser). Typically in single user mode, the local hard disk is read only, but because you are root, you can simply change that to write mode. Afterwards, its a matter of changing the password. If you aren’t a single user mode fan, Mac even puts a reset password link in the utilities menu of their installation disk that does the work manually.
So, using the single user mode shell, here is the procedure to resetting the password of your mac:
- Shut down the computer
- While holding the command (apple) key and S simultaneously, power the computer on
- The command line will come up shortly
- Type in “/sbin/mount -wu /” without the quotes, this enables writing to the root operating system directory
- type in “passwd <user>”, where <user> is the username whose password needs to be reset
- type in “reboot”
- Login as the user that you reset the password for, using the new password you set.
Tags: Mac, password, reset, root, single user mode
Posted in Hosting / Server Administration, Technology
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Posted on: July 4th, 2011 by Famous Phil
This blog is something that I know like the back of my hand, but I realize that others may not be as fluent in using crons. This blog is meant to be a reference to those individuals. Cron is a unix (and solaris, BSD) utility that runs tasks automatically in the background at regular intervals, its very similar to the Windows Task Scheduler. Cron can be referenced as a cron job, or cron tab (cron table). For simplicity, I will simply call it a cron.
Restrictions: Crons can be ran if your username is in the cron.allow file, the location of this file varies across different systems. If the cron.allow file does not exist, and your username does not exist in cron.deny, you can use crons. The format of each file is one username per line.
Commands: The most common command I use is “crontab -e” which means edit the crons that run under your user account. This command opens up the default editor of your system to do this. The “l” flag means display the crons that are configured under the user’s account. The “r” flag removes the current crons under a user’s account. Finally, the “v” tag shows the last modification time of the cron configuration for a user account, note that this command is not available on all systems.
Syntax: The cron file is set up with a certain syntax.
The first line can configure a default email address to email the completion (any script output) to or it can immediately start with cron jobs, using the default email address of the account (defined in the .forward file or a local mail queue usually).
Defining an email address on the first line:
#Don't email anything by default MAILTO="" #email all cron job completions to admin@example.com by default MAILTO="admin@example.com"
Each subsequent line looks like the following
* * * * * <command> - - - - - | | | | | | | | | +----- day of week (0 - 6) (Sunday=0) | | | +------- month (1 - 12) | | +--------- day of month (1 - 31) | +----------- hour (0 - 23) +------------- minute (0 - 59)
In the above, if you enter * (the wildcard character), the job will run for all possible points of the value. For example, if you do * for the minute value, this script will run at every minute. If you want to run a job every second (not recommended), you can specify the minute value as ” */60 ” meaning run at every 60th of a minute. This is not always supported, but for the majority of systems I use, it is.
The
Emails: Finally, if you want a certain command to not email you regardless of completion, you can do the following (using the above example):
0 0 * * * /usr/bin/sa-update > /dev/null 2>&1
Adding ” > /dev/null 2>&1 ” to the end of the command redirects the output of the script running to the null device (/dev/null), which is a special file that discards all data that is written to it. Essentially /dev/null is the trash can. The > symbol is a unix pipe symbol that redirects the output of the left side to a file descriptor (or device) located on the right side. the “2>&1″ at the end says pipe the standard error output (device 2) to the standard output device (device 1), so this essentially unifies all error and regular messages from the program so that they both can be sent to /dev/null. In case you’re wondering, device 0 is standard input from the command line. You can understand this a lot more thoroughly by looking at Linux file descriptors and pipes.
Path: Cron usually invokes commands using (/bin/sh) which is the default shell on most systems, it typically starts in the user’s home directory with a very simplified PATH. If you believe your cron isn’t working properly, try using absolute paths in your commands from /.
Credit: I’d like to finally credit http://adminschoice.com/crontab-quick-reference in helping me make my reference more comprehensive, I didn’t want to completely write this from my own experience.
Tags: crontab, device, file descriptor, syntax
Posted in Hosting / Server Administration
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Posted on: July 3rd, 2011 by Famous Phil
Over the past couple of months, I’ve found that the script that I posted at http://famousphil.com/blog/2011/01/a-decent-backup-strategy-for-exchange-2010-sp1/ hasn’t been working perfectly for my needs. This relatively short blog is kind of a back track blog to explain the issues and provide some fixes for them.
The original script I posted does not verify that the backups actually completed. The emails I got were simply gibberish. I was willing to accept that for a while until during monthly maintenance when I manually verify backups, I was finding that backups didn’t always complete. I’ve tracked this down in the error logs and found that the memory in the server isn’t enough for the backups at times which has them fail at certain times. Due to the lack of user base on my server (4 light users), I can’t justify adding more ram (I currently have 4GB) because I’d have to upgrade the entire server. So instead, I did some RAM optimization and re-wrote the backup script to email me the actual backup names that completed successfully.
First for the tips. I recently learned that Active Directory can be modified from the backend, so using this, I modified the Information Store service (store.exe) in Exchange to only use at most 512MB of ram. I used the information at http://terrytlslau.blogspot.com/2011/03/limiting-exchange-server-2007-and-2010.html for doing this, I briefly repeat the procedure here in the even that this link is no longer reachable.
1. At Domain Controller, login as a Domain Administrator. 2. Click "Start", enter "adsiedit.msc" into the search box, hit enter. 3. Right-click "ADSI Edit", select "Connect to". 4. Enable the Naming Context view, click ok to connect 4. Under the "Naming Context" menu, select "Configuration". 6. Expand to "Configuration > Services > Microsoft Exchange > > Administrative Groups > Exchnage Administrative Group > Servers > > InformationStore". 7. Right-click "InformationStore", select "Properties". 8. Select "msExchESEParamCacheSizeMax". 9. This value is set in pages, in Exchange 2010 the size is 32KB/page; Exchange 2007 is 8KB/page. Simply figure out the number of pages for the amount of ram you want to limit store.exe to using. For instance, if you want to limit the Database Cache to 4 GB of an Exchange 2010 server, set msExchESEParamCacheSizeMax to 131072 (4 GB = 4.194.304 KB / 32 KB). If you want to limit the Database Cache to 2 GB of an Exchange 2007 server, set msExchESEParamCacheSizeMax to 262144 (2 GB = 2.097.152 KB / 8KB). 10. Ok everything and restart the Information Store service (possibly the server)
After limiting the Exchange Information Store service, I simply restarted the Information Store service and that seems to have fixed the gouging memory issue.
As a second optimization procedure, I started tackling the IIS Worker Processes. Exchange has several application pools that it uses, you can think of an application pool in IIS as a separate instance of Tomcat or Apache for each website. Application Pools isolate websites to that they can’t affect each other. On the downside, application pools also hog a great amount of memory and for the features of Exchange that you may not use often (e.g. powershell, calendar, exchange control panel), it takes some time for these features to load initially (for me, its about 30 seconds). My solution was to limit Exchange to two application pools. For anything service related, I used the Exchange Service Pool (e.g. EWS, Powershell, Autodiscover), and anything client site based (e.g. OWA, Calendar, ECP, ActiveSync) in the OWA pool. I still do not know if any update to Exchange may reverse this or break this, but I do keep it in mind during updates. The result of doing this is that not only is memory consumption reduced significantly, but Outlook Web Access, Exchange’s Calendar display (for the public), and Exchange Control Panel all load much faster now since the overhead in IIS is already loaded. Of course, I wouldn’t recommend doing this unless you can’t easily upgrade the amount of memory in your server.
Finally, I will leave you with an improved export script that replaces the script in my previous blog at http://famousphil.com/blog/2011/01/a-decent-backup-strategy-for-exchange-2010-sp1/. This script verifies that all of the users were actually uploaded and emails the complete report to you (instead of some garble). I’ve found it to be very helpful in determining if a mailbox was failing to export to a PST without having to login to the file server and check. As always, use this script at your own risk, I am willing to provide limited support as time permits.
# Exchange 2010 SP1 Mailbox Export Script
# Originally from Steve Goodman.
# Modified by Philip Matuskiewicz for Matthouse.us / famousphil.com 1/2/11 FIXED *7/2/11*
#define information here
$server = "host.example.com" #server hostname
$users = @("Joe", "Mary", "Phil") #users to archive
$destination = "localhostpstbackups" #network share to backup to
$emailfrom = "server@yourdomain.com"
$emailto = "you@yourdomain.com"
#define some internal variables
$output = ""
$error = 0
$date = Get-Date
#check for errors
if (!(Get-ExchangeServer $server -ErrorAction SilentlyContinue)){
$output += "Exchange Server $server not found`n";
$error = 1
}
if (!(Get-MailboxDatabase -Server $server -ErrorAction SilentlyContinue)){
$output += "Exchange Server $server does not have mailbox databases";
$error = 1
}
#create a batch job if the above tests succeeded
if ($error -ne 1){
$jobname = "Export_$($date.Year)-$($date.Month)-$($date.Day)_$($date.Hour)-$($date.Minute)-$($date.Second)"
$output += "Job title is: '$($jobname)' `n"
Write-Output "Job title is: '$($jobname)' "
foreach ($mailbox in $users){
#remove existing PST file
if (Get-Item "$($destination)$($mailbox).PST" -ErrorAction SilentlyContinue){
Remove-Item "$($destination)$($mailbox).PST" -Confirm:$false
$output += "Existing PST was deleted (Normal): '$($mailbox)' `n"
Write-Output "Existing PST was deleted (Normal): '$($mailbox)' "
} # end if
#request a backup of the mailbox, Exclude the recoverable items / deleted items
$mailboxjobname = "$($mailbox)-$($jobname)"
New-MailboxExportRequest -BatchName $jobname -Mailbox $($mailbox) -FilePath "$($destination)$($mailbox).PST" -ExcludeDumpster -Name $mailboxjobname
$output += "Mailbox Queued: '$($mailbox)' `n"
Write-Output "Mailbox Queued: '$($mailbox)' "
} #end foreach
} #end $error -ne 1
#wait for the jobs to complete
$time = 0;
while ((Get-MailboxExportRequest -BatchName $jobname | Where {$_.Status -eq "Queued" -or $_.Status -eq "InProgress"})){
Write-Output "Waiting on backup, it has been $($time) seconds"
$output += "Waiting on backup, it has been $($time) seconds `n"
sleep 600 #10 minutes
$time = $time + 720;
} #end while
#check for any jobs that didn't complete
$incomplete = Get-MailboxExportRequest -BatchName $jobname | Where {$_.Status -ne "Completed"} | Get-MailboxExportRequestStatistics | Format-List
$complete = Get-MailboxExportRequest -BatchName $jobname | Where {$_.Status -eq "Completed"} | Get-MailboxExportRequestStatistics | Format-List
if($incomplete){
Write-Output "ERROR: Something didn't complete, output is '$($incomplete)'"
$output += "ERROR: Something didn't complete, output is '$($incomplete)' `n"
}
if($complete){
Write-Output "Completed Successfully, output is '$($complete)'"
$output += "Completed Successfully, output is '$($complete)' `n"
}
# Remove Requests and clean up
Write-Output "Cleaning up requests that were part of the job '$($jobname)'"
$output += "Cleaning up requests that were part of the job '$($jobname)' `n"
Get-MailboxExportRequest -BatchName $jobname | Remove-MailboxExportRequest -Confirm:$false
#verify that all the PST files were created...
foreach ($mailbox in $users){
#remove existing PST file
if (Get-Item "$($destination)$($mailbox).PST" -ErrorAction SilentlyContinue){
$output += "PST FOUND!!!: '$($mailbox)' `n"
Write-Output "PST FOUND!!!: '$($mailbox)' "
}else{
$output += "ERROR: PST NOT FOUND: '$($mailbox)' `n"
Write-Output "ERROR: PST NOT FOUND: '$($mailbox)' "
}
}
$SmtpClient = new-object system.net.mail.smtpClient("double.matthouse.org")
$msg = new-object Net.Mail.MailMessage
$msg.From = "$($emailfrom)"
$msg.To.Add("$($emailto)")
$msg.Subject = "EXCHANGE EMAIL BACKUP DETAILS"
$msg.Body = $output
$SmtpClient.Send($msg)
Write-Output "Script complete!"
Tags: backup, exchange 2010, powershell, pst, script
Posted in Hosting / Server Administration, Technology
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Posted on: July 2nd, 2011 by Famous Phil
Last night, I was tasked with moving 25,000 files (3GB worth) between two of my Linux systems. Traditionally, I use tar and gunzip (tar czf file.tar.gz directory/) to archive files for network transfer, but for whatever reason, I used the zip utility that is bundled with most Linux distributions (zip -r file.zip directory/).
The zip process went through fine and created a zip archive of the directory, but this is because the zip was done on a 64 bit build of CentOS Linux (where zip is compiled for large file support). I transferred the archive to the destination server (32 bit build of CentOS Linux). As any decent admin does, I verified that the checksum (openssl md5 file.zip) matched on both ends (to check for corruption). The md5 checksums matched, so I proceeded to unzip the file (unzip file.zip). Below is the error I received:
End-of-central-directory signature not found. Either this file is nota zipfile, or it constitutes one disk of a multi-part archive. In the latter case the central directory and zipfile comment will be found on the last disk(s) of this archive. unzip: cannot find zipfile directory in one of file.zip or file.zip.zip, and cannot find file.zip.ZIP, period.
It turns out that the 32 bit version of CentOS includes the zip utility that isn’t compiled with large file support. To rectify this, we must download the zip source code and recompile with large file support. The instructions that I used are at http://www.stevenbarre.com/blog/2007/03/04/how-to-unzip-large-files-greater-than-2-gb/
1. install zlib and zlib_devel using yum if you don’t already have them.
2. Download the source code of unzip from http://www.info-zip.org/.
wget http://sourceforge.net/projects/infozip/files/UnZip%205.x%20and%20earlier/5.52/unzip552.tar.gz/download
3. Extract the source code and move the appropriate make file to the main directory
tar xzf unzip552.tar.gz cd unzip-5.52/ mv unix/Makefile ./
4. Modify the MakeFile to enable large file support
Find:
CF="-O3 -Wall -I. -DASM_CRC $(LOC)"
Replace With:
CF="-O3 -Wall -I. -DASM_CRC -DLARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 $(LOC)"
5. Compile unzip
make linux
6. Use the executable unzip to extract file.zip
#assume file.zip is at /root/test/file.zip mv unzip /root/test cd .. #clean up the directory, remove unzip's source code rm -Rf unzip-5.52 rm unzip552.tar.gz #unzip the file cd /root/test ./unzip file.zip
Tags: archive, end-of-central-directory signature, large file, large file support, Unzip, Zip
Posted in Hosting / Server Administration, Programming, Technology
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Posted on: July 1st, 2011 by Famous Phil
Often times, I find myself working in a remote Linux terminal window. The other day, I had the need to share what I was doing with a friend, but I didn’t want to share my entire local desktop because sharing a full desktop is slow and laggy. So I quickly looked into sharing a screen session with him so he’d only see the command line window that I was in, and I know I will need it again, so its going up here. For those of you who have a Mac or Linux, you might know that you can have multiple desktops and go through them by some key combination (usually ctrl-alt-arrow). In a very simplified nutshell, screen basically allows for the user to exploit multiple desktops.
Here is how you share a screen session:
#User 1, initiator of the screen session screen -R sessionName #User 2, connecting to an existing session screen -x -R sessionName
The -R flag means try to reattach to an existing session, if the existing session does not exist, create a new session and attach to that. The -x flag means to connect to an already attached session, which allows for session sharing.
I ran into a problem as a non-root user (that I normally run as) when I first started using shared screen sessions. The error is as follows:
Cannot open your terminal '/dev/pts/0' - please check.
There are several terminal devices that screen can use under the /dev/pts directory, starting with 0. Only root can traditionally access these terminal devices, therefore, we need to modify each necessary device to allow normal users access. I didn’t research the security implications that the following fix has, so use this at your own risk. The server that I was using has only trusted users on it, so I was not concerned about possible risks.
#run this as root, or as sudo #this gives others read and write access to the device chmod o+rw /dev/pts/0
Finally, up until last week, I could never get myself out of a screen session safely without completely closing my putty terminal window. Here is the proper key sequence to detach from a screen session.
ctrl-A followed by ctrl-D
To terminate a session in screen, simply type exit.
Tags: Linux, screen, shared session, unix
Posted in Hosting / Server Administration, Programming, Technology
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Posted on: June 18th, 2011 by Famous Phil
This is a topic that I should have blogged about a long time ago (when I actually did it), but I was busy at the time and stuff gets pushed onto a back burner (or even the freezer) when I don’t have the time. Oh well, this article is better late than never. I will also provide a script that powers https://www.matthouse.us/status.php.
Nagios is a server monitoring solution that can monitor entire systems and services running on those systems. For Matthouse, Nagios runs on a reliable virtual private server that has a SLA to be up all of the time, the provider I choose has complete redundancy so that this VPS will not go down due to localized hardware, network, or power failures. Nagios also runs on a system that is completely off-site from all of my other servers, so it can see if a datacenter goes down and notify me properly. If you’re going to host Nagios yourself, I’d strongly suggest getting a similar setup since you don’t want your monitoring system to fail with everything else!
So let’s get into the actual installation of Nagios. (THIS WAS UPDATED 6/23/11) Read the rest of this entry »
Tags: CentOS, install, monitor, nagios, server
Posted in Hosting / Server Administration, Technology
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Posted on: June 13th, 2011 by Famous Phil
I bring you a guest post from Jason who is associated with the subtext project which is a blog written in ASP.net! Disclaimer… I do not guarantee (or verify) the accuracy of guest posts.
A webmaster has many things to think about from choosing the right host to making sure everything is running smoothly on the backend servers. Fortunately, different tools, applications and developments exist that can help us simplify the process of running a website. Subtext skins can help designers more effectively and efficiently create the styles used for personal blogs on their website.
While you can always decrease your workload by choosing options like managed hosting, if you are responsible for web design then you should look into the many advantages of Subtext skins for blogging.
What is a Subtext skin?
Subtext is a blogging platform offered as open source software under the BSD license. The whole concept behind Subtext was to create a very simplified blogging engine that allows bloggers to concentrate on creating actual blog content rather than trying to figure out how to use the blogging software.
Almost all websites these days have their own blogs. In addition, many sites offer blogging as a service to their users who can sign up to create their own personal blogs. You can use Subtext both for the site’s own blog and to offer blogs to site members.
A Subtext skin refers to the styling and layout of the blog page. Skins are versatile as they allow you to create page formats and designs without coding from scratch. A Subtext skin is actually made up of five separate style sheets that can be used to format different elements on the page like divs, spans, boxes, headers, footers, sidebars and forms.
The five style sheets used for each Subtext skin are:
• style.css – the default style sheet that determines the basic underlying skin layout.
• secondary style sheet – this file handles the specific Stylesheet attribute of the skin. The secondary style sheet is generally used to create styling contrasts over the style.css file. For example, the web designer may choose to give the header a different border than the sidebars where in the style.css file they use the same border.
• custom.css – this style sheet is used for custom design features set by the blog author. Primarily used to set styles and layout for personal badges or for the actual post content.
• non-attribute css files – generally used for CSS frameworks or for system styles.
• css files with limited attributes – these stylesheets have a title and media attribute, and cannot be merged with other css files. The attributes specify IE version compatibility and that they are applicable only in screen mode or in printing mode.
Packaged and custom Subtext skins
Web designers can choose from a large library of pre-designed skins or they can create their own custom skins. Creating a custom Subtext skin requires some basic knowledge of CSS scripting and also learning the basic Subtext parsing rules.
Fortunately, Subtext is highly simplified to allow users to quickly master the underlying script.
Skin templates are folders that can be used to render different Subtext skins. Each folder actually contains a number of skins that are related in certain attributes and themes. The folders or templates have their own series of controls that are used to render a skin in that template along with associated style sheets.
Once you have a library of packaged and/or custom skins, you will be able to style blogs quickly after learning how to tweak the skins and templates.
Instead of racking your brain each time you need to come up with a new design, you can simply browse through your selection of Subtext skins. Each skin can be modified according to the primary and secondary CSS files associated with the skin. You can easily find the types of skins you are looking for because they will be arranged in skin templates or families according to related attributes. For example, you can have a Rainbow template. a Geometric template and an Origami template – each having multiple skins that express the same theme. The number of templates is only limited by your imagination and willingness to create custom skins.
When using the Subtext blogging software, the skin templates are arranged in folders in an easy to manage directory system. The setup makes it simple to find the skin you are looking for and simply click on the selection to implement it on the Subtext blog.
By using Subtext skins, you can save time and energy creating page designs and layouts for multiple blogs. No need to code style sheets from scratch when you can access an easy-to-use Subtext skin library and quickly find what you need.
Each skin will handle the styling and layout of all page elements including headers, footers, sidebars, text format, boxes and forms.
You can find out more about Subtext and skins at the Subtext Project Site: http://www.subtextproject.com/.
Tags: asp, blog, engine, skin, subtext, theme, wordpress alternative
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