Posts Tagged ‘thing’
Thursday, January 22nd, 2015 
I'm responsbile for a project environment made up of 3 components which is occasionally dying. Here is a short raw overview of environment
- Apache Reverse Proxy (entry door to app server)
- Tomcat Server with an Application enabling web access
- A Java Standalone application using SQLite database
The Tomcat and Java Standalone application is running on top of Windows 2008 RC2 Standard, the overall environment is becoming inacessible periodically and in order to solve that the customer decided to implement a daily Windows server reboot in my opinion this is very bad approach as it is much better to just set an auto reboot of each of components using few tiny batch scripts and Windows Taskmgr, however as the customer is king and decided to implement the reboot its their own thing.
However even fter the daily server reboot was set once a week or so the application was becoming inaccessible and a Tomcat server restart was necessery as a fix.
Finally as a work-around to the issue, I've proposed the logical thing to automatically restart Tomcat once a day early in morning, here is how Tomcat auto Restart was implemented on the Win server:
1. Check out the name of running Tomcat service
First thing is to use the sc command to find out the Tomcat application name:
C:UsersGeorgi>sc query state= all| findstr "Tomcat"
SERVICE_NAME: Tomcat7_r2c
DISPLAY_NAME: Apache Tomcat Tomcat7_r2c
C:UsersGeorgi>
2. Create bat script to stop and start Tomcat service
Press keyboard Win-button + R, start notepad type inside:
@echo off
sc stop Tomcat7_r2c && sc start Tomcat7_r2c
(
Don't be confused from screenshot that I have Tomcat7_MyApp instead of Tomcat7_r2c, but I made screenshot in hurry for another app.
Save the file, somewhere (preferrably) in application folder/bin/ it is best to save it once with bat extension MyApp-Tomcat_Restart.bat and once as MyApp-Tomcat_Restart.xml (XML format file is later needed for import to Task Scheduler which understands .XMLs). The .bat file is good to have because it is useful to somtimes restart Tomcat manually by running it (in case of some sudden Tomcat Appserver occurs even though the auto-restart script).
3. Create new Task using command line (cmd.exe)
Task can be created also from command line using following syntax:
schtasks /Create [/S [/U [/P [ ]]]]
/XML <xmlfile> /TN <taskname>
Simple way to create a new Windows task is shown in below command, it will set my Tomcat Restart script to run everyday in 05:00 early morning when no employees are using the system:
schTasks /Create /SC DAILY /TN "My Task" /TR "C:UsersGeorgiDesktopmyApp-Tomcat_Restart.bat" /ST 05:00
SUCCESS: The scheduled task "Tomcat Restart Task" has successfully been created.
4. Create / Import new Windows "Cron" job
Alternative way is to use Task Scheduler GUI frontend and create new (Basic Task) or import just created script
To run Windows Task Scheduler from comamnd line :
Taskschd.msc
To import already existing .XML formatted file for Task scheduler, right click on the Task Scheduler (Local) and select Import task
Import the myApp-Tomcat_Restart.XML previously created file
Adjust settings to suit your needs, but what change atleast:
- the path to the myApp-Tomcat_Restart.bat file in Actions tab
- the Local User account with which script will be running (administrator) in General tab
After making all changes you will be prompted for server Administrator account password
5. check existing Win Cron job from command line
To see the configured (Scheduled Tasks) in command line mode with a command:
Schtasks.exe
The command is Windows equivalent to UNIX / Linux's crontab, e.g.:
crontab -u root -l
6. Delete existing Windows Task Job from Command line
If you happen to need to delete just created task or any other task from command line (Assuming that you know the previously created task name), use cmd:
C:>schtasks /Delete /TN "Tomcat Restart Task"
WARNING: Are you sure you want to remove the task "Tomcat Restart Task" (Y/N)? y
SUCCESS: The scheduled task "Tomcat Restart Task" was successfully deleted.
Task completed, Tomcat will auto-restart on Windows host at your scheduled time. Feedback is mostly welcome 🙂
Enjoy
Tags: Apache Tomcat Tomcat7_r2c, auto reboot, command, community, Create Import, customer, Delete, door, environment, job, line, opinion, scripts, state, syntax, thing, Tomcat Restart Task, Windows Taskmgr
Posted in Everyday Life, System Administration, Various, Web and CMS, Windows | 2 Comments »
Sunday, March 9th, 2008 
We (Me and My Family) had to stand up early in the morning around 4:30 in Saturday and we traveled to Burgas. First we had to go to a herbman to prescribe me some Herbs. The herbamn is called “bai Dimitar” where bai is a bulgarian specific title for a man on age after the middle age he is located in Kamenartzi village (a small village near Bourgas). He is a sort of strange guy and is speaking very strange things. I hope this herbs will help me. I have to boil them and drink them five times a day. After that we went to Bourgas in my aunt Galia and uncle Galen’s apartment. Everything was a sort was going smooth, Gergana my cousin which was going to merry dressed with a bride dress and waited for his future man (son-in-law). The guy appeared with a limosine and an orchestra. Some ordinary Bulgarian rituals were followed after that the ceremony continued in the council house. Where they became man and wife officially (in front of Bulgaria). After that it followed a celebration in a Bourgas Hotel called “Bulgaria”. The celebration of the marriage included again different traditional Bulgarian dances, guest also danced and ofcourse the Bulgarian familiar horos. I did eat a lot of food and drinked a lot of the meaningless of marriage and all this vanity into celebrity and a lot of empty words spokened there I also convinced myself that I would NEVER EVER allow to have a marriage celebration like this. Some 20 or 30% of the music was Chalga which ofcourse drived me mad. In somewhere 05:00 in the morning we traveled back by car with my father driving. My father is driver from some few months and I definetely can’t say he is an experiencable type of driver which may allow himself to drive with speed higher than the maximum allowed, anywayz he did and I just tried to make him aware that he is braking the driver codex rules. He instead of taking my notes which I made with the idea that I would like to be home back ALIVE, nagged him and he started yelling at me and telling me to stop to complain. That ended in again making me hate him and regret I have parents like this which was a expected to happen since I was angry at all the stupidity and the low intelectual level of most of the ppl who were invited into the Marriage ceremony (although most of them were businessman and a ppl with a high degrees, education). The thing that irritated me the most that the had a marriage ceremony in a orthodox Church and they probably did this just because this is the ordinary way most ppl in Bulgaria does. PFF.. I have slept just for a hour or two today so I probably will go to sleep soon. But first I intend to go for a Liturgy in St. George’s orthodox church. This is after 20 minutes from now. Well thats most of how I spend my saturday on “nothing”. The good thing from all that was that Niki, a.k.a. Nomen’s brother has given me his PSP for the weekend. So I had the time to examine it and generally play with it. I even used a free wifi access in the restaurant where we were and did a bit of browsing :)END—–
Tags: age, anywayz, apartment, bai, bourgas, bride dress, Bulgarian, bulgarian dances, celebrity, ceremony, chalga, church, council, council house, Cousin, Dimitar, driving, driving my father, everything, future man, galen, galia, guy, herbman, Herbs, horos, house, Kamenartzi, limosine, lot, man and wife, man son, marriage celebration, middle age, morning, ppl, quot, rituals, saturday, sort, strange guy, strange things, thing, type, vanity, village
Posted in Everyday Life, Self Healing | No Comments »
Wednesday, February 5th, 2014 
Last Saturday evening I and my future wife Svetlana went to get train tickets (Sofia Dobrich), cause next week me and Svetlana will be travelling to Dobrich. Afterwards we went to Russian Church in center of Sofia – St. Nicolas for the evening service and confessed. The evening service was led by Archimandrite Philip who is currently Russian Church's prior.
At the end of Church service there was an oilment, as always being on a Russian Holy Liturgy is astonishing experience. On Sunday morning 2nd February we were in Russian Church again for the Russian Liturgy and we took the holy sacraments as it is proper (according to Orthodox Church tradition the marrying couple should confess and receive the sacraments before marrying in Church). After Church service we went to Church crypt to venerate holy relics of Archimandrate Seraphim Sobolev. A big thing is happening in my life nowdays as I will have marriage this week on Friday 7-th of February:)
We prepared so far almost everything for marriage. My parents helped with finding a marriage resturant and finding musicians for post marriage restaurant celebration. We also travelled to Asenovgrad to look for Svetlana's wedding dress and we got one I bough a marriage suit 2 weeks back and we ordered a marriage rings. There is already agreement with a priest father Vasilij – who will merry us in Church St. Trinity this Friday. Father Vasilij serves in Church "Dormition of Virgin Mary" in Kavarna . We choose father Vasilij to make the Marriage vows for the reason he is nativily Russian speaking (like Svetlana) plus the father is a good example of a true Christian priest. Today the parents of Svetlana (mama Vera and papa Alexander) arrived in the airport in Varna for the marriage (thanks God they had safe flight). Sunday night I send Svetlana to Train Station here in Sofia to make latest preparations for marriage. I will be travelling to Dobrich on Wednesday night 1 day before marriage. The rest of things happening around are not so interesting. In y job in HP work is complicated as usual. On my job I'm learning HPSM (HP Service Manager) and how to open new Changes in system and that's mostly my life these days. When I have time I'm playing OpenTyrian and a couple of nice arcade games on my ZTE Android mobile phone and reading some saint livings on mobile.
Tags: arcade games, Archimandrite Philip, Asenovgrad, bride dress, center, couple, Dormition, end, Evening, experience, February, future, games, last, last days, life, look, make, musicians, nowdays, Russian, russian church, Russian Holy Liturgy, sacraments, svetlana, thing, today, Wednesday, week
Posted in Christianity, Everyday Life, Various | No Comments »
Monday, November 18th, 2013 
Earlier I blogged how to create SSH tunnels on Linux. Another interesting thing is how to make SSH tunnels on Windows. This can be done with multiple SSH clients but probably quickest and most standard way is to do create SSH tunnel with Putty. So why would one want to make SSH tunnel to a Windows host? Lets say your remote server has a port filtered to the Internet but available to a local network to which you don't have direct access, the only way to access the port in question then is to create SSH tunnel between your computer and remote machine on some locally binded port (lets say you need to access port 80 on remote host and you will access it through localhost tunneled through 8080). Very common scenario where tunneling comes handy if you have a Tomcat server behind firewalled DMZ| / load balancer or Reverse Proxy. Usually on well secured networks direct access to Tomcat application server will be disabled to its listen port (lets say 11444). Another important great think of SSH tunnels is all information between Remote server and local PC are transferred in strong SSH crypted form so this adds extra security level to your communication.
Once "real life" case of SSH tunnel is whether you have to deploy an application which fails after deployment with no meaningful message but error is returned by Apache Reverse Proxy. To test directly tomcat best thing is to create SSH tunnel between remote host 11444 and local host through 11444 (or any other port of choice). Other useful case would be if you have to access directly via CLI interface an SQL server lets say MySQL (remote port 3306 filtered) and inaccessible with mysql cli or Oracle DB with Db listener on port 1521 (needed to accessed via sqlplus).
In that case Putty's Tunneling capabilities comes handy especially if you don't have a Linux box at hand.
To create new SSH tunnel in putty to MySQL port 3306 on localhost (3306) – be sure MySQL is not running on localhost 😉
Open Putty Navigate in left pane config bar to:
SSH -> Tunnels
Type in
Source Port
– port on which SSH tunnel will be binded on your Windows (localhost / 127.0.0.1) in this example case 3306.
Then for
Destination
– IP address or host of remote host with number of port to which SSH tunnel will be opened.
N.B. ! in order to make tunneling possible you will need to have opened access to SSH port of remote (Destination) host
Once click Open you will be prompted for username on remote host in my case to my local router 83.228.93.76. Once you login to remote host open command prompt and try to connect Windows Command prompt Start -> Run (cmd.exe) ;
C:\Users\\hipo> telnet localhost 3306
Connection should be succesful and you from there on assuming you have the MySQL cli version for windows installed you can use to login to remote SQL via SSH tunnel with;
C:\Users\\hipo> mysql -u root -h localhost -p
To later remove existing SSH Tunnel go again to SSH -> Tunnels press on SSH tunnel and choose Remove
Further you can craete multiple SSH tunnels for all services to remote host where access is needed. Important think to remember when creating multiple SSH connections is source port on localhost to remote machine should be unique
Tags: client, direct access, host, How to, Internet, Linux, localhost, machine, port, Putty, Reverse Proxy, running, say, server, ssh, standard, thing, Windows
Posted in System Administration, Various, Windows | No Comments »
Thursday, November 7th, 2013 
Not of a the latest thing out there but I believe a must know for every geek is existence of Raspberry Pi mini computer Linux board. It is a geek credit-card sized mini PC on extremely cheap price between 25$ and 35$ bucks (e.g. Raspberry Pi model A and Raspberry Pi Model B).
Raspberry Pi hardware you get for this ultra low price is as follows:
- Broadcom BCM2835 system on chip
- ARM Mobile processor model ARM1176JZF running at 700 Mhz (overlocking up to 1Ghz is possible – overclocked RP is called Turbo 🙂 )!
- VideoCore IV GPU with 512 MBytes of ram
- No Build hard disk or solid-state drive but instead designed to use SD-Card as a Storage
- two video outputs
- composite RCA and an HDMI port
- 3.5mm audio output
- 2 or 1SD/MMC/SDIO card slot (depending on device model A or model B)
- Micro USB adapter power charger 500mA (2.5 watts) – Model and 700mA (3.5 watts)
The idea of whole device is to make cheap affordable device for pupils and people from third countries who can't afford to pay big money for a full-featured computer. Achievement is unique all you need to Raspberry Pi credit card sized device is external keyboard a mouse, SD-card and a monitor, this makes a 700Mhz featured almost fully functional computer for less than lets say 80$ whether used with a second hand monitor / mouse and kbd :). A fully functional computer or full functional thin client for as less as 80$ yes that's what RaspberryPi is!
It is recommendable that SD-Card storage on which it is installed is at least 4GB as this is part of its minimum requirement, however it is best if you can get an SD-Card of 32GBytes whether you plan to use its whole graphic functionalities.
Raspberry Pi Hardware is not too powerful to run a version of Windows as well as there is no free version of MS-Windows for ARM Processor, so basicly device is planned to run free software OSes GNU / Linux. 5 operating systems are working fine with the mini-board device as time of writting;
- Raspbian – Debian "Wheezy" Linux port
- Pidora – Fedora mixed version ported to run on Raspberry Pi
- Risk OS port
- Arch Linux port for ARM devices
- Slackware Arm
FreeBSD / NetBSD
- QtonPi
Recommended and probably best distro port is for Debian Squeeze
To boot an OS into raspberry PI dowbnload respective image from raspberrypi.org
– Use application for copying and extracting image to SD-Card like Win32 Disk Imager – whether on Windows platform
– Or from Linux format SD-Card with gparted (N!B! format disk to be in FAT32 filesystem), extrat files and copy them to SD-CARD.
Once Raspberry Pi loads up it will drop you into Linux console, so further configuration will have to be done manually with invoking plenty of apt-get commands (which I will not talk about here as there are plenty of manuals already) – you will have to manually install your Desktop … Default shipped Web browser in Debian is Midori and due to lack of ported version of flash player for ARM streaming video websites like youtube.com / vimeo.com does not work in browser. There is a Google Chrome for Raspberry Pi port but just like with Midori heavy object loaded websites works very slow and thus not very suitable for multimedia.
Raspberry Pi device is very suitable for ThinClient use there is a special separate project – Raspberry ThinClient Project – using which a hobbyist can save 400$ for buying proprietary ThinClient.
Tags: Arch Linux, ARM, boot, card, client, com, Debian Squeeze Linux, distro, drive, functionalities, geek, HDMI, hobbyist, Linux, OS, Pc, PI, power, price, Raspberry Pi, run, state, thing, use, version, working, youtube
Posted in Curious Facts, Everyday Life, Linux, Various | 4 Comments »
Monday, April 2nd, 2012 I've hit an interesting article explaining how to check unread gmail email messages in Linux terminal. The original article is here
Being able to read your latest gmail emails in terminal/console is great thing, especially for console geeks like me.
Here is the one liner script:
curl -u GMAIL-USERNAME@gmail.com:SECRET-PASSWORD \
--silent "https://mail.google.com/mail/feed/atom" | tr -d '\n' \
| awk -F '' '{for (i=2; i<=NF; i++) {print $i}}' \
| sed -n "s/
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As you see this one liner uses curl to fetch the information from mail.google.com's atom feed and then uses awk and sed to parse the returned content and make it suitable for display.
If you want to use the script every now and then on a Linux server or your Linux desktop you can download the above code in a script file -quick_gmail_new_mail_check.sh here
Here is a screenshot of script's returned output:
A good use of a modified version of the script is in conjunction with a 15 minutes cron job to launch for new gmail mails and launch your favourite desktop mail client.
This method is useful if you don't want a constant hanging Thunderbird or Evolution, pop3 / imap client on your system to just take up memory or dangle down the window list.
I've done a little modification to the script to simply, launch a predefined email reader program, if gmail atom feed returns new unread mails are available, check or download my check_gmail_unread_mail.sh here
Bear in mind, on occasions of errors with incorrect username or password, the script will not return any errors. The script is missing a properer error handling.Therefore, before you use the script make sure:
gmail_username='YOUR-USERNAME';
gmail_password='YOUR-PASSWORD';
are 100% correct.
To launch the script on 15 minutes cronjob, put it somewhere and place a cron in (non-root) user:
# crontab -u root -e
...
*/15 * * * * /path/to/check_gmail_unread_mail.sh
Once you read your new emails in lets say Thunderbird, close it and on the next delivered unread gmail mails, your mail client will pop up by itself again. Once the mail client is closed the script execution will be terminated.
Consised that if you get too frequently gmail emails, using the script might be annoying as every 15 minutes your mail client will be re-opened.
If you use any of the shell scripts, make sure there are well secured (make it owned only by you). The gmail username and pass are in plain text, so someone can steal your password, very easily. For a one user Linux desktops systems as my case, security is not such a big concern, putting my user only readable script permissions (e.g. chmod 0700)is enough.
Tags: article, atom, Auto, awk, client, com, cron, Desktop, download, Draft, ebay, email, email marketing, email messages, facebook, Fri, geeks, Gmail, GMAIL-USERNAME, GNU, gnu linux, google, Group, https mail, liner, LinkedIn, Linux, linux server, linux users group, mail, marketing, news today, OFF, original article, password, quot, rizki, sat 3, script, SECRET-PASSWORD, terminal, thing, top news, twitter, username, Users, Weekly
Posted in Linux, System Administration, Various | 2 Comments »
