Linux System Administration Jobs

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Hourly - Intermediate ($$) - Est. Time: Less than 1 week, 10-30 hrs/week - Posted
We have a script that connects a Web Call to USB device. The main scenario is, we have a tablet application, which is on WiFi, It sends a URL call via local Wifi to some Lighting Hardware connected via USB to a RaspberryPi, which is running Apache/PHP etc. So from a browser you can type: http://192.168.0.3/serial/model.php?communication_board_command=chr(2).chr(0).chr(0).chr(0).chr(2).chr(5) It will go to the script, and send a message to the USB device. The issue is, that when we send many of these URL calls, once in a while it freezes randomly with no apparent pattern, it seems the USB port or connection is left open or something, that does not allow the next call in. Then it will start working again after a next call. So, we want to remove any chance of this freeze. The simple PHP code we are using is: <?php if($_GET['communication_board_command']){​ ini_set('display_errors', 1); $codes = explode(",",$_GET['communication_board_command']); foreach( $codes as $code){​ eval("\$code = $code;"); echo "\n lighting-code-sent"; echo $code; file_put_contents("/dev/ttyUSB0", $code); file_put_contents("/dev/ttyUSB1", $code); }​ echo "\n php-ok1"; }​ ?> So this works fine, and a command is sent to the USB, and the lighting board connected lights. However, sometimes it does not, and the call is ignored, or it stays lit with the old code sent when a new one is sent. We have tried sending the code twice, or with a usleep delay, or via calling a redirected script twice. We have tried with fopen(), fwrite(), fclose(); But it has no effect... sometimes there is still a Pause. --- If we run the same script on Windows, WAMP setup, it works fine, it does not seem to have the delay as on Linux / RaspberryPi, The script on Windows is: <?php error_reporting(E_ALL & ~E_NOTICE & ~E_DEPRECATED); if($_GET['lcode']){​ ini_set('display_errors', 1); `mode com3: BAUD=38400 PARITY=N data=8 stop=1 xon=off`; $codes = explode(",",$_GET['lcode']); foreach( $codes as $code){​ eval("\$code = $code;"); echo "\n lighting-code-sent"; echo $code; file_put_contents(com3, $code); }​ }​ echo "\n php-ok"; ?> As above we can set the Baud, Parity etc. But on Linux, it does not seem like this is done, when trying the same code. Or its set somewhere else previously? And it calls the COM port, via USB/Serial drivers. It just seems on windows, the socket call is dealt with differently, and the issue will not happen. --- In anycase we need help with this code on Raspberry Pi, to have the Web Call sent but not have any Freezes / Pauses, so that the USB call, is opened and closed, and can have multiple calls in a regular frequency, as per any local web call. - Another issue is when we plug in the USB cannot be sure if it will go to /dev/ttyUSB0 or /dev/ttyUSB1 which is why have them both there, or if the USB is taken out, sometimes its lost if reconnected... so another task is to always get the USB to ttyUSB0 and allow the script to call it. So for now we need help with these 2 points, and there might be others, as the projects progresses, as we need to create a very stable system for these Web Calls. As above its currently done in PHP, but I dont mind using Python to do it, or other scripts / executables, but we do need to have full understanding and control of whats happening. Can be Pay by the hour or a fixed price.
Skills: Linux System Administration Bash shell scripting Debian OS PHP
Fixed-Price - Intermediate ($$) - Est. Budget: $80 - Posted
I’m looking for an experienced server admin to investigate a problem with the WordPress install on the Ubuntu 14.04 server I have. It’s a 512mb DigitalOcean cloud droplet (VPS). What’s happening is that every few days the MySQL server crashes and requires a full server reboot to get working again. The solution is for the root cause to be fixed, or for some kind of monitoring system to be put in place. I have root access and can provide SSH access.
Skills: Linux System Administration System Administration Ubuntu WordPress
Hourly - Entry Level ($) - Est. Time: Less than 1 week, 10-30 hrs/week - Posted
Привет На русском пишу, чтоб индусы не спамили Нужен опытный Линукс админ. Nginx+uwsgi Есть ряд серверов. На них джанго приложухи. На днях начали переезд с одного сервака на другой. Нужно завершить) Я сам программист и не силен в системном администрировании. Спасибо
Skills: Linux System Administration Nginx
Hourly - Expert ($$$) - Est. Time: More than 6 months, 10-30 hrs/week - Posted
Looking for a experience Kali linux trainer to teach every Wednesday evening via Skype and Teamviewer from 1800hr to 2200hr GMT. Optional: flexible for extra adhoc lessons. Will be training 2 people from scratch up (beginners) to the standard where they will be able to do pen-testing on both networks and web apps / sites on there own. Not interested in qualification but only the skills and confidence to perform full testing on their own. Have access to virtual labs and will expect the trainer to give pre-req to set up testing labs. But also require the trainer to assist in setting advance labs. Will expect the train to give exercises for the trainees to practice at the end of each lesson. The lessons must not be missed or moved, as this would incur financial loss for the trainees in hiring a venue to train Open to offers in Per hour or fixed price Happy to do per hour if get good quality training and something out of each training session, will use ongoing to get to much more advanced levels. this will be a very long and ongoing contract
Skills: Linux System Administration Administrative Support Computer Networking Penetration Testing
Hourly - Expert ($$$) - Est. Time: 3 to 6 months, 10-30 hrs/week - Posted
We are looking for an experienced linux system administrator to support a tomcat/oracle based production application. You will be working alongside a small team of experienced infrastructure engineers, however, will be the primary point of contact for this particular application. Someone with deep experience with RedHat, Java, Tomcat and Oracle in a virtualized environment would be ideal. Experience with small to mid sized companies, configuration management (ansible/chef/etc) and AWS would help make this a longer term engagement. A full job description will be shared with interested candidates.
Skills: Linux System Administration Apache Tomcat Database Administration
Fixed-Price - Expert ($$$) - Est. Budget: $250 - Posted
Hello Freelancer, We need an expert to support us on installation of 2 certificates on Apache HTTP server. You need to have good knowledge of 2 WAY SSL You need to create Truststore & Keystore on Apache HTTP Server. Where you have to Install our certificate UNDER TRUSTORE and another third party Certificate under KEYSTORE We need only an expert who have done similar work in past.
Skills: Linux System Administration SSL
Fixed-Price - Expert ($$$) - Est. Budget: $100 - Posted
I need an expert who will be able to deliver automated "robot" that would resize images in web administration based on the instructions. It needs to be running on a linux server - Digitalocean cloud VPS. Run daily using cron. I have many other crawler/scraper jobs so I prefer someone who will want to cooperate more in the future. you can see what I mean here: (more detailed instructions will be given to the developer I choose) https://docs.google.com/spreadsheets/d/1iHWYOGpcrU8WF2tVakdSyiPjcj0Q2XhHEJFxzIM_FYg/edit?usp=sharing
Skills: Linux System Administration PHP Web scraping