Category Archives: Linux

/etc/network/if-up.d/ on CentOS & RedHat EL

On debian machines there is a folder /etc/network/if-up.d/ that will run executable scripts when the network connection goes up. On CentOS and RedHat it works differently – it checks to see if there is a file /sbin/ifup-local and will execute that if it is available. to create it: sudo vi /sbin/ifup-local sudo chmod +x /sbin/ifup-local Debian’s directory structure is cleaner but I don’t think there is an out-of-the-box 1:1 on enterprise linux… yet.

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Chef – ERROR: EOFError: end of file reached

Recently when using opscode’s chef server and knife I was getting the error message: ERROR: EOFError: end of file reached When trying to execute commands like knife client list I ended up finding out that the problem has to do with how the configuration for chef 11 has changed from chef 10. In your knife.rb file there is a line that gives you the default address / address of your cloud server – you will even see the default if you are running the interactive knife configuration tool (knife configure -i): Please enter the chef server URL: [] The big changes for chef 11 are two hard to spot things for the new chef server / knife access url: Port 4000 goes away The server now runs on HTTPS / SSL (which implies port 443) Change this to use SSL / HTTPS and your ERROR: EOFError: end of file reached message will go away. I was getting that error when trying to access chef on port 5672 which is the port that RabbitMQ runs on.

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RabbitMQ: users disappear / settings gone after reboot / restart

If you are using RabbitMQ on am Amazon EC2 instance and your node settings and users seem to disappear on reboot, it may be because of how the RabbitMQ server works. Settings, users, vhosts, and the rest of the RabbitMQ are all bound based on the node name – or the hostname. You can check by running either hostname or hostname -f for the FQDN. You will also notice that RabbitMQ stores settings in: /var/lib/rabbitmq/ And more specifically in: /var/lib/rabbitmq/mnesia If you check the contents you will see something like: drwxr-xr-x 5 rabbitmq rabbitmq 4096 Feb 27 14:55 [email protected]/ drwxr-xr-x 2 rabbitmq rabbitmq 4096 Feb 27 14:55 [email protected]/ drwxr-xr-x 5 rabbitmq rabbitmq 4096 Feb 25 15:08 [email protected]/ drwxr-xr-x 2 rabbitmq rabbitmq 4096 Feb 25 14:41 [email protected]/ drwxr-xr-x 5 rabbitmq rabbitmq 4096 Feb 23 04:48 [email protected]/ -rw-r–r– 1 rabbitmq rabbitmq 5 Feb 23 04:41 [email protected] drwxr-xr-x 2 rabbitmq rabbitmq 4096 Feb 23 04:41 [email protected]/ drwxr-xr-x 4 rabbitmq rabbitmq 4096 Feb 18 17:31 [email protected]/ drwxr-xr-x 2 rabbitmq rabbitmq 4096 Feb 18 17:28 [email protected]/ drwxr-xr-x 4 rabbitmq rabbitmq 4096 Feb 26 15:32 [email protected]/ drwxr-xr-x 2 rabbitmq rabbitmq 4096 Feb 26 15:26 [email protected]/ Why do RabbitMQ settings disappear on restart? Well, if you “stop” an amazon ec2 instance and then “start” it, it will have a new IP address unless you are using static IP addresses. Note that this doesn’t happen on “reboots” – just “stop” and “start” for EBS / (Elastic Block Storage) volumes. If you are not using an EBS volume then … Continue reading

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What is the SIPS equivalent in Linux / Unix?

If you’re used to the OSX sips utility to convert and resize images, you might be surprised when you are on a linux box and realize that utility is not available. According to the OS X man page, SIPS is: sips — scriptable image processing system. On unix and linux there are some great alternatives, but the one I like to use is imagemagick ( ) According to their site: Use ImageMagick to convert, edit, or compose bitmap images in a variety of formats. In addition, resize, rotate, shear, distort or transform images automagically. How to Geek has a good blog post showing how to use the convert utility to change image sizes easily: The syntax is something like this: convert example.png -resize 200×100 example.png

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Connect to a Shared Folder with VirtualBox and Windows XP

Connecting to a Shared Folder with VirtualBox and Windows XP is easy. In the following example Windows XP (TinyXP) is being used to connect to VirtualBox on Mac OS X Mountain Lion. On your list of VirtualBox machines choose the windows XP machine you want to share a folder with and then click “Settings” Choose the “Shared Folders” tab and then select the path on your host computer that you want to share with the Virtual Machine Select the options “Auto mount” and “Make permanent” if you would like this connection to persist If your Windows XP virtual machine is running you may need to restart it Open “My Computer” and from the “Tools” menu choose “Map Network Drive” When the “Map Network Drive” dialog box opens click on “Browse” Choose “Virtualbox Shared Folders” and then “\VBOXSVR” and then the name of your shared folder – (VBOXSVR is how virtualbox refers your host machine – opposed to Remote Desktop / Terminal services which refers to it as \tsclient / tsclient ) Click OK and now you should have your new drive appearing in “My Computer”

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Jeff Bezos to speak at “AWS re: Invent”

We are excited to announce that Jeff Bezos, Founder and CEO of Amazon has been added to the AWS re: Invent agenda in Las Vegas, November 27-29. Jeff will keynote the conference alongside Andy Jassy, Sr. VP of AWS and Werner Vogels, CTO of Amazon. Register today to hear these visionary technology leaders speak at AWS’s inaugural customer and partner conference. In addition to these keynotes, AWS re:Invent will feature 150 sessions delivered by the engineering teams behind the AWS Cloud and customers from around the world such as Netflix, NASA JPL, McGraw Hill, Robert Half International, Thomson Reuters, Nokia Siemens, Intuit, Pinterest, SocialCam, SmugMug, TinyCo, and more.

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MailChimp for Gravity Forms: Ajax error while selecting a form

If you’re using MailChimp Add-On v1.7 with Gravity Forms 1.6 in WordPress, and trying to set up a MailChimp Feed on the page /wp-admin/admin.php?page=gf_mailchimp, you may possibly be getting the following error: Ajax error while selecting a form This plugin is supposed to be easy to set up forms and lists with MailChimp, but why am I getting a Server 500 error? I looked into the PHP error logs and came across this: PHP Fatal error: Call to undefined method MCAPI::listInterestGroupings() in wp-content/plugins/gravityformsmailchimp/mailchimp.php on line 1123 There is a listInterestGroupings() function but the calling function which uses this code: $api = self::get_api(); self::log_debug(“Retrieving groups”); $groupings = $api->listInterestGroupings($selected_list_id); Is having trouble with it. The workaround for me was to comment out line 1123 which contains: $groupings = $api->listInterestGroupings($selected_list_id); The next part of the function has an if(!empty()) conditional. So until the developers get around to fixing this bug this seems to allow me to move on to the next steps with my Mailchimp widget.

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Amazon RDS Webinars Available

Dear EC2 User, I work in the Business Development team for Amazon Database Services. We co-ordinate interactions between AWS customers and the product teams for DynamoDB, ElastiCache, and Amazon Relational Database Service (RDS). In case you’re not familiar with RDS, it’s a web service designed to make it easy to set up, operate, and scale a relational database in the cloud. We’re running a series of free webinars that will highlight examples and best practices used by RDS customers to help improve performance, reduce costs, and eliminate most of the effort of database administration. Details of the next event are: Save time and effort. Focus on your app with Amazon RDS Amazon RDS simplifies database administration, giving you more time to build and optimize your applications 13 September 2012, 10.00AM to 11:00AM PDT This webinar will provide detailed information on customer use cases and best practices.Topics include: performance, security, migration and data protection. I hope you can make it. Regards, David Pearson Business Development Manager

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Raspberry Pi – shipping delay

Dear customer, Thanks again for your Raspberry Pi order. We are busy working with the suppliers who provide components for your Raspberry Pi to ensure you receive your order as quickly as possible. Since receiving your order, we have been advised that our next batch of approximately 40,000 Raspberry Pi’s will now be arriving during September, with further deliveries expected in October. This delay is due to the very high level of demand on the core Raspberry Pi processor chip. Unfortunately, this means that your order could be delayed by up to 8 weeks, although we are trying to reduce this as much as possible. We have updated the delivery schedule displayed in our FAQ’s and on the Raspberry Pi forum. As soon as we receive confirmation of any improvements from our manufacturers, we will advise you. Please accept our apologies for this delay and be assured we are doing everything we can to ensure the fastest possible delivery of your Raspberry Pi. Yours sincerely, RS Components & Allied Electronics

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10 Cloud Backup Services

Barracuda Networks End-to-end protection Druva Amazon S3 zipcloud SOS Online backup SugarSync livedrive mozy dropbox box carbonite

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