Monthly Archives: June 2013

Networking Heisenbugs

Posted on June 16, 2013 by Lorin Hochstein

While debugging an issue with OpenStack and floating ips, I ran into a strange issue where running tcpdump on the bridge interface on the network controller would cause packets to be forwarded successfully to a compute node, but if I … Continue reading →

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XPath and Chrome dev tools

Posted on June 13, 2013 by Lorin Hochstein

Here’s a simple way to get the XPath of an element on an HTML page in page. Right-click on the element on the web page, choose “Inspect Element” from the context-menu Right-click on the highlighted HTML line that appears in … Continue reading →

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Fun with Windows TCP/IP debugging

Posted on June 6, 2013 by Lorin Hochstein

Today I learned… In Windows, if a process listens on a port, spawns a child, then dies, then no other process can listen on that port until all of the children have been terminated. So, if you were running, say, … Continue reading →

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Test, test

Posted on June 6, 2013 by Lorin Hochstein

Test, test Testing out the new Byword functionality of posting to WordPress.

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The infamous checksum bug

Posted on June 5, 2013 by Lorin Hochstein

Another networking issue with an instance. Occasionally, a precise instance would come up but the networking wasn’t working, it wouldn’t get an IP address. Interestingly, this only seemed to happen when it was running on the head node. (Yes, we … Continue reading →

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