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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for March 15th, 2018

Tumbleweed on Raspberry Pi 3 – Bug 1084419 – Glibc update to 2.27 causes segfault during name resolution

Posted by jpluimers on 2018/03/15

Need to watch these:

A few notes:

  • It is inside the glibc name resolution
  • IPv6 is OK, IPv4 fails.
  • ping/nslookup (which do not depend on glibc) are OK
  • there is an intermediate fix requiring direct osc downloads

A simple test case

Failing situation

$ curl --silent --show-error http://example.org > /dev/null
Segmentation fault (core dumped)

Succeeding situation

$ curl --silent --show-error http://example.org > /dev/null

Non related, but in hindsight my own stupid fault during a similar update: a post mortem

Most important bits of my external infrastructure - page 1

Most important bits of my external infrastructure – page 1

I thought I had forgot about the SuSEfirewall2 changes (On my research list: migrate from OpenSuSE SuSEfirewall2 to firewalld) so assumed that was the reason I broke one of my secondaries (which runs on a Raspberry Pi 2):

Mistakes like these are the reason to have secondaries in the first place https://infrastatus.wiert.me and do port-mortems.

Which is kind of odd, as the SuSEfirewall2 didn’t throw any warnings like at this similar one:

This one still works because it is on the firewall in front of the Raspberry Pi 2:

(Screenshots of the above URLs are below).

In fact it was another mistake: I had forgotten to make the DHCP lease static, which resulted in a wrong IP address to be assigned upon reboot, instantly making the firewall rules invalid:

I could have fixed this remotely when I had thought about this.

–jeroen

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Posted in *nix, Development, Hardware Development, Linux, openSuSE, Power User, Raspberry Pi, SuSE Linux, Tumbleweed | 3 Comments »

EmbarcaderoMonitoring – monitoring the Embarcadero internet related services

Posted by jpluimers on 2018/03/15

Over time, there are lots of complaints about Embarcadero related internet services (like forums, QC, Appanalytics, docwiki, blogs, web site, maintenance, …) so to track uptime, I’ve created a set of EmbarcaderoMonitoring pages:

This is preliminary work based on my own lists of Embarcadero endpoints combined with some research like [WayBack] dnsdumpster embarcadero.com.png and [WayBack] IdentIPSpy

Underneath, they run on the uptimerobot.com infrastructure which has a limit of 50 free monitors.

It means I have to:

  • trim this down for relevancy
  • better document the endpoint
  • find correct endpoint targets for the black (disabled) and red (down) entries as a few of them might need tweaking
  • maybe split off an insecure and secure version (now most subdomains have both http and https monitored)

Any ideas on improving this are welcome: please post a comment here on on the resulting G+ thread.

Note it likely won’t show cases like when the website was hacked or TLS certificate issues like in SSLLabs security reports for some embarcadero subdomains. I need to think about a means for those, as it will certainly help monitoring my own infrastructure in a similar way.

–jeroen

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Posted in *nix, Cloud, Development, DevOps, Infrastructure, Monitoring, Power User, Software Development, Uptimerobot | Leave a Comment »

Stop using anemic daily stand-up questions | Software on a String

Posted by jpluimers on 2018/03/15

TL;DR:

Reminding everybody of the actual purpose of the daily stand-up and of the goal(s) you have for the sprint may be all that’s needed to give the shortened versions some much needed context and focus.

Always read the Scrum guide, as it states the purpose of this meeting:

The Daily Scrum is a 15-minute time-boxed event for the Development Team to synchronize activities and create a plan for the next 24 hours.

Source: [WayBack] Stop using anemic daily stand-up questions | Software on a String

via: [WayBack] Marjan Venema – Google+

–jeroen

Posted in Agile, Development, Scrum, Software Development | Leave a Comment »

Delphi: do not mix interfaces and classes part X

Posted by jpluimers on 2018/03/15

A very interesting discussion on what the mixing of interfaces and classes can get you into: [WayBack] I’ve got an interface with generics which accepts classes:IMyGeneric = interface…..end;What I want to do is to allow this interface to… – John Kouraklis – Google+

TL;DR: do not mix interfaces and classes.

As often, Asbjørn Heid chimes in showing some insight on clever mixing of the two with sample code accepting an unconstrained type. Don’t do that unless you really know what’s going on behind the scenes.

–jeroen

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Posted in Delphi, Development, Software Development | 4 Comments »

 
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