Website moved to new Uberspace with HTTPS

After migrating my domain to Route 53 I finally transferred my website to a new Uberspace host which supports Let’s Encrypt. You should be automatically redirect to HTTPS when visiting www.schakko.de. The whole procedure took 2 hours, including setting up the new Uberspace, importing the existing databases and changing the DNS records. Most of this was straight forward as the Uberspace team has a really good documentation for this. BTW: Route 53 sets the TTL Read more…

Fixing periodically occurring WiFi lags when running Claymore’s Ethereum miner

This is a blog post which literally drove me crazy for a week. After building our mining rig I experienced a bad WiFi connection with high pings, periodically occuring every 30 seconds. Just scroll down to see my – fairly simple – solution. Getting into the mining business A few weeks ago some of my co-workers and I decided to build a simple mining rig to make some Ethereum tokens. The current exchange rate for Read more…

Transferring DNS from Uberspace to AWS Route 53

Vacation time means administration time. I am one of these Uberspace customers whose domain has been registered and managed not by an external DNS registrar but by Uberspace (or Jonas Pasche) itself. Since a few years Uberspace has not been providing this service. Actually this was not a problem and everything worked fine. The reason why I had to deal with it was, that I originally wanted to enable Let’s Encrypt for www.schakko.de – for obvious Read more…

Running multiple Claymore miner instances with different wallets and GPUs

A few days ago I switched from ethminer to Claymore’s Dual Ethereum Miner because ethminer has problems running multiple instances with multiple GPUs. My blog post How to run same ethminer instance with multiple GPUs is still valid but ethminer simply can’t handle two or more parallel running instances. In addition to my previous blog post I want to show you how to mine with multiple GPUs into different Ethereum wallets. The following has been Read more…

How to pass multiple parameters to systemd’s ExecStart – Running same ethminer instance with multiple GPUs with systemd

For our Ethereum mining rig a coworker of mine wrote a systemd template unit so it is relatively easy to configure which graphic card in the rig is assigned to whom. For each of the GPU owners exist a custom configuration file /etc/sysconfig/ethminer-$USERNAME (/etc/sysconfig/ethminer-ckl in my case). The file contains the following parameters: Each user has its own configuration file and all services can be started like But when ethminer was started by using systemctl Read more…

Attempting to perform the InitializeDefaultDrives operation on the ‘FileSystem’ provider failed.

Yesterday, one of our check_mk monitoring scripts based upon PowerShell failed, because the error Attempting to perform the InitializeDefaultDrives operation on the ‘FileSystem’ provider failed. showed up. The initial reason for this is unknown to me but it has to do with the New-PSDrive and Remove-PSDrive PowerShell commands we were using inside the check_mk scripts. Symptoms for the problem are: The network drive is shown as disconnected in the Windows Explorer but you can still Read more…

Cross-domain migration from Windows Server 2008 R2 to Windows Server 2012 R2

In the first weeks of our company I made the mistake to set up the Active Directory domain with a .local suffix which caused a lot of problems with Windows and Linux-based clients in the longer run. Besides that after I have shifted back my work to my original tasks – I am still a developer – the network infrastructure went into some kind of unplanned chaos. Too many people tried too many things for which they had Read more…

w32tm: “No valid response has been received from manually configured peer”

This was one of those network bugs which took some time to fix. To give you a short background: In the last weeks we had random time NTP drifts in our Linux infrastructure, nothing serious but it was odd as they disappeared after restarting the ntpd or chrony service. During the weekend my co-worker and I were upgrading some parts of the network infrastructure (new cables, new cabling between server and switches, upgrade to the Read more…

Side project: A tool for preparing and calculating quotes with Neo4j

One part of my work is to inspect request for quotes (RfQs), gather customer requirements, estimate the effort and prepare a written offer. Most of our customers do not want to pay a separate bill for every sprint or user story but get a number or range for the total costs of the project. A big problem is the complexity of our projects. We do not only do software development but also do user interface design Read more…

Executing a CQL wildcard search in CMDBuild’s REST API

For our internal search engine I am currently developing a simple microservice to make our CMDBuild instance searchable. The microservice provides a fairly simple JSON API which itself queries the REST API of CMDBuild. Because of the insufficient documentation of CMDBuild I had to dig into the the source how to write a wildcard search query. CMDBuild has its own query language called CQL (CMDBuild Query Language). The CQL statements are converted into SQL which Read more…