Embedded OrientDB on a OpenShift / Kubernetes cluster

A few tips on setting up an embedded OrientDB to run on OpenShift / Kubernetes cluster.

Set the ORIENTDB_NODE_NAME system property or environment variable. If your database volumes are host volumes, you can use the downwards API spec.nodeName. If the node name contains dots, replace those with dashes for example. If you use something like OpenShift persistence volumes, make sure that the running pods ORIENTDB_NODE_NAME matches with the node name values it reads from the DB.

Use at least 3 replicas and don't use even number due to split-brain clustering issues

If you use rolling upgrade strategy, give the pods some time to start up the DBs so no more than one pod is unavailable at a time. This way syncing up the cluster status becomes smoother.

Use the newNodeStrategy dynamic OrientDb distribution configuration parameter so unreachable nodes don't break up the write quorum so easily.

Use Hazelcast to discover the cluster members. There is a library for that. If that does not work you might need to do a custom implementation using the Openshift / Kubernetes REST API and node labels to find all the members. This means calling the API from the container with a custom Hazelcast resolver

If possible, create a liveness probe which checks if you can query a database. Avoid using writes since there is the danger of killing all pods due to unreachable quorum if multiple pods are down simultaneously.

Comments

I'm not a passionate developer

A family friend of mine is an airlane pilot. A dream job for most, right? As a child, I certainly thought so. Now that I can have grown-up talks with him, I have discovered a more accurate description of his profession. He says that the truth about the job is that it is boring. To me, that is not that surprising. Airplanes are cool and all, but when you are in the middle of the Atlantic sitting next to the colleague you have been talking to past five years, how stimulating can that be? When he says the job is boring, it is not a bad kind of boring. It is a very specific boring. The "boring" you would want as a passenger. Uneventful. Yet, he loves his job. According to him, an experienced pilot is most pleased when each and every tiny thing in the flight plan - goes according to plan. Passengers in the cabin of an expert pilot sit in the comfort of not even noticing who is flying. As someone employed in a field where being boring is not exactly in high demand, this sounds pro

Extracting object properties from an IFC file with IfcOpenShell

Besides the object geometry information, IFC files may contain properties for the IFC objects. The properties can be, for example, some predefined dimension information such as an object volume or a choice of material. Some of the properties are predefined in the IFC standards, but custom ones can be added. IFC files can be massive and resource-intensive to process, so in some cases, it helps to separate the object properties from the geometry data. IfcOpenShell is a toolset for processing IFC files. It is written mostly in C++ but also provides a Python interface. To read an IFC file >>> ifc_file = ifcopenshell.open("model.ifc") Fetch all objects of type IfcSlab >>> slab = ifc_file.by_type("IfcSlab")[1] Get the list of properties >>> slab.IsDefinedBy (#145075=IfcRelDefinesByType('2_fok0__fAcBZmMlQcYwie',#1,$,$,(#27,#59),#145074), #145140=IfcRelDefinesByProperties('3U2LyORgXC2f_hWf6I16C1',#1,$,$,(#27,#59),#145141), #145142

Hubristic developer

Almost half of any Finnish generation goes through a shared experience: the conscript army. An integral part of that experience is learning military slang, a set way people in the army talk. The stories told with said jargon often spread outside of the barracks. It is not uncommon to hear strangers bonding together over beers reminiscing and feeling nostalgic about freezing cold nights spent in tents. There is a similar phenomenon detectable among us coders. To be part of the coder tribe, there is at least one type of story that one must master. That is - of course - ranting about legacy codebases. "Can you believe how much of a mess the previous coders left? Hear, hear!" There is no better way to onboard a new team member than to blame some previous B-team for all the murky parts of the system at hand. This can be seen as harmless, a subject for a good meme . Rarely do we hold real grudges against "the legacy folk" and can be the best of friends in a social gather

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