What Nobody Understands Anymore, but Everyone Still Uses

20, 100, 500+ configuration objects - and no one dares to delete a thing.

Date
Topic
Config lifecycle
Reading time
2 min
Version
Translation

Read the German original

A mid-sized setup quickly ends up with 20 configuration objects in the mesh. One that has grown over time has 100. A large one, more than 500. Spread across VirtualServices, DestinationRules, ServiceEntries, AuthorizationPolicies, EnvoyFilters.

Graphic: OMNI52 Open the figure at full size
Figure as text

Sankey diagram of the service mesh configuration lifecycle, flowing from who created each object, to what is active in the cluster, to its status today. The takeaway: the red zone grows faster than the green one.

With five clusters, we’re talking several thousand objects. At ten or more, sooner or later everyone loses track.

The problem isn’t the volume. It’s the asymmetry.

A lot goes in. Almost nothing ever comes back out.

Every new feature brings a new policy. Every migration, a handful of ServiceEntries. Every external consultant, every proof of concept, every “we just need this for a bit” leaves configuration behind in the cluster. And then it stays there.

An example I see a lot: ServiceEntries in a mesh running REGISTRY_ONLY. At some point, someone opened up an external host. The use case is long gone. The ServiceEntry is still there. Nobody dares to delete it, because nobody knows whether anything still depends on it.

Over the years, this builds up a layer of objects that are active, but whose origin and purpose no one can explain anymore. “Probably still needed, better leave it alone.” That’s technical debt disguised as caution.

At the core of the problem is a question most teams have never answered: who is actually allowed to take something back out?

Almost anyone can create. Nobody dares to delete. As long as that asymmetry exists, the red zone grows faster than the green one, and every year the mesh gets a little harder to understand.

Who decides in your team what gets to come back out? That’s the topic for next week.

About the author

Portrait of Uli Renz

Uli Renz has been building and hardening service meshes in highly regulated enterprise environments since Istio 1.4. The patterns in these reports come from that work.

If your mesh already runs in production, the Posture Check is the place to start: 13 review areas, each finding rated by severity and backed by evidence from the config. In 90 minutes we go through the list together.

Request a strategy call

The request form on istio-consulting.de is in German.