What are the risks in running single Zookeeper instance in production?

Remi Despres-Smyth

8/21/23, 12:26 PM

I'm considering using Zookeeper to manage shared configuration across multiple services that live on a single application server. Usage would be very low volume, mostly reads. My production system uses 2 VMs: one application server and one database server.

Zookeeper docs suggest that, in production, you want an ensemble of at least 3 instances.

I have two obvious options:

Install two Zookeeper instances on one of the two VMs, and one on the other.
Use only one Zookeeper instance.

If I only use one instance, and I can live with some downtime if Zookeeper happens to go down (which I would hope only occurs rarely), are there serious risks with only using one instance? When maintaining the server I'd be bringing Zookeeper down regardless.

There is the possible issue of file corruption in the data folder. Are additional instances required to recover in this scenario? Or can one simply delete the most recent snapshot and fall back to the previous one (with possible data loss)?

Can anyone speak to the risks involved? How bad an idea is this?

0 + 0

zookeeper

djdomi

8/21/23, 5:15 PM

Does this answer your question? [Can you help me with my capacity planning?](https://serverfault.com/questions/384686/can-you-help-me-with-my-capacity-planning)

Remi Despres-Smyth

8/21/23, 6:12 PM

@djdomi No. My question isn't related to capacity or capacity planning; a single server would have plenty of resources for the use I'm going to put it to. But if I run Zookeeper on a single server - against their recommendations - there are certainly risks to that. I'm looking for info regarding what those risks are.

djdomi

8/22/23, 3:50 AM

but even that, opinion based questions are also off topic ;)

Remi Despres-Smyth

8/22/23, 12:01 PM

@djdomi Not looking for opinions, looking for people familiar with the project who can tell me what can go wrong if this is done. I would hope possible failure modes to be known to people who know the project well.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: What are the risks in running single Zookeeper instance in production?

TH: อะไรคือความเสี่ยงในการเรียกใช้อินสแตนซ์ Zookeeper เดี่ยวในการผลิต

RO: Care sunt riscurile în rularea unei singure instanțe Zookeeper în producție?

RU: Каковы риски запуска одного экземпляра Zookeeper в рабочей среде?

VI: Rủi ro khi chạy phiên bản Zookeeper duy nhất trong sản xuất là gì?

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