Re: Shared Redis instance

[Kevin Fenzi]

On Thu, Nov 24, 2022 at 10:56:57AM +0100, Aurelien Bompard wrote:
>  Hey folks!
>  
>  The new version of FMN will run in OpenShift and will use Redis as a
>  cache backends (we chose it over memcached because it can do native
>  "is-this-string-in-this-set" operations).
>  
>  I can deploy redis inside my openshift project easily enough , but I
>  was wondering if it would be worthwhile to have a shared Redis
>  instance, like we have a shared PostgreSQL instance.
>  It's not just for ease of use, but I expect to store quite a bit of
>  data in our Redis instance, and since we don't attach persistent
>  storage to OpenShift that means that it will live in the pod's memory.
>  So I'm being conscious of the memory hog it can become.
>  Unless I'm mistaken there can be several databases in the same Redis
>  instance, so we could share it between projects without stepping on
>  each other's toes.
>  
>  What do you think? 
We have talked about it before, but I think the tradeoffs come down on
the side of seperate instances. They aren't too hard to spin up in
openshift. 

It avoids a single point of failure for a bunch of services. 

Contention/resource problems. (ie, one app is hammering the shared
instance and starving other apps for resources). 

etc.

So, I would say we should do seperate ones per service...

kevin