Skip to main content

Cloud databases

In Distributed workers we realized we need a cloud database in order to be able to have workers in a private cloud (PSI).

Since we already have AWS account (log in with your kerberos credentials here) we decided to use RDS PostgreSQL as database and SQS as Celery broker.

Simple Queue Service - SQS

At the moment we use only one Celery queue (default, named celery) per packit service deployment. With redis instance (separate one per deployment) as a broker, each deployment has its separate celery queue. But with SQS the deployments (prod and stg) can't both use celery queue, so we use packit-$DEPLOYMENT- prefix in order to have packit-prod-celery and packit-stg-celery queues. They are Standard type (best-effort ordering). FIFO would probably be better since it's not OK when for example 'build finished' event is processed before 'build started', but FIFO queue costs more and Celery uses by default Standard type so let's start with it. The queues can be accessed (send to, receive from) only by our packit user. Other than that (and proper Tags) they're configured with default values.


For stg (there's no DB for prod atm) we have a db.t3.micro (cheapest/slowest) class PostgreSQL (11.x) DB in default VPC with public-all security group. For prod db we might investigate restricting it so that it could be accessed only from Openshift cluster(s) we use. To import data from our local postgres instance to RDS:

oc rsh postgres-1-r2vnd pg_dump -v -U <user> -d <db name> -f /tmp/packit.dump
oc rsync postgres-1-r2vnd:/tmp/packit.dump ./
psql -f packit.dump --host --username <user> --password --dbname <db name>


At the moment of writing this only stg uses SQS & RDS, prod still runs its own redis & postgres. So far stg seems to be running OK with it and redis & postgres turned off. The downside we've noticed is that dashboard is several times slower (due to the DB instance class we use). Also we can't use readiness and liveness probes for workers.

I also temporarily deployed one packit worker in our cyborg-stage project @ PSI. I proved that it was accepting tasks from AWS SQS and tore it down again. I saw no backend related error so I believe it was able to connect to AWS RDS PostgreSQL as well. To make it build (S)RPMS I'd need a separate sandbox project there which I don't have atm.

(jpopelka, September 2020)