Where should I run my Database? Databases on Kubernetes?

As of today, there are two main ways to run your database: in the cloud, consumed as a service; and self-hosted.

Self-hosting was the only option before cloud; was replaced as the default option by DBaaS; and is now making a comeback. With reason.But would you self-host your database as it was done before? Surely not.
Enter DBaaS-like services on Kubernetes. We will explore:
* What Kelsey Hightower thinks about the topic.
* Why you should use operators for databases on Kubernetes.
* What capabilities databases on Kubernetes provide vs what cloud does.
* How to decide where you should run your database.
* What’s the current landscape of solutions to run your database on Kubernetes.

This talk also featured a short live demo to showcase how to run databases on EKS with StackGres (https://stackgres.io), an open source Postgres operator.

Transcript

1. Databases on Kubernetes: Yay or Nay? Where should I run my database? Databases on Kubernetes? Alvaro Hernandez @ahachete
2. Databases on Kubernetes: Yay or Nay? ` whoami ` Alvaro Hernandez <aht@ongres.com> aht.es • Founder & CEO, OnGres • 20+ years Postgres user and DBA • Mostly doing R&D to create new, innovative software on Postgres • More than 120 tech talks, most about Postgres • Founder and President of the NPO Fundación PostgreSQL • AWS Data Hero
3. Databases on Kubernetes: Yay or Nay? Where may I run my DB?
4. Databases on Kubernetes: Yay or Nay? Possible options to run your DB • On-prem (or cloud instances) • DBaaS (managed service) • Kubernetes (cloud or on-prem)
5. Databases on Kubernetes: Yay or Nay? Deploying Postgres “on-prem”
6. Databases on Kubernetes: Yay or Nay? apt-get install postgresql # yes but well... # will you deploy this to prod? How to deploy Postgres
7. Databases on Kubernetes: Yay or Nay? OK, we need to tune the database 2-8h Postgres DBA
8. Databases on Kubernetes: Yay or Nay? We need to add connection pooling pg_bench, scale 2000, m4.large (2 vCPU, 8GB RAM, 1k IOPS) 4-16h DevOps / pgDBA
9. Databases on Kubernetes: Yay or Nay? And High Availability! 8-24h DevOps / pgDBA • HA software (e.g. Patroni) • Distributed configuration • Entrypoint: ◦ DNS? ◦ Virtual IP? ◦ External discovery service (e.g. Consul)?
10. Databases on Kubernetes: Yay or Nay? Do you backup your data? 4-16h DevOps • Backup software (e.g. WAL-G, pgBackRest) • Backup Storage • Backups lifecycle management • Backup testing / restoration
11. Databases on Kubernetes: Yay or Nay? You wouldn’t deploy Postgres without monitoring, would you? 8-24h DevOps / pgDBA
12. Databases on Kubernetes: Yay or Nay? Do you leave Postgres logs on each server? 4-48h DevOps • Configure CSV logging • Add a logging agent (e.g. FluentBit) to export logs • Add a logging collector (e.g. Fluentd) to collect logs, write code to store it and manage lifecycle. • Or use a paid logs-as-a-Service
13. Databases on Kubernetes: Yay or Nay? Install cluster management software ?h DevOps ??????????????
14. Databases on Kubernetes: Yay or Nay? IaC: Infrastructure as Code 48-96h DevOps
15. Databases on Kubernetes: Yay or Nay? Managed Services (DBaaS)
16. Databases on Kubernetes: Yay or Nay? DBaaS (e.g. RDS) • They provide great value: ◦ High availability with automated failover ◦ Automated backups ◦ Monitoring ◦ Typically a bit of database parameter tuning • But be aware of what they don’t: ◦ No database support (not infra support, I mean db support!) ◦ Deep parameter tuning. Query tuning. DDL tuning. ◦ Day 2 operations like bloat removal, reindex, etc. ◦ ChatGPT is not managing your DB yet!
17. Databases on Kubernetes: Yay or Nay? Be aware of DBaaS costs vs instances • Good service costs money • Instances cost: 85%-150% more expensive: ◦ E.g. RDS vs EC2 is 1.85x ◦ Plus you need an extra instance (N+1) for high availability ◦ Estimate price overhead as 1.8*(N+1)/N → N the number of instances • Storage costs: ◦ AWS: higher cost on RDS (gp2, gp3 overpriced vs EC2) ◦ Pay separately for I/O ops (e.g. Aurora)
18. Databases on Kubernetes: Yay or Nay? Managed service == you can’t do anything you want • Not all Postgres extensions are available: ◦ RDS: 80 ◦ E.g. StackGres: 160+, adding new every week ◦ No/few clouds support Timescale (Apache + TSL) or Citus • Connection pooling: ◦ RDS: not by default, additional cost (RDS Proxy). ◦ Other DBaaS not even an option. • Limited automation for “Day 2 operations”
19. Databases on Kubernetes: Yay or Nay? Deploying Postgres on Kubernetes
20. Databases on Kubernetes: Yay or Nay? What Kelsey Hightower thinks https://twitter.com/kelseyhightower/status /1624081136073994240
21. Databases on Kubernetes: Yay or Nay? Meeting Kubernetes half way • Kelsey Hightower argues that you need to “fight” K8s to run stateful workloads. • Certainly, a bit. But is doable. • Operators have done this already. Don’t run databases on Kuberntes “by hand”, use operators.
22. Databases on Kubernetes: Yay or Nay? Deploy a simple cluster with Kubernetes (w/ StackGres) 1h CKA apiVersion: stackgres.io/v1 kind: SGCluster metadata: name: simple spec: instances: 2 postgres: version: 'latest' pods: persistentVolume: size: '100Gi'
23. Databases on Kubernetes: Yay or Nay? Deploy an advanced cluster with Kubernetes (w/ StackGres) 4-16h CKA • Create YAMLs for several CRDs • Create Ingress if needed • Expose Web Console (Ingress/LB) • Integrate with GitOps
24. Databases on Kubernetes: Yay or Nay? • Kubernetes also allows to automate Day 2 operations • CKA is enough, mostly no Postgres expertise needed • E.g. Day 2 operations implemented in StackGres: ◦ Repack ◦ Vacuum ◦ Repack ◦ Minor version upgrade ◦ Major version upgrade ◦ Controlled restart ◦ Benchmark Automating Day 2 operations
25. Databases on Kubernetes: Yay or Nay? Postgres operators for Kubernetes Fully Open Source • CloudNativePG • KubeDB • Kubegres (unmaintained?) • Percona • StackGres • Zalando • New upcoming operators… • … Proprietary/paid-for (production) • Crunchydata • EnterpriseDB • Fujitsu • VMware Tanzu • …
26. Databases on Kubernetes: Yay or Nay? Operator Feature Matrix https://github.com/dokc/operator-feature-matrix
27. Databases on Kubernetes: Yay or Nay? Demo
28. Databases on Kubernetes: Yay or Nay? Q & A Alvaro Hernandez @ahachete