➕️ Add small CNPG section

slides/k8s/cnpg.md

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+# CloudNativePG
+
+- CloudNativePG (CNPG) is an operator to run PostreSQL on Kubernetes
+
+- Makes it easy to run production Postgres on K8S
+
+- Supports streaming replication, backups, PITR, TLS, monitoring...
+
+- Open source
+
+- Accepted to CNCF on January 21, 2025 at the Sandbox maturity level
+
+  (https://www.cncf.io/projects/cloudnativepg/)
+
+---
+
+## A few examples
+
+- [EphemeraSearch](https://www.ephemerasearch.com/)
+
+  *personal project, ~200 GB database, tiny budget*
+
+- [Sellsy](https://enix.io/en/clients/)
+
+  *40,000 databases across 50 clusters, Talos, Proxmox VE*
+
+- MistralAI
+
+  *30 production clusters, each from a few GB to a few TB size*
+
+→ CNPG works for environments with small, big, and many clusters!
+
+---
+
+## Typical operation
+
+- Decide what kind of storage we want to use
+
+  (cloud, local, distributed, hyperconverged...)
+
+- Decide on backup strategy
+
+  (typically object store, e.g. S3-compatible)
+
+- Set up `StorageClass` if needed
+
+- Install CNPG
+
+- Deploy Postgres cluster(s) with YAML manifests
+
+- Profit!
+
+---
+
+## Local vs remote storage
+
+- Local storage can feel less safe
+
+  (compared to a SAN, cloud block device, distributed volume...)
+
+- However, it can be much faster
+
+  (much lower latency, much higher throughput)
+
+- If we're using replication, losing a local volume is no problem
+
+- Distributed storage can also fail
+
+  (or be unavailable for a while)
+
+---
+
+## CNPG installation
+
+Example with Helm:
+```bash
+helm upgrade --install --namespace cnpg-system --create-namespace \
+  --repo https://cloudnative-pg.io/charts/ \
+  cloudnative-pg cloudnative-pg \
+  --version 1.25.1
+```
+
+Interesting options to add, to integrate with Prometheus Operator:
+```bash
+--set monitoring.podMonitorEnabled=true
+--set monitoring.grafanaDashboard.create=true
+--set monitoring.grafanaDashboard.namespace=prom-system
+```
+
+---
+
+## Minimal Postgres cluster
+
+```yaml
+apiVersion: postgresql.cnpg.io/v1
+kind: Cluster
+metadata:
+  name: minimal
+spec:
+  instances: 2
+  storage:
+    size: 10G
+```
+
+Note: this is missing (notably) resource requests and backups!
+
+---
+
+## `kubectl` plugin
+
+- There is a `kubectl-cnpg` plugin
+
+- Install it (e.g. with `krew`)
+
+- Check commands like:
+
+  `k cnpg status`
+
+  `k cnpg psql`
+
+  `k cnpg backup`
+
+  `k cnpg promote`
+
+---
+
+## Production clusters
+
+Check the following YAML manifest:
+
+https://github.com/jpetazzo/pozok/blob/main/cluster-production.yaml
+
+If you want to test this, you need an S3-compatible object store.
+
+- Set the required variables:
+
+  `$CLUSTER_NAME`, `$AWS_ACCESS_KEY_ID`, `$AWS_SECRET_ACCESS_KEY`, `$AWS_DEFAULT_REGION`, `$BUCKET_NAME`, `$AWS_ENDPOINT_URL`
+
+- Then `envsubst < cluster-production.yaml | kubectl apply -f-`
+
+- Cluster comes up; backups and WAL segments land in the S3 bucket!
+
+---
+
+## Automated switchover
+
+- CNPG detects when we `kubectl cordon` a node
+
+- It assumes "cordon = maintenance"
+
+- If the node hosts a primary server, it initiates a switchover
+
+- It also uses Pod Disruption Budgets (PDB) to collaborate with evictions
+
+  (the PDB prevents the eviction of the primary until it gets demoted)
+
+---
+
+## Benchmarking
+
+- Postgres has `pgbench`
+
+- Step 1: execute e.g. `pgbench -i -s 10` to prepare the database
+
+  (`-s` is an optional "scaling factor" for a bigger dataset)
+
+- Step 2: execute `pgbench -P1 -T10` to run the benchmark
+
+  (`-P1` = report progress every second, `-T10` = run for 10 seconds)
+
+- These commands can be executed in the pod running the primary, e.g.:
+
+  `kubectl exec minimal-1 -- pgbench app -i -s 10`
+
+  `kubectl exec minimal-1 -- pgbench app -P1 -T60`
+
+---
+
+## CNPG lab 1
+
+- Install CNPG on a managed cluster with a default `StorageClass`
+
+- Provision a CNPG cluster (primary+replica)
+
+- Run a `pgbench` (e.g. 60 seconds)
+
+- Note the number of transactions / second
+
+- Install another `StorageClass` (e.g. `rancher/local-path-provisioner`)
+
+- Provision another CNPG cluster with that storage class
+
+- Run a benchmark and compare the numbers
+
+- Discuss!
+
+---
+
+## CNPG lab 2
+
+- This one requires access to an S3-compatible object store
+
+- Deploy a cluster sending backups to the object store
+
+- Run a benchmark (to populate the database)
+
+- Trigger a backup (e.g. with `k cnpg backup`)
+
+- Create a new cluster from the backup
+
+- Confirm that the numbers of rows (e.g. in `pgbench_history`) is the same
+
+???
+
+:EN:- Deploying Postgres clusters with CloudNativePG
+:FR:- Déployer des clusters Postgres avec CloudNativePG