postgreslet

postgreslet

Postgreslet contains a kubernetes controller which reconciles instances of FI-TS CustomResourceDefinition postgres by using Zalando postgres operator. .

Architecture

Postgreslet is a kubernetes deployment, residing in every cluster on FT-TS Cloud. It watches crd postgres instances created in the control plane cluster and creates a series of kubernetes resources for each instance in the service cluster. One of them is the Zalando postgres operator which manages the postgres database pod(s). More information can be found in ARCHITECTURE.md.

Demo

Postgres is highly integrated with FI-TS cloudctl and cloudapi, but we can still try it out with kubectl on top of kind.

The instance we're going to create in the control-plane-cluster:

apiVersion: database.fits.cloud/v1
kind: Postgres
metadata:
  namespace: metal-extension-cloud
  name: complete
spec:
  accessList:
    sourceRanges:
    - 1.2.3.4/24
  maintenance:
    - "Sun:21:00-22:00"
  numberOfInstances: 2
  partitionID: sample-partition
  projectID: sample-project
  size:
    cpu: 500m
    memory: 512Mi
    storageSize: 1Gi
  tenant: sample-tenant
  version: "12"

We assume kubectl and kind had already installed. Then, the single command to create two kind clusters, deploy postgreslet, and create an postgres instance:

make two-kind-clusters

Check the results in the control-plane-cluster.

watch kubectl --kubeconfig kubeconfig get postgres -A

Eventually, the result reads:

NAMESPACE               NAME       TENANT          VERSION   REPLICAS   IP    PORT    STATUS
metal-extension-cloud   complete   sample-tenant   12        2                32000   Running

Check the results in the service-cluster.

watch kubectl get pod -A

Eventually, the results read:

NAMESPACE                            NAME                                         READY   STATUS    RESTARTS   AGE
kube-system                          coredns-f9fd979d6-6gbfn                      1/1     Running   0          62s
kube-system                          coredns-f9fd979d6-p8gbc                      1/1     Running   0          62s
kube-system                          etcd-kind-control-plane                      1/1     Running   0          67s
kube-system                          kindnet-7tdn9                                1/1     Running   0          62s
kube-system                          kube-apiserver-kind-control-plane            1/1     Running   0          67s
kube-system                          kube-controller-manager-kind-control-plane   0/1     Running   0          66s
kube-system                          kube-proxy-728df                             1/1     Running   0          62s
kube-system                          kube-scheduler-kind-control-plane            0/1     Running   0          66s
local-path-storage                   local-path-provisioner-78776bfc44-t5sjh      1/1     Running   0          62s
postgreslet-system                   postgreslet-8464df785c-2cf55                 1/1     Running   0          62s
sampleproject-bd8ff6bd0a2d4edf96f4   postgres-operator-7c45557b9b-xhqgf           1/1     Running   0          52s
sampleproject-bd8ff6bd0a2d4edf96f4   sampleproject-bd8ff6bd0a2d4edf96f4-0         3/3     Running   0          43s
sampleproject-bd8ff6bd0a2d4edf96f4   sampleproject-bd8ff6bd0a2d4edf96f4-1         3/3     Running   0          6s

The postgreslet and the corresponding pods to the postgres instance, i.e. postgres-operator and database instances, can be observed.

cloudctl

In production, cloudctl is the client. More info can be found with:

cloudctl postgres --help