patroni/kubernetes

Kubernetes deployment examples

Below you will find examples of Patroni deployments using kind.

Patroni on K8s

The Patroni cluster deployment with a StatefulSet consisting of three Pods.

Example session:

$ kind create cluster
Creating cluster "kind" ...
 ✓ Ensuring node image (kindest/node:v1.25.3) 🖼
 ✓ Preparing nodes 📦
 ✓ Writing configuration 📜
 ✓ Starting control-plane 🕹️
 ✓ Installing CNI 🔌
 ✓ Installing StorageClass 💾
Set kubectl context to "kind-kind"
You can now use your cluster with:

kubectl cluster-info --context kind-kind

Thanks for using kind! 😊

$ docker build -t patroni .
Sending build context to Docker daemon  138.8kB
Step 1/9 : FROM postgres:16
...
Successfully built e9bfe69c5d2b
Successfully tagged patroni:latest

$ kind load docker-image patroni
Image: "" with ID "sha256:e9bfe69c5d2b319dec0cf564fb895484537664775e18f37f9b707914cc5537e6" not yet present on node "kind-control-plane", loading...

$ kubectl apply -f patroni_k8s.yaml
service/patronidemo-config created
statefulset.apps/patronidemo created
endpoints/patronidemo created
service/patronidemo created
service/patronidemo-repl created
secret/patronidemo created
serviceaccount/patronidemo created
role.rbac.authorization.k8s.io/patronidemo created
rolebinding.rbac.authorization.k8s.io/patronidemo created
clusterrole.rbac.authorization.k8s.io/patroni-k8s-ep-access created
clusterrolebinding.rbac.authorization.k8s.io/patroni-k8s-ep-access created

$ kubectl get pods -L role
NAME            READY   STATUS    RESTARTS   AGE   ROLE
patronidemo-0   1/1     Running   0          34s   primary
patronidemo-1   1/1     Running   0          30s   replica
patronidemo-2   1/1     Running   0          26s   replica

$ kubectl exec -ti patronidemo-0 -- bash
postgres@patronidemo-0:~$ patronictl list
+ Cluster: patronidemo (7186662553319358497) ----+----+-----------+
| Member        | Host       | Role    | State   | TL | Lag in MB |
+---------------+------------+---------+---------+----+-----------+
| patronidemo-0 | 10.244.0.5 | Leader  | running |  1 |           |
| patronidemo-1 | 10.244.0.6 | Replica | running |  1 |         0 |
| patronidemo-2 | 10.244.0.7 | Replica | running |  1 |         0 |
+---------------+------------+---------+---------+----+-----------+

Citus on K8s

The Citus cluster with the StatefulSets, one coordinator with three Pods and two workers with two pods each.

Example session:

$ kind create cluster
Creating cluster "kind" ...
 ✓ Ensuring node image (kindest/node:v1.25.3) 🖼
 ✓ Preparing nodes 📦
 ✓ Writing configuration 📜
 ✓ Starting control-plane 🕹️
 ✓ Installing CNI 🔌
 ✓ Installing StorageClass 💾
Set kubectl context to "kind-kind"
You can now use your cluster with:

kubectl cluster-info --context kind-kind

Thanks for using kind! 😊

demo@localhost:~/git/patroni/kubernetes$ docker build -f Dockerfile.citus -t patroni-citus-k8s .
Sending build context to Docker daemon  138.8kB
Step 1/11 : FROM postgres:16
...
Successfully built 8cd73e325028
Successfully tagged patroni-citus-k8s:latest

$ kind load docker-image patroni-citus-k8s
Image: "" with ID "sha256:8cd73e325028d7147672494965e53453f5540400928caac0305015eb2c7027c7" not yet present on node "kind-control-plane", loading...

$ kubectl apply -f citus_k8s.yaml
service/citusdemo-0-config created
service/citusdemo-1-config created
service/citusdemo-2-config created
statefulset.apps/citusdemo-0 created
statefulset.apps/citusdemo-1 created
statefulset.apps/citusdemo-2 created
endpoints/citusdemo-0 created
service/citusdemo-0 created
endpoints/citusdemo-1 created
service/citusdemo-1 created
endpoints/citusdemo-2 created
service/citusdemo-2 created
service/citusdemo-workers created
secret/citusdemo created
serviceaccount/citusdemo created
role.rbac.authorization.k8s.io/citusdemo created
rolebinding.rbac.authorization.k8s.io/citusdemo created
clusterrole.rbac.authorization.k8s.io/patroni-k8s-ep-access created
clusterrolebinding.rbac.authorization.k8s.io/patroni-k8s-ep-access created

$ kubectl get sts
NAME          READY   AGE
citusdemo-0   1/3     6s  # coodinator (group=0)
citusdemo-1   1/2     6s  # worker (group=1)
citusdemo-2   1/2     6s  # worker (group=2)

$ kubectl get pods -l cluster-name=citusdemo -L role
NAME            READY   STATUS    RESTARTS   AGE    ROLE
citusdemo-0-0   1/1     Running   0          105s   primary
citusdemo-0-1   1/1     Running   0          101s   replica
citusdemo-0-2   1/1     Running   0          96s    replica
citusdemo-1-0   1/1     Running   0          105s   primary
citusdemo-1-1   1/1     Running   0          101s   replica
citusdemo-2-0   1/1     Running   0          105s   primary
citusdemo-2-1   1/1     Running   0          101s   replica

$ kubectl exec -ti citusdemo-0-0 -- bash
postgres@citusdemo-0-0:~$ patronictl list
+ Citus cluster: citusdemo -----------+----------------+---------+----+-----------+
| Group | Member        | Host        | Role           | State   | TL | Lag in MB |
+-------+---------------+-------------+----------------+---------+----+-----------+
|     0 | citusdemo-0-0 | 10.244.0.10 | Leader         | running |  1 |           |
|     0 | citusdemo-0-1 | 10.244.0.12 | Replica        | running |  1 |         0 |
|     0 | citusdemo-0-2 | 10.244.0.14 | Quorum Standby | running |  1 |         0 |
|     1 | citusdemo-1-0 | 10.244.0.8  | Leader         | running |  1 |           |
|     1 | citusdemo-1-1 | 10.244.0.11 | Quorum Standby | running |  1 |         0 |
|     2 | citusdemo-2-0 | 10.244.0.9  | Leader         | running |  1 |           |
|     2 | citusdemo-2-1 | 10.244.0.13 | Quorum Standby | running |  1 |         0 |
+-------+---------------+-------------+----------------+---------+----+-----------+

postgres@citusdemo-0-0:~$ psql citus
psql (16.4 (Debian 16.4-1.pgdg120+1))
Type "help" for help.

citus=# table pg_dist_node;
 nodeid | groupid |  nodename   | nodeport | noderack | hasmetadata | isactive | noderole  | nodecluster | metadatasynced | shouldhaveshards
--------+---------+-------------+----------+----------+-------------+----------+-----------+-------------+----------------+------------------
      1 |       0 | 10.244.0.10 |     5432 | default  | t           | t        | primary   | default     | t              | f
      2 |       1 | 10.244.0.8  |     5432 | default  | t           | t        | primary   | default     | t              | t
      3 |       2 | 10.244.0.9  |     5432 | default  | t           | t        | primary   | default     | t              | t
      4 |       0 | 10.244.0.14 |     5432 | default  | t           | t        | secondary | default     | t              | f
      5 |       0 | 10.244.0.12 |     5432 | default  | t           | t        | secondary | default     | t              | f
      6 |       1 | 10.244.0.11 |     5432 | default  | t           | t        | secondary | default     | t              | t
      7 |       2 | 10.244.0.13 |     5432 | default  | t           | t        | secondary | default     | t              | t
(7 rows)