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b470ade20e
This commit is a breaking change: 1. `role` in DCS is written as "primary" instead of "master". 2. `role` in REST API responses is also written as "primary". 3. REST API no longer accepts role=master in requests (for example switchover/failover/restart endpoints). 4. `/metrics` REST API endpoint will no longer report `patroni_master`. 5. `patronictl` no longer accepts `--master` argument. 6. `no_master` option in declarative configuration of custom replica creation methods is no longer treated as a special option, please use `no_leader` instead. 7. `patroni_wale_restore` doesn't accept `--no_master` anymore. 8. `patroni_barman` doesn't accept `--role=master` anymore. 9. callback scripts will be executed with role=primary instead of role=master 10. On Kubernetes Patroni by default will set role label to primary. In case if you want to keep old behavior and avoid downtime or lengthy complex migrations you can configure `kubernetes.leader_label_value` and `kubernetes.standby_leader_label_value` to `master`. However, a few exceptions regarding master are still in place: 1. `GET /master` REST API endpoint will continue to work. 2. `master_start_timeout` and `master_stop_timeout` in global configuration are still accepted. 3. `master` tag is still preserved in Consul services in addition to `primary`. Rationale for these exceptions: DBA doesn't always 100% control the infrastructure and can't adjust the configuration.
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)