ConfigMap is used to store the configuration of the operator
$ kubectl create -f manifests/configmap.yaml
Deploying the operator
First you need to install the service account definition in your Minikube cluster.
$ kubectl create -f manifests/operator-service-account-rbac.yaml
Next deploy the postgres-operator from the docker image Zalando is using:
$ kubectl create -f manifests/postgres-operator.yaml
If you prefer to build the image yourself follow up down below.
Check if CustomResourceDefinition has been registered
$ kubectl get crd NAME KIND postgresqls.acid.zalan.do CustomResourceDefinition.v1beta1.apiextensions.k8s.io
How to configure PostgreSQL operator
Select the namespace to deploy to
The operator can run in a namespace other than
default. For example, to use
test namespace, run the following before deploying the operator's
$ kubectl create namespace test $ kubectl config set-context --namespace=test
kubectl commands will work with the
test namespace. The
operator will run in this namespace and look up needed resources - such as its
config map - there.
Specify the namespace to watch
Watching a namespace for an operator means tracking requests to change Postgresql clusters in the namespace such as "increase the number of Postgresql replicas to 5" and reacting to the requests, in this example by actually scaling up.
By default, the operator watches the namespace it is deployed to. You can
change this by altering the
WATCHED_NAMESPACE env var in the operator
deployment manifest or the
watched_namespace field in the operator configmap.
In the case both are set, the env var takes the precedence. To make the
operator listen to all namespaces, explicitly set the field/env var to "
Note that for an operator to manage pods in the watched namespace, the
operator's service account (as specified in the operator deployment manifest)
has to have appropriate privileges to access the watched namespace. The
operator may not be able to function in the case it watches all namespaces but
lacks access rights to any of them (except Kubernetes system namespaces like
kube-system). The reason is that for multiple namespaces operations such as
'list pods' execute at the cluster scope and fail at the first violation of
The watched namespace also needs to have a (possibly different) service account
in the case database pods need to talk to the Kubernetes API (e.g. when using
Kubernetes-native configuration of Patroni). The operator checks that the
pod_service_account_name exists in the target namespace, and, if not, deploys
pod_service_account_definition from the operator
Config with the default value of:
apiVersion: v1 kind: ServiceAccount metadata: name: operator
In this definition, the operator overwrites the account's name to match
pod_service_account_name and the
default namespace to match the target
namespace. The operator performs no further syncing of this account.
Role-based access control for the operator
manifests/operator-rbac.yaml defines cluster roles and bindings needed
for the operator to function under access control restrictions. To deploy the
operator with this RBAC policy use:
$ kubectl create -f manifests/configmap.yaml $ kubectl create -f manifests/operator-rbac.yaml $ kubectl create -f manifests/postgres-operator.yaml $ kubectl create -f manifests/minimal-postgres-manifest.yaml
Note that the service account in
operator-rbac.yaml is named
zalando-postgres-operator. You may have to change the
in the operator configmap and
serviceAccountName in the postgres-operator
This is done intentionally, as to avoid breaking those setups that already work
with the default
operator account. In the future the operator should ideally
be run under the
zalando-postgres-operator service account.
The service account defined in
operator-rbac.yaml acquires some privileges
not really used by the operator (i.e. we only need list and watch on
configmaps), this is also done intentionally to avoid breaking things if
someone decides to configure the same service account in the operator's
configmap to run postgres clusters.
Use taints and tolerations for dedicated PostgreSQL nodes
To ensure Postgres pods are running on nodes without any other application pods, you can use taints and tolerations and configure the required toleration in the operator ConfigMap.
As an example you can set following node taint:
$ kubectl taint nodes <nodeName> postgres=:NoSchedule
And configure the toleration for the PostgreSQL pods by adding following line to the ConfigMap:
apiVersion: v1 kind: ConfigMap metadata: name: postgres-operator data: toleration: "key:postgres,operator:Exists,effect:NoSchedule" ...
Custom Pod Environment Variables
It is possible to configure a config map which is used by the Postgres pods as an additional provider for environment variables.
One use case is to customize the Spilo image and configure it with environment variables. The config map with the additional settings is configured in the operator's main config map:
apiVersion: v1 kind: ConfigMap metadata: name: postgres-operator data: # referencing config map with custom settings pod_environment_configmap: postgres-pod-config ...
apiVersion: v1 kind: ConfigMap metadata: name: postgres-pod-config namespace: default data: MY_CUSTOM_VAR: value
This ConfigMap is then added as a source of environment variables to the Postgres StatefulSet/pods.
Limiting the number of instances in clusters with
As a preventive measure, one can restrict the minimum and the maximum number of
instances permitted by each Postgres cluster managed by the operator. If either
max_instances is set to a non-zero value, the operator may
adjust the number of instances specified in the cluster manifest to match
either the min or the max boundary. For instance, of a cluster manifest has 1
instance and the min_instances is set to 3, the cluster will be created with 3
instances. By default, both parameters are set to -1.
For any Postgresql/Spilo cluster, the operator creates two separate k8s
services: one for the master pod and one for replica pods. To expose these
services to an outer network, one can attach load balancers to them by setting
true in the
cluster manifest. In the case any of these variables are omitted from the
manifest, the operator configmap's settings
enable_replica_load_balancer apply. Note that the operator settings affect
all Postgresql services running in a namespace watched by the operator.