Red Hat OpenShift v1

EDB Postgres for Kubernetes is certified to run on Red Hat OpenShift Container Platform (OCP) version 4.x and is available directly from the Red Hat Catalog.

The goal of this section is to help you decide the best installation method for EDB Postgres for Kubernetes based on your organizations' security and access control policies.

The first and critical step is to design the architecture of your PostgreSQL clusters in your OpenShift environment.

Once the architecture is clear, you can proceed with the installation. EDB Postgres for Kubernetes can be installed and managed via:

• OpenShift web console
• OpenShift command-line interface (CLI) called oc, for full control

EDB Postgres for Kubernetes supports all available install modes defined by OpenShift:

• cluster-wide, in all namespaces
• local, in a single namespace
• local, watching multiple namespaces (only available using oc)

In most cases, the default cluster-wide installation of EDB Postgres for Kubernetes is the recommended one, with either central management of PostgreSQL clusters or delegated management (limited to specific users/projects according to RBAC definitions - see "Important OpenShift concepts" and "Users and Permissions" below).

Architecture

The same concepts that have been included in the generic Kubernetes/PostgreSQL architecture page apply for OpenShift as well.

Here as well, the critical factor is the number of availability zones or data centers for your OpenShift environment.

As outlined in the "Disaster Recovery Strategies for Applications Running on OpenShift" blog article written by Raffaele Spazzoli back in 2020 about stateful applications, in order to fully exploit EDB Postgres for Kubernetes, you need to plan, design and implement an OpenShift cluster spanning 3 or more availability zones. While this doesn't pose an issue in most of the public cloud provider deployments, it is definitely a challenge in on-premise scenarios.

If your OpenShift cluster has only one availability zone, the zone is your Single Point of Failure (SPoF) from a High Availability standpoint - provided that you have wisely adopted a share-nothing architecture, making sure that your PostgreSQL clusters have at least one standby (two if using synchronous replication), and that each PostgreSQL instance runs on a different Kubernetes worker node using different storage. Make sure that continuous backup data is stored additionally in a storage service outside the OpenShift cluster, allowing you to perform Disaster Recovery operations beyond your data center.

Most likely you will have another OpenShift cluster in another data center, either in the same metropolitan area or in another region, in an active/passive strategy. You can set up an independent "Replica cluster", with the understanding that this is primarily a Disaster Recovery solution - very effective but with some limitations that require manual intervention, as explained in the feature page. The same solution can be applied to additional OpenShift clusters, even in a cascading manner.

On the other hand, if your OpenShift cluster spans multiple availability zones in a region, you can fully leverage the capabilities of the operator for resilience and self-healing, and the region can become your SPoF, i.e. it would take a full region outage to bring down your cluster. Moreover, you can take advantage of multiple OpenShift clusters in different regions by setting up replica clusters, as previously mentioned.

Reserving Nodes for PostgreSQL Workloads

For optimal performance and resource allocation in your PostgreSQL database operations, it is highly recommended to isolate PostgreSQL workloads by dedicating specific worker nodes solely to postgres in production. This is particularly crucial whether you're operating in a single availability zone or a multi-availability zone environment.

A worker node in OpenShift that is dedicated to running PostgreSQL workloads is commonly referred to as a Postgres node or postgres node.

This dedicated approach ensures that your PostgreSQL workloads are not competing for resources with other applications, leading to enhanced stability and performance.

For further details, please refer to the "Reserving Nodes for PostgreSQL Workloads" section within the broader "Architecture" documentation. The primary difference when working in OpenShift involves how labels and taints are applied to the nodes, as described below.

To label a node as a postgres node, execute the following command:

oc label node <NODE-NAME> node-role.kubernetes.io/postgres=

To apply a postgres taint to a node, use the following command:

oc adm taint node <NODE-NAME> node-role.kubernetes.io/postgres=:NoSchedule

By correctly labeling and tainting your nodes, you ensure that only PostgreSQL workloads are scheduled on these dedicated nodes via affinity and tolerations, reinforcing the stability and performance of your database environment.

Important OpenShift concepts

To understand how the EDB Postgres for Kubernetes operator fits in an OpenShift environment, you must familiarize yourself with the following Kubernetes-related topics:

• Operators
• Authentication
• Authorization via Role-based Access Control (RBAC)
• Service Accounts and Users
• Rules, Roles and Bindings
• Cluster RBAC vs local RBAC through projects

This is especially true in case you are not comfortable with the elevated permissions required by the default cluster-wide installation of the operator.

We have also selected the diagram below from the OpenShift documentation, as it clearly illustrates the relationships between cluster roles, local roles, cluster role bindings, local role bindings, users, groups and service accounts.

The "Predefined RBAC objects" section below contains important information about how EDB Postgres for Kubernetes adheres to Kubernetes and OpenShift RBAC implementation, covering default installed cluster roles, roles, service accounts.

If you are familiar with the above concepts, you can proceed directly to the selected installation method. Otherwise, we recommend that you read the following resources taken from the OpenShift documentation and the Red Hat blog:

• "Operator Lifecycle Manager (OLM) concepts and resources"
• "Understanding authentication"
• "Role-based access control (RBAC)", covering rules, roles and bindings for authorization, as well as cluster RBAC vs local RBAC through projects
• "Default project service accounts and roles"
• "With Kubernetes Operators comes great responsibility" blog article

Cluster Service Version (CSV)

Technically, the operator is designed to run in OpenShift via the Operator Lifecycle Manager (OLM), according to the Cluster Service Version (CSV) defined by EDB.

The CSV is a YAML manifest that defines not only the user interfaces (available through the web dashboard), but also the RBAC rules required by the operator and the custom resources defined and owned by the operator (such as the Cluster one, for example). The CSV defines also the available installModes for the operator, namely: AllNamespaces (cluster-wide), SingleNamespace (single project), MultiNamespace (multi-project), and OwnNamespace.

Limitations for multi-tenant management

Red Hat OpenShift Container Platform provides limited support for simultaneously installing different variations of an operator on a single cluster. Like any other operator, EDB Postgres for Kubernetes becomes an extension of the control plane. As the control plane is shared among all tenants (projects) of an OpenShift cluster, operators too become shared resources in a multi-tenant environment.

Operator Lifecycle Manager (OLM) can install operators multiple times in different namespaces, with one important limitation: they all need to share the same API version of the operator.

For more information, please refer to "Operator groups" in OpenShift documentation.

Channels

Since the release of version 1.16.0, EDB Postgres for Kubernetes is available in the following OLM channels:

• fast: the head version in the channel is always the latest available patch release in the latest available minor release of EDB Postgres for Kubernetes
• stable-vX.Y: the head version in the channel is always the latest available patch release in the X.Y minor release of EDB Postgres for Kubernetes

While fast might contain versions spanning over multiple minor versions, the stable-vX.Y branches include only patch versions of the same minor release.

Considering the both CloudNativePG and EDB Postgres for Kubernetes are developed using the trunk development and continuous delivery DevOps principles, our recommendation is to use the fast channel.

About the stable channel

The stable channel was previously used by EDB to distribute cloud-native-postgresql. This channel is obsolete and has been removed.

If you are currently using stable, you have two options for moving off of it:

1. Move to a stable-vX.Y channel to remain in a minor release (e.g. stable-v1.22 would remain in the 1.22 minor LTS release, consuming future patch releases).
2. Move to fast, which is the equivalent of stable before we introduced support for multiple minor releases

Installation via web console

Ensuring access to EDB private registry

The OpenShift install will use pull secrets in order to access the operand and operator images, which are held in a private repository.

Once you have credentials to the private repository, you will need to create a pull secret in the openshift-operators namespace, named:

• postgresql-operator-pull-secret, for the EDB Postgres for Kubernetes operator images

You can create each secret via the oc create command, as follows:

oc create secret docker-registry postgresql-operator-pull-secret \
  -n openshift-operators --docker-server=docker.enterprisedb.com \
  --docker-username="@@REPOSITORY@@" \
  --docker-password="@@TOKEN@@"

where:

• @@REPOSITORY@@ is the name of the repository, as explained in "Which repository to choose?"
• @@TOKEN@@ is the repository token for your EDB account, as explained in "How to retrieve the token"

The EDB Postgres for Kubernetes operator can be found in the Red Hat OperatorHub directly from your OpenShift dashboard.

1. Navigate in the web console to the Operators -> OperatorHub page:

   

2. Scroll in the Database section or type a keyword into the Filter by keyword box (in this case, "PostgreSQL") to find the EDB Postgres for Kubernetes Operator, then select it:

   

3. Read the information about the Operator and select Install.

4. The following Operator installation page expects you to choose:

   • the installation mode: cluster-wide or single namespace installation
   • the update channel (see the "Channels" section for more information - if unsure, pick fast)
   • the approval strategy, following the availability on the market place of a new release of the operator, certified by Red Hat:
   • Automatic: OLM automatically upgrades the running operator with the new version
   • Manual: OpenShift waits for human intervention, by requiring an approval in the Installed Operators section

   Important

   The process of the operator upgrade is described in the "Upgrades" section.

Choosing cluster-wide vs local installation of the operator is a critical turning point. Trying to install the operator globally with an existing local installation is blocked, by throwing the error below. If you want to proceed you need to remove every local installation of the operator first.

Cluster-wide installation

With cluster-wide installation, you are asking OpenShift to install the Operator in the default openshift-operators namespace and to make it available to all the projects in the cluster. This is the default and normally recommended approach to install EDB Postgres for Kubernetes.

From the web console, select All namespaces on the cluster (default) as Installation mode:

As a result, the operator will be visible in every namespaces. Otherwise, as with any other OpenShift operator, check the logs in any pods in the openshift-operators project on the Workloads → Pods page that are reporting issues to troubleshoot further.

Single project installation

With single project installation, you are asking OpenShift to install the Operator in a given namespace, and to make it available to that project only.

From the web console, select A specific namespace on the cluster as Installation mode, then pick the target namespace (in our example proj-dev):

As a result, the operator will be visible in the selected namespace only. You can verify this from the Installed operators page:

In case of a problem, from the Workloads → Pods page check the logs in any pods in the selected installation namespace that are reporting issues to troubleshoot further.

This installation process can be repeated in multiple namespaces in the same OpenShift cluster, enabling independent installations of the operator in different projects. In this case, make sure you read "Limitations for multi-tenant management".

Installation via the oc CLI

Instead of using the OpenShift Container Platform web console, you can install the EDB Postgres for Kubernetes Operator from the OperatorHub and create a subscription using the oc command-line interface. Through the oc CLI you can install the operator in all namespaces, a single namespace or multiple namespaces.

This section primarily covers the installation of the operator in multiple projects with a simple example, by creating an OperatorGroup and a Subscription objects.

1. Check that the cloud-native-postgresql operator is available from the OperatorHub:

   → WrapCopy

    oc get packagemanifests -n openshift-marketplace cloud-native-postgresql

2. Inspect the operator to verify the installation modes (MultiNamespace in particular) and the available channels:

   → WrapCopy

    oc describe packagemanifests -n openshift-marketplace cloud-native-postgresql

3. Create an OperatorGroup object in the my-operators namespace so that it targets the web-staging, web-prod, bi-staging, and bi-prod namespaces:

   → WrapCopy

    apiVersion: operators.coreos.com/v1
    kind: OperatorGroup
    metadata:
      name: cloud-native-postgresql
      namespace: my-operators
    spec:
      targetNamespaces:
      - web-staging
      - web-prod
      - bi-staging
      - bi-prod

   !!! Important Alternatively, you can list namespaces using a label selector, as explained in "Target namespace selection".

4. Create a Subscription object in the my-operators namespace to subscribe to the fast channel of the cloud-native-postgresql operator that is available in the certified-operators source of the openshift-marketplace (as previously located in steps 1 and 2):

   → WrapCopy

    apiVersion: operators.coreos.com/v1alpha1
    kind: Subscription
    metadata:
      name: cloud-native-postgresql
      namespace: my-operators
    spec:
      channel: fast
      name: cloud-native-postgresql
      source: certified-operators
      sourceNamespace: openshift-marketplace

5. Use oc apply -f with the above YAML file definitions for the OperatorGroup and Subscription objects.

The method described in this section can be very powerful in conjunction with proper RoleBinding objects, as it enables mapping EDB Postgres for Kubernetes' predefined ClusterRoles to specific users in selected namespaces.

The result of the above operation can also be verified from the webconsole, as shown in the image below.

Cluster-wide installation with oc

If you prefer, you can also use oc to install the operator globally, by taking advantage of the default OperatorGroup called global-operators in the openshift-operators namespace, and create a new Subscription object for the cloud-native-postgresql operator in the same namespace:

apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: cloud-native-postgresql
  namespace: openshift-operators
spec:
  channel: fast
  name: cloud-native-postgresql
  source: certified-operators
  sourceNamespace: openshift-marketplace

Once you run oc apply -f with the above YAML file, the operator will be available in all namespaces.

Installing the OpenShift CLI (oc)

The oc command represents the OpenShift command-line interface (CLI). It is highly recommended to install it on your system. Below you find a basic set of instructions to install oc from your OpenShift dashboard.

First, select the question mark at the top right corner of the dashboard:

Then follow the instructions you are given, by downloading the binary that suits your needs in terms of operating system and architecture:

Upgrading the operator

In order to upgrade your operator safely, you need to be in a stable-vX.Y channel, or the fast channel if you want to follow the head of the development trunk of EDB Postgres for Kubernetes.

If you are currently in the stable channel, you need to either choose fast or progressively move to the latest Long Term Supported release of EDB Postgres for Kubernetes - currently stable-v1.22.

If you are in stable and your operator version is 1.15 or older, please move to stable-v1.15 and upgrade. Then repeat the operation with stable-v1.16, then stable-v1.17 to finally reach stable-v1.18 or fast.

If you are in stable and your operator version is 1.16, please move to stable-v1.16 and upgrade. Then repeat the operation with stable-v1.17 to finally reach stable-v1.18 or fast.

Predefined RBAC objects

EDB Postgres for Kubernetes comes with a predefined set of resources that play an important role when it comes to RBAC policy configuration.

Custom Resource Definitions (CRD)

The EDB Postgres for Kubernetes operator owns the following custom resource definitions (CRD):

• Backup
• Cluster
• Pooler
• ScheduledBackup
• ImageCatalog
• ClusterImageCatalog

You can verify this by running:

oc get customresourcedefinitions.apiextensions.k8s.io | grep postgresql

which returns something similar to:

backups.postgresql.k8s.enterprisedb.io                            20YY-MM-DDTHH:MM:SSZ
clusterimagecatalogs.postgresql.k8s.enterprisedb.io               20YY-MM-DDTHH:MM:SSZ
clusters.postgresql.k8s.enterprisedb.io                           20YY-MM-DDTHH:MM:SSZ
imagecatalogs.postgresql.k8s.enterprisedb.io                      20YY-MM-DDTHH:MM:SSZ
poolers.postgresql.k8s.enterprisedb.io                            20YY-MM-DDTHH:MM:SSZ
scheduledbackups.postgresql.k8s.enterprisedb.io                   20YY-MM-DDTHH:MM:SSZ

Service accounts

The namespace where the operator has been installed (by default openshift-operators) contains the following predefined service accounts: builder, default, deployer, and most importantly postgresql-operator-manager (managed by the CSV).

You can verify this by running:

oc get serviceaccounts -n openshift-operators

which returns something similar to:

NAME                          SECRETS   AGE
builder                       2         ...
default                       2         ...
deployer                      2         ...
postgresql-operator-manager   2         ...

The default service account is automatically created by Kubernetes and present in every namespace. The builder and deployer service accounts are automatically created by OpenShift (see "Default project service accounts and roles").

The postgresql-operator-manager service account is the one used by the Cloud Native PostgreSQL operator to work as part of the Kubernetes/OpenShift control plane in managing PostgreSQL clusters.

Cluster roles

The Operator Lifecycle Manager (OLM) automatically creates a set of cluster role objects to facilitate role binding definitions and granular implementation of RBAC policies. Some cluster roles have rules that apply to Custom Resource Definitions that are part of EDB Postgres for Kubernetes, while others that are part of the broader Kubernetes/OpenShift realm.

Cluster roles on EDB Postgres for Kubernetes CRDs

For every CRD owned by EDB Postgres for Kubernetes' CSV, OLM deploys some predefined cluster roles that can be used by customer facing users and service accounts. In particular:

• a role for the full administration of the resource (admin suffix)
• a role to edit the resource (edit suffix)
• a role to view the resource (view suffix)
• a role to view the actual CRD (crdview suffix)

You can verify the list of predefined cluster roles by running:

oc get clusterroles | grep postgresql

which returns something similar to:

backups.postgresql.k8s.enterprisedb.io-v1-admin                  YYYY-MM-DDTHH:MM:SSZ
backups.postgresql.k8s.enterprisedb.io-v1-crdview                YYYY-MM-DDTHH:MM:SSZ
backups.postgresql.k8s.enterprisedb.io-v1-edit                   YYYY-MM-DDTHH:MM:SSZ
backups.postgresql.k8s.enterprisedb.io-v1-view                   YYYY-MM-DDTHH:MM:SSZ
cloud-native-postgresql.VERSION-HASH                             YYYY-MM-DDTHH:MM:SSZ
clusterimagecatalogs.postgresql.k8s.enterprisedb.io-v1-admin     YYYY-MM-DDTHH:MM:SSZ
clusterimagecatalogs.postgresql.k8s.enterprisedb.io-v1-crdview   YYYY-MM-DDTHH:MM:SSZ
clusterimagecatalogs.postgresql.k8s.enterprisedb.io-v1-edit      YYYY-MM-DDTHH:MM:SSZ
clusterimagecatalogs.postgresql.k8s.enterprisedb.io-v1-view      YYYY-MM-DDTHH:MM:SSZ
clusters.postgresql.k8s.enterprisedb.io-v1-admin                 YYYY-MM-DDTHH:MM:SSZ
clusters.postgresql.k8s.enterprisedb.io-v1-crdview               YYYY-MM-DDTHH:MM:SSZ
clusters.postgresql.k8s.enterprisedb.io-v1-edit                  YYYY-MM-DDTHH:MM:SSZ
clusters.postgresql.k8s.enterprisedb.io-v1-view                  YYYY-MM-DDTHH:MM:SSZ
imagecatalogs.postgresql.k8s.enterprisedb.io-v1-admin            YYYY-MM-DDTHH:MM:SSZ
imagecatalogs.postgresql.k8s.enterprisedb.io-v1-crdview          YYYY-MM-DDTHH:MM:SSZ
imagecatalogs.postgresql.k8s.enterprisedb.io-v1-edit             YYYY-MM-DDTHH:MM:SSZ
imagecatalogs.postgresql.k8s.enterprisedb.io-v1-view             YYYY-MM-DDTHH:MM:SSZ
poolers.postgresql.k8s.enterprisedb.io-v1-admin                  YYYY-MM-DDTHH:MM:SSZ
poolers.postgresql.k8s.enterprisedb.io-v1-crdview                YYYY-MM-DDTHH:MM:SSZ
poolers.postgresql.k8s.enterprisedb.io-v1-edit                   YYYY-MM-DDTHH:MM:SSZ
poolers.postgresql.k8s.enterprisedb.io-v1-view                   YYYY-MM-DDTHH:MM:SSZ
scheduledbackups.postgresql.k8s.enterprisedb.io-v1-admin         YYYY-MM-DDTHH:MM:SSZ
scheduledbackups.postgresql.k8s.enterprisedb.io-v1-crdview       YYYY-MM-DDTHH:MM:SSZ
scheduledbackups.postgresql.k8s.enterprisedb.io-v1-edit          YYYY-MM-DDTHH:MM:SSZ
scheduledbackups.postgresql.k8s.enterprisedb.io-v1-view          YYYY-MM-DDTHH:MM:SSZ

You can inspect an actual role as any other Kubernetes resource with the get command. For example:

oc get -o yaml clusterrole clusters.postgresql.k8s.enterprisedb.io-v1-admin

By looking at the relevant skimmed output below, you can notice that the clusters.postgresql.k8s.enterprisedb.io-v1-admin cluster role enables everything on the cluster resource defined by the postgresql.k8s.enterprisedb.io API group:

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: clusters.postgresql.k8s.enterprisedb.io-v1-admin
rules:
- apiGroups:
  - postgresql.k8s.enterprisedb.io
  resources:
  - clusters
  verbs:
  - '*'

Cluster roles on Kubernetes CRDs

When installing a Subscription object in a given namespace (e.g. openshift-operators for cluster-wide installation of the operator), OLM also creates a cluster role that is used to grant permissions to the postgresql-operator-manager service account that the operator uses. The name of this cluster role varies, as it depends on the installed version of the operator and the time of installation.

You can retrieve it by running the following command:

oc get clusterrole --selector=olm.owner.kind=ClusterServiceVersion

You can then use the name returned by the above query (which should have the form of cloud-native-postgresql.VERSION-HASH) to look at the rules, resources and verbs via the describe command:

oc describe clusterrole cloud-native-postgresql.VERSION-HASH

Name:         cloud-native-postgresql.VERSION.HASH
Labels:       olm.owner=cloud-native-postgresql.VERSION
              olm.owner.kind=ClusterServiceVersion
              olm.owner.namespace=openshift-operators
              operators.coreos.com/cloud-native-postgresql.openshift-operators=
Annotations:  <none>
PolicyRule:
  Resources                                                     Non-Resource URLs  Resource Names  Verbs
  ---------                                                     -----------------  --------------  -----
  configmaps                                                    []                 []              [create delete get list patch update watch]
  secrets                                                       []                 []              [create delete get list patch update watch]
  services                                                      []                 []              [create delete get list patch update watch]
  deployments.apps                                              []                 []              [create delete get list patch update watch]
  poddisruptionbudgets.policy                                   []                 []              [create delete get list patch update watch]
  backups.postgresql.k8s.enterprisedb.io                        []                 []              [create delete get list patch update watch]
  clusters.postgresql.k8s.enterprisedb.io                       []                 []              [create delete get list patch update watch]
  poolers.postgresql.k8s.enterprisedb.io                        []                 []              [create delete get list patch update watch]
  scheduledbackups.postgresql.k8s.enterprisedb.io               []                 []              [create delete get list patch update watch]
  persistentvolumeclaims                                        []                 []              [create delete get list patch watch]
  pods/exec                                                     []                 []              [create delete get list patch watch]
  pods                                                          []                 []              [create delete get list patch watch]
  jobs.batch                                                    []                 []              [create delete get list patch watch]
  podmonitors.monitoring.coreos.com                             []                 []              [create delete get list patch watch]
  serviceaccounts                                               []                 []              [create get list patch update watch]
  rolebindings.rbac.authorization.k8s.io                        []                 []              [create get list patch update watch]
  roles.rbac.authorization.k8s.io                               []                 []              [create get list patch update watch]
  leases.coordination.k8s.io                                    []                 []              [create get update]
  events                                                        []                 []              [create patch]
  mutatingwebhookconfigurations.admissionregistration.k8s.io    []                 []              [get list update]
  validatingwebhookconfigurations.admissionregistration.k8s.io  []                 []              [get list update]
  customresourcedefinitions.apiextensions.k8s.io                []                 []              [get list update]
  namespaces                                                    []                 []              [get list watch]
  nodes                                                         []                 []              [get list watch]
  clusters.postgresql.k8s.enterprisedb.io/status                []                 []              [get patch update watch]
  poolers.postgresql.k8s.enterprisedb.io/status                 []                 []              [get patch update watch]
  configmaps/status                                             []                 []              [get patch update]
  secrets/status                                                []                 []              [get patch update]
  backups.postgresql.k8s.enterprisedb.io/status                 []                 []              [get patch update]
  scheduledbackups.postgresql.k8s.enterprisedb.io/status        []                 []              [get patch update]
  pods/status                                                   []                 []              [get]
  clusters.postgresql.k8s.enterprisedb.io/finalizers            []                 []              [update]
  poolers.postgresql.k8s.enterprisedb.io/finalizers             []                 []              [update]

The operator automates in a declarative way a lot of operations related to PostgreSQL management that otherwise would require manual and imperative interventions. Such operations also include security related matters at RBAC (e.g. service accounts), pod (e.g. security context constraints) and Postgres levels (e.g. TLS certificates).

For more information about the reasons why the operator needs these elevated permissions, please refer to the "Security / Cluster / RBAC" section.

Users and Permissions

A very common way to use the EDB Postgres for Kubernetes operator is to rely on the cluster-admin role and manage resources centrally.

Alternatively, you can use the RBAC framework made available by Kubernetes/OpenShift, as with any other operator or resources.

For example, you might be interested in binding the clusters.postgresql.k8s.enterprisedb.io-v1-admin cluster role to specific groups or users in a specific namespace, as any other cloud native application. The following example binds that cluster role to a specific user in the web-prod project:

kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: web-prod-admin
  namespace: web-prod
subjects:
  - kind: User
    apiGroup: rbac.authorization.k8s.io
    name: mario@cioni.org
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: clusters.postgresql.k8s.enterprisedb.io-v1-admin

The same process can be repeated with any other predefined ClusterRole.

If, on the other hand, you prefer not to use cluster roles, you can create specific namespaced roles like in this example:

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: web-prod-view
  namespace: web-prod
rules:
- apiGroups:
  - postgresql.k8s.enterprisedb.io
  resources:
  - clusters
  verbs:
  - get
  - list
  - watch

Then, assign this role to a given user:

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: web-prod-view
  namespace: web-prod
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: web-prod-view
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: User
  name: web-prod-developer1

This final example creates a role with administration permissions (verbs is equal to *) to all the resources managed by the operator in that namespace (web-prod):

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: web-prod-admin
  namespace: web-prod
rules:
- apiGroups:
  - postgresql.k8s.enterprisedb.io
  resources:
  - clusters
  - backups
  - scheduledbackups
  - poolers
  verbs:
  - '*'

Pod Security Standards

EDB Postgres for Kubernetes on OpenShift supports the restricted and restricted-v2 SCC (SecurityContextConstraints), which vary depending on the version of EDB Postgres for Kubernetes and OpenShift you are running. Please pay close attention to the following table and notes:

Since the operator has been developed with a security focus from the beginning, in addition to always adhering to the Red Hat Certification process, EDB Postgres for Kubernetes works under the new SCCs introduced in OpenShift 4.11.

By default, EDB Postgres for Kubernetes will drop all capabilities. This ensures that during its lifecycle the operator will never make use of any unsafe capabilities.

On OpenShift we inherit the SecurityContext.SeccompProfile for each Pod from the OpenShift deployment, which in turn is set by the Pod Security Admission Controller.

Customization of the Pooler image

By default, the Pooler resource creates pods having the pgbouncer container that runs with the quay.io/enterprisedb/pgbouncer image.

You can change the image name from the advanced interface, specifically by opening the "Template" section, then selecting "Add container" under "Spec > Containers":

Then:

• set pgbouncer as the name of the container (required field in the pod template)
• set the "Image" field as desired (see the image below)

OADP for Velero

The EDB Postgres for Kubernetes operator recommends the use of the Openshift API for Data Protection operator for managing Velero in OpenShift environments. Specific details about how EDB Postgres for Kubernetes integrates with Velero can be found in the Velero section of the Addons documentation. The OADP operator is a community operator that is not directly supported by EDB. The OADP operator is not required to use Velero with EDB Postgres but is a convenient way to install Velero on OpenShift.

Monitoring and metrics

OpenShift includes a Prometheus installation out of the box that can be leveraged for user-defined projects, including EDB Postgres for Kubernetes.

Grafana integration is out of scope for this guide, as Grafana is no longer included with OpenShift.

In this section, we show you how to get started with basic observability, leveraging the default OpenShift installation.

Please refer to the OpenShift monitoring stack overview for further background.

Depending on your OpenShift configuration, you may need to do a bit of setup before you can monitor your EDB Postgres for Kubernetes clusters.

You will need to have your OpenShift configured to enable monitoring for user-defined projects.

You should check, perhaps with your OpenShift administrator, if your installation has the cluster-monitoring-config configMap, and if so, if user workload monitoring is enabled.

You can check for the presence of this configMap (note that it should be in the openshift-monitoring namespace):

oc -n openshift-monitoring get configmap cluster-monitoring-config

To enable user workload monitoring, you might want to oc apply or oc edit the configmap to look something like this:

apiVersion: v1
kind: ConfigMap
metadata:
  name: cluster-monitoring-config
  namespace: openshift-monitoring
data:
  config.yaml: |
    enableUserWorkload: true 

After enableUserWorkload is set, several monitoring components will be created in the openshift-user-workload-monitoring namespace.

$ oc -n openshift-user-workload-monitoring get pod
NAME                                  READY   STATUS    RESTARTS   AGE
prometheus-operator-58768d7cc-28xb5   2/2     Running   0          5h10m
prometheus-user-workload-0            6/6     Running   0          5h10m
prometheus-user-workload-1            6/6     Running   0          5h10m
thanos-ruler-user-workload-0          3/3     Running   0          5h10m
thanos-ruler-user-workload-1          3/3     Running   0          5h10m

You should now be able to see metrics from any cluster enabling them.

For example, we can create the following cluster with monitoring on the foo namespace:

kubectl apply -n foo -f - <<EOF
---
apiVersion: postgresql.k8s.enterprisedb.io/v1
kind: Cluster
metadata:
  name: cluster-with-metrics
spec:
  instances: 3

  storage:
    size: 1Gi

  monitoring:
    enablePodMonitor: true
EOF

You should now be able to query for the default metrics that will be installed with this example. In the Observe section of OpenShift (in Developer perspective), you should see a Metrics submenu where you can write PromQL queries. Auto-complete is enabled, so you can peek the cnp_ prefix:

It is easy to define Alerts based on the default metrics as PrometheusRules. You can find some examples of rules in the prometheusrule.yaml file, which you can download.

Before applying the rules, again, some OpenShift setup may be necessary.

The monitoring-rules-edit or at least monitoring-rules-view roles should be assigned for the user wishing to apply and monitor the rules.

This involves creating a RoleBinding with that permission, for a namespace. Again, refer to the relevant OpenShift document page for further detail. Specifically, the Granting user permissions by using the web console section should be of interest.

Note that the RoleBinding for monitoring-rules-edit applies to a namespace, so make sure you get the right one/ones.

Suppose that the cnp-prometheusrule.yaml file that you have previouly downloaded now contains your alerts. You can install those rules as follows:

oc apply -n foo -f cnp-prometheusrule.yaml

Now you should be able to see Alerts, if there are any. Note that initially there might be no alerts.

Alert routing and notifications are beyond the scope of this guide.