241 lines
9.1 KiB
Markdown
241 lines
9.1 KiB
Markdown
<h1>Quickstart</h1>
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This guide aims to give you a quick look and feel for using the Postgres
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Operator on a local Kubernetes environment.
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## Prerequisites
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Since the Postgres Operator is designed for the Kubernetes (K8s) framework,
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hence set it up first. For local tests we recommend to use one of the following
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solutions:
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* [minikube](https://github.com/kubernetes/minikube/releases), which creates a
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single-node K8s cluster inside a VM (requires KVM or VirtualBox),
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* [kind](https://kind.sigs.k8s.io/) and [k3d](https://k3d.io), which allows creating multi-nodes K8s
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clusters running on Docker (requires Docker)
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To interact with the K8s infrastructure install its CLI runtime [kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl/#install-kubectl-binary-via-curl).
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This quickstart assumes that you have started minikube or created a local kind
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cluster. Note that you can also use built-in K8s support in the Docker Desktop
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for Mac to follow the steps of this tutorial. You would have to replace
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`minikube start` and `minikube delete` with your launch actions for the Docker
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built-in K8s support.
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## Configuration Options
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Configuring the Postgres Operator is only possible before deploying a new
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Postgres cluster. This can work in two ways: via a ConfigMap or a custom
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`OperatorConfiguration` object. More details on configuration can be found
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[here](reference/operator_parameters.md).
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## Deployment options
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The Postgres Operator can be deployed in the following ways:
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* Manual deployment
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* Kustomization
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* Helm chart
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### Manual deployment setup on Kubernetes
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The Postgres Operator can be installed simply by applying yaml manifests. Note,
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we provide the `/manifests` directory as an example only; you should consider
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adjusting the manifests to your K8s environment (e.g. namespaces).
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```bash
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# First, clone the repository and change to the directory
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git clone https://github.com/zalando/postgres-operator.git
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cd postgres-operator
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# apply the manifests in the following order
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kubectl create -f manifests/configmap.yaml # configuration
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kubectl create -f manifests/operator-service-account-rbac.yaml # identity and permissions
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kubectl create -f manifests/postgres-operator.yaml # deployment
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kubectl create -f manifests/api-service.yaml # operator API to be used by UI
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```
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There is a [Kustomization](https://github.com/kubernetes-sigs/kustomize)
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manifest that [combines the mentioned resources](https://github.com/zalando/postgres-operator/blob/master/manifests/kustomization.yaml)
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(except for the CRD) - it can be used with kubectl 1.14 or newer as easy as:
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```bash
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kubectl apply -k github.com/zalando/postgres-operator/manifests
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```
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For convenience, we have automated starting the operator with minikube using the
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`run_operator_locally` script. It applies the [`acid-minimal-cluster`](https://github.com/zalando/postgres-operator/blob/master/manifests/minimal-postgres-manifest.yaml).
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manifest.
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```bash
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./run_operator_locally.sh
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```
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### Manual deployment setup on OpenShift
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To install the Postgres Operator in OpenShift you have to change the config
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parameter `kubernetes_use_configmaps` to `"true"`. Otherwise, the operator
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and Patroni will store leader and config keys in `Endpoints` that are not
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supported in OpenShift. This requires also a slightly different set of rules
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for the `postgres-operator` and `postgres-pod` cluster roles.
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```bash
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oc create -f manifests/operator-service-account-rbac-openshift.yaml
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```
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### Helm chart
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Alternatively, the operator can be installed by using the provided
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[Helm](https://helm.sh/) chart which saves you the manual steps. The charts
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for both the Postgres Operator and its UI are hosted via the `gh-pages` branch.
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They only work only with Helm v3. Helm v2 support was dropped with v1.8.0.
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```bash
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# add repo for postgres-operator
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helm repo add postgres-operator-charts https://opensource.zalando.com/postgres-operator/charts/postgres-operator
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# install the postgres-operator
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helm install postgres-operator postgres-operator-charts/postgres-operator
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# add repo for postgres-operator-ui
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helm repo add postgres-operator-ui-charts https://opensource.zalando.com/postgres-operator/charts/postgres-operator-ui
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# install the postgres-operator-ui
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helm install postgres-operator-ui postgres-operator-ui-charts/postgres-operator-ui
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```
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## Check if Postgres Operator is running
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Starting the operator may take a few seconds. Check if the operator pod is
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running before applying a Postgres cluster manifest.
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```bash
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# if you've created the operator using yaml manifests
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kubectl get pod -l name=postgres-operator
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# if you've created the operator using helm chart
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kubectl get pod -l app.kubernetes.io/name=postgres-operator
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```
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If the operator doesn't get into `Running` state, either check the latest K8s
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events of the deployment or pod with `kubectl describe` or inspect the operator
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logs:
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```bash
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kubectl logs "$(kubectl get pod -l name=postgres-operator --output='name')"
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```
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## Deploy the operator UI
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In the following paragraphs we describe how to access and manage PostgreSQL
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clusters from the command line with kubectl. But it can also be done from the
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browser-based [Postgres Operator UI](operator-ui.md). Before deploying the UI
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make sure the operator is running and its REST API is reachable through a
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[K8s service](https://github.com/zalando/postgres-operator/blob/master/manifests/api-service.yaml). The URL to this API must be
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configured in the [deployment manifest](https://github.com/zalando/postgres-operator/blob/master/ui/manifests/deployment.yaml#L43)
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of the UI.
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To deploy the UI simply apply all its manifests files or use the UI helm chart:
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```bash
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# manual deployment
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kubectl apply -f ui/manifests/
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# or kustomization
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kubectl apply -k github.com/zalando/postgres-operator/ui/manifests
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# or helm chart
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helm install postgres-operator-ui ./charts/postgres-operator-ui
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```
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Like with the operator, check if the UI pod gets into `Running` state:
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```bash
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# if you've created the operator using yaml manifests
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kubectl get pod -l name=postgres-operator-ui
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# if you've created the operator using helm chart
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kubectl get pod -l app.kubernetes.io/name=postgres-operator-ui
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```
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You can now access the web interface by port forwarding the UI pod (mind the
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label selector) and enter `localhost:8081` in your browser:
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```bash
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kubectl port-forward svc/postgres-operator-ui 8081:80
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```
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Available option are explained in detail in the [UI docs](operator-ui.md).
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## Create a Postgres cluster
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If the operator pod is running it listens to new events regarding `postgresql`
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resources. Now, it's time to submit your first Postgres cluster manifest.
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```bash
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# create a Postgres cluster
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kubectl create -f manifests/minimal-postgres-manifest.yaml
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```
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After the cluster manifest is submitted and passed the validation the operator
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will create Service and Endpoint resources and a StatefulSet which spins up new
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Pod(s) given the number of instances specified in the manifest. All resources
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are named like the cluster. The database pods can be identified by their number
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suffix, starting from `-0`. They run the [Spilo](https://github.com/zalando/spilo)
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container image by Zalando. As for the services and endpoints, there will be one
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for the master pod and another one for all the replicas (`-repl` suffix). Check
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if all components are coming up. Use the label `application=spilo` to filter and
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list the label `spilo-role` to see who is currently the master.
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```bash
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# check the deployed cluster
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kubectl get postgresql
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# check created database pods
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kubectl get pods -l application=spilo -L spilo-role
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# check created service resources
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kubectl get svc -l application=spilo -L spilo-role
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```
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## Connect to the Postgres cluster via psql
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You can create a port-forward on a database pod to connect to Postgres. See the
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[user guide](user.md#connect-to-postgresql) for instructions. With minikube it's
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also easy to retrieve the connections string from the K8s service that is
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pointing to the master pod:
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```bash
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export HOST_PORT=$(minikube service acid-minimal-cluster --url | sed 's,.*/,,')
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export PGHOST=$(echo $HOST_PORT | cut -d: -f 1)
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export PGPORT=$(echo $HOST_PORT | cut -d: -f 2)
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```
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Retrieve the password from the K8s Secret that is created in your cluster.
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Non-encrypted connections are rejected by default, so set the SSL mode to
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require:
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```bash
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export PGPASSWORD=$(kubectl get secret postgres.acid-minimal-cluster.credentials.postgresql.acid.zalan.do -o 'jsonpath={.data.password}' | base64 -d)
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export PGSSLMODE=require
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psql -U postgres
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```
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## Delete a Postgres cluster
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To delete a Postgres cluster simply delete the `postgresql` custom resource.
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```bash
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kubectl delete postgresql acid-minimal-cluster
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```
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This should remove the associated StatefulSet, database Pods, Services and
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Endpoints. The PersistentVolumes are released and the PodDisruptionBudget is
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deleted. Secrets however are not deleted and backups will remain in place.
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When deleting a cluster while it is still starting up or got stuck during that
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phase it can [happen](https://github.com/zalando/postgres-operator/issues/551)
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that the `postgresql` resource is deleted leaving orphaned components behind.
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This can cause troubles when creating a new Postgres cluster. For a fresh setup
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you can delete your local minikube or kind cluster and start again.
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