add postgresql service links (#207)

* add postgresql service links

* remove outdated bitnami self-managed reference

Author: arska

docs/modules/ROOT/pages/how-to/install-postgres-db-helm.adoc

@@ -1,113 +1,5 @@
-= How to install a PostgreSQL via Helm
+= How to install PostgreSQL on {product}
 
-[INFO]
-====
-PostgreSQL is https://docs.appcat.ch/vshn-managed/postgresql/create.html[available] on cloudscale.ch through VSHN AppCat.
-Batteries and backups included.
-====
+== Managed PostgreSQL by VSHN
 
-This page explains how to install a current PostgreSQL database via the Helm tool on the {product} platform.
-
-This guide is based on the older guide documented here: https://docs.appuio.ch/en/latest/app/helmcharts.html
-
-== Step 1: Install helm
-
-You need first to install the `helm` CLI tool: https://helm.sh/docs/intro/quickstart/
-
-Make sure you add the Bitnami Helm Chart Repository, because we will use later the PostgreSQL Helm chart provided by Bitnami:
-
-[source,shell]
-----
-helm repo add bitnami https://charts.bitnami.com/bitnami
-----
-
-== Step 2: Create an adapted YAML file
-
-We use the Bitnami provided PostgreSQL helm chart documented here: https://github.com/bitnami/charts/tree/master/bitnami/postgresql
-
-To ensure that PostgreSQL works on {product} we need to adjust some chart parameters, for example the `securityContext` parameter and the resource limits.
-
-If users don't explicitly configure limits, the {product} platform injects limits of `cpu: 200m` and `memory: 200Mi`.
-See the reference docs of {product} for more details on xref:references/default-quota.adoc#_resource_limits_and_defaults[default resource limits].
-
-See also the https://github.com/bitnami/charts/blob/master/bitnami/postgresql/values.yaml[YAML file of the PostgreSQL Helm chart] for more details on configurable values.
-
-Create a custom `postgresql-values.yaml` (filename doesn't matter) file to override the needed chart parameters.
-
-Below is a full working example for deploying the Bitnami PostgreSQL chart on {product}.
-
-.postgresql-values.yaml
-[source,yaml]
-----
-global:
-  postgresql:
-    postgresqlUsername: YOUR_USERNAME <1>
-
-image:
-  tag: SOME_IMAGE_TAG <2>
-
-resources:
-  limits:
-    cpu: 250m
-    memory: 256Mi
-
-persistence:
-  size: 1Gi
-
-volumePermissions:
-  enabled: false
-  securityContext:
-    runAsUser: "auto"
-
-securityContext:
-  enabled: false
-
-shmVolume:
-  chmod:
-    enabled: false
-
-containerSecurityContext:
-  enabled: false
-----
-<1> Set your database user name
-<2> Set a valid PostgreSQL image tag
-
-By default the `storageClass` is empty and the {product} platform uses `ssd` as the default storage class.
-
-See the xref:explanation/storage-classes.adoc[documentation of available storage classes] on {product} for more details.
-
-
-== Step 3: Install the Helm chart with the custom YAML file
-
-Install the PostgreSQL Helm chart with the following command:
-
-[source,shell]
-----
-helm install -f postgresql-values.yaml --set global.postgresql.postgresqlPassword=<DB_PW> <MY_HELM_INSTANCE_NAME> --version 10 bitnami/postgresql
-----
-
-Replace the `<DB_PW>` with your database user password.
-
-Replace `<MY_HELM_INSTANCE_NAME>` with a descriptive name for your Helm installation, for example `service-xy-db`.
-
-The `-f postgresql-values.yaml` points to your custom YAML file, overriding the required Chart parameters.
-
-
-== Step 4: Check your installation
-
-You can check your installation with the following command:
-
-[source,shell]
-----
-helm list
-----
-
-
-== Related Links
-
-Check also for more details here:
-
-* https://github.com/appuio/appuio-cloud-community/discussions/27
-* https://dev.to/tylerauerbeck/deploying-bitnami-s-postgres-helm-chart-on-openshift-1mcl
-* https://github.com/bitnami/charts/issues/1336
-* https://github.com/bitnami/bitnami-docker-postgresql/issues/103
+Do you want a managed PostgreSQL that includes Backups, Monitoring, Updates, and optionally 24x7 Support? Check out the https://products.vshn.ch/appcat/postgresql.html[PostgreSQL by VSHN product description^] and https://docs.appcat.ch/vshn-managed/postgresql/create.html[technical documentation including how to instantiate^].