Allow use of kubectl to deploy installer job

Creates install.yml, uninstall.yml, update.yml that will create kube resources and job

Adds inventory_template that will be setup based on the environment variables
using envsubst.

Updates docker file to install envsubst

Updates pgo-install.sh to setup env defaults and generate an inventory file
based on the environment.

adds docs to use kubectl apply

Author: jmckulk

centos7/Dockerfile.pgo-installer.centos7

@@ -13,9 +13,11 @@ RUN yum -y install epel-release \
     --setopt=skip_missing_names_on_install=False \
     kubectl \
     ansible \ 
-    which
+    which \
+    gettext
 
 USER daemon
 
 COPY installers/ansible /ansible
-COPY installers/image/bin/pgo-install.sh pgo-install.sh
+COPY installers/image/bin/pgo-install.sh /pgo-install.sh
+COPY installers/image/inventory_template /inventory_template

docs/content/Installation/postgres-operator-installer/kubectl-install.md

@@ -0,0 +1,89 @@
+---
+title: "Deploy with Kubectl"
+date:
+draft: false
+weight: 20
+---
+
+The `pgo-installer` image can be deployed using the `kubectl` client. The resources
+needed to run the installer are described in the
+[pgo-installer]({{< relref "/installation/postgres-operator-installer/_index.md" >}})
+section of the documentation. The following yaml files include these resources
+that are needed to deploy the operator.
+
+### Resources
+
+Each of these resources is defined in the yaml file that is used to deploy the
+operator. These resources can be updated to customize your expirence with the
+Postgres-Operator but we provide sane defaults so that you can easily deploy.
+By default the installer will create each resource based on the resource
+definition in the job yaml.
+
+#### Namespace
+
+The namespace definiton will be used to create a namespace for the installer to 
+run. By default the installer will run in a separate namespace from where the
+Postgres-Operator will be deployed. If you want the jobs to run in a
+preconfigured namespace you can easily update this file to remove the
+namespace definition. The other resources will need to be updated to reference
+this preconfigured namespace.
+
+#### ServiceAccount and ClusterRoleBinding
+
+The installer image needs a service account that can access the Kubernetes
+cluster where the Postgres-Operator will be installed. The job yaml defines a
+service account and clusterrolebinding that gives the service account the
+cluster-admin role. This is required for the installer to run correctly. If you
+have a preconfigured service account with the cluster-admin role, you can remove
+this section of the yaml and update the service account name in the job spec.
+
+#### Job
+
+Once the resources have been configured the job spec will be used to deploy the
+Postgres-Operator in your Kubernetes environment. The job spec includes sane
+defaults that can be used to deploy a specific version of the Postgres-Operator
+based on the version of the pgo-installer image that is used. Each version will
+install the corresponding version of the Postgres-Operator.
+
+##### Deployment Options
+
+The installer image uses environment variables to specify deployment options for
+the Postgres-Operator. The environment variables that you can define are the
+same as the options in the inventory file for the ansible installer. These
+options can be found in the
+[Configuring the Inventory File]({{< relref "/installation/install-with-ansible/prerequisites.md" >}})
+section of the docs. The environment variables will be the same as the inventory
+options but in all capital letters. A full list of available environment
+variables can be found in the `$PGOROOT/installers/method/kubectl/full_options`
+file. The deployment options that are included in the default job spec are
+required.
+
+### Installing
+
+```
+kubectl apply -f $PGOROOT/installers/method/kubectl/install.yml
+```
+
+### Uninstalling
+
+```
+kubectl apply -f $PGOROOT/installers/method/kubectl/uninstall.yml
+```
+
+### Updating
+
+```
+kubectl apply -f $PGOROOT/installers/method/kubectl/update.yml
+```
+
+### Cleanup
+
+The job resources can be cleaned up by running a delete on the specific yaml
+file for each job. *Please not that this will delete the namespace where the
+installer ran. If this is the same as the Postgres-Operator namespace that will
+also be deleted.* The resources can also be delete manually through the kubectl
+client.
+
+```
+kubectl delete -f job.yml
+```

installers/image/bin/pgo-install.sh

@@ -1,3 +1,22 @@
 #!/bin/bash
 
-/usr/bin/env ansible-playbook -i /ansible-inventory/inventory --tags=$1 /ansible/main.yml
+export BACKREST_PORT=${BACKREST_PORT:-2022}
+export SERVICE_TYPE=${SERVICE_TYPE:-ClusterIP}
+export CRUNCHY_DEBUG=${CRUNCHY_DEBUG:-false}
+export PGO_CLIENT_INSTALL=${PGO_CLIENT_INSTALL:-true}
+export PGO_CLIENT_CONTAINER_INSTALL=${PGO_CLIENT_CONTAINER_INSTALL:-false}
+export PGO_CLUSTER_ADMIN=${PGO_CLUSTER_ADMIN:-false}
+export PGO_DISABLE_TLS=${PGO_DISABLE_TLS:-false}
+export PGO_TLS_NO_VERIFY=${PGO_TLS_NO_VERIFY:-false}
+export PGO_DISABLE_EVENTING=${PGO_DISABLE_EVENTING:-false}
+export PGO_APISERVER_PORT=${PGO_APISERVER_PORT:-8443}
+export PGO_ADD_OS_CA_STORE=${PGO_ADD_OS_CA_STORE:-false}
+export PGO_APISERVER_URL=${PGO_APISERVER_URL:-https://postgres-operator}
+export PGO_CLIENT_CERT_SECRET=${PGO_CLIENT_CERT_SECRET:-pgo.tls}
+export POD_ANTI_AFFINITY=${POD_ANTI_AFFINITY:-preferred}
+export DELETE_OPERATOR_NAMESPACE=${DELETE_OPERATOR_NAMESPACE:-false}
+export DELETE_WATCHED_NAMESPACE=${DELETE_WATCHED_NAMESPACE:-false}
+export DELETE_METRICS_NAMESPACE=${DELETE_METRICS_NAMESPACE:-false}
+
+cat /inventory_template | envsubst > /tmp/inventory
+/usr/bin/env ansible-playbook -i /tmp/inventory --tags=$1 /ansible/main.yml