# Install Percona Server for MongoDB on Google Kubernetes Engine (GKE)

This guide shows you how to deploy Percona Operator for MongoDB on Google
Kubernetes Engine (GKE). The document assumes some experience with the platform.
For more information on the GKE, see the [Kubernetes Engine Quickstart  :octicons-link-external-16:](https://cloud.google.com/kubernetes-engine/docs/quickstart).

## Prerequisites

All commands from this guide can be run either in the **Google Cloud shell** or in **your local shell**.

To use *Google Cloud shell*, you need nothing but a modern web browser.

If you would like to use *your local shell*, install the following:

1. [gcloud  :octicons-link-external-16:](https://cloud.google.com/sdk/docs/quickstarts). This tool is
    part of the Google Cloud SDK. To install it, select your operating
    system on the [official Google Cloud SDK documentation page  :octicons-link-external-16:](https://cloud.google.com/sdk/docs)
    and then follow the instructions.

2. [kubectl  :octicons-link-external-16:](https://cloud.google.com/kubernetes-engine/docs/quickstart#choosing_a_shell).
    It is the Kubernetes command-line tool you will use to manage and deploy
    applications. To install the tool, run the following command:

    ``` {.bash data-prompt="$" }
    $ gcloud auth login
    $ gcloud components install kubectl
    ```

## Create and configure the GKE cluster

You can configure the settings using the `gcloud` tool. You can run it either in
the [Cloud Shell  :octicons-link-external-16:](https://cloud.google.com/shell/docs/quickstart) or in your
local shell (if you have installed Google Cloud SDK locally on the previous
step). The following command will create a cluster named `my-cluster-name`:

``` {.bash data-prompt="$" }
$ gcloud container clusters create my-cluster-name --project <project name> --zone us-central1-a --cluster-version {{ gkerecommended }} --machine-type n1-standard-4 --num-nodes=3
```

!!! note

    You must edit the following command and other command-line statements to
    replace the `<project name>` placeholder with your project name. You may
    also be required to edit the *zone location*, which is set to `us-central1`
    in the above example. Other parameters specify that we are creating a
    cluster with 3 nodes and with machine type of 4 vCPUs.

You may wait a few minutes for the cluster to be generated.

???+ note "When the process is over, you can see it listed in the Google Cloud console"

    Select *Kubernetes Engine* → *Clusters* in the left menu panel:

    ![image](assets/images/gke-quickstart-cluster-connect.svg)

Now you should configure the command-line access to your newly created cluster
to make `kubectl` be able to use it.

In the Google Cloud Console, select your cluster and then click the *Connect*
shown on the above image. You will see the connect statement which configures
the command-line access. After you have edited the statement, you may run the
command in your local shell:

``` {.bash data-prompt="$" }
$ gcloud container clusters get-credentials my-cluster-name --zone us-central1-a --project <project name>
```

Finally, use your [Cloud Identity and Access Management (Cloud IAM)  :octicons-link-external-16:](https://cloud.google.com/iam)
to control access to the cluster. The following command will give you the
ability to create Roles and RoleBindings:

``` {.bash data-prompt="$" }
$ kubectl create clusterrolebinding cluster-admin-binding --clusterrole cluster-admin --user $(gcloud config get-value core/account)
```

??? example "Expected output"

    ``` {.text .no-copy}
    clusterrolebinding.rbac.authorization.k8s.io/cluster-admin-binding created
    ```

## Install the Operator and deploy your MongoDB cluster

1. Deploy the Operator. By default deployment will be done in the `default`
    namespace. If that's not the desired one, you can create a new namespace
    and/or set the context for the namespace as follows (replace the `<namespace name>` placeholder with some descriptive name):

    ``` {.bash data-prompt="$" }
    $ kubectl create namespace <namespace name>
    $ kubectl config set-context $(kubectl config current-context) --namespace=<namespace name>
    ```

    At success, you will see the message that `namespace/<namespace name>` was created, and the context (`gke_<project name>_<zone location>_<cluster name>`) was modified.

    Deploy the Operator [using  :octicons-link-external-16:](https://kubernetes.io/docs/reference/using-api/server-side-apply/) the following command:

    ``` {.bash data-prompt="$" }
    $ kubectl apply --server-side -f https://raw.githubusercontent.com/percona/percona-server-mongodb-operator/v{{ release }}/deploy/bundle.yaml
    ```

    ??? example "Expected output"

        ``` {.text .no-copy}
        customresourcedefinition.apiextensions.k8s.io/perconaservermongodbs.psmdb.percona.com serverside-applied
        customresourcedefinition.apiextensions.k8s.io/perconaservermongodbbackups.psmdb.percona.com serverside-applied
        customresourcedefinition.apiextensions.k8s.io/perconaservermongodbrestores.psmdb.percona.com serverside-applied
        role.rbac.authorization.k8s.io/percona-server-mongodb-operator serverside-applied
        serviceaccount/percona-server-mongodb-operator serverside-applied
        rolebinding.rbac.authorization.k8s.io/service-account-percona-server-mongodb-operator serverside-applied
        deployment.apps/percona-server-mongodb-operator serverside-applied
        ```

2. The operator has been started, and you can deploy your MongoDB cluster:

    ``` {.bash data-prompt="$" }
    $ kubectl apply -f https://raw.githubusercontent.com/percona/percona-server-mongodb-operator/v{{ release }}/deploy/cr.yaml
    ```

    ??? example "Expected output"

        ``` {.text .no-copy}
        perconaservermongodb.psmdb.percona.com/my-cluster-name created
        ```

    !!! note

        This deploys default MongoDB cluster configuration, three mongod, three mongos, and
        three config server instances. Please see [deploy/cr.yaml  :octicons-link-external-16:](https://raw.githubusercontent.com/percona/percona-server-mongodb-operator/v{{ release }}/deploy/cr.yaml)
        and [Custom Resource Options](operator.md#operator-custom-resource-options)
        for the configuration options. You can clone the repository with all
        manifests and source code by executing the following command:

        ```bash
        $ git clone -b v{{ release }} https://github.com/percona/percona-server-mongodb-operator
        ```

        After editing the needed options, apply your modified `deploy/cr.yaml` file as follows:

        ```bash
        $ kubectl apply -f deploy/cr.yaml
        ```

    The creation process may take some time. When the process is over your
    cluster will obtain the `ready` status. You can check it with the following
    command:

    ``` {.bash data-prompt="$" }
    $ kubectl get psmdb
    ```

    ??? example "Expected output"

        ``` {.text .no-copy}
        NAME              ENDPOINT                                           STATUS   AGE
        my-cluster-name   my-cluster-name-mongos.default.svc.cluster.local   ready    5m26s
        ```

??? note "You can also track the creation process in Google Cloud console via the Object Browser"

    When the creation process is finished, it will look as follows:

    ![image](assets/images/gke-quickstart-object-browser.svg)


## Verifying the cluster operation

It may take ten minutes to get the cluster started. When `kubectl get psmdb`
command finally shows you the cluster status as `ready`, you can try to connect
to the cluster.

{% include 'assets/fragments/connectivity.txt' %}

## Troubleshooting

If `kubectl get psmdb` command doesn't show `ready` status too long, you can 
check the creation process with the `kubectl get pods` command:

``` {.bash data-prompt="$" }
$ kubectl get pods
```

??? example "Expected output"

    --8<-- "cli/kubectl-get-pods-response.md"

If the command output had shown some errors, you can examine the problematic
Pod with the `kubectl describe <pod name>` command as follows:

``` {.bash data-prompt="$" }
$ kubectl describe pod my-cluster-name-rs0-2
```

Review the detailed information for `Warning` statements and then correct the
configuration. An example of a warning is as follows:

`Warning  FailedScheduling  68s (x4 over 2m22s)  default-scheduler  0/1 nodes are available: 1 node(s) didn’t match pod affinity/anti-affinity, 1 node(s) didn’t satisfy existing pods anti-affinity rules.`

??? note "Alternatively, you can examine your Pods via the object browser"

    The errors will look as follows:

    ![image](assets/images/gke-quickstart-object-browser-error.svg)

    Clicking the problematic Pod will bring you to the details page with the
    same warning:

    ![image](assets/images/gke-quickstart-object-browser-details.svg)

## Removing the GKE cluster

There are several ways that you can delete the cluster.

You can clean up the cluster with the `gcloud` command as follows:

``` {.bash data-prompt="$" }
$ gcloud container clusters delete <cluster name>
```

The return statement requests your confirmation of the deletion. Type `y` to confirm.

??? note "Also, you can delete your cluster via the Google Cloud console"

    Just click the `Delete` popup menu item in the clusters list:

    ![image](assets/images/gke-quickstart-cluster-connect.svg)

The cluster deletion may take time.

!!! warning

    After deleting the cluster, all data stored in it will be lost!