GKE Clusters

Kubernetes is not vendor specific; however, for the sake of providing explicit and complete instructions for deploying all elements of a multi-cluster Kubernetes Operator implementation, this section walks you through the process of deploying multiple Kubernetes clusters on GCP specifically.

Prerequisites

Before you begin, perform the following actions:

Create a GCP account.
Prepare a GCP project so that you can use it to create GKE (Google Kubernetes Engine) clusters.
Install the GCP CLI.
Authenticate with the gcloud auth login command.
Update as needed and set the environment variables defined in the following env_variables.sh file.

1# GCP project name - this is the only parameter that is mandatory to change here2export MDB_GKE_PROJECT="${MDB_GKE_PROJECT:="### Set your GKE project name here ###"}"3
4# Adjust the values for each Kubernetes cluster in your deployment.5# The deployment script references the following variables to get values for each cluster.6export K8S_CLUSTER_0="k8s-mdb-0${K8S_CLUSTER_SUFFIX:-""}"7export K8S_CLUSTER_0_ZONE="europe-central2-a"8export K8S_CLUSTER_0_NUMBER_OF_NODES=39export K8S_CLUSTER_0_MACHINE_TYPE="e2-standard-4"10export K8S_CLUSTER_0_CONTEXT_NAME="gke_${MDB_GKE_PROJECT}_${K8S_CLUSTER_0_ZONE}_${K8S_CLUSTER_0}"11
12export K8S_CLUSTER_1="k8s-mdb-1${K8S_CLUSTER_SUFFIX:-""}"13export K8S_CLUSTER_1_ZONE="europe-central2-b"14export K8S_CLUSTER_1_NUMBER_OF_NODES=315export K8S_CLUSTER_1_MACHINE_TYPE="e2-standard-4"16export K8S_CLUSTER_1_CONTEXT_NAME="gke_${MDB_GKE_PROJECT}_${K8S_CLUSTER_1_ZONE}_${K8S_CLUSTER_1}"17
18export K8S_CLUSTER_2="k8s-mdb-2${K8S_CLUSTER_SUFFIX:-""}"19export K8S_CLUSTER_2_ZONE="europe-central2-c"20export K8S_CLUSTER_2_NUMBER_OF_NODES=121export K8S_CLUSTER_2_MACHINE_TYPE="e2-standard-4"22export K8S_CLUSTER_2_CONTEXT_NAME="gke_${MDB_GKE_PROJECT}_${K8S_CLUSTER_2_ZONE}_${K8S_CLUSTER_2}"23
24# Preemptible nodes disabled — caused random mid-test evictions in CI.25# export GKE_SPOT_INSTANCES_SWITCH="--preemptible"

Source Code

You can find all included source code in the MongoDB Kubernetes Operator repository.

Procedure

Set your default gcloud project:

1gcloud config set project "${MDB_GKE_PROJECT}"

Create Kubernetes clusters.

Create three GKE (Google Kubernetes Engine) clusters:

1gcloud container clusters create "${K8S_CLUSTER_0}" \2      --zone="${K8S_CLUSTER_0_ZONE}" \3      --num-nodes="${K8S_CLUSTER_0_NUMBER_OF_NODES}" \4      --machine-type "${K8S_CLUSTER_0_MACHINE_TYPE}" \5      --tags=mongodb \6      ${GKE_SPOT_INSTANCES_SWITCH:+${GKE_SPOT_INSTANCES_SWITCH}}

1gcloud container clusters create "${K8S_CLUSTER_1}" \2      --zone="${K8S_CLUSTER_1_ZONE}" \3      --num-nodes="${K8S_CLUSTER_1_NUMBER_OF_NODES}" \4      --machine-type "${K8S_CLUSTER_1_MACHINE_TYPE}" \5      --tags=mongodb \6      ${GKE_SPOT_INSTANCES_SWITCH:+${GKE_SPOT_INSTANCES_SWITCH}}

1gcloud container clusters create "${K8S_CLUSTER_2}" \2      --zone="${K8S_CLUSTER_2_ZONE}" \3      --num-nodes="${K8S_CLUSTER_2_NUMBER_OF_NODES}" \4      --machine-type "${K8S_CLUSTER_2_MACHINE_TYPE}" \5      --tags=mongodb \6      ${GKE_SPOT_INSTANCES_SWITCH:+${GKE_SPOT_INSTANCES_SWITCH}}

Store credentials in your kubeconfig.

Obtain credentials and save contexts to the current kubeconfig file. By default, this file is located in the ~/.kube/config directory and referenced by the $KUBECONFIG environment variable.

1gcloud container clusters get-credentials "${K8S_CLUSTER_0}" --zone="${K8S_CLUSTER_0_ZONE}"2gcloud container clusters get-credentials "${K8S_CLUSTER_1}" --zone="${K8S_CLUSTER_1_ZONE}"3gcloud container clusters get-credentials "${K8S_CLUSTER_2}" --zone="${K8S_CLUSTER_2_ZONE}"

All kubectl commands reference these contexts using the following variables:

$K8S_CLUSTER_0_CONTEXT_NAME
$K8S_CLUSTER_1_CONTEXT_NAME
$K8S_CLUSTER_2_CONTEXT_NAME

Verify that `kubectl` has access to Kubernetes clusters.

1echo "Nodes in cluster ${K8S_CLUSTER_0_CONTEXT_NAME}"2kubectl --context "${K8S_CLUSTER_0_CONTEXT_NAME}" get nodes3echo; echo "Nodes in cluster ${K8S_CLUSTER_1_CONTEXT_NAME}"4kubectl --context "${K8S_CLUSTER_1_CONTEXT_NAME}" get nodes5echo; echo "Nodes in cluster ${K8S_CLUSTER_2_CONTEXT_NAME}"6kubectl --context "${K8S_CLUSTER_2_CONTEXT_NAME}" get nodes

1Nodes in cluster gke_scratch-kubernetes-team_europe-central2-a_k8s-mdb-0-cabcbfd835d45fd33b2NAME                                                  STATUS   ROLES    AGE    VERSION3gke-k8s-mdb-0-cabcbfd835-default-pool-41737e6e-52hc   Ready    <none>   112s   v1.36.4-gke.13910024gke-k8s-mdb-0-cabcbfd835-default-pool-41737e6e-7pds   Ready    <none>   113s   v1.36.4-gke.13910025gke-k8s-mdb-0-cabcbfd835-default-pool-41737e6e-k76f   Ready    <none>   113s   v1.36.4-gke.13910026
7Nodes in cluster gke_scratch-kubernetes-team_europe-central2-b_k8s-mdb-1-cabcbfd835d45fd33b8NAME                                                  STATUS   ROLES    AGE   VERSION9gke-k8s-mdb-1-cabcbfd835-default-pool-a593e388-0m6k   Ready    <none>   36s   v1.36.4-gke.139100210gke-k8s-mdb-1-cabcbfd835-default-pool-a593e388-5zq5   Ready    <none>   32s   v1.36.4-gke.139100211gke-k8s-mdb-1-cabcbfd835-default-pool-a593e388-zppj   Ready    <none>   31s   v1.36.4-gke.139100212
13Nodes in cluster gke_scratch-kubernetes-team_europe-central2-c_k8s-mdb-2-cabcbfd835d45fd33b14NAME                                                  STATUS   ROLES    AGE   VERSION15gke-k8s-mdb-2-cabcbfd835-default-pool-4a9f72a1-hn1q   Ready    <none>   44s   v1.36.4-gke.1495002

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