Demo: Multiple Deployments

This demo helps you to multiple services on same kubenetes cluster using kustomize.

Steps:

Create the resources files for wordpress service.
Create the resources files for mysql service.
Spin-up kubernetes cluster on local using kind.
Deploy the wordpress app using kustomize and verify the status.
Deploy the mysql app using kustomize on same "kind" cluster and verify the status.
Add and remove a resource to mysql service and verify prune.

First define a place to work:

DEMO_HOME=$(mktemp -d)

Alternatively, use

DEMO_HOME=~/hello

Establish the base

BASE=$DEMO_HOME/base
mkdir -p $BASE
OUTPUT=$DEMO_HOME/output
mkdir -p $OUTPUT

mkdir $BASE/wordpress
mkdir $BASE/mysql

curl -s -o "$BASE/wordpress/#1.yaml" "https://raw.githubusercontent.com\
/kubernetes-sigs/kustomize\
/master/examples/wordpress/wordpress\
/{deployment,kustomization,service}.yaml"

curl -s -o "$BASE/mysql/#1.yaml" "https://raw.githubusercontent.com\
/kubernetes-sigs/kustomize\
/master/examples/wordpress/mysql\
/{secret,deployment,kustomization,service}.yaml"

Create a grouping.yaml resource. By this, you are defining the grouping of the current directory, mysql. Kustomize uses the unique label in this file to track any future state changes made to this directory. Make sure the label key is kustomize.config.k8s.io/inventory-id and give any unique label value and DO NOT change it in future.

cat <<EOF >$BASE/mysql/grouping.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: inventory-map
  labels:
    kustomize.config.k8s.io/inventory-id: mysql-app
EOF

Delete any existing kind cluster and create a new one. By default the name of the cluster is "kind"

kind delete cluster
kind create cluster

Let's run the wordpress and mysql services.

export KUSTOMIZE_ENABLE_ALPHA_COMMANDS=true

kustomize resources apply $BASE/mysql --status;

status=$(mktemp);
kustomize status fetch $BASE/mysql > $OUTPUT/status

test 1 == \
  $(grep "mysql" $OUTPUT/status | grep "Deployment is available. Replicas: 1" | wc -l); \
  echo $?

test 1 == \
  $(grep "mysql-pass" $OUTPUT/status | grep "Resource is always ready" | wc -l); \
  echo $?

test 1 == \
  $(grep "mysql" $OUTPUT/status | grep "Service is ready" | wc -l); \
  echo $?

kustomize resources apply $BASE/wordpress --status;

status=$(mktemp);
kustomize status fetch $BASE/wordpress > $OUTPUT/status

test 1 == \
  $(grep "wordpress" $OUTPUT/status | grep "Deployment is available. Replicas: 1" | wc -l); \
  echo $?

test 1 == \
  $(grep "wordpress" $OUTPUT/status | grep "Service is ready" | wc -l); \
  echo $?

Let's replace the secret resource from mysql service and verify prune and addition of resource.

cat <<EOF >$BASE/mysql/secret2.yaml
apiVersion: v1
kind: Secret
metadata:
  name: mysql-pass2
type: Opaque
data:
  # Default password is "admin".
  password: YWRtaW5=
EOF

rm $BASE/mysql/secret.yaml

sed -i.bak 's/secret/secret2/' \
    $BASE/mysql/kustomization.yaml

sed -i.bak 's/mysql-pass/mysql-pass2/' \
    $BASE/mysql/deployment.yaml

kustomize resources apply $BASE/mysql --status;

status=$(mktemp);
kustomize status fetch $BASE/mysql > $OUTPUT/status

test 1 == \
  $(grep "mysql" $OUTPUT/status | grep "Deployment is available. Replicas: 1" | wc -l); \
  echo $?

test 1 == \
  $(grep "mysql-pass2" $OUTPUT/status | grep "Resource is always ready" | wc -l); \
  echo $?

test 1 == \
  $(grep "mysql" $OUTPUT/status | grep "Service is ready" | wc -l); \
  echo $?

Clean-up the cluster

kind delete cluster