@@ -32,7 +32,7 @@ In the following we will look at the files of our Minio Standalone application/c
### The Persistent Volume Claim
Minio needs persistent storage to store objects. Without persistent storage, the data stored in an application instance will be stored in the container file system, which will be destroyed as soon as the container restarts. This is true for any application needing to persist data on Slate. So, to persist data in your application use a persistent volume claim, or "PVC".
Minio needs persistent storage to store objects. The idea of persistent data applies to many data applictions, so this fundemental piece is applicable in many scenarios. Without persistent storage, the data stored in an application instance will be stored in the container file system, which will be destroyed as soon as the container restarts. This is true for any application needing to persist data on Slate. So, to persist data in your application use a persistent volume claim, or "PVC".
The file we use to do this is [minio-standalone-pvc.yaml](https://code.ornl.gov/ryu/slate_helm_examples/-/blob/prout-dev/charts/minio-standalone/templates/minio-standalone-pvc.yaml):
@@ -54,8 +54,108 @@ spec:
```
### The Deployment
A deployment encapsulates [ReplicaSets](https://kubernetes.io/docs/concepts/workloads/controllers/replicaset/) and [Pods](https://kubernetes.io/docs/concepts/workloads/pods/pod/). If a pod goes down, the replication controller makes sure another pod comes up automatically. This creates the ability to handle pod failures automatically, without you having to worry about them, enabliing stable applications and services.
The file we use to do this is [minio-standaline-deployment.yaml](https://code.ornl.gov/ryu/slate_helm_examples/-/blob/prout-dev/charts/minio-standalone/templates/minio-standalone-deployment.yaml):
```
apiVersion: apps/v1
kind: Deployment
metadata:
# This name uniquely identifies the Deployment
name: minio-standalone
spec:
selector:
matchLabels:
app: minio-standalone # has to match .spec.template.metadata.labels
strategy:
# Specifies the strategy used to replace old Pods by new ones
# This label is used as a selector in Service definition
app: minio-standalone
spec:
# Volumes used by this deployment
volumes:
- name: data
# This volume is based on PVC
persistentVolumeClaim:
# Name of the PVC created earlier
claimName: minio-standalone-pv-claim
containers:
- name: minio
# Volume mounts for this container
volumeMounts:
# Volume 'data' is mounted to path '/data'
- name: data
mountPath: "/data"
# Pulls the lastest Minio image from Docker Hub
image: minio/minio:RELEASE.2020-05-08T02-40-49Z
args:
- server
- /data
env:
# MinIO access key and secret key
- name: MINIO_ACCESS_KEY
valueFrom:
secretKeyRef:
key: SECRET_TOKEN
name: minio-standalone-access-key
- name: MINIO_SECRET_KEY
valueFrom:
secretKeyRef:
key: SECRET_TOKEN
name: minio-standalone-secret-key
ports:
- containerPort: 9000
# Readiness probe detects situations when MinIO server instance
# is not ready to accept traffic. Kubernetes doesn't forward
# traffic to the pod while readiness checks fail.
readinessProbe:
httpGet:
path: /minio/health/ready
port: 9000
initialDelaySeconds: 120
periodSeconds: 20
# Liveness probe detects situations where MinIO server instance
# is not working properly and needs restart. Kubernetes automatically
# restarts the pods if liveness checks fail.
livenessProbe:
httpGet:
path: /minio/health/live
port: 9000
initialDelaySeconds: 120
periodSeconds: 20
```
### The Service
### The Network Policy
A service allows us to expose our deployment externally. There are three major service types - the default is ClusterIP, which exposes a service to connection from inside the cluster. The NodePort and LoadBalancer types enable the ability to expose services to external traffic directly.
In this example we use the ClusterIP type in our [minio-standalone-service.yaml](https://code.ornl.gov/ryu/slate_helm_examples/-/blob/prout-dev/charts/minio-standalone/templates/minio-standalone-service.yaml):
```
apiVersion: v1
kind: Service
metadata:
# This name uniquely identifies the service
name: minio-standalone-service
labels:
app: minio-standalone
spec:
type: ClusterIP
ports:
- name: 9000-tcp
port: 9000
targetPort: 9000
protocol: TCP
selector:
# Looks for labels `app:minio-standalone` in the namespace and applies the spec
