In this example below we will show how to get a Single instance Stateful MySQL application pod on vSphere 7 with Kubernetes. For an introduction to vSphere 7 with Kubernetes see this blog link below.
A first look a running a Kubernetes cluster on "vSphere 7 with Kubernetes"
http://theblasfrompas.blogspot.com/2020/04/a-first-look-running-kubenetes-cluster.html
Steps
1. If you followed the Blog above you will have a Namespace as shown in the image below. The namespace we are using is called "ns1"
2. Click on "ns1" and ensure you have added storage using the "Storage" card
3. Now let's connect to our supervisor cluster and switch to the Namespace "ns1"
kubectl vsphere login --server=SUPERVISOR-CLUSTER-CONTROL-PLANE-IP-ADDRESS
--vsphere-username VCENTER-SSO-USER
Example:
$ kubectl vsphere login --insecure-skip-tls-verify --server wcp.haas-yyy.pez.pivotal.io -u administrator@vsphere.local
Password:
Logged in successfully.
You have access to the following contexts:
ns1
wcp.haas-yyy.pez.pivotal.io
If the context you wish to use is not in this list, you may need to try
logging in again later, or contact your cluster administrator.
To change context, use `kubectl config use-context `
4. At this point we need to switch to the Namespace we created at step 2 which is "ns1".
$ kubectl config use-context ns1
Switched to context "ns1".
5. Use one of the following commands to verify that the storage class is the one which we added to the Namespace as per #2 above, in this case "pacific-gold-storage-policy".
$ kubectl get storageclass
NAME PROVISIONER AGE
pacific-gold-storage-policy csi.vsphere.vmware.com 5d20h
$ kubectl describe namespace ns1
Name: ns1
Labels: vSphereClusterID=domain-c8
Annotations: ncp/extpoolid: domain-c8:1d3e6bfb-af68-4494-a9bf-c8560a7a6aef-ippool-10-193-191-129-10-193-191-190
ncp/snat_ip: 10.193.191.141
ncp/subnet-0: 10.244.0.240/28
ncp/subnet-1: 10.244.1.16/28
vmware-system-resource-pool: resgroup-67
vmware-system-vm-folder: group-v68
Status: Active
Resource Quotas
Name: ns1-storagequota
Resource Used Hard
-------- --- ---
pacific-gold-storage-policy.storageclass.storage.k8s.io/requests.storage 20Gi 9223372036854775807
No resource limits.
As a DevOps engineer, you can use the storage class in your persistent volume claim specifications. You can then deploy an application that uses storage from the persistent volume claim.
6. At this point we can create a Persistent Volume Claim using YAML as follows. In the example below we reference storage class name ""pacific-gold-storage-policy".
Note: We are using a Supervisor Cluster Namespace here for our Stateful MySQL application but the storage class name will also appear in any Tanzu Kubernetes clusters you have created.
Example:
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: mysql-pv-claim
spec:
storageClassName: pacific-gold-storage-policy
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 20Gi
$ kubectl apply -f mysql-pvc.yaml
persistentvolumeclaim/mysql-pv-claim created
7. Let's view the PVC we just created
$ kubectl get pvc NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE mysql-pv-claim Bound pvc-a60f2787-ccf4-4142-8bf5-14082ae33403 20Gi RWO pacific-gold-storage-policy 39s
8. Now let's create a Deployment that will mount this PVC we created above using the name "mysql-pv-claim"
Example:
apiVersion: v1
kind: Service
metadata:
name: mysql
spec:
ports:
- port: 3306
selector:
app: mysql
clusterIP: None
---
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
name: mysql
spec:
selector:
matchLabels:
app: mysql
strategy:
type: Recreate
template:
metadata:
labels:
app: mysql
spec:
containers:
- image: mysql:5.6
name: mysql
env:
# Use secret in real usage
- name: MYSQL_ROOT_PASSWORD
value: password
ports:
- containerPort: 3306
name: mysql
volumeMounts:
- name: mysql-persistent-storage
mountPath: /var/lib/mysql
volumes:
- name: mysql-persistent-storage
persistentVolumeClaim:
claimName: mysql-pv-claim
$ kubectl apply -f mysql-deployment.yaml
service/mysql created
deployment.apps/mysql created
9. Let's verify we have a running Deployment with a MySQL POD as shown below
$ kubectl get all NAME READY STATUS RESTARTS AGE pod/mysql-c85f7f79c-gskkr 1/1 Running 0 78s pod/nginx 1/1 Running 0 3d21h NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/mysql ClusterIP None <none> 3306/TCP 79s service/tkg-cluster-1-60657ac113b7b5a0ebaab LoadBalancer 10.96.0.253 10.193.191.68 80:32078/TCP 5d19h service/tkg-cluster-1-control-plane-service LoadBalancer 10.96.0.222 10.193.191.66 6443:30659/TCP 5d19h NAME READY UP-TO-DATE AVAILABLE AGE deployment.apps/mysql 1/1 1 1 79s NAME DESIRED CURRENT READY AGE replicaset.apps/mysql-c85f7f79c 1 1 1 79s
10. If we return to vSphere client we will see our MySQL Stateful deployment as shown below
11. We can also view the PVC we have created in vSphere client as well
12. Finally let's connect to the MySQL database which is done as follows by
$ kubectl run -it --rm --image=mysql:5.6 --restart=Never mysql-client -- mysql -h mysql -ppassword
If you don't see a command prompt, try pressing enter.
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.47 MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+---------------------+
| Database |
+---------------------+
| information_schema |
| #mysql50#lost+found |
| mysql |
| performance_schema |
+---------------------+
4 rows in set (0.02 sec)
mysql>
More Information
Deploy a Stateful Application
https://docs.vmware.com/en/VMware-vSphere/7.0/vmware-vsphere-with-kubernetes/GUID-D875DED3-41A1-484F-A1CD-13810D674420.html
Display Storage Classes in a Supervisor Namespace or Tanzu Kubernetes Cluster
https://docs.vmware.com/en/VMware-vSphere/7.0/vmware-vsphere-with-kubernetes/GUID-883E60F9-03C5-40D7-9AB8-BE42835B7B52.html#GUID-883E60F9-03C5-40D7-9AB8-BE42835B7B52
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