Deploying External OpenStack Cloud Provider with Kubeadm
This document describes how to install a single control-plane Kubernetes cluster v1.15 with kubeadm on CentOS, and then deploy an external OpenStack cloud provider and Cinder CSI plugin to use Cinder volumes as persistent volumes in Kubernetes.
Preparation in OpenStack
This cluster runs on OpenStack VMs, so let’s create a few things in OpenStack first.
- A project/tenant for this Kubernetes cluster
- A user in this project for Kubernetes, to query node information and attach volumes etc
- A private network and subnet
- A router for this private network and connect it to a public network for floating IPs
- A security group for all Kubernetes VMs
- A VM as a control-plane node and a few VMs as worker nodes
The security group will have the following rules to open ports for Kubernetes.
Control-Plane Node
Protocol | Port Number | Description |
---|---|---|
TCP | 6443 | Kubernetes API Server |
TCP | 2379-2380 | etcd server client API |
TCP | 10250 | Kubelet API |
TCP | 10251 | kube-scheduler |
TCP | 10252 | kube-controller-manager |
TCP | 10255 | Read-only Kubelet API |
Worker Nodes
Protocol | Port Number | Description |
---|---|---|
TCP | 10250 | Kubelet API |
TCP | 10255 | Read-only Kubelet API |
TCP | 30000-32767 | NodePort Services |
CNI ports on both control-plane and worker nodes
Protocol | Port Number | Description |
---|---|---|
TCP | 179 | Calico BGP network |
TCP | 9099 | Calico felix (health check) |
UDP | 8285 | Flannel |
UDP | 8472 | Flannel |
TCP | 6781-6784 | Weave Net |
UDP | 6783-6784 | Weave Net |
CNI specific ports are only required to be opened when that particular CNI plugin is used. In this guide, we will use Weave Net. Only the Weave Net ports (TCP 6781-6784 and UDP 6783-6784), will need to be opened in the security group.
The control-plane node needs at least 2 cores and 4GB RAM. After the VM is launched, verify its hostname and make sure it is the same as the node name in Nova.
If the hostname is not resolvable, add it to /etc/hosts
.
For example, if the VM is called master1, and it has an internal IP 192.168.1.4. Add that to /etc/hosts
and set hostname to master1.
echo "192.168.1.4 master1" >> /etc/hosts
hostnamectl set-hostname master1
Install Docker and Kubernetes
Next, we’ll follow the official documents to install docker and Kubernetes using kubeadm.
Install Docker following the steps from the container runtime documentation.
Note that it is a best practice to use systemd as the cgroup driver for Kubernetes. If you use an internal container registry, add them to the docker config.
# Install Docker CE
## Set up the repository
### Install required packages.
yum install yum-utils device-mapper-persistent-data lvm2
### Add Docker repository.
yum-config-manager \
--add-repo \
https://download.docker.com/linux/centos/docker-ce.repo
## Install Docker CE.
yum update && yum install docker-ce-18.06.2.ce
## Create /etc/docker directory.
mkdir /etc/docker
# Configure the Docker daemon
cat > /etc/docker/daemon.json <<EOF
{
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2",
"storage-opts": [
"overlay2.override_kernel_check=true"
]
}
EOF
mkdir -p /etc/systemd/system/docker.service.d
# Restart Docker
systemctl daemon-reload
systemctl restart docker
systemctl enable docker
Install kubeadm following the steps from the Installing Kubeadm documentation.
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
# Set SELinux in permissive mode (effectively disabling it)
# Caveat: In a production environment you may not want to disable SELinux, please refer to Kubernetes documents about SELinux
setenforce 0
sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config
yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes
systemctl enable --now kubelet
cat <<EOF > /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system
# check if br_netfilter module is loaded
lsmod | grep br_netfilter
# if not, load it explicitly with
modprobe br_netfilter
The official document about how to create a single control-plane cluster can be found from the Creating a single control-plane cluster with kubeadm documentation.
We’ll largely follow that document but also add additional things for the cloud provider.
To make things more clear, we’ll use a kubeadm-config.yml
for the control-plane node.
In this config we specify to use an external OpenStack cloud provider, and where to find its config.
We also enable storage API in API server’s runtime config so we can use OpenStack volumes as persistent volumes in Kubernetes.
apiVersion: kubeadm.k8s.io/v1beta1
kind: InitConfiguration
nodeRegistration:
kubeletExtraArgs:
cloud-provider: "external"
---
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: "v1.15.1"
apiServer:
extraArgs:
enable-admission-plugins: NodeRestriction
runtime-config: "storage.k8s.io/v1=true"
controllerManager:
extraArgs:
external-cloud-volume-plugin: openstack
extraVolumes:
- name: "cloud-config"
hostPath: "/etc/kubernetes/cloud-config"
mountPath: "/etc/kubernetes/cloud-config"
readOnly: true
pathType: File
networking:
serviceSubnet: "10.96.0.0/12"
podSubnet: "10.224.0.0/16"
dnsDomain: "cluster.local"
Now we’ll create the cloud config, /etc/kubernetes/cloud-config
, for OpenStack.
Note that the tenant here is the one we created for all Kubernetes VMs in the beginning.
All VMs should be launched in this project/tenant.
In addition you need to create a user in this tenant for Kubernetes to do queries.
The ca-file is the CA root certificate for OpenStack’s API endpoint, for example https://openstack.cloud:5000/v3
At the time of writing the cloud provider doesn’t allow insecure connections (skip CA check).
[Global]
region=RegionOne
username=username
password=password
auth-url=https://openstack.cloud:5000/v3
tenant-id=14ba698c0aec4fd6b7dc8c310f664009
domain-id=default
ca-file=/etc/kubernetes/ca.pem
[LoadBalancer]
subnet-id=b4a9a292-ea48-4125-9fb2-8be2628cb7a1
floating-network-id=bc8a590a-5d65-4525-98f3-f7ef29c727d5
[BlockStorage]
bs-version=v2
[Networking]
public-network-name=public
ipv6-support-disabled=false
Next run kubeadm to initiate the control-plane node
kubeadm init --config=kubeadm-config.yml
With the initialization completed, copy admin config to .kube
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
At this stage, the control-plane node is created but not ready. All the nodes have the taint node.cloudprovider.kubernetes.io/uninitialized=true:NoSchedule
and are waiting to be initialized by the cloud-controller-manager.
# kubectl describe no master1
Name: master1
Roles: master
......
Taints: node-role.kubernetes.io/master:NoSchedule
node.cloudprovider.kubernetes.io/uninitialized=true:NoSchedule
node.kubernetes.io/not-ready:NoSchedule
......
Now deploy the OpenStack cloud controller manager into the cluster, following using controller manager with kubeadm.
Create a secret with the cloud-config for the openstack cloud provider.
kubectl create secret -n kube-system generic cloud-config --from-literal=cloud.conf="$(cat /etc/kubernetes/cloud-config)" --dry-run -o yaml > cloud-config-secret.yaml
kubectl apply -f cloud-config-secret.yaml
Get the CA certificate for OpenStack API endpoints and put that into /etc/kubernetes/ca.pem
.
Create RBAC resources.
kubectl apply -f https://github.com/kubernetes/cloud-provider-openstack/raw/release-1.15/cluster/addons/rbac/cloud-controller-manager-roles.yaml
kubectl apply -f https://github.com/kubernetes/cloud-provider-openstack/raw/release-1.15/cluster/addons/rbac/cloud-controller-manager-role-bindings.yaml
We’ll run the OpenStack cloud controller manager as a DaemonSet rather than a pod.
The manager will only run on the control-plane node, so if there are multiple control-plane nodes, multiple pods will be run for high availability.
Create openstack-cloud-controller-manager-ds.yaml
containing the following manifests, then apply it.
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: cloud-controller-manager
namespace: kube-system
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: openstack-cloud-controller-manager
namespace: kube-system
labels:
k8s-app: openstack-cloud-controller-manager
spec:
selector:
matchLabels:
k8s-app: openstack-cloud-controller-manager
updateStrategy:
type: RollingUpdate
template:
metadata:
labels:
k8s-app: openstack-cloud-controller-manager
spec:
nodeSelector:
node-role.kubernetes.io/master: ""
securityContext:
runAsUser: 1001
tolerations:
- key: node.cloudprovider.kubernetes.io/uninitialized
value: "true"
effect: NoSchedule
- key: node-role.kubernetes.io/master
effect: NoSchedule
- effect: NoSchedule
key: node.kubernetes.io/not-ready
serviceAccountName: cloud-controller-manager
containers:
- name: openstack-cloud-controller-manager
image: docker.io/k8scloudprovider/openstack-cloud-controller-manager:v1.15.0
args:
- /bin/openstack-cloud-controller-manager
- --v=1
- --cloud-config=$(CLOUD_CONFIG)
- --cloud-provider=openstack
- --use-service-account-credentials=true
- --address=127.0.0.1
volumeMounts:
- mountPath: /etc/kubernetes/pki
name: k8s-certs
readOnly: true
- mountPath: /etc/ssl/certs
name: ca-certs
readOnly: true
- mountPath: /etc/config
name: cloud-config-volume
readOnly: true
- mountPath: /usr/libexec/kubernetes/kubelet-plugins/volume/exec
name: flexvolume-dir
- mountPath: /etc/kubernetes
name: ca-cert
readOnly: true
resources:
requests:
cpu: 200m
env:
- name: CLOUD_CONFIG
value: /etc/config/cloud.conf
hostNetwork: true
volumes:
- hostPath:
path: /usr/libexec/kubernetes/kubelet-plugins/volume/exec
type: DirectoryOrCreate
name: flexvolume-dir
- hostPath:
path: /etc/kubernetes/pki
type: DirectoryOrCreate
name: k8s-certs
- hostPath:
path: /etc/ssl/certs
type: DirectoryOrCreate
name: ca-certs
- name: cloud-config-volume
secret:
secretName: cloud-config
- name: ca-cert
secret:
secretName: openstack-ca-cert
When the controller manager is running, it will query OpenStack to get information about the nodes and remove the taint. In the node info you’ll see the VM’s UUID in OpenStack.
# kubectl describe no master1
Name: master1
Roles: master
......
Taints: node-role.kubernetes.io/master:NoSchedule
node.kubernetes.io/not-ready:NoSchedule
......
sage:docker: network plugin is not ready: cni config uninitialized
......
PodCIDR: 10.224.0.0/24
ProviderID: openstack:///548e3c46-2477-4ce2-968b-3de1314560a5
Now install your favourite CNI and the control-plane node will become ready.
For example, to install Weave Net, run this command:
kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"
Next we’ll set up worker nodes.
Firstly, install docker and kubeadm in the same way as how they were installed in the control-plane node. To join them to the cluster we need a token and ca cert hash from the output of control-plane node installation. If it is expired or lost we can recreate it using these commands.
# check if token is expired
kubeadm token list
# re-create token and show join command
kubeadm token create --print-join-command
Create kubeadm-config.yml
for worker nodes with the above token and ca cert hash.
apiVersion: kubeadm.k8s.io/v1beta2
discovery:
bootstrapToken:
apiServerEndpoint: 192.168.1.7:6443
token: 0c0z4p.dnafh6vnmouus569
caCertHashes: ["sha256:fcb3e956a6880c05fc9d09714424b827f57a6fdc8afc44497180905946527adf"]
kind: JoinConfiguration
nodeRegistration:
kubeletExtraArgs:
cloud-provider: "external"
apiServerEndpoint is the control-plane node, token and caCertHashes can be taken from the join command printed in the output of ‘kubeadm token create’ command.
Run kubeadm and the worker nodes will be joined to the cluster.
kubeadm join --config kubeadm-config.yml
At this stage we’ll have a working Kubernetes cluster with an external OpenStack cloud provider. The provider tells Kubernetes about the mapping between Kubernetes nodes and OpenStack VMs. If Kubernetes wants to attach a persistent volume to a pod, it can find out which OpenStack VM the pod is running on from the mapping, and attach the underlying OpenStack volume to the VM accordingly.
Deploy Cinder CSI
The integration with Cinder is provided by an external Cinder CSI plugin, as described in the Cinder CSI documentation.
We’ll perform the following steps to install the Cinder CSI plugin. Firstly, create a secret with CA certs for OpenStack’s API endpoints. It is the same cert file as what we use in cloud provider above.
kubectl create secret -n kube-system generic openstack-ca-cert --from-literal=ca.pem="$(cat /etc/kubernetes/ca.pem)" --dry-run -o yaml > openstack-ca-cert.yaml
kubectl apply -f openstack-ca-cert.yaml
Then create RBAC resources.
kubectl apply -f https://raw.githubusercontent.com/kubernetes/cloud-provider-openstack/release-1.15/manifests/cinder-csi-plugin/cinder-csi-controllerplugin-rbac.yaml
kubectl apply -f https://github.com/kubernetes/cloud-provider-openstack/raw/release-1.15/manifests/cinder-csi-plugin/cinder-csi-nodeplugin-rbac.yaml
The Cinder CSI plugin includes a controller plugin and a node plugin.
The controller communicates with Kubernetes APIs and Cinder APIs to create/attach/detach/delete Cinder volumes. The node plugin in-turn runs on each worker node to bind a storage device (attached volume) to a pod, and unbind it during deletion.
Create cinder-csi-controllerplugin.yaml
and apply it to create csi controller.
kind: Service
apiVersion: v1
metadata:
name: csi-cinder-controller-service
namespace: kube-system
labels:
app: csi-cinder-controllerplugin
spec:
selector:
app: csi-cinder-controllerplugin
ports:
- name: dummy
port: 12345
---
kind: StatefulSet
apiVersion: apps/v1
metadata:
name: csi-cinder-controllerplugin
namespace: kube-system
spec:
serviceName: "csi-cinder-controller-service"
replicas: 1
selector:
matchLabels:
app: csi-cinder-controllerplugin
template:
metadata:
labels:
app: csi-cinder-controllerplugin
spec:
serviceAccount: csi-cinder-controller-sa
containers:
- name: csi-attacher
image: quay.io/k8scsi/csi-attacher:v1.0.1
args:
- "--v=5"
- "--csi-address=$(ADDRESS)"
env:
- name: ADDRESS
value: /var/lib/csi/sockets/pluginproxy/csi.sock
imagePullPolicy: "IfNotPresent"
volumeMounts:
- name: socket-dir
mountPath: /var/lib/csi/sockets/pluginproxy/
- name: csi-provisioner
image: quay.io/k8scsi/csi-provisioner:v1.0.1
args:
- "--provisioner=csi-cinderplugin"
- "--csi-address=$(ADDRESS)"
env:
- name: ADDRESS
value: /var/lib/csi/sockets/pluginproxy/csi.sock
imagePullPolicy: "IfNotPresent"
volumeMounts:
- name: socket-dir
mountPath: /var/lib/csi/sockets/pluginproxy/
- name: csi-snapshotter
image: quay.io/k8scsi/csi-snapshotter:v1.0.1
args:
- "--connection-timeout=15s"
- "--csi-address=$(ADDRESS)"
env:
- name: ADDRESS
value: /var/lib/csi/sockets/pluginproxy/csi.sock
imagePullPolicy: Always
volumeMounts:
- mountPath: /var/lib/csi/sockets/pluginproxy/
name: socket-dir
- name: cinder-csi-plugin
image: docker.io/k8scloudprovider/cinder-csi-plugin:v1.15.0
args :
- /bin/cinder-csi-plugin
- "--v=5"
- "--nodeid=$(NODE_ID)"
- "--endpoint=$(CSI_ENDPOINT)"
- "--cloud-config=$(CLOUD_CONFIG)"
- "--cluster=$(CLUSTER_NAME)"
env:
- name: NODE_ID
valueFrom:
fieldRef:
fieldPath: spec.nodeName
- name: CSI_ENDPOINT
value: unix://csi/csi.sock
- name: CLOUD_CONFIG
value: /etc/config/cloud.conf
- name: CLUSTER_NAME
value: kubernetes
imagePullPolicy: "IfNotPresent"
volumeMounts:
- name: socket-dir
mountPath: /csi
- name: secret-cinderplugin
mountPath: /etc/config
readOnly: true
- mountPath: /etc/kubernetes
name: ca-cert
readOnly: true
volumes:
- name: socket-dir
hostPath:
path: /var/lib/csi/sockets/pluginproxy/
type: DirectoryOrCreate
- name: secret-cinderplugin
secret:
secretName: cloud-config
- name: ca-cert
secret:
secretName: openstack-ca-cert
Create cinder-csi-nodeplugin.yaml
and apply it to create csi node.
kind: DaemonSet
apiVersion: apps/v1
metadata:
name: csi-cinder-nodeplugin
namespace: kube-system
spec:
selector:
matchLabels:
app: csi-cinder-nodeplugin
template:
metadata:
labels:
app: csi-cinder-nodeplugin
spec:
serviceAccount: csi-cinder-node-sa
hostNetwork: true
containers:
- name: node-driver-registrar
image: quay.io/k8scsi/csi-node-driver-registrar:v1.1.0
args:
- "--v=5"
- "--csi-address=$(ADDRESS)"
- "--kubelet-registration-path=$(DRIVER_REG_SOCK_PATH)"
lifecycle:
preStop:
exec:
command: ["/bin/sh", "-c", "rm -rf /registration/cinder.csi.openstack.org /registration/cinder.csi.openstack.org-reg.sock"]
env:
- name: ADDRESS
value: /csi/csi.sock
- name: DRIVER_REG_SOCK_PATH
value: /var/lib/kubelet/plugins/cinder.csi.openstack.org/csi.sock
- name: KUBE_NODE_NAME
valueFrom:
fieldRef:
fieldPath: spec.nodeName
imagePullPolicy: "IfNotPresent"
volumeMounts:
- name: socket-dir
mountPath: /csi
- name: registration-dir
mountPath: /registration
- name: cinder-csi-plugin
securityContext:
privileged: true
capabilities:
add: ["SYS_ADMIN"]
allowPrivilegeEscalation: true
image: docker.io/k8scloudprovider/cinder-csi-plugin:v1.15.0
args :
- /bin/cinder-csi-plugin
- "--nodeid=$(NODE_ID)"
- "--endpoint=$(CSI_ENDPOINT)"
- "--cloud-config=$(CLOUD_CONFIG)"
env:
- name: NODE_ID
valueFrom:
fieldRef:
fieldPath: spec.nodeName
- name: CSI_ENDPOINT
value: unix://csi/csi.sock
- name: CLOUD_CONFIG
value: /etc/config/cloud.conf
imagePullPolicy: "IfNotPresent"
volumeMounts:
- name: socket-dir
mountPath: /csi
- name: pods-mount-dir
mountPath: /var/lib/kubelet/pods
mountPropagation: "Bidirectional"
- name: kubelet-dir
mountPath: /var/lib/kubelet
mountPropagation: "Bidirectional"
- name: pods-cloud-data
mountPath: /var/lib/cloud/data
readOnly: true
- name: pods-probe-dir
mountPath: /dev
mountPropagation: "HostToContainer"
- name: secret-cinderplugin
mountPath: /etc/config
readOnly: true
- mountPath: /etc/kubernetes
name: ca-cert
readOnly: true
volumes:
- name: socket-dir
hostPath:
path: /var/lib/kubelet/plugins/cinder.csi.openstack.org
type: DirectoryOrCreate
- name: registration-dir
hostPath:
path: /var/lib/kubelet/plugins_registry/
type: Directory
- name: kubelet-dir
hostPath:
path: /var/lib/kubelet
type: Directory
- name: pods-mount-dir
hostPath:
path: /var/lib/kubelet/pods
type: Directory
- name: pods-cloud-data
hostPath:
path: /var/lib/cloud/data
type: Directory
- name: pods-probe-dir
hostPath:
path: /dev
type: Directory
- name: secret-cinderplugin
secret:
secretName: cloud-config
- name: ca-cert
secret:
secretName: openstack-ca-cert
When they are both running, create a storage class for Cinder.
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: csi-sc-cinderplugin
provisioner: csi-cinderplugin
Then we can create a PVC with this class.
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: myvol
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
storageClassName: csi-sc-cinderplugin
When the PVC is created, a Cinder volume is created correspondingly.
# kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
myvol Bound pvc-14b8bc68-6c4c-4dc6-ad79-4cb29a81faad 1Gi RWO csi-sc-cinderplugin 3s
In OpenStack the volume name will match the Kubernetes persistent volume generated name. In this example it would be: pvc-14b8bc68-6c4c-4dc6-ad79-4cb29a81faad
Now we can create a pod with the PVC.
apiVersion: v1
kind: Pod
metadata:
name: web
spec:
containers:
- name: web
image: nginx
ports:
- name: web
containerPort: 80
hostPort: 8081
protocol: TCP
volumeMounts:
- mountPath: "/usr/share/nginx/html"
name: mypd
volumes:
- name: mypd
persistentVolumeClaim:
claimName: myvol
When the pod is running, the volume will be attached to the pod. If we go back to OpenStack, we can see the Cinder volume is mounted to the worker node where the pod is running on.
# openstack volume show 6b5f3296-b0eb-40cd-bd4f-2067a0d6287f
+--------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Field | Value |
+--------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| attachments | [{u'server_id': u'1c5e1439-edfa-40ed-91fe-2a0e12bc7eb4', u'attachment_id': u'11a15b30-5c24-41d4-86d9-d92823983a32', u'attached_at': u'2019-07-24T05:02:34.000000', u'host_name': u'compute-6', u'volume_id': u'6b5f3296-b0eb-40cd-bd4f-2067a0d6287f', u'device': u'/dev/vdb', u'id': u'6b5f3296-b0eb-40cd-bd4f-2067a0d6287f'}] |
| availability_zone | nova |
| bootable | false |
| consistencygroup_id | None |
| created_at | 2019-07-24T05:02:18.000000 |
| description | Created by OpenStack Cinder CSI driver |
| encrypted | False |
| id | 6b5f3296-b0eb-40cd-bd4f-2067a0d6287f |
| migration_status | None |
| multiattach | False |
| name | pvc-14b8bc68-6c4c-4dc6-ad79-4cb29a81faad |
| os-vol-host-attr:host | rbd:volumes@rbd#rbd |
| os-vol-mig-status-attr:migstat | None |
| os-vol-mig-status-attr:name_id | None |
| os-vol-tenant-attr:tenant_id | 14ba698c0aec4fd6b7dc8c310f664009 |
| properties | attached_mode='rw', cinder.csi.openstack.org/cluster='kubernetes' |
| replication_status | None |
| size | 1 |
| snapshot_id | None |
| source_volid | None |
| status | in-use |
| type | rbd |
| updated_at | 2019-07-24T05:02:35.000000 |
| user_id | 5f6a7a06f4e3456c890130d56babf591 |
+--------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
Summary
In this walk-through, we deployed a Kubernetes cluster on OpenStack VMs and integrated it with OpenStack using an external OpenStack cloud provider. Then on this Kubernetes cluster we deployed Cinder CSI plugin which can create Cinder volumes and expose them in Kubernetes as persistent volumes.