Deploying bluespice-free in Kubernetes - docker

Question

According to this source, I can store to my/data/folder by following:
docker run -d -p 80:80 -v {/my/data/folder}:/data bluespice/bluespice-free
I have created following deployment but not sure how to use persistent volume.
apiVersion: apps/v1
kind: Deployment
metadata:
name: bluespice
namespace: default
labels:
app: bluespice
spec:
replicas: 1
selector:
matchLabels:
app: bluespice
template:
metadata:
labels:
app: bluespice
spec:
containers:
- name: bluespice
image: bluespice/bluespice-free
ports:
- containerPort: 80
env:
- name: bs_url
value: "https://bluespice.mycompany.local"
My persistent volume claim name is bluespice-pvc.
Also I have deployed the pod without persistent volume. Can I attach persistent volume on the fly to keep data?

Answer 1

if you want to mount a local directory, you don't have to deal with PVC since you can't force a specific host path in a PersistentVolumeClaim. For testing locally, you can use hostPath as it explained in the documentation:
A hostPath volume mounts a file or directory from the host node's filesystem into your Pod. This is not something that most Pods will need, but it offers a powerful escape hatch for some applications.
For example, some uses for a hostPath are:
running a container that needs access to Docker internals; use a hostPath of /var/lib/docker
running cAdvisor in a container; use a hostPath of /sys
allowing a Pod to specify whether a given hostPath should exist prior to the Pod running, whether it should be created, and what it should exist as
In addition to the required path property, you can optionally specify a type for a hostPath volume.
hostPath configuration example:
apiVersion: apps/v1
kind: Deployment
metadata:
name: bluespice
namespace: default
labels:
app: bluespice
spec:
replicas: 1
selector:
matchLabels:
app: bluespice
template:
metadata:
labels:
app: bluespice
spec:
containers:
- image: bluespice/bluespice-free
name: bluespice
volumeMounts:
- mountPath: /data
name: bluespice-volume
volumes:
- name: bluespice-volume
hostPath:
# directory location on host
path: /my/data/folder
# this field is optional
type: Directory
However, if you want to move to a production cluster, you should consider more reliable option since allowing HostPaths has a lack of security and it's not portable:
HostPath volumes present many security risks, and it is a best practice to avoid the use of HostPaths when possible. When a HostPath volume must be used, it should be scoped to only the required file or directory, and mounted as ReadOnly.
If restricting HostPath access to specific directories through AdmissionPolicy, volumeMounts MUST be required to use readOnly mounts for the policy to be effective.
For more information about PersistentVolumes, you can check the official Kubernetes documents
A PersistentVolume (PV) is a piece of storage in the cluster that has been provisioned by an administrator or dynamically provisioned using Storage Classes. It is a resource in the cluster just like a node is a cluster resource. PVs are volume plugins like Volumes, but have a lifecycle independent of any individual Pod that uses the PV. This API object captures the details of the implementation of the storage, be that NFS, iSCSI, or a cloud-provider-specific storage system.
A PersistentVolumeClaim (PVC) is a request for storage by a user. It is similar to a Pod. Pods consume node resources and PVCs consume PV resources. Pods can request specific levels of resources (CPU and Memory). Claims can request specific size and access modes (e.g., they can be mounted ReadWriteOnce, ReadOnlyMany or ReadWriteMany, see AccessModes).
Therefore, I would recommend to use some cloud solutions like GCP or AWS, or at least by using a NFS share directly from Kubernetes. Also check this topic on StackOverFlow.
About your last question: it's impossible to attach Persistent Volume on the fly.