Allow adding extra volumes to openstack-exporter deployment

[Lirt]

This small change allows consumers to mount arbitrary volumes into openstack-exporter Deployment.

Here are example values to mount CA certificate of someone's company as ConfigMap into the Deployment.

extraVolumes:
- name: company-ca
  configMap:
    name: my-company-ca
    items:
    - key: ca
      path: my-company-ca

extraVolumeMounts:
- mountPath: /etc/ssl/certs/my-company-ca
  name: company-ca
  subPath: my-company-ca

ConfigMap can look like this:

kind: ConfigMap
apiVersion: v1
metadata:
  name: my-company-ca
data:
  ca: |
    -----BEGIN CERTIFICATE-----
    ....
    -----END CERTIFICATE-----

This CaCert can be then used within cloud config cloud.yaml:

clouds:
  default:
    region_name: RegionZero
    auth:
      username: "user"
      password: "pass"
      project_name: "my-project"
      project_domain_name: "project-domain"
      user_domain_name: "user-domain"
      auth_url: "https://keystone.example.com:5000"
    verify: true
    cacert: /etc/ssl/certs/my-company-ca

Signed-off-by: Ondrej Vasko o.vasko@pan-net.eu

[Lirt]

Hello @mnaser, please let me know if this change makes sense to you.

It's similar thing as for example velero helm chart supports, to give more space for customization. It's intended mainly for purposes of mounting internal CA file for Openstack cloud (there could be other use-cases however).

[Lirt]

@niedbalski Hello, can you please check this PR?

[Jonher937]

LGTM