You can still use kadalu even when you have your storage nodes outside
of the kubernetes (k8s) cluster. We describe this
kind of setup as
‘External’. Such a description is intended to indicate that the storage
server processes are not managed by kadalu operator.
In this mode, we expect gluster volume to be created and is in ‘Started’ state. kadalu storage config takes one of the node IP/hostname, and gluster volume name to use it as the storage for PVs. The PVs would be provided as subdirectories - this is similar to how a PV is created in kadalu native way.
The best example for this is, what we use in our CI. Checkout this sample yaml file
# file: external-config.yaml --- apiVersion: kadalu-operator.storage/v1alpha1 kind: KadaluStorage metadata: name: ext-config spec: type: External details: - gluster_host: gluster1.kadalu.io gluster_volname: kadalu gluster_options: log-level=DEBUG # file: pvc-from-external-gluster.yaml --- kind: PersistentVolumeClaim apiVersion: v1 metadata: name: pv-ext-kadalu spec: # Add 'kadalu.external.' to name from KadaluStorage kind storageClassName: kadalu.external.ext-config accessModes: - ReadWriteMany resources: requests: # This needs to be set using 'kadalu-quotad' storage: 500Mi
Please edit ‘gluster_host’ and ‘gluster_volname’ parameters in config section.
You can also setup the external storage through our
kubectl kadalu CLI.
$ kubectl kadalu storage-add store-name --external gluster.kadalu.io:/kadalu
After this, just use
kadalu.external.store-name (note that ‘store-name’ is
name used for
storage-add) in PVC yaml, like below:
... spec: storageClassName: kadalu.external.store-name ...
Note that, if you have an existing gluster setup inside the k8s cluster, you can treat that also as ‘External’ and use kadalu to manage it. In this case, you will need to provide the pre-created gluster volume name for the config.
In this mode, 1 Gluster Volume would be 1 PV. Something very similar to how heketi project allocates PVs. We don’t encourage using this mode, nor recommend it in a new setup. This mode is provided just as an option for those who are consuming gluster volumes in this mode. This helps to use the PVs used in other deployments to be still consumed.
In this mode, you don’t need storage config, but all you need is to have a sample like below
# file: external-gluster-as-pv.yaml --- kind: StorageClass apiVersion: storage.k8s.io/v1 metadata: name: kadalu.external.pv-ext # Keep changing the name for different volumes provisioner: kadalu parameters: hostvol_type: "External" gluster_host: gluster1.kadalu.io # Change to your gluster host gluster_volname: test # Change to existing gluster volume gluster_options: log-level=DEBUG # Comma separated options --- kind: PersistentVolumeClaim apiVersion: v1 metadata: name: pv-ext spec: storageClassName: kadalu.external.pv-ext accessModes: - ReadWriteMany resources: requests: storage: 200Mi # This gets ignored in this case.
Please edit ‘gluster_host’ and ‘gluster_volname’ parameters in Storage Class.
kubectl apply -f ./external-gluster-as-pv.yaml
Note that in this mode, there would be as many ‘StorageClass’ as number of PVs, but that is not avoidable at present because we can’t pass user driven input from PV claim yaml.