zfs-localpv/pkg/config/config.go
Pawan Prakash Sharma 1b30116e5f
feat(migration): adding support to migrate the PV to a new node (#304)
Usecase: A node in the Kubernetes cluster is replaced with a new node. The 
new node gets a different `kubernetes.io/hostname`. The storage devices
that were attached to the old node are re-attached to the new node. 

Fix: Instead of using the default `kubenetes.io/hostname` as the node affinity 
label, this commit changes to use `openebs.io/nodeid`. The ZFS LocalPV driver 
will pick the value from the nodes and set the affinity.

Once the old node is removed from the cluster, the K8s scheduler will continue 
to schedule applications on the old node only.

User can now modify the value of `openebs.io/nodeid` on the new node to the same
value that was available on the old node. This will make sure the pods/volumes are 
scheduled to the node now. 


Note: Now to migrate the PV to the other node, we have to move the disks to the other node
and remove the old node from the cluster and set the same label on the new node using
the same key, which will let k8s scheduler to schedule the pods to that node.

Other updates: 
* adding faq doc
* renaming the config variable to nodename

Signed-off-by: Pawan <pawan@mayadata.io>
Co-authored-by: Akhil Mohan <akhilerm@gmail.com>

* Update docs/faq.md

Co-authored-by: Akhil Mohan <akhilerm@gmail.com>
2021-05-01 19:05:01 +05:30

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Go

/*
Copyright © 2019 The OpenEBS Authors
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package config
// Config struct fills the parameters of request or user input
type Config struct {
// DriverName to be registered at CSI
DriverName string
// PluginType flags if the driver is
// it is a node plugin or controller
// plugin
PluginType string
// Version of the CSI controller/node driver
Version string
// Endpoint on which requests are made by kubelet
// or external provisioner
//
// NOTE:
// - Controller/node plugin will listen on this
// - This will be a unix based socket
Endpoint string
// Nodename helps in differentiating the nodes on
// which node drivers are running. This is used
// to set the topologies for the driver
Nodename string
}
// Default returns a new instance of config
// required to initialize a driver instance
func Default() *Config {
return &Config{}
}