Remove Rebalance status file before start

[aravindavk]

Before starting the rebalance process(Fix layout or Migrate data), remove the status file because Rebalance process will not start if complete: true.

Reproduce:

kadalu volume create dev/vol1 kadalu-dev:/exports/vol1/s1
mkdir -p /mnt/vol1
kadalu mount dev/vol1 /mnt/vol1
mkdir -p /mnt/vol1/d1/d2/d3
kadalu volume expand dev/vol1 kadalu-dev:/exports/vol1/s2
ls /exports/vol1/s2
# Run expand again
kadalu volume expand dev/vol1 kadalu-dev:/exports/vol1/s3
ls /exports/vol1/s3 # <- No Rebalance is run because previous status file is not removed.

[vatsa287]

Cool will send fix to delete the status file for particular volume only if status complete: true.

[vatsa287]

Guess this should work,

def status_file_check(rollback_volume)
  workdir = "/var/lib/kadalu"
  status_file = reb.status_file("fix-layout")
  fix_layout_status_file_path = Path[workdir].join("rebalance-fix-layout-#{rollback_volume.not_nil!.distribute_groups[0].storage_units[0].path.gsub("/", "%2F")}.json")
  if File.exists?(fix_layout_status_file_path)
    data = MoanaTypes::FixLayoutRebalanceStatus.from_json(File.read(fix_layout_status_file_path))
    FileUtils.rm(fix_layout_status_file_path) if data.complete
  end
end

But as of now manage_services node action is made to run on all unique nodes, But adding this to that node action will add additional complexity of checking for status file in every node.

[aravindavk]

Before start of {fix-layout|migrate-data} rebalance, remove the status file. No need to check for the complete state.

https://github.com/kadalu/moana/blob/main/mgr/src/server/plugins/volume_utils.cr#L139

[aravindavk]

Change this id to match the status file path. https://github.com/kadalu/moana/blob/main/mgr/src/server/services/fix_layout.cr#L13

So that you can delete the status file as

      elsif svc.name == "fixlayoutservice" || svc.name == "migratedataservice"
        status_file = "/var/lib/kadalu/#{svc.id}.json"
        FileUtils.rm(status_file) if File.exists?(status_file)
        svc.start