# Storage Guide

This is a overview of how Cinder is implemented in Kolla so that it is easier to understand how to use it. Keep in mind, this is the first iteration for Cinder as support for Ceph and physical devices will follow.

## Overview

Kolla's setup for Cinder uses tgtd as the default iSCSI helper to implement persistent targets.  By default, we use a loop back file that is defined by CINDER_LVM_LO_VOLUME_SIZE to create the cinder-volumes volume group.

## Configure Cinder

Listed below are the default configurations for Cinder.  For more info on what each variable does look at the [integration guide.](https://github.com/stackforge/kolla/blob/master/docs/integration-guide.md):

    # Cinder Volume
    CINDER_ENABLED_BACKEND=lvm57
    CINDER_LVM_LO_VOLUME_SIZE=4G
    CINDER_VOLUME_API_LISTEN=$HOST_IP
    CINDER_VOLUME_BACKEND_NAME=LVM_iSCSI57
    CINDER_VOLUME_DRIVER=cinder.volume.drivers.lvm.LVMISCSIDriver
    CINDER_VOLUME_GROUP=cinder-volumes
    ISCSI_HELPER=tgtadm
    ISCSI_IP_ADDRESS=$HOST_IP

## Using Cinder

After you've started all you containers, you should be able to interact with Cinder.

    cinder list

Next, you will want to create a volume and attach it to a running instance.

    cinder create 1
    nova volume-attach <instance_id> <volume_id>

## Debugging and deleting volumes

The cinder-volumes volume group can't be seen from the host.  In order to interact with an existing volume, you need to jump into the Cinder Volume container.

    sudo docker exec -it <cinder_volume_container> /bin/bash
    sudo vgs

Running 'vgs' will list the volumes groups.  From there, you can look at specific volumes to make sure volume creation succeeded.

To delete the cinder-volumes volume group from within the container run:

    sudo vgs remove cinder-volumes

Add a doc for Cinder
Add a doc for Cinder

Cinder is unique in that interaction with the volumes
must occur in the container as opposed to from the host.
This doc will lay out a guide for Cinder and useful
debugging tips.

Change-Id: I5cdff42ba3a40c1a20a11570649ac42a1c3aa837
