[Kimchi-devel] [PATCHv5 2/2] Integrate nfs path check before create nfs pool

[Aline Manera]

On 01/15/2014 07:14 AM, lvroyce at linux.vnet.ibm.com wrote:
> From: Royce Lv <lvroyce at linux.vnet.ibm.com>
>
> Before creating nfs pool, reload the prevalidation for the path
> and see if it is able to complish a quick mount.
> If not, deny this storage pool from being created.
>
> Signed-off-by: Royce Lv <lvroyce at linux.vnet.ibm.com>
> ---
>   src/kimchi/model.py | 29 +++++++++++++++++++++++++++--
>   1 file changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/src/kimchi/model.py b/src/kimchi/model.py
> index 671af02..f49dc68 100644
> --- a/src/kimchi/model.py
> +++ b/src/kimchi/model.py
> @@ -68,9 +68,11 @@ from kimchi.featuretests import FeatureTests
>   from kimchi.iscsi import TargetClient
>   from kimchi.isoinfo import IsoImage
>   from kimchi.objectstore import ObjectStore
> +from kimchi.rollbackcontext import RollbackContext
>   from kimchi.scan import Scanner
>   from kimchi.screenshot import VMScreenshot
>   from kimchi.utils import get_enabled_plugins, is_digit, kimchi_log
> +from kimchi.utils import run_command, parse_cmd_output
>   from kimchi.vmtemplate import VMTemplate
>
>
> @@ -1557,8 +1559,31 @@ class NetfsPoolDef(StoragePoolDef):
>           self.path = '/var/lib/kimchi/nfs_mount/' + self.poolArgs['name']
>
>       def prepare(self, conn):
> -        # TODO: Verify the NFS export can be actually mounted.
> -        pass
> +        export_path = "%s:%s" % (
> +            self.poolArgs['source']['host'], self.poolArgs['source']['path'])
> +        mount_cmd = ["mount", "-o", 'soft,timeo=100,retrans=3,retry=0',
> +               export_path, self.path]
> +        umount_cmd = ["umount", "-f", export_path]
> +        mounted = False
> +

> +        if not os.path.isdir(self.path):
> +            os.mkdir(self.path)

os.mkdir only creates one directory which can be a problem if 
'/var/lib/kimchi/nfs_mount/' doesn't exist

I'd suggest to use a temp dir to mount it (instead of the real path)
And then libvirt will be responsible to create the path when creating 
the storage pool.

> +
> +        with RollbackContext() as rollback:
> +            run_command(mount_cmd, 30)
> +            rollback.prependDefer(run_command, umount_cmd)
> +
> +            with open("/proc/mounts" , "rb") as f:
> +                rawMounts = f.read()
> +            output_items = ['dev_path', 'mnt_point', 'type']
> +            mounts = parse_cmd_output(rawMounts, output_items)
> +            for item in mounts:
> +                if 'dev_path' in item and item['dev_path'] == export_path:
> +                    mounted =  True
> +
> +            if not mounted:
> +                raise InvalidParameter(
> +                    "Export path %s may block during nfs mount" % export_path)
>
>       @property
>       def xml(self):