On Mon, Mar 11, 2013 at 6:17 AM, Helga Velroyen <[email protected]> wrote: > This patch updates the design doc "Design correct reporting of storage > free space". The modifications were chosen to not conflict with any > future changes of Ganeti regarding storage pools. > > Signed-off-by: Helga Velroyen <[email protected]> > --- > doc/design-storagespace.rst | 118 > +++++++++++++++++++++++++++++++------------- > 1 file changed, 83 insertions(+), 35 deletions(-) > > diff --git a/doc/design-storagespace.rst b/doc/design-storagespace.rst > index 919479f..67603e8 100644 > --- a/doc/design-storagespace.rst > +++ b/doc/design-storagespace.rst > @@ -20,21 +20,19 @@ interaction with different storage types. > Configuration changes > --------------------- > > -Each storage type will have a new "pools" parameter added (type list of > -strings). This will be list of vgs for plain and drbd (note that we make > -no distinction at this level between allowed vgs and metavgs), the list > -of rados pools for rados, or the storage directory for file and > -sharedfile. The parameters already present in the cluster config object > -will be moved to the storage parameters. > - > -Since currently file and sharedfile only support a single directory this > -list will be limited to one. In the future if we'll have support for > -more directories, or for per-nodegroup directories this can be changed. > - > -Note that these are just "mechanisms" parameters that define which > -storage pools the cluster can use. Further filtering about what's > -allowed can go in the ipolicy, but these changes are not covered in this > -design doc. > +Add a new attribute "enabled_storage_methods" (type: list of strings) to the > +cluster config which holds the types of storages, for example, "plain", > "drbd", > +or "ext". We consider the first one of the list as the default method. > + > +For file storage, we'll report the storage space on the file storage dir, > +which is currently limited to one directory. In the future, if we'll have > +support for more directories, or for per-nodegroup directories this can be > +changed. > + > +Note that the abovementioned enabled_storage_methods are just "mechanisms" > +parameters that define which storage methods the cluster can use. Further > +filtering about what's allowed can go in the ipolicy, but these changes are > +not covered in this design doc. > > Since the ipolicy currently has a list of enabled storage types, we'll > use that to decide which storage type is the default, and to self-select > @@ -47,17 +45,23 @@ RPC changes > ----------- > > The noded RPC call that reports node storage space will be changed to > -accept a list of <method>,<key> string tuples. For each of them it will > -report the free amount of space found on storage <key> as known by the > -requested method. Methods are for example ``lvm``, ``filesystem``, > -``rados``, and the key would be a volume group name in the case of lvm, > -a directory name for the filesystem and a rados pool name, for > -rados_pool. > +accept a list of <method>,<key> string tuples. For each of them, it will > +report the free amount of storage space found on storage <key> as known > +by the requested storage type method. For example methods are ``lvm``, > +``filesystem``, or ``rados``, and the key would be a volume group name, in > +the case of lvm, a directory name for the filesystem and a rados pool name > +for rados storage. > + > +For now, we will implement only the storage reporting for non-shared storage, > +that is ``filesystem`` and ``lvm``. For shared storage methods like ``rados`` > +and ``ext`` we will not implement a free space calculation, because it does > +not make sense to query each node for the free space of a commonly used > +storage. > > Masterd will know (through a constant map) which storage type uses which > method for storage calculation (i.e. ``plain`` and ``drbd`` use ``lvm``, > -``file`` and ``sharedfile`` use ``filesystem``, etc) and query the one > -needed (or all of the needed ones). > +``file`` uses ``filesystem``, etc) and query the one needed (or all of the > +needed ones). > > Note that for file and sharedfile the node knows which directories are > allowed and won't allow any other directory to be queried for security > @@ -73,18 +77,40 @@ Ganeti reporting > > ``gnt-node list`` will by default report information just about the > default storage type. It will be possible to add fields to ask about > -other ones, if they're enabled. > - > -``gnt-node info`` will report information about all enabled storage > -types, without querying them (just say which ones are supported > -according to the cluster configuration). > - > -``gnt-node list-storage`` will change to report information about all > -available storage pools in each storage type. An extra flag will be > -added to filter by storage pool name (alternatively we can implement > -this by allowing to query by a list of ``type:pool`` string tuples to > -have a more comprehensive filter). > - > +other ones, if they're enabled. Examples: > + > +> gnt-node list > +Node DTotal DFree MTotal MNode MFree Pinst Sinst > +mynode1 3.6T 3.6T 64.0G 1023M 62.2G 1 0 > +mynode2 3.6T 3.6T 64.0G 1023M 62.0G 2 1 > +mynode3 3.6T 3.6T 64.0G 1023M 62.3G 0 2 > + > +> gnt-node list -o dtotal/lvm/myvg,dfree/rados/myrados > +Node DTotal (Lvm, myvg) DFree (Rados, myrados) > +mynode1 3.6T - > +mynode2 3.6T - > +
Could you add a note on how one is supposed to find about the "myrados" and "myvg" parts, and perhaps we can also have just dtotal/lvm that gives the "first/default" lvm. Also with storage pools, won't we go directly dtotal/pool_name without specifying "lvm" or "rados" in between? So perhaps we should "just" as an interim allow two levels, or allow three levels in between but go towards having two, in the future. Thanks, Guido
