On Tue, Nov 18, 2014 at 4:45 PM, Aaron Karper <[email protected]> wrote: > On Tue, Nov 18, 2014 at 11:57:43AM +0100, Michele Tartara wrote: >> On Mon, Nov 17, 2014 at 11:29 AM, 'Aaron Karper' via ganeti-devel >> <[email protected]> wrote: >> > For many users the change from uniform disk templates would make their >> > lifes more difficult. Therefore we want to be externally compatible as >> > far as possible. >> > >> > Signed-off-by: Aaron Karper <[email protected]> >> > --- >> > doc/design-disks.rst | 26 ++++++++++++++++++++++++++ >> > 1 file changed, 26 insertions(+) >> > >> > diff --git a/doc/design-disks.rst b/doc/design-disks.rst >> > index 18fb75c..b5d0fab 100644 >> > --- a/doc/design-disks.rst >> > +++ b/doc/design-disks.rst >> > @@ -169,6 +169,32 @@ with the instance's disk objects. So in the backend >> > we will only have to >> > replace the ``disks`` slot with ``disks_info``. >> > >> > >> > +Supporting the old interface >> > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> > + >> > +The current interface is designed with a uniform disk type in mind and >> > +this interface should still be supported to not break tools and >> > +workflows downstream. >> > + >> > +The behaviour is fully compatible for instances with constantly >> > +attached, uniform disks. >> > + >> > +Whenever an operation operates on an instance, the operation will only >> > +consider the disks attached. If the operation is specific to a disk >> > +type, it will only consider disks with that type and ignore the rest >> > +(but throw an error as before if no disk of that type is attached). >> >> I'm not entirely sure about this. If the operation is specific to a >> disk type, should it operate only on disks of that type, or should it >> operate on the instance only if all the disks attached to that >> instance are of the given type, and error out otherwise? >> Which approch would be less surprising to the user? >> > > You're probably right, the user would be more confused if the instance > is for example "half-backed-up" or something similar. > > commit c1f3ebd5cb5ecde5e737c5fad3231b0c0b16cc5e > Author: Aaron Karper <[email protected]> > Date: Tue Nov 18 16:44:01 2014 +0100 > > Harsher errors > > diff --git a/doc/design-disks.rst b/doc/design-disks.rst > index b5d0fab..e55fa1f 100644 > --- a/doc/design-disks.rst > +++ b/doc/design-disks.rst > @@ -181,8 +181,8 @@ attached, uniform disks. > > Whenever an operation operates on an instance, the operation will only > consider the disks attached. If the operation is specific to a disk > -type, it will only consider disks with that type and ignore the rest > -(but throw an error as before if no disk of that type is attached). > +type, it will throw an error if any disks of a type not supported are > +attached. > > When setting the disk template of an instance, we convert all currently > attached disks to that template. This means that all disk types > >> > + >> > +When setting the disk template of an instance, we convert all currently >> > +attached disks to that template. This means that all disk types >> > +currently attached must be convertible to the new template. >> > + >> > +Since the disk template as a configuration value is going away, it needs >> > +to be replaced for queries. If the instance has no disks, the >> > +disk_template will be 'diskless', if it has disks of a single type, its >> > +disk_template will be that type, and if it has disks of multiple types, >> > +the new disk template 'mixed' will be returned. >> > + >> > + >> > Eliminating the disk template from the instance >> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> > >> > -- >> > 2.1.0.rc2.206.gedb03e5 >> > >> >> Thanks, >> Michele >> >> -- >> Google Germany GmbH >> Dienerstr. 12 >> 80331 München >> >> Registergericht und -nummer: Hamburg, HRB 86891 >> Sitz der Gesellschaft: Hamburg >> Geschäftsführer: Graham Law, Christine Elizabeth Flores > > -- > Google Germany GmbH > Dienerstr. 12 > 80331 München > > Registergericht und -nummer: Hamburg, HRB 86891 > Sitz der Gesellschaft: Hamburg > Geschäftsführer: Graham Law, Christine Elizabeth Flores
LGTM, thanks. Michele -- Google Germany GmbH Dienerstr. 12 80331 München Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg Geschäftsführer: Graham Law, Christine Elizabeth Flores
