rbd: New parameter auth-client-required
Parameter auth-client-required lets you configure authentication
methods. We tried to provide that in v2.9.0, but backed out due to
interface design doubts (commit
464444fcc16).
This commit is similar to what we backed out, but simpler: we use a
list of enumeration values instead of a list of objects with a member
of enumeration type.
Let's review our reasons for backing out the first try, as stated in
the commit message:
* The implementation uses deprecated rados_conf_set() key
"auth_supported". No biggie.
Fixed: we use "auth-client-required".
* The implementation makes -drive silently ignore invalid parameters
"auth" and "auth-supported.*.X" where X isn't "auth". Fixable (in
fact I'm going to fix similar bugs around parameter server), so
again no biggie.
That fix is commit
2836284db60. This commit doesn't bring the bugs
back.
* BlockdevOptionsRbd member @password-secret applies only to
authentication method cephx. Should it be a variant member of
RbdAuthMethod?
We've had time to ponder, and we decided to stick to the way Ceph
configuration works: the key configured separately, and silently
ignored if the authentication method doesn't use it.
* BlockdevOptionsRbd member @user could apply to both methods cephx
and none, but I'm not sure it's actually used with none. If it
isn't, should it be a variant member of RbdAuthMethod?
Likewise.
* The client offers a *set* of authentication methods, not a list.
Should the methods be optional members of BlockdevOptionsRbd instead
of members of list @auth-supported? The latter begs the question
what multiple entries for the same method mean. Trivial question
now that RbdAuthMethod contains nothing but @type, but less so when
RbdAuthMethod acquires other members, such the ones discussed above.
Again, we decided to stick to the way Ceph configuration works, except
we make auth-client-required a list of enumeration values instead of a
string containing keywords separated by delimiters.
* How BlockdevOptionsRbd member @auth-supported interacts with
settings from a configuration file specified with @conf is
undocumented. I suspect it's untested, too.
Not actually true, the documentation for @conf says "Values in the
configuration file will be overridden by options specified via QAPI",
and we've tested this.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>