There's a branch pending that lets you do the remainder of the most common crush map changes via teh cli. The command set breaks down like so: Updating leaves (devices): ceph osd crush set <osd-id> <weight> <loc1> [<loc2> ...] ceph osd crush add <osd-id> <weight> <loc1> [<loc2> ...] ceph osd crush create-or-move <osd-id> <initial-weight> <loc1> [<loc2> ...] These let you create, add, and move devices in teh map. The different between add and set is that add will create an additional instance of the osd (leaf), while set will move the old instance. This is useful for some configurations. The loc ... bits let you specify the 'where' part in teh form of key/value pairs, like 'host=foo rack=bar root=default'. It will find the most-specific pair that matches an existing item, and create any intervening ancestors. For example, if my map has only a root=default node (nothing else) and I do ceph osd crush set osd.0 1 host=foo rack=myrack row=first root=default it will create teh row, rack, and host nodes, and then stick osd.0 inside host=foo. Create-or-move is similar to set except that it won't ever change teh weight of the device; only set the initial weight if it has to create it. This is used by the upstart hook so that it doesn't inadvertantly clobber changes the admin has made. The next set of commands adjust the map structure. Although people usually create a tree structure, in reality the crush map is a DAG (directed acyclic graph). ceph osd crush rm <name> [ancestor] Will remove an osd or internal node from the, assuming there are no children. With the optional ancestor arg, it will remove only instances under the given ancestor. Otherwise, all instances are removed. If it is a bucket and non-empty, it does nothing. ceph osd crush unlink <bucketname> [ancestor] Is similar, but will let you remove a (or all) link(s) to a bucket even if it is non-empty. ceph osd crush move <bucketname> <loc1> [<loc2> ...] will unlink the bucket from its existing location(s) and link it in a new position. ceph osd crush link <bucketname> <loc1> [<loc2> ...] Doesn't touch existing links, only adds a new one. Finally, ceph osd crush add-bucket <bucketname> <type> is the one command that will create an internal node with no parent. Normally this is just used to create the root of the tree (e.g., root=default). Once it is there, then devices can be added beneath with it set, add, link, etc. and loc... bit will add any intervening ancestors that are missing. This maps cleanly on to the internal data model that CRUSH is using. As long as it doesn't bend everyone's mind in uncomfortable ways, I'd like to stick with it (or something like it)... but if there is something here that seems wrong, let me know! sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
