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If a node can be reached on two LNet networks, it is sometimes desirable to designate a fail-over network. Currently in lustre there is the concept of High Availability (HA) which allows servicenode nids to be defined as described in the lustre manual section 11.2. By using the syntax described in that section, two nids to the same peer can also be defined. However, this approach suffers from the current limitation in the lustre software, where the NIDs are exposed to layers above LNet. It is ideal to keep network failures handling contained within LNet and only let lustre worry about defining HA.
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The DLC library will provide the outlined APIs to expose a way to create, delete and show rules.
Once rules are created and stored in the kernel, they are assigned an ID. This ID is returned and shown in the show command, which dumps the rules. This ID can be referenced later to delete a rule. The process is described in more details below.
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/* * lustre_lnet_add_net_sel_pol * Add a net selection policy. If there already exists a * policy for this net it will be updated. * net - Network for the selection policy * priority - priority of the rule */ int lustre_lnet_add_net_sel_pol(char *net, int priority); /* * lustre_lnet_del_net_sel_pol * Delete a net selection policy. * net - Network for the selection policy * id - [OPTIONAL] ID of the policy. This can be retrieved via a show command. */ int lustre_lnet_del_net_sel_pol(char *net, int id); /* * lustre_lnet_show_net_sel_pol * Show configured net selection policies. * net - filter on the net provided. */ int lustre_lnet_show_net_sel_pol(char *net); /* * lustre_lnet_add_nid_sel_pol * Add a nid selection policy. If there already exists a * policy for this nid it will be updated. NIDs can be either * local NIDs or remote NIDs. * nid - NID for the selection policy * priority - priority of the rule */ int lustre_lnet_add_nid_sel_pol(char *nid, int priority); /* * lustre_lnet_del_nid_sel_pol * Delete a nid selection policy. * nid - NID for the selection policy * id - [OPTIONAL] ID of the policy. This can be retrieved via a show command. */ int lustre_lnet_del_nid_sel_pol(char *nid, int id); /* * lustre_lnet_show_nid_sel_pol * Show configured nid selection policies. * nid - filter on the NID provided. */ int lustre_lnet_show_nid_sel_pol(char *nid); /* * lustre_lnet_add_nid_sel_pol * Add a peer to peer selection policy. If there already exists a * policy for the pair it will be updated. * src_nid - source NID * dst_nid - destination NID * priority - priority of the rule */ int lustre_lnet_add_peer_sel_pol(char *src_nid, char *dst_nid, int priority); /* * lustre_lnet_del_peer_sel_pol * Delete a peer to peer selection policy. * src_nid - source NID * dst_nid - destination NID * id - [OPTIONAL] ID of the policy. This can be retrieved via a show command. */ int lustre_lnet_del_peer_sel_pol(char *src_nid, char *dst_nid, int id); /* * lustre_lnet_show_peer_sel_pol * Show peer to peer selection policies. * src_nid - [OPTIONAL] source NID. If provided the output will be filtered * on this value. * dst_nid - [OPTIONAL] destination NID. If provided the output will be filtered * on this value. */ int lustre_lnet_show_peer_sel_pol(char *src_nid, char *dst_nid); |
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