)]}'
{"specs/liberty/approved/enhance-instance-operations-during-live-migration.rst":[{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":24,"context_line":"a lot of instance actions for the duration, and a block live migration of a"},{"line_number":25,"context_line":"busy instance can take a long time. In fact, for example the migration might be"},{"line_number":26,"context_line":"significantly faster if the instance became paused but there\u0027s no way to do"},{"line_number":27,"context_line":"that."},{"line_number":28,"context_line":""},{"line_number":29,"context_line":"Use Cases"},{"line_number":30,"context_line":"----------"}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_46309b9e","line":27,"updated":"2015-05-01 10:07:22.000000000","message":"There\u0027s a patch to enable pausing, as its a key required feature to ensure migration can complete\n\n https://review.openstack.org/#/c/163836/","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":46,"context_line":"There are many operations which could be allowed during a live migration. It"},{"line_number":47,"context_line":"may not be practical to implement all of these, but in rough priority order:"},{"line_number":48,"context_line":""},{"line_number":49,"context_line":"* pause / unpause"},{"line_number":50,"context_line":"* reboot"},{"line_number":51,"context_line":"* stop / start"},{"line_number":52,"context_line":"* volume-attach / volume-detach"}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_062aa32c","line":49,"updated":"2015-05-01 10:07:22.000000000","message":"Pause is a critical feature.\n\nUnpause is not permitted, because during the switchover phase from source to dest, the VM needs to be paused - if libvirt were to allow unpause, there would be a potential race condition between QEMU pausing for switchover and libvirt unpausing. This could result in the VM running concurrently on both source + dest with predictably bad results.","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":47,"context_line":"may not be practical to implement all of these, but in rough priority order:"},{"line_number":48,"context_line":""},{"line_number":49,"context_line":"* pause / unpause"},{"line_number":50,"context_line":"* reboot"},{"line_number":51,"context_line":"* stop / start"},{"line_number":52,"context_line":"* volume-attach / volume-detach"},{"line_number":53,"context_line":"* console-log"}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_c61cab15","line":50,"updated":"2015-05-01 10:07:22.000000000","message":"Depends what you mean by reboot here. If you are talking about a guest internal soft reboot, that\u0027s trivially permissible. If you are talking about a fake reboot by shutdown + start sequence, that will cause migration to be aborted.","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":48,"context_line":""},{"line_number":49,"context_line":"* pause / unpause"},{"line_number":50,"context_line":"* reboot"},{"line_number":51,"context_line":"* stop / start"},{"line_number":52,"context_line":"* volume-attach / volume-detach"},{"line_number":53,"context_line":"* console-log"},{"line_number":54,"context_line":"* lock / unlock"}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_26debf3f","line":51,"updated":"2015-05-01 10:07:22.000000000","message":"Stop is permissible but would obviously cause migration to be aborted. NB, you also have a potential race to worry about. ie you see the VM is still on source and go to stop it on the source, but by the time you try todo this it has moved to the dest.","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":49,"context_line":"* pause / unpause"},{"line_number":50,"context_line":"* reboot"},{"line_number":51,"context_line":"* stop / start"},{"line_number":52,"context_line":"* volume-attach / volume-detach"},{"line_number":53,"context_line":"* console-log"},{"line_number":54,"context_line":"* lock / unlock"},{"line_number":55,"context_line":"* get-vnc-console"}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_06e183fe","line":52,"updated":"2015-05-01 10:07:22.000000000","message":"Any changes to virtual hardware are entirely forbidden during migration.","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":50,"context_line":"* reboot"},{"line_number":51,"context_line":"* stop / start"},{"line_number":52,"context_line":"* volume-attach / volume-detach"},{"line_number":53,"context_line":"* console-log"},{"line_number":54,"context_line":"* lock / unlock"},{"line_number":55,"context_line":"* get-vnc-console"},{"line_number":56,"context_line":"* rebuild"}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_e6e8c7e4","line":53,"updated":"2015-05-01 10:07:22.000000000","message":"This is purely a nova side feature, with no interaction with KVM itself, so is permissible regardless of guest operation state.","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":51,"context_line":"* stop / start"},{"line_number":52,"context_line":"* volume-attach / volume-detach"},{"line_number":53,"context_line":"* console-log"},{"line_number":54,"context_line":"* lock / unlock"},{"line_number":55,"context_line":"* get-vnc-console"},{"line_number":56,"context_line":"* rebuild"},{"line_number":57,"context_line":"* rescue / unrescue"}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_c6e38b04","line":54,"updated":"2015-05-01 10:07:22.000000000","message":"Again, a nova feature, so permissible.","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":52,"context_line":"* volume-attach / volume-detach"},{"line_number":53,"context_line":"* console-log"},{"line_number":54,"context_line":"* lock / unlock"},{"line_number":55,"context_line":"* get-vnc-console"},{"line_number":56,"context_line":"* rebuild"},{"line_number":57,"context_line":"* rescue / unrescue"},{"line_number":58,"context_line":"* rename"}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_a6f2cfd0","line":55,"updated":"2015-05-01 10:07:22.000000000","message":"As above.","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":54,"context_line":"* lock / unlock"},{"line_number":55,"context_line":"* get-vnc-console"},{"line_number":56,"context_line":"* rebuild"},{"line_number":57,"context_line":"* rescue / unrescue"},{"line_number":58,"context_line":"* rename"},{"line_number":59,"context_line":"* shelve / unshelve"},{"line_number":60,"context_line":""}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_46be5bd5","line":57,"updated":"2015-05-01 10:07:22.000000000","message":"These would both entail the migration being aborted, so IIUC they involve stopping the current KVM process.","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":55,"context_line":"* get-vnc-console"},{"line_number":56,"context_line":"* rebuild"},{"line_number":57,"context_line":"* rescue / unrescue"},{"line_number":58,"context_line":"* rename"},{"line_number":59,"context_line":"* shelve / unshelve"},{"line_number":60,"context_line":""},{"line_number":61,"context_line":"The implementation would apply the operation immediately if possible, otherwise"}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_06b863e4","line":58,"updated":"2015-05-01 10:07:22.000000000","message":"Presumably this is entirely a nova feature which doesn\u0027t interact with the guest, so permissible any time.","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"9867f9604b4800a949d7c84d0027c96c716b4eb1","unresolved":false,"context_lines":[{"line_number":56,"context_line":"* rebuild"},{"line_number":57,"context_line":"* rescue / unrescue"},{"line_number":58,"context_line":"* rename"},{"line_number":59,"context_line":"* shelve / unshelve"},{"line_number":60,"context_line":""},{"line_number":61,"context_line":"The implementation would apply the operation immediately if possible, otherwise"},{"line_number":62,"context_line":"apply the operation to the instance after migration (ie on the target if the"}],"source_content_type":"text/x-rst","patch_set":1,"id":"3acd31a7_e6cfa77d","line":59,"updated":"2015-05-01 10:07:22.000000000","message":"These would both entail migration being aborted.","commit_id":"084f38672b3243c5c57df10c671853df8afdd8c9"}]}