# HG changeset patch
# User David Scott <dave.scott@xxxxxxxxxxxxx>
# Date 1268739025 0
# Node ID 012936d9d680683cd83cdcd2cd772985de142c50
# Parent d455f3c74966447903add709174b57c8c50cc511
CA-38944: prevent the artificial-reboot-delay being accidentally applied to an
API-driven reboot.
When the request queueing was fixed, a deliberate race was created between the
background event thread and the API VM.reboot (etc). One of these threads wins
the race and then the second thread becomes a no-op. Unfortunately the
background event thread will apply the artificial-reboot-delay unless it is
somehow prevented. We prevent it by storing the next reboot delay in xenstore
(rather than the database) and setting it to 0 in the API call path.
Signed-off-by: David Scott <dave.scott@xxxxxxxxxxxxx>
diff -r d455f3c74966 -r 012936d9d680 ocaml/xapi/events.ml
--- a/ocaml/xapi/events.ml Fri Mar 12 15:19:41 2010 +0000
+++ b/ocaml/xapi/events.ml Tue Mar 16 11:30:25 2010 +0000
@@ -103,34 +103,16 @@
with _ -> 0. (* ages ago *) in
Unix.gettimeofday () -. start_time
+ let artificial_reboot_key domid = Hotplug.get_private_path domid ^ "/" ^
Xapi_globs.artificial_reboot_delay
+
(* When a VM is rebooted too quickly (from within) we insert a delay; on
each _contiguous_
quick reboot, this delay doubles *)
- let insert_reboot_delay ~__context ~vm =
+ let calculate_reboot_delay ~__context ~vm domid =
let delay_cap = 60 in (* 1 minute cap on reboot delays *)
- let other_config = Db.VM.get_other_config ~__context ~self:vm in
- let delay =
- try
- let delay = int_of_string (List.assoc
Xapi_globs.last_artificial_reboot_delay_key other_config) in
- let next_delay = min (delay*2) delay_cap in (* next delay doubles,
capped at delay_cap *)
- Db.VM.remove_from_other_config ~__context ~self:vm
~key:Xapi_globs.last_artificial_reboot_delay_key;
- Db.VM.add_to_other_config ~__context ~self:vm
~key:Xapi_globs.last_artificial_reboot_delay_key ~value:(string_of_int
next_delay);
- delay
- with _ -> (* no delay on first quick reboot, 2s next time *)
- (* in line below, we try to remove key from other-config anyway, just
in-case this exn was generated because there _was_
- a last reboot delay key in there, but it had invalid data contained
it, causing the int_of_string to fail *)
- (try Db.VM.remove_from_other_config ~__context ~self:vm
~key:Xapi_globs.last_artificial_reboot_delay_key with _ -> ());
- Db.VM.add_to_other_config ~__context ~self:vm
~key:Xapi_globs.last_artificial_reboot_delay_key ~value:(string_of_int 2);
- 0 in
- if Xapi_fist.disable_reboot_delay ()
- then debug "FIST: disable_reboot_delay"
- else begin
- debug "Adding artificial delay on reboot for VM: %s. delay time=%d
seconds" (Ref.string_of vm) delay;
- Thread.delay (float_of_int delay)
- end
+ let delay = try int_of_string (with_xs (fun xs -> xs.Xs.read
(artificial_reboot_key domid))) with _ -> 0 in
+ let next_delay = min (delay * 2 + 2) delay_cap in
+ delay, next_delay
- let clear_reboot_delay ~__context ~vm =
- try Db.VM.remove_from_other_config ~__context ~self:vm
~key:Xapi_globs.last_artificial_reboot_delay_key with _ -> ()
-
let perform_destroy ~__context ~vm token =
TaskHelper.set_description ~__context "destroy";
Xapi_vm.Shutdown.in_dom0_already_locked { Xapi_vm.TwoPhase.__context =
__context; vm=vm; api_call_name="destroy"; clean=false };
@@ -142,13 +124,24 @@
let perform_restart ~__context ~vm token =
TaskHelper.set_description ~__context "restart";
- if time_vm_ran_for ~__context ~vm <
Xapi_globs.minimum_time_between_reboot_with_no_added_delay
- then insert_reboot_delay ~__context ~vm
- else clear_reboot_delay ~__context ~vm;
-
+ let domid = Helpers.domid_of_vm ~__context ~self:vm in
+ let delay, next_delay =
+ if Xapi_fist.disable_reboot_delay () then begin
+ debug "FIST: disable_reboot_delay";
+ 0, 0
+ end else if time_vm_ran_for ~__context ~vm <
Xapi_globs.minimum_time_between_reboot_with_no_added_delay then begin
+ calculate_reboot_delay ~__context ~vm domid
+ end else 0, 0 in
+ if delay <> 0 then begin
+ debug "Adding artificial delay on reboot for VM: %s. delay time=%d
seconds" (Ref.string_of vm) delay;
+ Thread.delay (float_of_int delay);
+ end;
try
- Xapi_vm.Reboot.in_dom0_already_locked { Xapi_vm.TwoPhase.__context =
__context; vm=vm; api_call_name="reboot"; clean=false };
- update_allowed_ops_using_api ~__context vm
+ Xapi_vm.Reboot.in_dom0_already_locked {
Xapi_vm.TwoPhase.__context = __context; vm=vm; api_call_name="reboot";
clean=false };
+ let domid' = Helpers.domid_of_vm ~__context ~self:vm in
+ assert (domid <> domid');
+ (with_xs (fun xs -> xs.Xs.write (artificial_reboot_key domid')
(string_of_int next_delay)));
+ update_allowed_ops_using_api ~__context vm
with e ->
(* NB this can happen if the user has change the VM configuration to onw
which
cannot boot (eg not enough memory) and then rebooted inside the guest
*)
diff -r d455f3c74966 -r 012936d9d680 ocaml/xapi/xapi_globs.ml
--- a/ocaml/xapi/xapi_globs.ml Fri Mar 12 15:19:41 2010 +0000
+++ b/ocaml/xapi/xapi_globs.ml Tue Mar 16 11:30:25 2010 +0000
@@ -375,8 +375,8 @@
(* Default backlog supplied to Unix.listen *)
let listen_backlog = 128
-(* Key on VM.other_config that records last artificial reboot delay *)
-let last_artificial_reboot_delay_key = "last_artificial_reboot_delay"
+(* Where the next artificial delay is stored in xenstore *)
+let artificial_reboot_delay = "artificial-reboot-delay"
(* Xapi script hooks root *)
let xapi_hooks_root = "/etc/xapi.d/"
diff -r d455f3c74966 -r 012936d9d680 ocaml/xapi/xapi_vm.ml
--- a/ocaml/xapi/xapi_vm.ml Fri Mar 12 15:19:41 2010 +0000
+++ b/ocaml/xapi/xapi_vm.ml Tue Mar 16 11:30:25 2010 +0000
@@ -366,6 +366,8 @@
error "VM: %s halted when asked to reboot"
(Ref.string_of vm)
end else begin
debug "%s phase 0/3: no shutdown request required since this is
a hard_reboot" api_call_name;
+ (* Make sure no-one inserts an artificial delay at this point *)
+ (with_xs (fun xs -> xs.Xs.write (Hotplug.get_private_path domid
^ "/" ^ Xapi_globs.artificial_reboot_delay) "0"));
(* The domain might be killed by the event thread. Again, this
is ok. *)
Helpers.log_exn_continue (Printf.sprintf "Xc.domain_shutdown
domid=%d Xc.Reboot" domid)
(fun () ->
3 files changed, 27 insertions(+), 32 deletions(-)
ocaml/xapi/events.ml | 53 +++++++++++++++++++---------------------------
ocaml/xapi/xapi_globs.ml | 4 +--
ocaml/xapi/xapi_vm.ml | 2 +
xen-api.hg.patch
Description: Text Data
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