Reviewed-by: Steven Dake <sdake@xxxxxxxxxx>
On 01/10/2012 02:23 AM, Fabio M. Di Nitto wrote:
> From: "Fabio M. Di Nitto" <fdinitto@xxxxxxxxxx>
>
> this flag (0|1) can be configured via quorum.last_man_standing and when
> enabled, it allows expected_votes to be dynamically recalculated.
>
> Assuming an 8 nodes cluster, every node votes 1 (mandatory requirement for
> this feature).
>
> In the first event, 3 nodes are lost.
>
> The remaining partition of 5 is barely quorate.
>
> After a configurable timeout (quorum.last_man_standing_window, default 10sec)
> the quorate partition is allow to recalculate expected_votes based on
> the remaining nodes.
>
> This operation will bring expected_votes to 5 and quorum to 3.
>
> Repeating the above loop, in the next event, 2 more nodes are allowed to
> die. etc. etc.
>
> Signed-off-by: Fabio M. Di Nitto <fdinitto@xxxxxxxxxx>
> ---
> :100644 100644 0099cd7... 7a2078b... M exec/coroparse.c
> :100644 100644 9d46269... e56654a... M services/votequorum.c
> exec/coroparse.c | 2 ++
> services/votequorum.c | 39 +++++++++++++++++++++++++++++++++++++++
> 2 files changed, 41 insertions(+), 0 deletions(-)
>
> diff --git a/exec/coroparse.c b/exec/coroparse.c
> index 0099cd7..7a2078b 100644
> --- a/exec/coroparse.c
> +++ b/exec/coroparse.c
> @@ -360,6 +360,7 @@ static int main_config_parser_cb(const char *path,
> if ((strcmp(path, "quorum.expected_votes") == 0) ||
> (strcmp(path, "quorum.votes") == 0) ||
> (strcmp(path, "quorum.quorumdev_poll") == 0) ||
> + (strcmp(path, "quorum.last_man_standing_window") == 0) ||
> (strcmp(path, "quorum.leaving_timeout") == 0)) {
> i = atoi(value);
> icmap_set_uint32(path, i);
> @@ -369,6 +370,7 @@ static int main_config_parser_cb(const char *path,
> if ((strcmp(path, "quorum.two_node") == 0) ||
> (strcmp(path, "quorum.wait_for_all") == 0) ||
> (strcmp(path, "quorum.auto_tie_breaker") == 0) ||
> + (strcmp(path, "quorum.last_man_standing") == 0) ||
> (strcmp(path, "quorum.quorate") == 0)) {
> i = atoi(value);
> icmap_set_uint8(path, i);
> diff --git a/services/votequorum.c b/services/votequorum.c
> index 9d46269..e56654a 100644
> --- a/services/votequorum.c
> +++ b/services/votequorum.c
> @@ -79,6 +79,7 @@
> #define DEFAULT_EXPECTED 1024
> #define DEFAULT_QDEV_POLL 10000
> #define DEFAULT_LEAVE_TMO 10000
> +#define DEFAULT_LMS_WIN 10000
>
> LOGSYS_DECLARE_SUBSYS ("VOTEQ");
>
> @@ -121,9 +122,14 @@ static int cluster_is_quorate;
> static int first_trans = 1;
> static unsigned int quorumdev_poll = DEFAULT_QDEV_POLL;
> static unsigned int leaving_timeout = DEFAULT_LEAVE_TMO;
> +
> static uint8_t wait_for_all = 0;
> static uint8_t auto_tie_breaker = 0;
> static int lowest_node_id = -1;
> +static uint8_t last_man_standing = 0;
> +static uint32_t last_man_standing_window = DEFAULT_LMS_WIN;
> +static int last_man_standing_timer_set = 0;
> +static corosync_timer_handle_t last_man_standing_timer;
>
> static struct cluster_node *us;
> static struct cluster_node *quorum_device = NULL;
> @@ -375,6 +381,8 @@ static void votequorum_init(struct corosync_api_v1 *api,
>
> icmap_get_uint8("quorum.wait_for_all", &wait_for_all);
> icmap_get_uint8("quorum.auto_tie_breaker", &auto_tie_breaker);
> + icmap_get_uint8("quorum.last_man_standing", &last_man_standing);
> + icmap_get_uint32("quorum.last_man_standing_window", &last_man_standing_window);
>
> /*
> * TODO: we need to know the lowest node-id in the cluster
> @@ -875,6 +883,16 @@ static int quorum_exec_send_reconfigure(int param, int nodeid, int value)
> return ret;
> }
>
> +static void lms_timer_fn(void *arg)
> +{
> + ENTER();
> + last_man_standing_timer_set = 0;
> + if (cluster_is_quorate) {
> + recalculate_quorum(1,1);
> + }
> + LEAVE();
> +}
> +
> static void quorum_confchg_fn (
> enum totem_configuration_type configuration_type,
> const unsigned int *member_list, size_t member_list_entries,
> @@ -902,6 +920,17 @@ static void quorum_confchg_fn (
> }
> }
>
> + if (last_man_standing) {
> + if ((member_list_entries >= quorum) && (left_list_entries)) {
> + if (last_man_standing_timer_set) {
> + corosync_api->timer_delete(last_man_standing_timer);
> + last_man_standing_timer_set = 0;
> + }
> + corosync_api->timer_add_duration((unsigned long long)last_man_standing_window*1000000, NULL, lms_timer_fn, &last_man_standing_timer);
> + last_man_standing_timer_set = 1;
> + }
> + }
> +
> if (member_list_entries) {
> memcpy(quorum_members, member_list, sizeof(unsigned int) * member_list_entries);
> quorum_members_entries = member_list_entries;
> @@ -975,6 +1004,16 @@ static void message_handler_req_exec_votequorum_nodeinfo (
>
> log_printf(LOGSYS_LEVEL_DEBUG, "nodeinfo message: votes: %d, expected: %d wfa: %d\n", req_exec_quorum_nodeinfo->votes, req_exec_quorum_nodeinfo->expected_votes, req_exec_quorum_nodeinfo->wait_for_all);
>
> + if ((last_man_standing) && (req_exec_quorum_nodeinfo->votes > 1)) {
> + log_printf(LOGSYS_LEVEL_WARNING, "Last Man Standing feature is supported only when all"
> + "cluster nodes votes are set to 1. Disabling LMS.");
> + last_man_standing = 0;
> + if (last_man_standing_timer_set) {
> + corosync_api->timer_delete(last_man_standing_timer);
> + last_man_standing_timer_set = 0;
> + }
> + }
> +
> node->flags &= ~NODE_FLAGS_BEENDOWN;
>
> if (new_node || req_exec_quorum_nodeinfo->first_trans ||
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