cluster: RHEL6 - qdiskd: restrict master_wins to 2 node cluster

Gitweb: http://git.fedorahosted.org/git/?p=cluster.git;a=commitdiff;h=4b893d2a9f4... Commit: 4b893d2a9f46d643859fa50856ac63e0cdbd4a02 Parent: 982f2aa377fd1c0471b714945c401fdfe86e9bc1 Author: Fabio M. Di Nitto <fdinitto(a)redhat.com&gt; AuthorDate: Mon Jul 9 08:33:37 2012 +0200 Committer: Fabio M. Di Nitto <fdinitto(a)redhat.com&gt; CommitterDate: Fri Jul 27 08:47:10 2012 +0200 qdiskd: restrict master_wins to 2 node cluster given enough mingling of cluster.conf it was possible to break quorum rule #1: there is only one quorum in a cluster at any given time. this change restricts master_wins to 2 node cluster only and provides extra feedback to the user (via logging) on why the mode is disabled. Resolves: rhbz#838047 Signed-off-by: Fabio M. Di Nitto <fdinitto(a)redhat.com&gt; Reviewed-by: Lon Hohberger <lhh(a)redhat.com&gt; --- cman/man/qdisk.5 | 5 +++-- cman/qdisk/disk.h | 1 + cman/qdisk/main.c | 22 +++++++++++++++------- 3 files changed, 19 insertions(+), 9 deletions(-) diff --git a/cman/man/qdisk.5 b/cman/man/qdisk.5 index ca974fa..938ed69 100644 --- a/cman/man/qdisk.5 +++ b/cman/man/qdisk.5 @@ -297,8 +297,9 @@ and qdiskd's timeout (interval*tko) should be less than half of Totem's token timeout. See section 3.3.1 for more information. This option only takes effect if there are no heuristics -configured. Usage of this option in configurations with more than -two cluster nodes is undefined and should not be done. +configured and it is valid only for 2 node cluster. +This option is automatically disabled if heuristics are +defined or cluster has more than 2 nodes configured. In a two-node cluster with no heuristics and no defined vote count (see above), this mode is turned by default. If enabled in diff --git a/cman/qdisk/disk.h b/cman/qdisk/disk.h index 6bed41d..1d8f7c8 100644 --- a/cman/qdisk/disk.h +++ b/cman/qdisk/disk.h @@ -252,6 +252,7 @@ typedef struct { int qc_master; /* Master?! */ int qc_config; int qc_token_timeout; + int qc_auto_votes; disk_node_state_t qc_disk_status; disk_node_state_t qc_status; run_flag_t qc_flags; diff --git a/cman/qdisk/main.c b/cman/qdisk/main.c index 594e9e8..47ef5d2 100644 --- a/cman/qdisk/main.c +++ b/cman/qdisk/main.c @@ -1495,7 +1495,7 @@ auto_qdisk_votes(int desc) logt_print(LOG_ERR, "Unable to determine qdiskd votes " "automatically\n"); else - logt_print(LOG_DEBUG, "Setting votes to %d\n", ret); + logt_print(LOG_DEBUG, "Setting autocalculated votes to %d\n", ret); return (ret); } @@ -1657,6 +1657,8 @@ get_dynamic_config_data(qd_ctx *ctx, int ccsfd) ctx->qc_flags &= ~RF_AUTO_VOTES; } + ctx->qc_auto_votes = auto_qdisk_votes(ccsfd); + snprintf(query, sizeof(query), "/cluster/quorumd/@votes"); if (ccs_get(ccsfd, query, &val) == 0) { ctx->qc_votes = atoi(val); @@ -1664,7 +1666,7 @@ get_dynamic_config_data(qd_ctx *ctx, int ccsfd) if (ctx->qc_votes < 0) ctx->qc_votes = 0; } else { - ctx->qc_votes = auto_qdisk_votes(ccsfd); + ctx->qc_votes = ctx->qc_auto_votes; if (ctx->qc_votes < 0) { if (ctx->qc_config) { logt_print(LOG_WARNING, "Unable to determine " @@ -1930,15 +1932,21 @@ get_config_data(qd_ctx *ctx, struct h_data *h, int maxh, int *cfh) *cfh = configure_heuristics(ccsfd, h, maxh, ctx->qc_interval * (ctx->qc_tko - 1)); - if (*cfh) { - if (ctx->qc_flags & RF_MASTER_WINS) { - logt_print(LOG_WARNING, "Master-wins mode disabled\n"); + if (ctx->qc_flags & RF_MASTER_WINS) { + if (*cfh) { + logt_print(LOG_WARNING, "Master-wins mode disabled " + "(not compatible with heuristics)\n"); + ctx->qc_flags &= ~RF_MASTER_WINS; + } + if (ctx->qc_auto_votes != 1) { + logt_print(LOG_WARNING, "Master-wins mode disabled " + "(not compatible with more than 2 nodes)\n"); ctx->qc_flags &= ~RF_MASTER_WINS; } } else { if (ctx->qc_flags & RF_AUTO_VOTES && - !(ctx->qc_flags & RF_MASTER_WINS) && - ctx->qc_votes == 1) { + !*cfh && + ctx->qc_auto_votes == 1) { /* Two node cluster, no heuristics, 1 vote for * quorum disk daemon. Safe to enable master-wins. * In fact, qdiskd without master-wins in this config