pcmk_sched_probes.c

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/*
 * Copyright 2004-2022 the Pacemaker project contributors
 *
 * The version control history for this file may have further details.
 *
 * This source code is licensed under the GNU General Public License version 2
 * or later (GPLv2+) WITHOUT ANY WARRANTY.
 */

#include <crm_internal.h>

#include <glib.h>

#include <crm/crm.h>
#include <crm/pengine/status.h>
#include <pacemaker-internal.h>
#include "libpacemaker_private.h"

static void
add_expected_result(pe_action_t *probe, pe_resource_t *rsc, pe_node_t *node)
{
    // Check whether resource is currently active on node
    pe_node_t *running = pe_find_node_id(rsc->running_on, node->details->id);

    // The expected result is what we think the resource's current state is
    if (running == NULL) {
        pe__add_action_expected_result(probe, CRM_EX_NOT_RUNNING);

    } else if (rsc->role == RSC_ROLE_PROMOTED) {
        pe__add_action_expected_result(probe, CRM_EX_PROMOTED);
    }
}

bool
pcmk__probe_resource_list(GList *rscs, pe_node_t *node)
{
    bool any_created = false;

    for (GList *iter = rscs; iter != NULL; iter = iter->next) {
        pe_resource_t *rsc = (pe_resource_t *) iter->data;

        if (rsc->cmds->create_probe(rsc, node)) {
            any_created = true;
        }
    }
    return any_created;
}

static void
probe_then_start(pe_resource_t *rsc1, pe_resource_t *rsc2)
{
    if ((rsc1->allocated_to != NULL)
        && (g_hash_table_lookup(rsc1->known_on,
                                rsc1->allocated_to->details->id) == NULL)) {

        pcmk__new_ordering(rsc1, pcmk__op_key(rsc1->id, RSC_STATUS, 0), NULL,
                           rsc2, pcmk__op_key(rsc2->id, RSC_START, 0), NULL,
                           pe_order_optional, rsc1->cluster);
    }
}

static bool
guest_resource_will_stop(pe_node_t *node)
{
    pe_resource_t *guest_rsc = node->details->remote_rsc->container;

    /* Ideally, we'd check whether the guest has a required stop, but that
     * information doesn't exist yet, so approximate it ...
     */
    return node->details->remote_requires_reset
           || node->details->unclean
           || pcmk_is_set(guest_rsc->flags, pe_rsc_failed)
           || (guest_rsc->next_role == RSC_ROLE_STOPPED)

           // Guest is moving
           || ((guest_rsc->role > RSC_ROLE_STOPPED)
               && (guest_rsc->allocated_to != NULL)
               && (pe_find_node(guest_rsc->running_on,
                   guest_rsc->allocated_to->details->uname) == NULL));
}

static pe_action_t *
probe_action(pe_resource_t *rsc, pe_node_t *node)
{
    pe_action_t *probe = NULL;
    char *key = pcmk__op_key(rsc->id, RSC_STATUS, 0);

    crm_debug("Scheduling probe of %s %s on %s",
              role2text(rsc->role), rsc->id, pe__node_name(node));

    probe = custom_action(rsc, key, RSC_STATUS, node, FALSE, TRUE,
                          rsc->cluster);
    pe__clear_action_flags(probe, pe_action_optional);

    pcmk__order_vs_unfence(rsc, node, probe, pe_order_optional);
    add_expected_result(probe, rsc, node);
    return probe;
}

bool
pcmk__probe_rsc_on_node(pe_resource_t *rsc, pe_node_t *node)
{
    uint32_t flags = pe_order_optional;
    pe_action_t *probe = NULL;
    pe_node_t *allowed = NULL;
    pe_resource_t *top = uber_parent(rsc);
    const char *reason = NULL;

    CRM_CHECK((rsc != NULL) && (node != NULL), return false);

    if (!pcmk_is_set(rsc->cluster->flags, pe_flag_startup_probes)) {
        reason = "start-up probes are disabled";
        goto no_probe;
    }

    if (pe__is_guest_or_remote_node(node)) {
        const char *class = crm_element_value(rsc->xml, XML_AGENT_ATTR_CLASS);

        if (pcmk__str_eq(class, PCMK_RESOURCE_CLASS_STONITH, pcmk__str_none)) {
            reason = "Pacemaker Remote nodes cannot run stonith agents";
            goto no_probe;

        } else if (pe__is_guest_node(node)
                   && pe__resource_contains_guest_node(rsc->cluster, rsc)) {
            reason = "guest nodes cannot run resources containing guest nodes";
            goto no_probe;

        } else if (rsc->is_remote_node) {
            reason = "Pacemaker Remote nodes cannot host remote connections";
            goto no_probe;
        }
    }

    // If this is a collective resource, probes are created for its children
    if (rsc->children != NULL) {
        return pcmk__probe_resource_list(rsc->children, node);
    }

    if ((rsc->container != NULL) && !rsc->is_remote_node) {
        reason = "resource is inside a container";
        goto no_probe;

    } else if (pcmk_is_set(rsc->flags, pe_rsc_orphan)) {
        reason = "resource is orphaned";
        goto no_probe;

    } else if (g_hash_table_lookup(rsc->known_on, node->details->id) != NULL) {
        reason = "resource state is already known";
        goto no_probe;
    }

    allowed = g_hash_table_lookup(rsc->allowed_nodes, node->details->id);

    if (rsc->exclusive_discover || top->exclusive_discover) {
        // Exclusive discovery is enabled ...

        if (allowed == NULL) {
            // ... but this node is not allowed to run the resource
            reason = "resource has exclusive discovery but is not allowed "
                     "on node";
            goto no_probe;

        } else if (allowed->rsc_discover_mode != pe_discover_exclusive) {
            // ... but no constraint marks this node for discovery of resource
            reason = "resource has exclusive discovery but is not enabled "
                     "on node";
            goto no_probe;
        }
    }

    if (allowed == NULL) {
        allowed = node;
    }
    if (allowed->rsc_discover_mode == pe_discover_never) {
        reason = "node has discovery disabled";
        goto no_probe;
    }

    if (pe__is_guest_node(node)) {
        pe_resource_t *guest = node->details->remote_rsc->container;

        if (guest->role == RSC_ROLE_STOPPED) {
            // The guest is stopped, so we know no resource is active there
            reason = "node's guest is stopped";
            probe_then_start(guest, top);
            goto no_probe;

        } else if (guest_resource_will_stop(node)) {
            reason = "node's guest will stop";

            // Order resource start after guest stop (in case it's restarting)
            pcmk__new_ordering(guest, pcmk__op_key(guest->id, RSC_STOP, 0),
                               NULL, top, pcmk__op_key(top->id, RSC_START, 0),
                               NULL, pe_order_optional, rsc->cluster);
            goto no_probe;
        }
    }

    // We've eliminated all cases where a probe is not needed, so now it is
    probe = probe_action(rsc, node);

    /* Order the probe relative to the parent -- or the resource itself if
     * cloned or a fence device when unfencing is used.
     */
    if ((pcmk_is_set(rsc->flags, pe_rsc_fence_device)
         && pcmk_is_set(rsc->cluster->flags, pe_flag_enable_unfencing))
        || !pe_rsc_is_clone(top)) {
        top = rsc;
    }

    if (!pcmk_is_set(probe->flags, pe_action_runnable)
        && (rsc->running_on == NULL)) {
        /* Prevent the parent from starting if the resource can't, but don't
         * cause the parent to stop if already active.
         */
        pe__set_order_flags(flags, pe_order_runnable_left);
    }

    // Start or reload the parent after probing the resource
    pcmk__new_ordering(rsc, NULL, probe,
                       top, pcmk__op_key(top->id, RSC_START, 0), NULL,
                       flags, rsc->cluster);
    pcmk__new_ordering(rsc, NULL, probe, top, reload_key(rsc), NULL,
                       pe_order_optional, rsc->cluster);

    return true;

no_probe:
    pe_rsc_trace(rsc,
                 "Skipping probe for %s on %s because %s",
                 rsc->id, node->details->id, reason);
    return false;
}

static bool
probe_needed_before_action(pe_action_t *probe, pe_action_t *then)
{
    // Probes on a node are performed after unfencing it, not before
    if (pcmk__str_eq(then->task, CRM_OP_FENCE, pcmk__str_casei)
         && (probe->node != NULL) && (then->node != NULL)
         && (probe->node->details == then->node->details)) {
        const char *op = g_hash_table_lookup(then->meta, "stonith_action");

        if (pcmk__str_eq(op, "on", pcmk__str_casei)) {
            return false;
        }
    }

    // Probes should be done on a node before shutting it down
    if (pcmk__str_eq(then->task, CRM_OP_SHUTDOWN, pcmk__str_none)
        && (probe->node != NULL) && (then->node != NULL)
        && (probe->node->details != then->node->details)) {
        return false;
    }

    // Otherwise probes should always be done before any other action
    return true;
}

static void
add_probe_orderings_for_stops(pe_working_set_t *data_set)
{
    for (GList *iter = data_set->ordering_constraints; iter != NULL;
         iter = iter->next) {

        pe__ordering_t *order = iter->data;
        uint32_t order_flags = pe_order_optional;
        GList *probes = NULL;
        GList *then_actions = NULL;

        // Skip disabled orderings
        if (order->flags == pe_order_none) {
            continue;
        }

        // Skip non-resource orderings, and orderings for the same resource
        if ((order->lh_rsc == NULL) || (order->lh_rsc == order->rh_rsc)) {
            continue;
        }

        // Skip invalid orderings (shouldn't be possible)
        if (((order->lh_action == NULL) && (order->lh_action_task == NULL)) ||
            ((order->rh_action == NULL) && (order->rh_action_task == NULL))) {
            continue;
        }

        // Skip orderings for first actions other than stop
        if ((order->lh_action != NULL)
            && !pcmk__str_eq(order->lh_action->task, RSC_STOP, pcmk__str_none)) {
            continue;
        } else if ((order->lh_action == NULL)
                   && !pcmk__ends_with(order->lh_action_task, "_" RSC_STOP "_0")) {
            continue;
        }

        /* Do not imply a probe ordering for a resource inside of a stopping
         * container. Otherwise, it might introduce a transition loop, since a
         * probe could be scheduled after the container starts again.
         */
        if ((order->rh_rsc != NULL)
            && (order->lh_rsc->container == order->rh_rsc)) {

            if ((order->rh_action != NULL)
                && pcmk__str_eq(order->rh_action->task, RSC_STOP,
                                pcmk__str_none)) {
                continue;
            } else if ((order->rh_action == NULL)
                       && pcmk__ends_with(order->rh_action_task,
                                          "_" RSC_STOP "_0")) {
                continue;
            }
        }

        // Preserve certain order options for future filtering
        if (pcmk_is_set(order->flags, pe_order_apply_first_non_migratable)) {
            pe__set_order_flags(order_flags,
                                pe_order_apply_first_non_migratable);
        }
        if (pcmk_is_set(order->flags, pe_order_same_node)) {
            pe__set_order_flags(order_flags, pe_order_same_node);
        }

        // Preserve certain order types for future filtering
        if ((order->flags == pe_order_anti_colocation)
            || (order->flags == pe_order_load)) {
            order_flags = order->flags;
        }

        // List all scheduled probes for the first resource
        probes = pe__resource_actions(order->lh_rsc, NULL, RSC_STATUS, FALSE);
        if (probes == NULL) { // There aren't any
            continue;
        }

        // List all relevant "then" actions
        if (order->rh_action != NULL) {
            then_actions = g_list_prepend(NULL, order->rh_action);

        } else if (order->rh_rsc != NULL) {
            then_actions = find_actions(order->rh_rsc->actions,
                                        order->rh_action_task, NULL);
            if (then_actions == NULL) { // There aren't any
                g_list_free(probes);
                continue;
            }
        }

        crm_trace("Implying 'probe then' orderings for '%s then %s' "
                  "(id=%d, type=%.6x)",
                  order->lh_action? order->lh_action->uuid : order->lh_action_task,
                  order->rh_action? order->rh_action->uuid : order->rh_action_task,
                  order->id, order->flags);

        for (GList *probe_iter = probes; probe_iter != NULL;
             probe_iter = probe_iter->next) {

            pe_action_t *probe = (pe_action_t *) probe_iter->data;

            for (GList *then_iter = then_actions; then_iter != NULL;
                 then_iter = then_iter->next) {

                pe_action_t *then = (pe_action_t *) then_iter->data;

                if (probe_needed_before_action(probe, then)) {
                    order_actions(probe, then, order_flags);
                }
            }
        }

        g_list_free(then_actions);
        g_list_free(probes);
    }
}

static void
add_restart_orderings_for_probe(pe_action_t *probe, pe_action_t *after,
                                pe_working_set_t *data_set)
{
    GList *iter = NULL;
    bool interleave = false;
    pe_resource_t *compatible_rsc = NULL;

    // Validate that this is a resource probe followed by some action
    if ((after == NULL) || (probe == NULL) || (probe->rsc == NULL)
        || (probe->rsc->variant != pe_native)
        || !pcmk__str_eq(probe->task, RSC_STATUS, pcmk__str_casei)) {
        return;
    }

    // Avoid running into any possible loop
    if (pcmk_is_set(after->flags, pe_action_tracking)) {
        return;
    }
    pe__set_action_flags(after, pe_action_tracking);

    crm_trace("Adding probe restart orderings for '%s@%s then %s@%s'",
              probe->uuid, pe__node_name(probe->node),
              after->uuid, pe__node_name(after->node));

    /* Add restart orderings if "then" is for a different primitive.
     * Orderings for collective resources will be added later.
     */
    if ((after->rsc != NULL) && (after->rsc->variant == pe_native)
        && (probe->rsc != after->rsc)) {

            GList *then_actions = NULL;

            if (pcmk__str_eq(after->task, RSC_START, pcmk__str_casei)) {
                then_actions = pe__resource_actions(after->rsc, NULL, RSC_STOP,
                                                    FALSE);

            } else if (pcmk__str_eq(after->task, RSC_PROMOTE, pcmk__str_casei)) {
                then_actions = pe__resource_actions(after->rsc, NULL,
                                                    RSC_DEMOTE, FALSE);
            }

            for (iter = then_actions; iter != NULL; iter = iter->next) {
                pe_action_t *then = (pe_action_t *) iter->data;

                // Skip pseudo-actions (for example, those implied by fencing)
                if (!pcmk_is_set(then->flags, pe_action_pseudo)) {
                    order_actions(probe, then, pe_order_optional);
                }
            }
            g_list_free(then_actions);
    }

    /* Detect whether "then" is an interleaved clone action. For these, we want
     * to add orderings only for the relevant instance.
     */
    if ((after->rsc != NULL)
        && (after->rsc->variant > pe_group)) {
        const char *interleave_s = g_hash_table_lookup(after->rsc->meta,
                                                       XML_RSC_ATTR_INTERLEAVE);

        interleave = crm_is_true(interleave_s);
        if (interleave) {
            compatible_rsc = find_compatible_child(probe->rsc,
                                                   after->rsc,
                                                   RSC_ROLE_UNKNOWN,
                                                   FALSE);
        }
    }

    /* Now recursively do the same for all actions ordered after "then". This
     * also handles collective resources since the collective action will be
     * ordered before its individual instances' actions.
     */
    for (iter = after->actions_after; iter != NULL; iter = iter->next) {
        pe_action_wrapper_t *after_wrapper = (pe_action_wrapper_t *) iter->data;

        /* pe_order_implies_then is the reason why a required A.start
         * implies/enforces B.start to be required too, which is the cause of
         * B.restart/re-promote.
         *
         * Not sure about pe_order_implies_then_on_node though. It's now only
         * used for unfencing case, which tends to introduce transition
         * loops...
         */
        if (!pcmk_is_set(after_wrapper->type, pe_order_implies_then)) {
            /* The order type between a group/clone and its child such as
             * B.start-> B_child.start is:
             * pe_order_implies_first_printed | pe_order_runnable_left
             *
             * Proceed through the ordering chain and build dependencies with
             * its children.
             */
            if ((after->rsc == NULL)
                || (after->rsc->variant < pe_group)
                || (probe->rsc->parent == after->rsc)
                || (after_wrapper->action->rsc == NULL)
                || (after_wrapper->action->rsc->variant > pe_group)
                || (after->rsc != after_wrapper->action->rsc->parent)) {
                continue;
            }

            /* Proceed to the children of a group or a non-interleaved clone.
             * For an interleaved clone, proceed only to the relevant child.
             */
            if ((after->rsc->variant > pe_group) && interleave
                && ((compatible_rsc == NULL)
                    || (compatible_rsc != after_wrapper->action->rsc))) {
                continue;
            }
        }

        crm_trace("Recursively adding probe restart orderings for "
                  "'%s@%s then %s@%s' (type=%#.6x)",
                  after->uuid, pe__node_name(after->node),
                  after_wrapper->action->uuid,
                  pe__node_name(after_wrapper->action->node),
                  after_wrapper->type);

        add_restart_orderings_for_probe(probe, after_wrapper->action, data_set);
    }
}

static void
clear_actions_tracking_flag(pe_working_set_t *data_set)
{
    GList *gIter = NULL;

    for (gIter = data_set->actions; gIter != NULL; gIter = gIter->next) {
        pe_action_t *action = (pe_action_t *) gIter->data;

        pe__clear_action_flags(action, pe_action_tracking);
    }
}

static void
add_restart_orderings_for_rsc(pe_resource_t *rsc, pe_working_set_t *data_set)
{
    GList *probes = NULL;

    // For collective resources, order each instance recursively
    if (rsc->variant != pe_native) {
        g_list_foreach(rsc->children, (GFunc) add_restart_orderings_for_rsc,
                       data_set);
        return;
    }

    // Find all probes for given resource
    probes = pe__resource_actions(rsc, NULL, RSC_STATUS, FALSE);

    // Add probe restart orderings for each probe found
    for (GList *iter = probes; iter != NULL; iter = iter->next) {
        pe_action_t *probe = (pe_action_t *) iter->data;

        for (GList *then_iter = probe->actions_after; then_iter != NULL;
             then_iter = then_iter->next) {

            pe_action_wrapper_t *then = (pe_action_wrapper_t *) then_iter->data;

            add_restart_orderings_for_probe(probe, then->action, data_set);
            clear_actions_tracking_flag(data_set);
        }
    }

    g_list_free(probes);
}

static void
order_then_probes(pe_working_set_t *data_set)
{
#if 0
    /* Given an ordering "A then B", we would prefer to wait for A to be started
     * before probing B.
     *
     * For example, if A is a filesystem which B can't even run without, it
     * would be helpful if the author of B's agent could assume that A is
     * running before B.monitor will be called.
     *
     * However, we can't _only_ probe after A is running, otherwise we wouldn't
     * detect the state of B if A could not be started. We can't even do an
     * opportunistic version of this, because B may be moving:
     *
     *   A.stop -> A.start -> B.probe -> B.stop -> B.start
     *
     * and if we add B.stop -> A.stop here, we get a loop:
     *
     *   A.stop -> A.start -> B.probe -> B.stop -> A.stop
     *
     * We could kill the "B.probe -> B.stop" dependency, but that could mean
     * stopping B "too" soon, because B.start must wait for the probe, and
     * we don't want to stop B if we can't start it.
     *
     * We could add the ordering only if A is an anonymous clone with
     * clone-max == node-max (since we'll never be moving it). However, we could
     * still be stopping one instance at the same time as starting another.
     *
     * The complexity of checking for allowed conditions combined with the ever
     * narrowing use case suggests that this code should remain disabled until
     * someone gets smarter.
     */
    for (GList *iter = data_set->resources; iter != NULL; iter = iter->next) {
        pe_resource_t *rsc = (pe_resource_t *) iter->data;

        pe_action_t *start = NULL;
        GList *actions = NULL;
        GList *probes = NULL;

        actions = pe__resource_actions(rsc, NULL, RSC_START, FALSE);

        if (actions) {
            start = actions->data;
            g_list_free(actions);
        }

        if (start == NULL) {
            crm_err("No start action for %s", rsc->id);
            continue;
        }

        probes = pe__resource_actions(rsc, NULL, RSC_STATUS, FALSE);

        for (actions = start->actions_before; actions != NULL;
             actions = actions->next) {

            pe_action_wrapper_t *before = (pe_action_wrapper_t *) actions->data;

            pe_action_t *first = before->action;
            pe_resource_t *first_rsc = first->rsc;

            if (first->required_runnable_before) {
                for (GList *clone_actions = first->actions_before;
                     clone_actions != NULL;
                     clone_actions = clone_actions->next) {

                    before = (pe_action_wrapper_t *) clone_actions->data;

                    crm_trace("Testing '%s then %s' for %s",
                              first->uuid, before->action->uuid, start->uuid);

                    CRM_ASSERT(before->action->rsc != NULL);
                    first_rsc = before->action->rsc;
                    break;
                }

            } else if (!pcmk__str_eq(first->task, RSC_START, pcmk__str_none)) {
                crm_trace("Not a start op %s for %s", first->uuid, start->uuid);
            }

            if (first_rsc == NULL) {
                continue;

            } else if (uber_parent(first_rsc) == uber_parent(start->rsc)) {
                crm_trace("Same parent %s for %s", first_rsc->id, start->uuid);
                continue;

            } else if (!pe_rsc_is_clone(uber_parent(first_rsc))) {
                crm_trace("Not a clone %s for %s", first_rsc->id, start->uuid);
                continue;
            }

            crm_err("Applying %s before %s %d", first->uuid, start->uuid,
                    uber_parent(first_rsc)->variant);

            for (GList *probe_iter = probes; probe_iter != NULL;
                 probe_iter = probe_iter->next) {

                pe_action_t *probe = (pe_action_t *) probe_iter->data;

                crm_err("Ordering %s before %s", first->uuid, probe->uuid);
                order_actions(first, probe, pe_order_optional);
            }
        }
    }
#endif
}

void
pcmk__order_probes(pe_working_set_t *data_set)
{
    // Add orderings for "probe then X"
    g_list_foreach(data_set->resources, (GFunc) add_restart_orderings_for_rsc,
                   data_set);
    add_probe_orderings_for_stops(data_set);

    order_then_probes(data_set);
}

void
pcmk__schedule_probes(pe_working_set_t *data_set)
{
    // Schedule probes on each node in the cluster as needed
    for (GList *iter = data_set->nodes; iter != NULL; iter = iter->next) {
        pe_node_t *node = (pe_node_t *) iter->data;
        const char *probed = NULL;

        if (!node->details->online) { // Don't probe offline nodes
            if (pcmk__is_failed_remote_node(node)) {
                pe_fence_node(data_set, node,
                              "the connection is unrecoverable", FALSE);
            }
            continue;

        } else if (node->details->unclean) { // ... or nodes that need fencing
            continue;

        } else if (!node->details->rsc_discovery_enabled) {
            // The user requested that probes not be done on this node
            continue;
        }

        /* This is no longer needed for live clusters, since the probe_complete
         * node attribute will never be in the CIB. However this is still useful
         * for processing old saved CIBs (< 1.1.14), including the
         * reprobe-target_rc regression test.
         */
        probed = pe_node_attribute_raw(node, CRM_OP_PROBED);
        if (probed != NULL && crm_is_true(probed) == FALSE) {
            pe_action_t *probe_op = NULL;

            probe_op = custom_action(NULL,
                                     crm_strdup_printf("%s-%s", CRM_OP_REPROBE,
                                                       node->details->uname),
                                     CRM_OP_REPROBE, node, FALSE, TRUE,
                                     data_set);
            add_hash_param(probe_op->meta, XML_ATTR_TE_NOWAIT,
                           XML_BOOLEAN_TRUE);
            continue;
        }

        // Probe each resource in the cluster on this node, as needed
        pcmk__probe_resource_list(data_set->resources, node);
    }
}