/* search the node lists list for a node to takeover this ip.
pick the node that currently are serving the least number of ips
so that the ips get spread out evenly.
*/
int find_takeover_node(struct ipalloc_state *ipalloc_state,
struct public_ip_list *ip)
{
int pnn, min=0, num;
int i, numnodes;
numnodes = ipalloc_state->num;
pnn = -1;
for (i=0; i<numnodes; i++) {
/* verify that this node can serve this ip */
if (!can_node_takeover_ip(ipalloc_state, i, ip)) {
/* no it couldnt so skip to the next node */
continue;
}
num = node_ip_coverage(i, ipalloc_state->all_ips);
/* was this the first node we checked ? */
if (pnn == -1) {
pnn = i;
min = num;
} else {
if (num < min) {
pnn = i;
min = num;
}
}
}
if (pnn == -1) {
DEBUG(DEBUG_WARNING,(__location__ " Could not find node to take over public address '%s'\n",
ctdb_sock_addr_to_string(ipalloc_state,
&ip->addr)));
return -1;
}
ip->pnn = pnn;
return 0;
}
/* LCP2 algorithm for rebalancing the cluster. Given a candidate node
* to move IPs from, determines the best IP/destination node
* combination to move from the source node.
*/
static bool lcp2_failback_candidate(struct ipalloc_state *ipalloc_state,
int srcnode,
uint32_t *lcp2_imbalances,
bool *rebalance_candidates)
{
int dstnode, mindstnode, numnodes;
uint32_t srcimbl, srcdsum, dstimbl, dstdsum;
uint32_t minsrcimbl, mindstimbl;
struct public_ip_list *minip;
struct public_ip_list *t;
/* Find an IP and destination node that best reduces imbalance. */
srcimbl = 0;
minip = NULL;
minsrcimbl = 0;
mindstnode = -1;
mindstimbl = 0;
numnodes = ipalloc_state->num;
DEBUG(DEBUG_DEBUG,(" ----------------------------------------\n"));
DEBUG(DEBUG_DEBUG,(" CONSIDERING MOVES FROM %d [%d]\n",
srcnode, lcp2_imbalances[srcnode]));
for (t = ipalloc_state->all_ips; t != NULL; t = t->next) {
/* Only consider addresses on srcnode. */
if (t->pnn != srcnode) {
continue;
}
/* What is this IP address costing the source node? */
srcdsum = ip_distance_2_sum(&(t->addr),
ipalloc_state->all_ips,
srcnode);
srcimbl = lcp2_imbalances[srcnode] - srcdsum;
/* Consider this IP address would cost each potential
* destination node. Destination nodes are limited to
* those that are newly healthy, since we don't want
* to do gratuitous failover of IPs just to make minor
* balance improvements.
*/
for (dstnode = 0; dstnode < numnodes; dstnode++) {
if (!rebalance_candidates[dstnode]) {
continue;
}
/* only check nodes that can actually takeover this ip */
if (!can_node_takeover_ip(ipalloc_state, dstnode,
t)) {
/* no it couldnt so skip to the next node */
continue;
}
dstdsum = ip_distance_2_sum(&(t->addr),
ipalloc_state->all_ips,
dstnode);
dstimbl = lcp2_imbalances[dstnode] + dstdsum;
DEBUG(DEBUG_DEBUG,(" %d [%d] -> %s -> %d [+%d]\n",
srcnode, -srcdsum,
ctdb_sock_addr_to_string(
ipalloc_state, &(t->addr)),
dstnode, dstdsum));
if ((dstimbl < lcp2_imbalances[srcnode]) &&
(dstdsum < srcdsum) && \
((mindstnode == -1) || \
((srcimbl + dstimbl) < (minsrcimbl + mindstimbl)))) {
minip = t;
minsrcimbl = srcimbl;
mindstnode = dstnode;
mindstimbl = dstimbl;
}
}
}
DEBUG(DEBUG_DEBUG,(" ----------------------------------------\n"));
if (mindstnode != -1) {
/* We found a move that makes things better... */
DEBUG(DEBUG_INFO,
("%d [%d] -> %s -> %d [+%d]\n",
srcnode, minsrcimbl - lcp2_imbalances[srcnode],
ctdb_sock_addr_to_string(ipalloc_state, &(minip->addr)),
mindstnode, mindstimbl - lcp2_imbalances[mindstnode]));
lcp2_imbalances[srcnode] = minsrcimbl;
lcp2_imbalances[mindstnode] = mindstimbl;
minip->pnn = mindstnode;
return true;
}
return false;
}
/* Allocate any unassigned addresses using the LCP2 algorithm to find
* the IP/node combination that will cost the least.
*/
static void lcp2_allocate_unassigned(struct ipalloc_state *ipalloc_state,
uint32_t *lcp2_imbalances)
{
struct public_ip_list *t;
int dstnode, numnodes;
int minnode;
uint32_t mindsum, dstdsum, dstimbl;
uint32_t minimbl = 0;
struct public_ip_list *minip;
bool should_loop = true;
bool have_unassigned = true;
numnodes = ipalloc_state->num;
while (have_unassigned && should_loop) {
should_loop = false;
DEBUG(DEBUG_DEBUG,(" ----------------------------------------\n"));
DEBUG(DEBUG_DEBUG,(" CONSIDERING MOVES (UNASSIGNED)\n"));
minnode = -1;
mindsum = 0;
minip = NULL;
/* loop over each unassigned ip. */
for (t = ipalloc_state->all_ips; t != NULL ; t = t->next) {
if (t->pnn != -1) {
continue;
}
for (dstnode = 0; dstnode < numnodes; dstnode++) {
/* only check nodes that can actually takeover this ip */
if (!can_node_takeover_ip(ipalloc_state,
dstnode,
t)) {
/* no it couldnt so skip to the next node */
continue;
}
dstdsum = ip_distance_2_sum(&(t->addr),
ipalloc_state->all_ips,
dstnode);
dstimbl = lcp2_imbalances[dstnode] + dstdsum;
DEBUG(DEBUG_DEBUG,
(" %s -> %d [+%d]\n",
ctdb_sock_addr_to_string(ipalloc_state,
&(t->addr)),
dstnode,
dstimbl - lcp2_imbalances[dstnode]));
if ((minnode == -1) || (dstdsum < mindsum)) {
minnode = dstnode;
minimbl = dstimbl;
mindsum = dstdsum;
minip = t;
should_loop = true;
}
}
}
DEBUG(DEBUG_DEBUG,(" ----------------------------------------\n"));
/* If we found one then assign it to the given node. */
if (minnode != -1) {
minip->pnn = minnode;
lcp2_imbalances[minnode] = minimbl;
DEBUG(DEBUG_INFO,(" %s -> %d [+%d]\n",
ctdb_sock_addr_to_string(
ipalloc_state,
&(minip->addr)),
minnode,
mindsum));
}
/* There might be a better way but at least this is clear. */
have_unassigned = false;
for (t = ipalloc_state->all_ips; t != NULL; t = t->next) {
if (t->pnn == -1) {
have_unassigned = true;
}
}
}
/* We know if we have an unassigned addresses so we might as
* well optimise.
*/
if (have_unassigned) {
for (t = ipalloc_state->all_ips; t != NULL; t = t->next) {
if (t->pnn == -1) {
DEBUG(DEBUG_WARNING,
("Failed to find node to cover ip %s\n",
ctdb_sock_addr_to_string(ipalloc_state,
&t->addr)));
}
}
}
}