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storcon: avoid promoting too many shards of the same tenant

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This commit is contained in:
Vlad Lazar
2024-06-19 14:12:50 +01:00
parent c789ec21f6
commit 3a74253bcb
2 changed files with 24 additions and 4 deletions
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2
libs/pageserver_api/src/shard.rs
View File

@@ -43,7 +43,7 @@ use utils::id::TenantId;
pub struct ShardNumber(pub u8);
#[derive(Ord, PartialOrd, Eq, PartialEq, Clone, Copy, Serialize, Deserialize, Debug, Hash)]
pub struct ShardCount(u8);
pub struct ShardCount(pub u8);
/// Combination of ShardNumber and ShardCount. For use within the context of a particular tenant,
/// when we need to know which shard we're dealing with, but do not need to know the full

26
storage_controller/src/service.rs
View File

@@ -5394,6 +5394,9 @@ impl Service {
/// throughout the cluster. We achieve this by picking tenant shards from each node,
/// starting from the ones with the largest number of attached shards, until the node
/// reaches the expected cluster average.
/// 3. Avoid promoting more shards of the same tenant than required. The upper bound
/// for the number of tenants from the same shard promoted to the node being filled is:
/// shard count for the tenant divided by the number of nodes in the cluster.
fn fill_node_plan(&self, node_id: NodeId) -> Vec<TenantShardId> {
let mut locked = self.inner.write().unwrap();
let fill_requirement = locked.scheduler.compute_fill_requirement(node_id);
@@ -5415,8 +5418,18 @@ impl Service {
let expected_attached = locked.scheduler.expected_attached_shard_count();
let nodes_by_load = locked.scheduler.nodes_by_attached_shard_count();
let mut promoted_per_tenant: HashMap<TenantId, usize> = HashMap::new();
let mut plan = Vec::new();
for (node_id, attached) in nodes_by_load {
let available = locked
.nodes
.get(&node_id)
.map_or(false, |n| n.is_available());
if !available {
continue;
}
if plan.len() >= fill_requirement
|| tids_by_node.is_empty()
|| attached <= expected_attached
@@ -5424,13 +5437,20 @@ impl Service {
break;
}
let can_take = attached - expected_attached;
let mut can_take = attached - expected_attached;
let mut remove_node = false;
for _ in 0..can_take {
while can_take > 0 {
match tids_by_node.get_mut(&node_id) {
Some(tids) => match tids.pop() {
Some(tid) => {
plan.push(tid);
let max_promote_for_tenant =
std::cmp::max(tid.shard_count.0 as usize / locked.nodes.len(), 1);
let promoted = promoted_per_tenant.entry(tid.tenant_id).or_default();
if *promoted < max_promote_for_tenant {
plan.push(tid);
*promoted += 1;
can_take -= 1;
}
}
None => {
remove_node = true;