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get migration IDs from a better place
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@gjcolombo
gjcolombo committed Jun 17, 2024
1 parent bf7e0b9 commit c1a6054
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Showing 3 changed files with 45 additions and 72 deletions.
111 changes: 43 additions & 68 deletions sled-agent/src/common/instance.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -114,82 +114,57 @@ impl ObservedPropolisState {
/// runtime state and an instance state monitor response received from
/// Propolis.
pub fn new(
instance_runtime: &InstanceRuntimeState,
propolis_id: PropolisUuid,
migration: Option<&MigrationRuntimeState>,
propolis_state: &InstanceStateMonitorResponse,
) -> Self {
// Decide which of Propolis's reported migrations to pay attention to.
// If this Propolis is currently a migration target (evidenced by its ID
// appearing in the `dst_propolis_id` field in the instance record),
// look at the current migration in. Otherwise, look at the reported
// migration out.
let role = if instance_runtime
.dst_propolis_id
.is_some_and(|id| id == propolis_id)
{
MigrationRole::Target
} else {
MigrationRole::Source
// If there's no migration currently registered with this sled, report
// the current state and that no migration is currently in progress,
// even if Propolis has some migration data to share. (This case arises
// when Propolis returns state from a previous migration that sled agent
// has already retired.)
let Some(migration) = migration else {
return Self {
vmm_state: PropolisInstanceState(propolis_state.state),
migration_status: ObservedMigrationStatus::NoMigration,
time: Utc::now(),
};
};

let propolis_migration = match role {
MigrationRole::Source => &propolis_state.migration.migration_out,
MigrationRole::Target => &propolis_state.migration.migration_in,
// Sled agent believes a live migration may be in progress. See if
// either of the Propolis migrations corresponds to it.
let propolis_migration = match (
&propolis_state.migration.migration_in,
&propolis_state.migration.migration_out,
) {
(Some(inbound), _) if inbound.id == migration.migration_id => {
inbound
}
(_, Some(outbound)) if outbound.id == migration.migration_id => {
outbound
}
_ => {
// Sled agent believes this instance should be migrating, but
// Propolis isn't reporting a matching migration yet, so assume
// the migration is still pending.
return Self {
vmm_state: PropolisInstanceState(propolis_state.state),
migration_status: ObservedMigrationStatus::Pending,
time: Utc::now(),
};
}
};

// Determine the status of the current active migration, if there is
// one. This procedure assumes that when a Propolis participates in a
// migration, its sled agent learns about that migration (and records
// the migration ID in its runtime state) before Propolis itself starts
// reporting that migration's status.
let migration_status =
match (instance_runtime.migration_id, propolis_migration) {
// If the runtime state and Propolis state agree that there's
// a migration in progress, and they agree on its ID, the
// Propolis migration state determines the migration status.
(Some(this_id), Some(propolis_migration))
if this_id == propolis_migration.id =>
{
match propolis_migration.state {
PropolisMigrationState::Finish => {
ObservedMigrationStatus::Succeeded
}
PropolisMigrationState::Error => {
ObservedMigrationStatus::Failed
}
_ => ObservedMigrationStatus::InProgress,
}
}

// Propolis continues to report the status of failed migrations
// until they are supplanted by new attempts to migrate. If both
// sides have a migration ID, but the IDs don't match, assume
// that Propolis is reporting stale status from an earlier
// migration and that a new migration is about to begin.
(Some(_), Some(_)) => ObservedMigrationStatus::Pending,

// A migration source's migration IDs get set before its
// Propolis actually gets asked to migrate, so it's possible for
// the runtime state to contain an ID while the Propolis has
// none, in which case the migration is pending.
(Some(_), None) => ObservedMigrationStatus::Pending,

// If the instance runtime state has no migration ID, don't
// report any migration status, even if Propolis had some status
// to report. (Nexus and sled agent won't remove migration IDs
// from an instance's runtime state until the migration is
// actually finished, so the migration Propolis is reporting in
// this case must be stale.)
(None, Some(_)) => ObservedMigrationStatus::NoMigration,

// If neither side has a migration ID, then there's clearly no
// migration.
(None, None) => ObservedMigrationStatus::NoMigration,
};

Self {
vmm_state: PropolisInstanceState(propolis_state.state),
migration_status,
migration_status: match propolis_migration.state {
PropolisMigrationState::Finish => {
ObservedMigrationStatus::Succeeded
}
PropolisMigrationState::Error => {
ObservedMigrationStatus::Failed
}
_ => ObservedMigrationStatus::InProgress,
},
time: Utc::now(),
}
}
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3 changes: 1 addition & 2 deletions sled-agent/src/instance.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -373,8 +373,7 @@ impl InstanceRunner {
match request {
Some(Update { state, tx }) => {
let observed = ObservedPropolisState::new(
self.state.instance(),
self.state.propolis_id(),
self.state.migration(),
&state,
);
let reaction = self.observe_state(&observed).await;
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3 changes: 1 addition & 2 deletions sled-agent/src/sim/instance.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -278,8 +278,7 @@ impl SimInstanceInner {
}

self.state.apply_propolis_observation(&ObservedPropolisState::new(
&self.state.instance(),
self.state.propolis_id(),
self.state.migration(),
&self.last_response,
))
} else {
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