MiraCluster

For: anyone writing the custom resource the operator reconciles.

mira.miradb.dev/v1alpha1, namespaced, short name mira. The schema below is the one the API server stores, which is the one that decides what survives a write: a field it does not name is pruned on apply, with no error anywhere.

Installing it is Install; what the operator builds out of it, and how a scale-in is sequenced, is the chart reference.

spec

A Mira storage tier and the proxy in front of it.

Field	Type	Default	What it sets
coldStorageClaim	string	unset	Name of an existing claim holding the cold store, mounted into the drain Job at the first path segment of offload.
image	string	required	The Mira image the storage pods and the drain Jobs both run.
maxReplicas	integer ≥ 1	10	Replica ceiling. Scale-out stops here rather than filling the cluster.
offload	string	unset	Where a drained replica's blocks are copied before its volume is deleted. ${node} interpolates to the replica name.
proxy	object	—	The mira proxy tier that fans out across the replicas.
proxy.replicas	integer	2	How many proxy pods. Zero disables the proxy entirely and leaves the storage pods addressable only through the headless Service.
proxy.resources	ResourceRequirements	unset	CPU and memory for one proxy pod.
replicas	integer ≥ 1	1	Replica floor. The tier never shrinks below this.
resources	ResourceRequirements	unset	CPU and memory for one storage replica, and for the drain Job that archives its volume.
route	object	unset	An HTTPRoute in front of the tier, attached to Gateways you already run.
route.hostnames	array	unset	Hostnames the route answers on. Unset answers on every hostname its listener accepts.
route.parentRefs	array	required	The Gateways to attach to. At least one, or the route binds to nothing and the apiserver accepts it anyway.
route.parentRefs[].name	string	required	metadata.name of the Gateway.
route.parentRefs[].namespace	string	unset	The Gateway's namespace. Unset is this MiraCluster's own.
route.parentRefs[].sectionName	string	unset	spec.listeners[].name to attach to. Unset attaches to every listener that will have it.
scaling	object	—	When to add a replica, and when to take one away.
scaling.cooldownSeconds	integer	600	Seconds after any scaling action before another may be considered.
scaling.downWhenFreeAbove	number	0.6	Remove a replica when every replica's free_fraction is above this.
scaling.drainDeadlineSeconds	integer	3600	Seconds a drain Job may run before Kubernetes fails it.
scaling.upWhenFreeBelow	number	0.15	Add a replica when the fullest replica's free_fraction drops below this.
storage	object	required	Per-replica volume.
storage.className	string	unset	StorageClass. Unset uses the cluster default.
storage.size	quantity	required	Volume size, as a Kubernetes quantity — 100Gi.

status

A subresource, so the operator writes it without touching the spec, and an unsatisfiable spec lands here rather than in a log line nobody reads.

Field	Type	Default	What it reports
draining	integer	unset	Replica ordinal currently being drained, if any. Set before the drain Job is created and cleared only once the volume has been released, so a controller restart mid-drain resumes rather than abandoning a half-copied tier.
freeFraction	string	unset	The lowest free_fraction seen across the tier, rendered to two decimals. A string and not a float because this is a printcolumn, and kubectl renders a float64 status field in scientific notation.
lastScaled	string	unset	RFC3339 of the last completed scaling action, for the cooldown.
message	string	unset	Human-readable reason for the current phase.
phase	string	unset	Ready, ScalingUp, Draining or Degraded.
replicas	integer	0	Replica count the operator is currently asking for.

Refused on write

Enforced by the API server rather than by the operator, so the kubectl that would break the tier fails instead of the reconcile that follows it.

Rule	Message
self.spec.maxReplicas >= self.spec.replicas	maxReplicas must be at least replicas

kubectl get miraclusters

Column	Read from
Replicas	.status.replicas
Free	.status.freeFraction
Phase	.status.phase
Age	.metadata.creationTimestamp