m/{node,proto}: implement Node Labels
Nodes can now have Labels attached to them. These are string key/value
data designed after Kubernetes labels. They are meant to be used to
attach metadata to nodes, for example external IDs, nicknames or
geographical information.
This change implements just the core functionality: storing them within
etcd, retrieving them via management and curator APIs, and mutating them
via a new management RPC.
Followup changes will impelement provisioning labels at
bootstrap/registration time and accessing label data from metroctl.
Change-Id: I556b452a65061294e7c51037723a6db31d587716
Reviewed-on: https://review.monogon.dev/c/monogon/+/3101
Reviewed-by: Jan Schär <jan@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/proto/common/common.proto b/metropolis/proto/common/common.proto
index b870d20..a0e8c73 100644
--- a/metropolis/proto/common/common.proto
+++ b/metropolis/proto/common/common.proto
@@ -64,6 +64,34 @@
KubernetesController kubernetes_controller = 3;
}
+// NodeLabels are labels assigned to a node.
+//
+// Labels are string key/value pairs modeled after the Kubernetes label concept.
+// They can be used to assign user-specific metadata to nodes like IDs from other
+// systems or geographical location. They are treated like opaque strings by
+// Metropolis itself.
+//
+// Every key and value must be a string between 1 and 63 characters long
+// (inclusive). Each character must be a valid ASCII character from the following
+// range: a-z, A-Z, 0-9 '-', '_' or '.'. The first character must be a-z, A-Z or
+// 0-9. This is close but not exact to DNS label requirements (for example, '.'
+// or '_' are generally not valid DNS label parts... but that's a discussion for
+// another day).
+//
+// Keys must not repeat across node labels - that is, NodeLabels must be
+// convertable to/from a string/string map in Go. Pair ordering is not preserved,
+// but pair order in labels received from Metropolis API calls is stable (however
+// it is arbitrary).
+//
+// A node cannot have more than 128 labels.
+message NodeLabels {
+ message Pair {
+ string key = 1;
+ string value = 2;
+ }
+ repeated Pair pairs = 1;
+}
+
// NodeState is the state of a Metropolis node from the point of view of the
// cluster it is a part of (or intending to be a part of).
enum NodeState {