feat(lb): prefix default balancer names with an optional cluster name

README.md

@@ -48,7 +48,7 @@ Setting `ROBOTLB_DYNAMIC_NODE_SELECTOR` to `false` replaces both with the node s
 
 A balancer type caps how many targets it holds: `lb11`, the default type, holds 25. When more nodes are selected than the type holds, the extra ones are dropped in a stable order and a warning names the limit. Pick a bigger type through `ROBOTLB_DEFAULT_LB_TYPE` or the `robotlb/balancer-type` annotation to use the whole cluster.
 
-robotlb labels every balancer it creates with `robotlb/service-uid` set to the UID of the service, finds the balancer of a service by that label, and changes or deletes only a balancer labelled for that service. A balancer is never deleted by its name. Without the `robotlb/balancer` annotation the balancer is named `<service>.<namespace>`. The name is only used to create the balancer: changing the annotation later does not rename it. When the name is taken by a balancer labelled for another service, or by an unlabelled balancer that does not target the nodes of the service, robotlb leaves that balancer alone and reports it in a warning event on the service. Two services therefore cannot share a balancer through the same `robotlb/balancer` annotation: the second one gets the warning. A service recreated with a new UID, for example restored from a backup, is another service to robotlb, because its old balancer is labelled with the old UID. When that balancer has the name the service asks for, the warning names the old UID. When it has the name of an earlier release, robotlb creates a new balancer with a new IP instead, without a warning, and the old one stays in the project and keeps being billed; `hcloud load-balancer list --selector robotlb/service-uid=<old UID>` finds it. After checking that no service with the old UID is left, hand the balancer over with `hcloud load-balancer add-label --overwrite '<balancer>' robotlb/service-uid=<new UID>`, or delete it. An unlabelled balancer whose targets are all IPs, at least one of them a node of the service, is adopted: robotlb adds its label, keeps the name, and from then on manages and deletes it like its own. This is how balancers of earlier releases are taken over, and it applies to any balancer created later under that name that matches.
+robotlb labels every balancer it creates with `robotlb/service-uid` set to the UID of the service, finds the balancer of a service by that label, and changes or deletes only a balancer labelled for that service. A balancer is never deleted by its name. Without the `robotlb/balancer` annotation the balancer is named `<service>.<namespace>`, or `<cluster>.<service>.<namespace>` when `ROBOTLB_CLUSTER_NAME` is set, so that clusters sharing a Hetzner project do not pick the same name. A name longer than the 128 characters Hetzner allows is cut and ends in `-` and a 16-digit hex hash of the whole name. The cluster name is not added to a name from the annotation. Balancers that already carry the `robotlb/service-uid` label are found by it, so setting a cluster name later does not rename them. The name is only used to create the balancer: changing the annotation later does not rename it. When the name is taken by a balancer labelled for another service, or by an unlabelled balancer that does not target the nodes of the service, robotlb leaves that balancer alone and reports it in a warning event on the service. Two services therefore cannot share a balancer through the same `robotlb/balancer` annotation: the second one gets the warning. A service recreated with a new UID, for example restored from a backup, is another service to robotlb, because its old balancer is labelled with the old UID. When that balancer has the name the service asks for, the warning names the old UID. When it has the name of an earlier release, robotlb creates a new balancer with a new IP instead, without a warning, and the old one stays in the project and keeps being billed; `hcloud load-balancer list --selector robotlb/service-uid=<old UID>` finds it. After checking that no service with the old UID is left, hand the balancer over with `hcloud load-balancer add-label --overwrite '<balancer>' robotlb/service-uid=<new UID>`, or delete it. An unlabelled balancer whose targets are all IPs, at least one of them a node of the service, is adopted: robotlb adds its label, keeps the name, and from then on manages and deletes it like its own. This is how balancers of earlier releases are taken over, and it applies to any balancer created later under that name that matches.
 
 Every port of the service needs an allocated `nodePort`. A Hetzner load balancer forwards traffic to the IP of a node, so a port is reachable only through its `nodePort`: ports without one are skipped, and `allocateLoadBalancerNodePorts: false` is not supported. When no port of a service can be exposed, no balancer is created for it, an existing balancer and the service's external IP are kept as they are, and a warning event on the service reports the problem.
 
@@ -88,6 +88,8 @@ Options:
 
           [env: ROBOTLB_HCLOUD_TOKEN=]
 
+      --cluster-name <CLUSTER_NAME>
+          Name of the cluster, put in front of default balancer names so that clusters sharing a Hetzner project do not pick the same ones. A DNS label: lowercase letters, digits and `-`, at most 63 characters [env: ROBOTLB_CLUSTER_NAME=]
       --default-network <DEFAULT_NETWORK>
           Default network to use for load balancers. If not set, then only network from the service annotation will be used
 

helm/values.yaml

@@ -14,6 +14,9 @@ fullnameOverride: ""
 
 envs:
   ROBOTLB_LOG_LEVEL: "INFO"
+  # Put in front of default balancer names when several clusters share a Hetzner
+  # project. A DNS label: lowercase letters, digits and `-`, at most 63 characters.
+  # ROBOTLB_CLUSTER_NAME: "prod"
 
 existingSecrets: []
 

src/config.rs

@@ -8,6 +8,12 @@ pub struct OperatorConfig {
     #[arg(short = 't', long, env = "ROBOTLB_HCLOUD_TOKEN")]
     pub hcloud_token: String,
 
+    /// Name of the cluster, put in front of default balancer names so that clusters
+    /// sharing a Hetzner project do not pick the same ones. A DNS label: lowercase
+    /// letters, digits and `-`, at most 63 characters.
+    #[arg(long, env = "ROBOTLB_CLUSTER_NAME", value_parser = crate::lb::parse_cluster_name)]
+    pub cluster_name: Option<String>,
+
     /// Default network to use for load balancers.
     /// If not set, then only network from the service annotation will be used.
     #[arg(long, env = "ROBOTLB_DEFAULT_NETWORK", default_value = None)]