Clarify error even futher, allow using --force to try leaving automat…

…ically

Signed-off-by: Kimmo Lehto <[email protected]>

phase/validate_facts.go

@@ -96,9 +96,17 @@ func (p *ValidateFacts) validateControllerSwap() error {
 		}
 		log.Debugf("%s: host is new, checking if etcd members list %+v already contains %s", h, p.Config.Metadata.EtcdMembers, h.PrivateAddress)
 		if slices.Contains(p.Config.Metadata.EtcdMembers, h.PrivateAddress) {
-			return fmt.Errorf("controller %s is listed as an existing etcd member but k0s is not found installed on it, host may have been replaced", h)
+			if Force {
+				leader := p.Config.Spec.K0sLeader()
+				if err := leader.Exec(leader.Configurer.K0sCmdf("etcd leave --peer-address %s", h.PrivateAddress)); err != nil {
+					return fmt.Errorf("controller %s is listed as an existing etcd member but k0s is not found installed on it, the host may have been replaced. attempted etcd leave for the address %s but it failed: %w", h, h.PrivateAddress, err)
+				}
+			} else {
+				return fmt.Errorf("controller %s is listed as an existing etcd member but k0s is not found installed on it, the host may have been replaced. check the host and use `k0s etcd leave --peer-address %s on a controller or re-run apply with --force", h, h.PrivateAddress)
+			}
+		} else {
+			log.Debugf("%s: no match, assuming its safe to install", h)
 		}
-		log.Debugf("%s: no match, assuming its safe to install", h)
 	}
 
 	return nil