Merge pull request prometheus-operator#32 from nvtkaszpir/patch-3

content/runbooks/etcd/etcdNoLeader.md

@@ -4,6 +4,9 @@
 
 This alert is triggered when etcd cluster does not have a leader for more than 1
 minute.
+This can happen if nodes from the cluster are orphaned - they were part of the cluster
+but now they are in minority and thus can not form a cluster,
+for example due to network partition. 
 
 ## Impact
 
@@ -12,6 +15,9 @@ as expected and cluster cannot process any writes or reads, and any write
 requests are queued for processing until a new leader is elected. Operations
 that preserve the health of the workloads cannot be performed.
 
+In general loosing quorum will switch etcd to read only, which effectively renders k8s api read only.
+It is possible to read the current state, but not possible to update it.
+
 ## Diagnosis
 
 ### Control plane nodes issue