A number of clusters in the wild on 4.1.z (15-20?) are reporting one etcd member down via the `up` metric, but no alerts related to etcd failure are being reported. Other clusters with one etcd member reported down ARE reporting alerts related to a bad member: 80f5da7e-7527-41d2-8d6e-774b388a42a4 reports the following alerts: KubeDeploymentReplicasMismatch, KubePodNotReady, TargetDown, Watchdog and two down services up{_id="80f5da7e-7527-41d2-8d6e-774b388a42a4",endpoint="etcd-metrics",instance="172.16.0.34:9979",job="etcd",monitor="prometheus",namespace="openshift-etcd",pod="etcd-member-host-172-16-0-34",prometheus="openshift-monitoring/k8s",prometheus_replica="prometheus-telemeter-0",replica="$(HOSTNAME)",service="etcd"} 0 up{_id="80f5da7e-7527-41d2-8d6e-774b388a42a4",endpoint="metrics",instance="172.16.0.40:9101",job="sdn",monitor="prometheus",namespace="openshift-sdn",pod="sdn-wtl58",prometheus="openshift-monitoring/k8s",prometheus_replica="prometheus-telemeter-0",replica="$(HOSTNAME)",service="sdn"} This is a UPI cluster at 4.1.4. We may have a scheduling issue with the etcd proxy, but more data needs to be gathered.
Ok, looking into this we have a gap in our alerts. Today we have etcdInsufficientMembers which depends on the etcd service being present but down (we must have 3 up series). However, when this happens we only fire TargetDown and that's concerning since we're really degraded. We need to have a better alert for degradation Second, there is a different failure mode where a node is completely removed, at which point the number of series in up is 2, and the alerts do not fire correctly. This is a valid failure mode that our alerts don't cover. The query `count(sum by (To) (rate(etcd_network_peer_sent_failures_total[2m])) > 0) > 0` roughly approximates this.
Verfied with 4.1.0-0.nightly-2019-08-06-212225, shutdown 1 etcd member, then check Monitoring section in web console, got expected alert msg: etcdMembersDown etcd cluster "etcd": members are down (1). Pending Since 2 minutes ago
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2019:2417