CephOSDDiskUnavailable

1. Check Description

Severity: Error

Potential Customer Impact: High

2. Overview

A disk device is not accessible on one of the host.

Detailed Description: A disk device is not accessible on one of the host and its corresponding OSD is marked out by the ceph cluster. This alert is raised when a ceph node failed to recover within 10 mins.

3. Prerequsities

3.1. Verify cluster access

Check the output to ensure you are in the correct context for the cluster mentioned in the alert. If not, please change context and proceed.

List clusters you have permission to access:
ocm list clusters

From the list above, find the cluster id of the cluster named in the alert. If you do not see the alerting cluster in the list above please refer Effective communication with SRE Platform

Create a tunnel through backplane by provdiing SSH key passphrase:
ocm backplane tunnel <cluster_id>
In a new tab, login to target cluster using backplane by provdiing 2FA:
ocm backplane login <cluster_id>

3.2. Check Alerts

Set port-forwarding for alertmanager:
oc port-forward alertmanager-managed-ocs-alertmanager-0 9093 -n openshift-storage
Check all alerts
curl http://localhost:9093/api/v1/alerts | jq '.data[] | select( .labels.alertname) | { ALERT: .labels.alertname, STATE: .status.state}'

3.3. Check OCS Ceph Cluster Health

You may directly check OCS Ceph Cluster health by using the rook-ceph toolbox.

Step 1: Check and document ceph cluster health:
TOOLS_POD=$(oc get pods -n openshift-storage -l app=rook-ceph-tools -o name)
oc rsh -n openshift-storage $TOOLS_POD
Step 2: From the rsh command prompt, run the following and capture the output.
ceph status
ceph osd status
exit

If 'ceph status' is not in HEALTH_OK, please look at the Troubleshooting section to resolve issue.

3.4. Further info

3.4.1. OpenShift Data Foundation Dedicated Architecture

Red Hat OpenShift Data Foundation Dedicated (ODF Dedicated) is deployed in converged mode on OpenShift Dedicated Clusters by the OpenShift Cluster Manager add-on infrastructure.

Related Links
Step 3: Check the links to identify the errors.

1) https://access.redhat.com/documentation/en-us/red_hat_ceph_storage/4/html/troubleshooting_guide/troubleshooting-ceph-osds#common-ceph-osd-error-messages-in-the-ceph-logs_diag 2) https://access.redhat.com/documentation/en-us/red_hat_ceph_storage/4/html/troubleshooting_guide/troubleshooting-ceph-placement-groups#inconsistent-placement-groups_diag

4. Alert

4.1. Make changes to solve alert

This alert is raised when a ceph node failed to recover within 10 mins. This procedure determines which node has failures.

4.1.1. Determine failed OCS Node

Run the following to get the list of worker nodes and check for the node status:
oc get nodes --selector='node-role.kubernetes.io/worker','!node-role.kubernetes.io/infra'
Describe the node which is of NotReady status to get more information on the failure:
oc describe node <node_name>

(Optional log gathering)

Document Ceph Cluster health check:
oc adm must-gather --image=registry.redhat.io/ocs4/ocs-must-gather-rhel8:v4.6

5. Troubleshooting

  • Issue encountered while following the SOP

Any issues while following the SOP should be documented here.