12.3. Diagnosing DataVolumes using events and conditions
Use the oc describe command to analyze and help resolve issues with DataVolumes.
12.3.1. About conditions and events
Diagnose DataVolume issues by examining the output of the Conditions and Events sections generated by the command:
$ oc describe dv <DataVolume>
There are three Types in the Conditions section that display:
-
Bound -
Running -
Ready
The Events section provides the following additional information:
-
Typeof event -
Reasonfor logging -
Sourceof the event -
Messagecontaining additional diagnostic information.
The output from oc describe does not always contains Events.
An event is generated when either Status, Reason, or Message changes. Both conditions and events react to changes in the state of the DataVolume.
For example, if you misspell the URL during an import operation, the import generates a 404 message. That message change generates an event with a reason. The output in the Conditions section is updated as well.
12.3.2. Analyzing DataVolumes using conditions and events
By inspecting the Conditions and Events sections generated by the describe command, you determine the state of the DataVolume in relation to PersistentVolumeClaims (PVCs), and whether or not an operation is actively running or completed. You might also receive messages that offer specific details about the status of the DataVolume, and how it came to be in its current state.
There are many different combinations of conditions. Each must be evaluated in its unique context.
Examples of various combinations follow.
Bound– A successfully bound PVC displays in this example.Note that the
TypeisBound, so theStatusisTrue. If the PVC is not bound, theStatusisFalse.When the PVC is bound, an event is generated stating that the PVC is bound. In this case, the
ReasonisBoundandStatusisTrue. TheMessageindicates which PVC owns the DataVolume.Message, in theEventssection, provides further details including how long the PVC has been bound (Age) and by what resource (From), in this casedatavolume-controller:Example output
Status: Conditions: Last Heart Beat Time: 2020-07-15T03:58:24Z Last Transition Time: 2020-07-15T03:58:24Z Message: PVC win10-rootdisk Bound Reason: Bound Status: True Type: Bound Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Bound 24s datavolume-controller PVC example-dv Bound
Running– In this case, note thatTypeisRunningandStatusisFalse, indicating that an event has occurred that caused an attempted operation to fail, changing the Status fromTruetoFalse.However, note that
ReasonisCompletedand theMessagefield indicatesImport Complete.In the
Eventssection, theReasonandMessagecontain additional troubleshooting information about the failed operation. In this example, theMessagedisplays an inability to connect due to a404, listed in theEventssection’s firstWarning.From this information, you conclude that an import operation was running, creating contention for other operations that are attempting to access the DataVolume:
Example output
Status: Conditions: Last Heart Beat Time: 2020-07-15T04:31:39Z Last Transition Time: 2020-07-15T04:31:39Z Message: Import Complete Reason: Completed Status: False Type: Running Events: Type Reason Age From Message ---- ------ ---- ---- ------- Warning Error 12s (x2 over 14s) datavolume-controller Unable to connect to http data source: expected status code 200, got 404. Status: 404 Not Found
Ready– IfTypeisReadyandStatusisTrue, then the DataVolume is ready to be used, as in the following example. If the DataVolume is not ready to be used, theStatusisFalse:Example output
Status: Conditions: Last Heart Beat Time: 2020-07-15T04:31:39Z Last Transition Time: 2020-07-15T04:31:39Z Status: True Type: Ready
