must-gather fails with error running backup collection: errors occurred while gathering data

Environment

• Red Hat OpenShift Container Platform (RHOCP)
  • 4
• Must gather

Issue

• While executing the oc adm must-gather command, errors similar to the following one is shown in the command output:

  error running backup collection: errors occurred while gathering data:
  [skipping gathering <resource>/<resource_name> due to error: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
  

Resolution

Those messages indicates that there are some resources that cannot be collected, but must-gather has a fallback mechanism in case it has issues gathering data, and in most of the cases the must-gather is collected with few missing information.

If the must-gather directory contains several directories inside, like the ones shown in the Diagnostic Steps section, and it is at least several MB size, please compact it and upload to the case, providing also the output with the error messages.

For different errors like "unable to download output from pod must-gather-XXXXX: No available strategies to copy", refer to error generating must-gather: No available strategies to copy.

Root Cause

Must-gather has a fallback mechanism in case it has issues gathering data.

Diagnostic Steps

Check if the generated must-gather directory contains data, checking there are different directories inside and the size of the directory is from several MB to GB:

$ du -sh must-gather.local.[random-ID]/
886M     must-gather.local.[random-ID]/

$ tree -L 2 must-gather.local.[random-ID]/
must-gather.local.[random-ID]/
├── event-filter.html
├── quay-io-openshift-release-dev-ocp-v4-0-art-dev-sha256-[sha256]
│   ├── cluster-scoped-resources
│   ├── etcd_info
│   ├── event-filter.html
│   ├── host_service_logs
│   ├── ingress_controllers
│   ├── insights-data
│   ├── monitoring
│   ├── namespaces
│   ├── network_logs
│   ├── pod_network_connectivity_check
│   ├── static-pods
│   ├── timestamp
│   ├── version
│   └── web_hooks
└── timestamp

$ tree -L 3 must-gather.local.[random-ID]/
[...]

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