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Chapter 8. Troubleshooting

When troubleshooting OpenShift sandboxed containers, you can open a support case and provide debugging information using the must-gather tool.

If you are a cluster administrator, you can also review logs on your own, enabling a more detailed level of logs.

8.1. Collecting data for Red Hat Support

When opening a support case, it is helpful to provide debugging information about your cluster to Red Hat Support.

The must-gather tool enables you to collect diagnostic information about your OpenShift Container Platform cluster, including virtual machines and other data related to OpenShift sandboxed containers.

For prompt support, supply diagnostic information for both OpenShift Container Platform and OpenShift sandboxed containers.

Using the must-gather tool

The oc adm must-gather CLI command collects the information from your cluster that is most likely needed for debugging issues, including:

  • Resource definitions
  • Service logs

By default, the oc adm must-gather command uses the default plugin image and writes into ./must-gather.local.

Alternatively, you can collect specific information by running the command with the appropriate arguments as described in the following sections:

  • To collect data related to one or more specific features, use the --image argument with an image, as listed in a following section.

    For example: 

    $ oc adm must-gather --image=registry.redhat.io/openshift-sandboxed-containers/osc-must-gather-rhel9:1.6.0

  • To collect the audit logs, use the -- /usr/bin/gather_audit_logs argument, as described in a following section.

    For example: 

    $ oc adm must-gather -- /usr/bin/gather_audit_logs
    Note

    Audit logs are not collected as part of the default set of information to reduce the size of the files.

When you run oc adm must-gather, a new pod with a random name is created in a new project on the cluster. The data is collected on that pod and saved in a new directory that starts with must-gather.local. This directory is created in the current working directory.

For example: 

NAMESPACE                      NAME                 READY   STATUS      RESTARTS      AGE
...
openshift-must-gather-5drcj    must-gather-bklx4    2/2     Running     0             72s
openshift-must-gather-5drcj    must-gather-s8sdh    2/2     Running     0             72s
...

Optionally, you can run the oc adm must-gather command in a specific namespace by using the --run-namespace option.

For example: 

$ oc adm must-gather --run-namespace <namespace> --image=registry.redhat.io/openshift-sandboxed-containers/osc-must-gather-rhel9:1.6.0

8.2. Collecting log data

The following features and objects are associated with OpenShift sandboxed containers:

  • All namespaces and their child objects that belong to OpenShift sandboxed containers resources
  • All OpenShift sandboxed containers custom resource definitions (CRDs)

You can collect the following component logs for each pod running with the kata runtime:

  • Kata agent logs
  • Kata runtime logs
  • QEMU logs
  • Audit logs
  • CRI-O logs

8.2.1. Enabling debug logs for CRI-O runtime

You can enable debug logs by updating the logLevel field in the KataConfig CR. This changes the log level in the CRI-O runtime for the worker nodes running OpenShift sandboxed containers.

Prerequisites

  • You have installed the OpenShift CLI (oc).
  • You have access to the cluster as a user with the cluster-admin role.

Procedure

  1. Change the logLevel field in your existing KataConfig CR to debug: 

    $ oc patch kataconfig <kataconfig> --type merge --patch '{"spec":{"logLevel":"debug"}}'

  2. Monitor the kata-oc machine config pool until the value of UPDATED is True, indicating that all worker nodes are updated: 

    $ oc get mcp kata-oc

    Example output

    NAME     CONFIG                 UPDATED  UPDATING  DEGRADED  MACHINECOUNT  READYMACHINECOUNT  UPDATEDMACHINECOUNT  DEGRADEDMACHINECOUNT  AGE
kata-oc  rendered-kata-oc-169   False    True      False     3             1                  1                    0                     9h

Verification

  1. Start a debug session with a node in the machine config pool: 

    $ oc debug node/<node_name>

  2. Change the root directory to /host: 

    # chroot /host

  3. Verify the changes in the crio.conf file: 

    # crio config | egrep 'log_level

    Example output

    log_level = "debug"

8.2.2. Viewing debug logs for components

Cluster administrators can use the debug logs to troubleshoot issues. The logs for each node are printed to the node journal.

You can review the logs for the following OpenShift sandboxed containers components:

  • Kata agent
  • Kata runtime (containerd-shim-kata-v2)
  • virtiofsd

QEMU only generates warning and error logs. These warnings and errors print to the node journal in both the Kata runtime logs and the CRI-O logs with an extra qemuPid field.

Example of QEMU logs

Mar 11 11:57:28 openshift-worker-0 kata[2241647]: time="2023-03-11T11:57:28.587116986Z" level=info msg="Start logging QEMU (qemuPid=2241693)" name=containerd-shim-v2 pid=2241647 sandbox=d1d4d68efc35e5ccb4331af73da459c13f46269b512774aa6bde7da34db48987 source=virtcontainers/hypervisor subsystem=qemu

Mar 11 11:57:28 openshift-worker-0 kata[2241647]: time="2023-03-11T11:57:28.607339014Z" level=error msg="qemu-kvm: -machine q35,accel=kvm,kernel_irqchip=split,foo: Expected '=' after parameter 'foo'" name=containerd-shim-v2 pid=2241647 qemuPid=2241693 sandbox=d1d4d68efc35e5ccb4331af73da459c13f46269b512774aa6bde7da34db48987 source=virtcontainers/hypervisor subsystem=qemu

Mar 11 11:57:28 openshift-worker-0 kata[2241647]: time="2023-03-11T11:57:28.60890737Z" level=info msg="Stop logging QEMU (qemuPid=2241693)" name=containerd-shim-v2 pid=2241647 sandbox=d1d4d68efc35e5ccb4331af73da459c13f46269b512774aa6bde7da34db48987 source=virtcontainers/hypervisor subsystem=qemu

The Kata runtime prints Start logging QEMU when QEMU starts, and Stop Logging QEMU when QEMU stops. The error appears in between these two log messages with the qemuPid field. The actual error message from QEMU appears in red.

The console of the QEMU guest is printed to the node journal as well. You can view the guest console logs together with the Kata agent logs.

Prerequisites

  • You have installed the OpenShift CLI (oc).
  • You have access to the cluster as a user with the cluster-admin role.

Procedure

  • To review the Kata agent logs and guest console logs, run the following command: 

    $ oc debug node/<nodename> -- journalctl -D /host/var/log/journal -t kata -g “reading guest console”

  • To review the Kata runtime logs, run the following command: 

    $ oc debug node/<nodename> -- journalctl -D /host/var/log/journal -t kata

  • To review the virtiofsd logs, run the following command: 

    $ oc debug node/<nodename> -- journalctl -D /host/var/log/journal -t virtiofsd

  • To review the QEMU logs, run the following command: 

    $ oc debug node/<nodename> -- journalctl -D /host/var/log/journal -t kata -g "qemuPid=\d+"

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