Known issues

This section lists known issues with workarounds for the Mirantis Container Cloud release 2.7.0 including the Cluster release 5.14.0 and 6.14.0.

Note

This section also outlines still valid known issues from previous Container Cloud releases.


AWS

[8013] Managed cluster deployment requiring PVs may fail

Fixed in the Cluster release 7.0.0

Note

The issue below affects only the Kubernetes 1.18 deployments. Moving forward, the workaround for this issue will be moved from Release Notes to Operations Guide: Troubleshooting.

On a management cluster with multiple AWS-based managed clusters, some clusters fail to complete the deployments that require persistent volumes (PVs), for example, Elasticsearch. Some of the affected pods get stuck in the Pending state with the pod has unbound immediate PersistentVolumeClaims and node(s) had volume node affinity conflict errors.

Warning

The workaround below applies to HA deployments where data can be rebuilt from replicas. If you have a non-HA deployment, back up any existing data before proceeding, since all data will be lost while applying the workaround.

Workaround:

  1. Obtain the persistent volume claims related to the storage mounts of the affected pods:

    kubectl get pod/<pod_name1> pod/<pod_name2> \
    -o jsonpath='{.spec.volumes[?(@.persistentVolumeClaim)].persistentVolumeClaim.claimName}'
    

    Note

    In the command above and in the subsequent steps, substitute the parameters enclosed in angle brackets with the corresponding values.

  2. Delete the affected Pods and PersistentVolumeClaims to reschedule them: For example, for StackLight:

    kubectl -n stacklight delete \
    
      pod/<pod_name1> pod/<pod_name2> ...
      pvc/<pvc_name2> pvc/<pvc_name2> ...
    


vSphere

[14458] Failure to create a container for pod: cannot allocate memory

Fixed in 2.9.0 for new clusters

Newly created pods may fail to run and have the CrashLoopBackOff status on long-living Container Cloud clusters deployed on RHEL 7.8 using the VMware vSphere provider. The following is an example output of the kubectl describe pod <pod-name> -n <projectName> command:

State:        Waiting
Reason:       CrashLoopBackOff
Last State:   Terminated
Reason:       ContainerCannotRun
Message:      OCI runtime create failed: container_linux.go:349:
              starting container process caused "process_linux.go:297:
              applying cgroup configuration for process caused
              "mkdir /sys/fs/cgroup/memory/kubepods/burstable/<pod-id>/<container-id>>:
              cannot allocate memory": unknown

The issue occurs due to the Kubernetes and Docker community issues.

According to the RedHat solution, the workaround is to disable the kernel memory accounting feature by appending cgroup.memory=nokmem to the kernel command line.

Note

The workaround below applies to the existing clusters only. The issue is resolved for new Container Cloud 2.9.0 deployments since the workaround below automatically applies to the VM template built during the vSphere-based management cluster bootstrap.

Apply the following workaround on each machine of the affected cluster.

Workaround

  1. SSH to any machine of the affected cluster using mcc-user and the SSH key provided during the cluster creation to proceed as the root user.

  2. In /etc/default/grub, set cgroup.memory=nokmem for GRUB_CMDLINE_LINUX.

  3. Update kernel:

    yum install kernel kernel-headers kernel-tools kernel-tools-libs kexec-tools
    
  4. Update the grub configuration:

    grub2-mkconfig -o /boot/grub2/grub.cfg
    
  5. Reboot the machine.

  6. Wait for the machine to become available.

  7. Wait for 5 minutes for Docker and Kubernetes services to start.

  8. Verify that the machine is Ready:

    docker node ls
    kubectl get nodes
    
  9. Repeat the steps above on the remaining machines of the affected cluster.



OpenStack

[10424] Regional cluster cleanup fails by timeout

An OpenStack-based regional cluster cleanup fails with the timeout error.

Workaround:

  1. Wait for the Cluster object to be deleted in the bootstrap cluster:

    kubectl --kubeconfig <(./bin/kind get kubeconfig --name clusterapi) get cluster
    

    The system output must be empty.

  2. Remove the bootstrap cluster manually:

    ./bin/kind delete cluster --name clusterapi
    


Bare metal

[7655] Wrong status for an incorrectly configured L2 template

Fixed in 2.11.0

If an L2 template is configured incorrectly, a bare metal cluster is deployed successfully but with the runtime errors in the IpamHost object.

Workaround:

If you suspect that the machine is not working properly because of incorrect network configuration, verify the status of the corresponding IpamHost object. Inspect the l2RenderResult and ipAllocationResult object fields for error messages.



Storage

[7073] Cannot automatically remove a Ceph node

When removing a worker node, it is not possible to automatically remove a Ceph node. The workaround is to manually remove the Ceph node from the Ceph cluster as described in Operations Guide: Add, remove, or reconfigure Ceph nodes before removing the worker node from your deployment.

Note

Moving forward, the workaround for this issue will be moved from Release Notes to Operations Guide: Troubleshoot Ceph.

[10050] Ceph OSD pod is in the CrashLoopBackOff state after disk replacement

Fixed in 2.11.0

If you use a custom BareMetalHostProfile, after disk replacement on a Ceph OSD, the Ceph OSD pod switches to the CrashLoopBackOff state due to the Ceph OSD authorization key failing to be created properly.

Workaround:

  1. Export kubeconfig of your managed cluster. For example:

    export KUBECONFIG=~/Downloads/kubeconfig-test-cluster.yml
    
  2. Log in to the ceph-tools pod:

    kubectl -n rook-ceph exec -it $(kubectl -n rook-ceph get pod -l "app=rook-ceph-tools" -o jsonpath='{.items[0].metadata.name}') bash
    
  3. Delete the authorization key for the failed Ceph OSD:

    ceph auth del osd.<ID>
    
  4. SSH to the node on which the Ceph OSD cannot be created.

  5. Clean up the disk that will be a base for the failed Ceph OSD. For details, see official Rook documentation.

    Note

    Ignore failures of the sgdisk --zap-all $DISK and blkdiscard $DISK commands if any.

  6. On the managed cluster, restart the Rook operator:

    kubectl -n rook-ceph delete pod -l app=rook-ceph-operator
    

[12723] ceph_role_* labels remain after deleting a node from KaaSCephCluster

Fixed in 2.8.0

The ceph_role_mon and ceph_role_mgr labels that Ceph controller assigns to a node during a Ceph cluster creation are not automatically removed after deleting a node from KaaSCephCluster.

As a workaround, manually remove the labels using the following commands:

kubectl unlabel node <nodeName> ceph_role_mon
kubectl unlabel node <nodeName> ceph_role_mgr

IAM

[13385] MariaDB pods fail to start after SST sync

Fixed in 2.12.0

The MariaDB pods fail to start after MariaDB blocks itself during the State Snapshot Transfers sync.

Workaround:

  1. Verify the failed pod readiness:

    kubectl describe pod -n kaas <failedMariadbPodName>
    

    If the readiness probe failed with the WSREP not synced message, proceed to the next step. Otherwise, assess the MariaDB pod logs to identify the failure root cause.

  2. Obtain the MariaDB admin password:

    kubectl get secret -n kaas mariadb-dbadmin-password -o jsonpath='{.data.MYSQL_DBADMIN_PASSWORD}' | base64 -d ; echo
    
  3. Verify that wsrep_local_state_comment is Donor or Desynced:

    kubectl exec -it -n kaas <failedMariadbPodName> -- mysql -uroot -p<mariadbAdminPassword> -e "SHOW status LIKE \"wsrep_local_state_comment\";"
    
  4. Restart the failed pod:

    kubectl delete pod -n kaas <failedMariadbPodName>
    


LCM

[13845] Cluster update fails during the LCM agent upgrade with x509 error

Fixed in 2.11.0

During update of a managed cluster from the Cluster releases 6.12.0 to 6.14.0, the LCM agent upgrade fails with the following error in logs:

lcmAgentUpgradeStatus:
    error: 'failed to download agent binary: Get https://<mcc-cache-address>/bin/lcm/bin/lcm-agent/v0.2.0-289-gd7e9fa9c/lcm-agent:
      x509: certificate signed by unknown authority'

Only clusters initially deployed using Container Cloud 2.4.0 or earlier are affected.

As a workaround, restart lcm-agent using the service lcm-agent-* restart command on the affected nodes.


[13381] Management and regional clusters with enabled proxy are unreachable

Fixed in 2.8.0

After bootstrap, requests to apiserver fail on the management and regional clusters with enabled proxy.

As a workaround, before running bootstrap.sh, add the entire range of IP addresses that will be used for floating IPs to the NO_PROXY environment variable.

[13402] Cluster fails with error: no space left on device

Fixed in 2.8.0 for new clusters and in 2.10.0 for existing clusters

If an application running on a Container Cloud management or managed cluster fails frequently, for example, PostgreSQL, it may produce an excessive amount of core dumps. This leads to the no space left on device error on the cluster nodes and, as a result, to the broken Docker Swarm and the entire cluster.

Core dumps are disabled by default on the operating system of the Container Cloud nodes. But since Docker does not inherit the operating system settings, disable core dumps in Docker using the workaround below.

Warning

The workaround below does not apply to the baremetal-based clusters, including MOS deployments, since Docker restart may destroy the Ceph cluster.

Workaround:

  1. SSH to any machine of the affected cluster using mcc-user and the SSH key provided during the cluster creation.

  2. In /etc/docker/daemon.json, add the following parameters:

    {
        ...
        "default-ulimits": {
            "core": {
                "Hard": 0,
                "Name": "core",
                "Soft": 0
            }
        }
    }
    
  3. Restart the Docker daemon:

    systemctl restart docker
    
  4. Repeat the steps above on each machine of the affected cluster one by one.


[8112] Nodes occasionally become Not Ready on long-running clusters

On long-running Container Cloud clusters, one or more nodes may occasionally become Not Ready with different errors in the ucp-kubelet containers of failed nodes.

As a workaround, restart ucp-kubelet on the failed node:

ctr -n com.docker.ucp snapshot rm ucp-kubelet
docker rm -f ucp-kubelet

Note

Moving forward, the workaround for this issue will be moved from Release Notes to Operations Guide: Troubleshooting.

[10029] Authentication fails with the 401 Unauthorized error

Authentication may not work on some controller nodes after a managed cluster creation. As a result, the Kubernetes API operations with the managed cluster kubeconfig fail with Response Status: 401 Unauthorized.

As a workaround, manually restart the ucp-controller and ucp-auth Docker services on the affected node.

Note

Moving forward, the workaround for this issue will be moved from Release Notes to Operations Guide: Troubleshooting.

[6066] Helm releases get stuck in FAILED or UNKNOWN state

During a management, regional, or managed cluster deployment, Helm releases may get stuck in the FAILED or UNKNOWN state although the corresponding machines statuses are Ready in the Container Cloud web UI. For example, if the StackLight Helm release fails, the links to its endpoints are grayed out in the web UI. In the cluster status, providerStatus.helm.ready and providerStatus.helm.releaseStatuses.<releaseName>.success are false.

HelmBundle cannot recover from such states and requires manual actions. The workaround below describes the recovery steps for the stacklight release that got stuck during a cluster deployment. Use this procedure as an example for other Helm releases as required.

Workaround:

  1. Verify the failed release has the UNKNOWN or FAILED status in the HelmBundle object:

    kubectl --kubeconfig <regionalClusterKubeconfigPath> get helmbundle <clusterName> -n <clusterProjectName> -o=jsonpath={.status.releaseStatuses.stacklight}
    
    In the command above and in the steps below, replace the parameters
    enclosed in angle brackets with the corresponding values of your cluster.
    

    Example of system response:

    stacklight:
    attempt: 2
    chart: ""
    finishedAt: "2021-02-05T09:41:05Z"
    hash: e314df5061bd238ac5f060effdb55e5b47948a99460c02c2211ba7cb9aadd623
    message: '[{"occurrence":1,"lastOccurrenceDate":"2021-02-05 09:41:05","content":"error
      updating the release: rpc error: code = Unknown desc = customresourcedefinitions.apiextensions.k8s.io
      \"helmbundles.lcm.mirantis.com\" already exists"}]'
    notes: ""
    status: UNKNOWN
    success: false
    version: 0.1.2-mcp-398
    
  2. Log in to the helm-controller pod console:

    kubectl --kubeconfig <affectedClusterKubeconfigPath> exec -n kube-system -it helm-controller-0 sh -c tiller
    
  3. Remove the failed release. For example:

    ./helm --host=localhost:44134 delete stacklight
    

    If the version of the failed Helm release is v3:

    1. Download the Helm v3 binary. For details, see official Helm documentation.

    2. Remove the failed release:

      helm delete <failed-release-name>
      

    Once done, the release triggers for redeployment.



Upgrade

[13292] Local volume provisioner pod stuck in Terminating status after upgrade

After upgrade of Container Cloud from 2.6.0 to 2.7.0, the local volume provisioner pod in the default project is stuck in the Terminating status, even after upgrade to 2.8.0.

This issue does not affect functioning of the management, regional, or managed clusters. The issue does not prevent the successful upgrade of the cluster.

Workaround:

  1. Verify that the cluster is affected:

    kubectl get pods -n default | grep local-volume-provisioner
    

    If the output contains a pod with the Terminating status, the cluster is affected.

    Capture the affected pod name, if any.

  2. Delete the affected pod:

    kuebctl -n default delete pod <LVPPodName> --force
    

[9899] Helm releases get stuck in PENDING_UPGRADE during cluster update

Helm releases may get stuck in the PENDING_UPGRADE status during a management or managed cluster upgrade. The HelmBundle controller cannot recover from this state and requires manual actions. The workaround below describes the recovery process for the openstack-operator release that stuck during a managed cluster update. Use it as an example for other Helm releases as required.

Workaround:

  1. Log in to the helm-controller pod console:

    kubectl exec -n kube-system -it helm-controller-0 sh -c tiller
    
  2. Identify the release that stuck in the PENDING_UPGRADE status. For example:

    ./helm --host=localhost:44134 history openstack-operator
    

    Example of system response:

    REVISION  UPDATED                   STATUS           CHART                      DESCRIPTION
    1         Tue Dec 15 12:30:41 2020  SUPERSEDED       openstack-operator-0.3.9   Install complete
    2         Tue Dec 15 12:32:05 2020  SUPERSEDED       openstack-operator-0.3.9   Upgrade complete
    3         Tue Dec 15 16:24:47 2020  PENDING_UPGRADE  openstack-operator-0.3.18  Preparing upgrade
    
  3. Roll back the failed release to the previous revision. For example:

    ./helm --host=localhost:44134 rollback openstack-operator 2
    

    If the version of the failed Helm release is v3:

    1. Download the Helm v3 binary. For details, see official Helm documentation.

    2. Roll back the failed release:

      helm rollback <failed-release-name>
      

    Once done, the release will be reconciled.



Container Cloud web UI

[249] A newly created project does not display in the Container Cloud web UI

A project that is newly created in the Container Cloud web UI does not display in the Projects list even after refreshing the page. The issue occurs due to the token missing the necessary role for the new project. As a workaround, relogin to the Container Cloud web UI.