Known issues

This section lists known issues with workarounds for the Mirantis Container Cloud release 2.26.0 including the Cluster releases 17.1.0 and 16.1.0.

For other issues that can occur while deploying and operating a Container Cloud cluster, see Deployment Guide: Troubleshooting and Operations Guide: Troubleshooting.


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

Bare metal

[24005] Deletion of a node with ironic Pod is stuck in the Terminating state

During deletion of a manager machine running the ironic Pod from a bare metal management cluster, the following problems occur:

  • All Pods are stuck in the Terminating state

  • A new ironic Pod fails to start

  • The related bare metal host is stuck in the deprovisioning state

As a workaround, before deletion of the node running the ironic Pod, cordon and drain the node using the kubectl cordon <nodeName> and kubectl drain <nodeName> commands.


[40747] Unsupported Cluster release is available for managed cluster deployment

The Cluster release 16.0.0, which is not supported for greenfield vSphere-based deployments, is still available in the drop-down menu of the cluster creation window in the Container Cloud web UI.

Do not select this Cluster release to prevent deployment failures. Use the latest supported version instead.


[40036] Node is not removed from a cluster when its Machine is disabled

During the ClusterRelease update of a MOSK cluster, a node cannot be removed from the Kubernetes cluster if the related Machine object is disabled.

As a workaround, remove the finalizer from the affected Node object.

[39437] Failure to replace a master node on a Container Cloud cluster

During the replacement of a master node on a cluster of any type, the process may get stuck with Kubelet's NodeReady condition is Unknown in the machine status on the remaining master nodes.

As a workaround, log in on the affected node and run the following command:

docker restart ucp-kubelet

[31186,34132] Pods get stuck during MariaDB operations

Due to the upstream MariaDB issue, during MariaDB operations on a management cluster, Pods may get stuck in continuous restarts with the following example error:

[ERROR] WSREP: Corrupt buffer header: \
addr: 0x7faec6f8e518, \
seqno: 3185219421952815104, \
size: 909455917, \
ctx: 0x557094f65038, \
flags: 11577. store: 49, \
type: 49


  1. Create a backup of the /var/lib/mysql directory on the mariadb-server Pod.

  2. Verify that other replicas are up and ready.

  3. Remove the galera.cache file for the affected mariadb-server Pod.

  4. Remove the affected mariadb-server Pod or wait until it is automatically restarted.

After Kubernetes restarts the Pod, the Pod clones the database in 1-2 minutes and restores the quorum.

[30294] Replacement of a master node is stuck on the calico-node Pod start

During replacement of a master node on a cluster of any type, the calico-node Pod fails to start on a new node that has the same IP address as the node being replaced.


  1. Log in to any master node.

  2. From a CLI with an MKE client bundle, create a shell alias to start calicoctl using the mirantis/ucp-dsinfo image:

    alias calicoctl="\
    docker run -i --rm \
    --pid host \
    --net host \
    -e constraint:ostype==linux \
    -e ETCD_ENDPOINTS=<etcdEndpoint> \
    -e ETCD_KEY_FILE=/var/lib/docker/volumes/ucp-kv-certs/_data/key.pem \
    -e ETCD_CA_CERT_FILE=/var/lib/docker/volumes/ucp-kv-certs/_data/ca.pem \
    -e ETCD_CERT_FILE=/var/lib/docker/volumes/ucp-kv-certs/_data/cert.pem \
    -v /var/run/calico:/var/run/calico \
    -v /var/lib/docker/volumes/ucp-kv-certs/_data:/var/lib/docker/volumes/ucp-kv-certs/_data:ro \
    mirantis/ucp-dsinfo:<mkeVersion> \
    calicoctl \
    alias calicoctl="\
    docker run -i --rm \
    --pid host \
    --net host \
    -e constraint:ostype==linux \
    -e ETCD_ENDPOINTS=<etcdEndpoint> \
    -e ETCD_KEY_FILE=/ucp-node-certs/key.pem \
    -e ETCD_CA_CERT_FILE=/ucp-node-certs/ca.pem \
    -e ETCD_CERT_FILE=/ucp-node-certs/cert.pem \
    -v /var/run/calico:/var/run/calico \
    -v ucp-node-certs:/ucp-node-certs:ro \
    mirantis/ucp-dsinfo:<mkeVersion> \
    calicoctl --allow-version-mismatch \

    In the above command, replace the following values with the corresponding settings of the affected cluster:

    • <etcdEndpoint> is the etcd endpoint defined in the Calico configuration file. For example, ETCD_ENDPOINTS=

    • <mkeVersion> is the MKE version installed on your cluster. For example, mirantis/ucp-dsinfo:3.5.7.

  3. Verify the node list on the cluster:

    kubectl get node
  4. Compare this list with the node list in Calico to identify the old node:

    calicoctl get node -o wide
  5. Remove the old node from Calico:

    calicoctl delete node kaas-node-<nodeID>

[5782] Manager machine fails to be deployed during node replacement

During replacement of a manager machine, the following problems may occur:

  • The system adds the node to Docker swarm but not to Kubernetes

  • The node Deployment gets stuck with failed RethinkDB health checks


  1. Delete the failed node.

  2. Wait for the MKE cluster to become healthy. To monitor the cluster status:

    1. Log in to the MKE web UI as described in Connect to the Mirantis Kubernetes Engine web UI.

    2. Monitor the cluster status as described in MKE Operations Guide: Monitor an MKE cluster with the MKE web UI.

  3. Deploy a new node.

[5568] The calico-kube-controllers Pod fails to clean up resources

During the unsafe or forced deletion of a manager machine running the calico-kube-controllers Pod in the kube-system namespace, the following issues occur:

  • The calico-kube-controllers Pod fails to clean up resources associated with the deleted node

  • The calico-node Pod may fail to start up on a newly created node if the machine is provisioned with the same IP address as the deleted machine had

As a workaround, before deletion of the node running the calico-kube-controllers Pod, cordon and drain the node:

kubectl cordon <nodeName>
kubectl drain <nodeName>


[26441] Cluster update fails with the MountDevice failed for volume warning

Update of a managed cluster based on bare metal and Ceph enabled fails with PersistentVolumeClaim getting stuck in the Pending state for the prometheus-server StatefulSet and the MountVolume.MountDevice failed for volume warning in the StackLight event logs.


  1. Verify that the description of the Pods that failed to run contain the FailedMount events:

    kubectl -n <affectedProjectName> describe pod <affectedPodName>

    In the command above, replace the following values:

    • <affectedProjectName> is the Container Cloud project name where the Pods failed to run

    • <affectedPodName> is a Pod name that failed to run in the specified project

    In the Pod description, identify the node name where the Pod failed to run.

  2. Verify that the csi-rbdplugin logs of the affected node contain the rbd volume mount failed: <csi-vol-uuid> is being used error. The <csi-vol-uuid> is a unique RBD volume name.

    1. Identify csiPodName of the corresponding csi-rbdplugin:

      kubectl -n rook-ceph get pod -l app=csi-rbdplugin \
      -o jsonpath='{.items[?(@.spec.nodeName == "<nodeName>")]}'
    2. Output the affected csiPodName logs:

      kubectl -n rook-ceph logs <csiPodName> -c csi-rbdplugin
  3. Scale down the affected StatefulSet or Deployment of the Pod that fails to 0 replicas.

  4. On every csi-rbdplugin Pod, search for stuck csi-vol:

    for pod in `kubectl -n rook-ceph get pods|grep rbdplugin|grep -v provisioner|awk '{print $1}'`; do
      echo $pod
      kubectl exec -it -n rook-ceph $pod -c csi-rbdplugin -- rbd device list | grep <csi-vol-uuid>
  5. Unmap the affected csi-vol:

    rbd unmap -o force /dev/rbd<i>

    The /dev/rbd<i> value is a mapped RBD volume that uses csi-vol.

  6. Delete volumeattachment of the affected Pod:

    kubectl get volumeattachments | grep <csi-vol-uuid>
    kubectl delete volumeattacmhent <id>
  7. Scale up the affected StatefulSet or Deployment back to the original number of replicas and wait until its state becomes Running.


[36928] The helm-controller Deployment is stuck during cluster update

During a cluster update, a Kubernetes helm-controller Deployment may get stuck in a restarting Pod loop with Terminating and Running states flapping. Other Deployment types may also be affected.

As a workaround, restart the Deployment that got stuck:

kubectl -n <affectedProjectName> get deploy <affectedDeployName> -o yaml

kubectl -n <affectedProjectName> scale deploy <affectedDeployName> --replicas 0

kubectl -n <affectedProjectName> scale deploy <affectedDeployName> --replicas <replicasNumber>

In the command above, replace the following values:

  • <affectedProjectName> is the Container Cloud project name containing the cluster with stuck Pods

  • <affectedDeployName> is the Deployment name that failed to run Pods in the specified project

  • <replicasNumber> is the original number of replicas for the Deployment that you can obtain using the get deploy command

Container Cloud web UI

[41806] Configuration of a management cluster fails without Keycloak settings

During configuration of a management cluster settings using the Configure cluster web UI menu, updating the Keycloak Truststore settings is mandatory, despite being optional.

As a workaround, update the management cluster using the API or CLI.