Troubleshooting upgrade

For a high level overview of the upgrade lifecycle and components, please refer to the related document.

Rancher side

In this example we upgraded the cluster nodes with the following ManagedOSImage definition:

apiVersion: elemental.cattle.io/v1beta1
kind: ManagedOSImage
metadata:
  name: my-upgrade
  namespace: fleet-default
spec:
  # Set to the new {elemental-product-name} version you would like to upgrade to or track the latest tag
  osImage: "registry.suse.com/rancher/sle-micro/5.5:latest"
  clusterTargets:
    - clusterName: my-cluster

Once the ManagedOSImage is applied, the elemental-operator will verify it and generate a related Bundle. The Bundle name will be prefixed with mos and then the ManagedOSImage name. In this case mos-my-upgrade.

In the Bundle definition, you will find the details about the upgrade plan and the desired target. For example:

kubectl -n fleet-default get bundle mos-my-upgrade -o yaml

Click here for details

apiVersion: fleet.cattle.io/v1alpha1
kind: Bundle
metadata:
  creationTimestamp: "2023-06-16T09:01:47Z"
  generation: 1
  name: mos-my-upgrade
  namespace: fleet-default
  ownerReferences:
  - apiVersion: elemental.cattle.io/v1beta1
    controller: true
    kind: ManagedOSImage
    name: my-upgrade
    uid: e468ed21-23bb-487a-a022-dbc7ef753720
  resourceVersion: "1038645"
  uid: 35e83fc4-28c8-4b10-8059-cae6cdff2cda
spec:
  resources:
  - content: '{"kind":"ClusterRole","apiVersion":"rbac.authorization.k8s.io/v1","metadata":{"name":"os-upgrader-my-upgrade","creationTimestamp":null},"rules":[{"verbs":["update","get","list","watch","patch"],"apiGroups":[""],"resources":["nodes"]},{"verbs":["list"],"apiGroups":[""],"resources":["pods"]}]}'
    name: ClusterRole--os-upgrader-my-upgrade-296a3abf3451.yaml
  - content: '{"kind":"ClusterRoleBinding","apiVersion":"rbac.authorization.k8s.io/v1","metadata":{"name":"os-upgrader-my-upgrade","creationTimestamp":null},"subjects":[{"kind":"ServiceAccount","name":"os-upgrader-my-upgrade","namespace":"cattle-system"}],"roleRef":{"apiGroup":"rbac.authorization.k8s.io","kind":"ClusterRole","name":"os-upgrader-my-upgrade"}}'
    name: ClusterRoleBinding--os-upgrader-my-upgrade-f63eaecde935.yaml
  - content: '{"kind":"ServiceAccount","apiVersion":"v1","metadata":{"name":"os-upgrader-my-upgrade","namespace":"cattle-system","creationTimestamp":null}}'
    name: ServiceAccount-cattle-system-os-upgrader-my-upgrade-ce93d-01096.yaml
  - content: '{"kind":"Secret","apiVersion":"v1","metadata":{"name":"os-upgrader-my-upgrade","namespace":"cattle-system","creationTimestamp":null},"data":{"cloud-config":""}}'
    name: Secret-cattle-system-os-upgrader-my-upgrade-a997ee6a67ef.yaml
  - content: '{"kind":"Plan","apiVersion":"upgrade.cattle.io/v1","metadata":{"name":"os-upgrader-my-upgrade","namespace":"cattle-system","creationTimestamp":null},"spec":{"concurrency":1,"nodeSelector":{},"serviceAccountName":"os-upgrader-my-upgrade","version":"latest","secrets":[{"name":"os-upgrader-my-upgrade","path":"/run/data"}],"tolerations":[{"operator":"Exists"}],"cordon":true,"upgrade":{"image":"registry.suse.com/suse/sle-micro/5.5","command":["/usr/sbin/suc-upgrade"]}},"status":{}}'
    name: Plan-cattle-system-os-upgrader-my-upgrade-273c2c09afca.yaml
  targets:
  - clusterName: my-cluster
.
.
.

SUSE® Rancher Prime: OS Manager Cluster side

Any SUSE® Rancher Prime: OS Manager node correctly registered and part of the target cluster will fetch the bundle and start applying it.
This operation is performed by the Rancher’s system-upgrade-controller running on the SUSE® Rancher Prime: OS Manager Cluster.
To monitor the correct operation of this controller, you can read its logs:

kubectl -n cattle-system logs deployment/system-upgrade-controller

If everything is correct, the system-upgrade-controller will create an upgrade Plan on the cluster:

kubectl -n cattle-system get plans

For each Plan, the controller will orchestrate the jobs that will apply it on each targeted node.
The job names will use the Plan name (os-upgrader-my-upgrade) and the target machine hostname (my-host) for easy discoverability.
For example: apply-os-upgrader-my-upgrade-on-my-host-7a25e
You can monitor these jobs with:

kubectl -n cattle-system get jobs

Each job will use a privileged: true container with the SLE Micro image specified in the ManagedOSImage definition. This container will try to upgrade the system and perform a reboot.

If the job fails, you can check its status by examining the logs:

kubectl -n cattle-system logs job.batch/apply-os-upgrader-my-upgrade-on-my-host-7a25e

Two stages job process

Note that the upgrade process is performed in two stages.
You will notice that the same job is ran twice and the first one ends with the Unknown Status and will not complete.
This is to be expected, as SUSE® Rancher Prime: OS Manager relies on the job to be ran again after the machine restarts, so that it can verify the new version was installed correctly.
You will notice a second run of the job, this time completing correctly.

kubectl -n cattle-system get jobs
NAMESPACE       NAME                                            COMPLETIONS   DURATION   AGE
cattle-system   apply-os-upgrader-my-upgrade-on-my-host-0b392   1/1           2m34s      6m23s
cattle-system   apply-os-upgrader-my-upgrade-on-my-host-7a25e   0/1           6m23s      6m23s

kubectl -n cattle-system get pods
NAME                                            READY   STATUS      RESTARTS      AGE
apply-os-upgrader-my-upgrade-on-my-host-zbkrh   0/1     Completed   0             9m40s
apply-os-upgrader-my-upgrade-on-my-host-zvrff   0/1     Unknown     0             12m

Recovering from failures

It is possible that the ManagedOSImage upgrade process will fail, leaving one or more nodes in a faulty state. For example, if the to-be-upgraded image is not found on the registry or otherwise broken, the upgrade job running on the downstream clusters will not succeed.

When this is the case, the nodes running the failing upgrade job will stay cordoned. You can update the ManagedOSImage with a functioning osImage, or alternatively delete it to stop any further upgrade attempt. In any case, in order to restore them and be able to also schedule following upgrades, the affected nodes need to be uncordoned manually.