Helm install in certain order

KubernetesKubernetes Helm

Kubernetes Problem Overview


I am trying to create a Helm Chart with the following resources:

  1. Secret
  2. ConfigMap
  3. Service
  4. Job
  5. Deployment

These are also in the order that I would like them to be deployed. I have put a hook in the Deployment so that it is post-install, but then Helm does not see it as a resource and I have to manually manage it.

The Job needs the information in the Secret and ConfigMap, otherwise I would make that a pre-install hook. But I can't make everything a hook or nothing will be managed in my release.

Does anyone have a solution or idea to be able to manage all of the resources within the Helm release AND make sure the Job finishes before the Deployment begins?

My only thought right now is two make two Charts: One with 1-4 and the second with 5 which would depend on the first.

Kubernetes Solutions


Solution 1 - Kubernetes

Helm collects all of the resources in a given Chart and it's dependencies, groups them by resource type, and then installs them in the following order (see here - Helm 2.10):

  1. Namespace
  2. ResourceQuota
  3. LimitRange
  4. PodSecurityPolicy
  5. Secret
  6. ConfigMap
  7. StorageClass
  8. PersistentVolume
  9. PersistentVolumeClaim
  10. ServiceAccount
  11. CustomResourceDefinition
  12. ClusterRole
  13. ClusterRoleBinding
  14. Role
  15. RoleBinding
  16. Service
  17. DaemonSet
  18. Pod
  19. ReplicationController
  20. ReplicaSet
  21. Deployment
  22. StatefulSet
  23. Job
  24. CronJob
  25. Ingress
  26. APIService

During uninstallation of a release, the order is reversed (see here).

Following this logic, in your case when your Job resource is created, both the Secret and the ConfigMap will already be applied, but Helm won't wait for the Job to complete before applying the Deployment. If you split your Chart to two parts (1-4, 5) and install them sequentially you would still have the problem of the Deployment being possibly applied before the Job is completed. What I would suggest is splitting your Chart to two parts (1-3, 4-5), in which the the Job has a pre-install hook, which would make sure it completes before your Deployment is applied.

Solution 2 - Kubernetes

Helm tries to install things in a certain order, but doesn't check if pods / deployments / jobs are running / completed before moving on. Also note that a chart and its dependencies are installed simultaneously, so you cannot use a chart with a dependency to re-order how Helm installs resources.

You can use chart hooks to change the order, but these aren't managed resources. In my case, the problem was that we needed custom resources up, then we needed a short script to run, and then we needed to start our deployments. With --wait, if the pod the script was in completed, Helm would mark the upgrade/install as a failure and rollback. The solution in this case was just to use a Job instead of a Pod, which commenters on that issue had more problems with than I did, and then accept that the deployments would restart a few times before everything finally became ready.

Helm 3.7 install order:

  1. Namespace
  2. NetworkPolicy
  3. ResourceQuota
  4. LimitRange
  5. PodSecurityPolicy
  6. PodDisruptionBudget
  7. ServiceAccount
  8. Secret
  9. SecretList
  10. ConfigMap
  11. StorageClass
  12. PersistentVolume
  13. PersistentVolumeClaim
  14. CustomResourceDefinition
  15. ClusterRole
  16. ClusterRoleList
  17. ClusterRoleBinding
  18. ClusterRoleBindingList
  19. Role
  20. RoleList
  21. RoleBinding
  22. RoleBindingList
  23. Service
  24. DaemonSet
  25. Pod
  26. ReplicationController
  27. ReplicaSet
  28. Deployment
  29. HorizontalPodAutoscaler
  30. StatefulSet
  31. Job
  32. CronJob
  33. Ingress
  34. APIService
  35. this closed git issue tells us CustomResources are last to be installed.

Source. Only difference from above is more resource types and the ServiceAccount got pushed up slightly in the list.

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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionwaterprincessView Question on Stackoverflow
Solution 1 - KubernetesYaniv OliverView Answer on Stackoverflow
Solution 2 - KubernetesjeremysprofileView Answer on Stackoverflow