Change Revision to Generation for consistency
Make reference to fact that Deployment and Stateful set both update from a specific revision to a specific revision
This commit is contained in:
Kenneth Owens
parent
708300f8ca
commit
ad19d350a4
|
|
@ -54,7 +54,7 @@ compensate for the application's scaling.
|
|||
- StatefulSet update must support singleton StatefulSets. However, an update in
|
||||
this case will cause a temporary outage. This is acceptable as a single
|
||||
process application is, by definition, not highly available.
|
||||
- Disruption in Kubernetes is controlled by PodDistruptionBugets. As
|
||||
- Disruption in Kubernetes is controlled by PodDistruptionBudgets. As
|
||||
StatefulSet updates progress one Pod at a time, and only occur when all
|
||||
other Pods have a Status of Running and a Ready Condition, they can not
|
||||
violate reasonable PodDisrutptionBugdets.
|
||||
|
|
@ -81,8 +81,10 @@ compensate for the application's scaling.
|
|||
- Stateful applications are likely to evolve wire protocols and storage formats
|
||||
between versions. In most cases, when updating the application's Pod's
|
||||
containers, it will not be safe to roll back or forward to an arbitrary
|
||||
version. StatefulSet update should work well when rolling out an update,
|
||||
or performing a rollback, between two specific revisions of the StatefulSet.
|
||||
version. Controller based Pod update should work well when rolling out an
|
||||
update, or performing a rollback, between two specific revisions of the
|
||||
controlled API object. This is how Deployment functions, and this property is,
|
||||
perhaps, even more critical for stateful applications.
|
||||
|
||||
## Requirements
|
||||
This design is based on the following requirements.
|
||||
|
|
@ -109,26 +111,26 @@ The following modifications will be made to the StatefulSetStatus API object.
|
|||
type StatefulSetStatus struct {
|
||||
// ObservedGeneration and Replicas fields are ommitted for brevity.
|
||||
|
||||
// TemplateRevision, if not nil, is the revision of the PodTemplate that was
|
||||
// TemplateGeneration, if not nil, is the generation of the PodTemplate that was
|
||||
// used to create Pods with ordinals in the sequence
|
||||
// [0,CurrentReplicas).
|
||||
TemplateRevision *int64 `json:"templateRevision,omitempty"`
|
||||
TemplateGeneration *int64 `json:"templateGeneration,omitempty"`
|
||||
|
||||
// TargetTemplateRevision, if not nil, is the revision of the PodTemplate
|
||||
// TargetTemplateGeneration, if not nil, is the generation of the PodTemplate
|
||||
// that was used to create Pods with ordinals in the sequence
|
||||
// [Replicas - UpdatedReplicas, Replicas).
|
||||
TargetTemplateRevision *int64 `json:"targetTemplateRevision,omitempty"`
|
||||
TargetTemplateGeneration *int64 `json:"targetTemplateGeneration,omitempty"`
|
||||
|
||||
// ReadyReplicas is the current number of Pods, created by the StatefulSet
|
||||
// controller, that have a Status for Running and a Ready Condition.
|
||||
ReadyReplicas int32 `json:"readyReplicas,omitempty"`
|
||||
|
||||
// CurrentRevisionReplicas is the number of Pods created by the StatefulSet
|
||||
// controller from the PodTemplateSpec indicated by CurrentTemplateRevision.
|
||||
// CurrentGenerationReplicas is the number of Pods created by the StatefulSet
|
||||
// controller from the PodTemplateSpec indicated by CurrentTemplateGeneration.
|
||||
CurrentReplicas int32 `json:"currentReplicas,omitempty"`
|
||||
|
||||
// UpdatedReplicas is the number of Pods created by the StatefulSet
|
||||
// controller from the PodTemplateSpec indicated by TargetTemplateRevision.
|
||||
// controller from the PodTemplateSpec indicated by TargetTemplateGeneration.
|
||||
UpdatedReplicas int32 `json:"taretReplicas,omitempty"`
|
||||
}
|
||||
```
|
||||
|
|
@ -141,25 +143,25 @@ type StatefulSetSpec struct {
|
|||
// ommitted for brevity.
|
||||
v1.PodTemplateSpec `json:"template"`
|
||||
|
||||
// TemplateRevision is a monotonically increasing, 64 bit, integer used to
|
||||
// TemplateGeneration is a monotonically increasing, 64 bit, integer used to
|
||||
// indicate the version of the of the PodTemplateSpec. If nil, the
|
||||
// StatefulSetController has not initialized its revision history,
|
||||
// change tracking is not enabled, and all Pods will be created from
|
||||
// Template.
|
||||
TemplateRevision *int64 `json:"templateRevision"`
|
||||
TemplateGeneration *int64 `json:"templateGeneration"`
|
||||
|
||||
// RevisionPartition partitions the Pods in the StatefulSet by ordinal such
|
||||
// GenerationPartition partitions the Pods in the StatefulSet by ordinal such
|
||||
// that all Pods with a lower ordinal will be created from the PodTemplate that
|
||||
// represents the current revision of the StatefulSet's revision history and
|
||||
// all Pods with an a greater or equal ordinal will be created from the
|
||||
// PodTemplate that represents the target revision of the StatefulSet's
|
||||
// revision history.
|
||||
RevisionPartition *int32 `json:"revisionPartition,omitempty`
|
||||
GenerationPartition *int32 `json:"generationPartition,omitempty`
|
||||
|
||||
// RevisionHistoryLimit is the maximum number of PodTemplates that will
|
||||
// be maintained in the StatefulSet's revision history. It must be at
|
||||
// least two.
|
||||
RevisionHisotryLimit int32 `json:historyRevisionDepth,omitempty`
|
||||
RevisionHisotryLimit int32 `json:revisionHistoryLimit,omitempty`
|
||||
}
|
||||
```
|
||||
|
||||
|
|
@ -171,10 +173,10 @@ Additionally, we introduce the following constants.
|
|||
// history.
|
||||
const StatefulSetPodTemplateLabel = "created-by-statefulset"
|
||||
|
||||
// StatefulSetTemplateRevisionLabel is the label applied to a PodTemplate or
|
||||
// StatefulSetTemplateGenerationLabel is the label applied to a PodTemplate or
|
||||
// Pod to indicate the position of the object's Template in the revision
|
||||
// history of a StatefulSet.
|
||||
const StatefulSetTemplateRevisionLabel = "statefulset-template-revision"
|
||||
const StatefulSetTemplateGenerationLabel = "statefulset-template-revision"
|
||||
```
|
||||
|
||||
## StatefulSet Controller
|
||||
|
|
@ -197,23 +199,23 @@ conform to the other. The conditions that define this state in terms of the
|
|||
StatefulSet's StatefulSetSpec and StatefulSetStatus are below.
|
||||
|
||||
1. The StatefulSet contains exactly `[0,.Spec.Replicas)` Pods.
|
||||
1. If StatefulSet's `.Spec.RevisionPartition` is nil, then the following is true.
|
||||
1. The StatefulSet's `.Status.TemplateRevision` is equal to its
|
||||
`.Status.TargetRevision`.
|
||||
1. If StatefulSet's `.Spec.GenerationPartition` is nil, then the following is true.
|
||||
1. The StatefulSet's `.Status.TemplateGeneration` is equal to its
|
||||
`.Status.TargetGeneration`.
|
||||
1. All Pods in the StatefulSet have been generated from the PodTemplate
|
||||
labeled with a `StatefulSetTemplateRevisionLabel` equal to its
|
||||
`.Status.TemplateRevision`.
|
||||
1. If the StatefulSet's `.Spec.RevisionPartition` is not nil, then the following
|
||||
labeled with a `StatefulSetTemplateGenerationLabel` equal to its
|
||||
`.Status.TemplateGeneration`.
|
||||
1. If the StatefulSet's `.Spec.GenerationPartition` is not nil, then the following
|
||||
is true.
|
||||
1. All Pods with ordinals is the sequence `[0,.Spec.RevisionPartition)` have
|
||||
1. All Pods with ordinals is the sequence `[0,.Spec.GenerationPartition)` have
|
||||
been generated from the PodTemplate in the StatefulSet's revision history
|
||||
that is labeled with a `StatefulSetTemplateRevisionLabel` equal to
|
||||
`.Status.TemplateRevision`.
|
||||
that is labeled with a `StatefulSetTemplateGenerationLabel` equal to
|
||||
`.Status.TemplateGeneration`.
|
||||
1. All Pods with ordinals in the sequence
|
||||
`[Spec.RevisionParition,.Spec.Replicas)` have been created with the
|
||||
`[Spec.GenerationParition,.Spec.Replicas)` have been created with the
|
||||
PodTemplate in the StatefulSet's revision history that is labeled with a
|
||||
`StatefulSetTemplateRevisionLabel` equal to
|
||||
`.Status.TargetTemplateRevision`.
|
||||
`StatefulSetTemplateGenerationLabel` equal to
|
||||
`.Status.TargetTemplateGeneration`.
|
||||
|
||||
### Revised Controller Algorithm
|
||||
The StatefulSet controller will use the following algorithm to continue to
|
||||
|
|
@ -274,10 +276,10 @@ StatefulSet's `.Spec.Template` field.
|
|||
`StatefulSetPodTemplateLabel` set to the StatefulSet's `.Name` to allow for
|
||||
selection of the PodTemplates that comprise the StatefulSet's revision history.
|
||||
1. The controller will label the PodTemplate with a
|
||||
`StaefulSetTemplateRevisionLabel` set to the StatefulSet's
|
||||
`.Spec.TemplateRevision`.
|
||||
`StaefulSetTemplateGenerationLabel` set to the StatefulSet's
|
||||
`.Spec.TemplateGeneration`.
|
||||
1. The controller will set the Name of the PodTemplate to a concatenation of the
|
||||
`.Name` of the StatefulSet and the `.Spec.TemplateRevision`.
|
||||
`.Name` of the StatefulSet and the `.Spec.TemplateGeneration`.
|
||||
1. The controller will then create the PodTemplate.
|
||||
|
||||
#### PodTemplate Deletion
|
||||
|
|
@ -297,7 +299,7 @@ and it will allow the PodTemplate to be deleted via garbage collection.
|
|||
In order to reconstruct the history of revisions to a StatefulSet, the
|
||||
StatefulSet controller will do the following.
|
||||
|
||||
1. If the StatefulSet's `.Spec.TemplateRevision` is nil, the StatefulSet
|
||||
1. If the StatefulSet's `.Spec.TemplateGeneration` is nil, the StatefulSet
|
||||
has never been updated, and its history has never been initialized. This is
|
||||
the state the object will be in when a cluster is first upgraded from a version
|
||||
that does not support StatefulSet update to a version that does. In this case,
|
||||
|
|
@ -311,12 +313,12 @@ ControllerRef matching the the StatefulSet. If the controller selects
|
|||
PodTemplates that it does not own, it will report an error, but it will continue
|
||||
reconstructing the StatefulSet's history.
|
||||
1. The controller will filter out all PodTemplates that do not have a
|
||||
`StatefulSetTemplateRevisionLabel` mapped to a valid revision. This can only
|
||||
`StatefulSetTemplateGenerationLabel` mapped to a valid revision. This can only
|
||||
occur if the user purposefully deletes the label. In this case, the
|
||||
controller will report an error, but it will continue reconstructing the
|
||||
StatefulSet's revision history.
|
||||
1. For all the remaining PodTemplates, the controller will sort them in
|
||||
ascending order by the value mapped to their `StatefulSetTemplateRevisionLabel`.
|
||||
ascending order by the value mapped to their `StatefulSetTemplateGenerationLabel`.
|
||||
This will reconstruct a list of PodTemplates from oldest to newest. Note that,
|
||||
as the revision is monotonically increasing for an individual StatefulSet, and
|
||||
as we use ControllerRef to mitigate selector overlap, the StatefulSet's history
|
||||
|
|
@ -331,13 +333,13 @@ the oldest PodTemplates from the StatefulSet's revision history.
|
|||
[reconstruct the revision history](#history-reconstruction)
|
||||
of the StatefulSet.
|
||||
1. If the number of PodTemplates in the StatefulSet's revision history is
|
||||
greater than the StatefulSet's `.Spec.RevisionHistoryLimit, the
|
||||
greater than the StatefulSet's `.Spec.RevisionHistoryLimit`, the
|
||||
StatefulSet controller will delete PodTemplates, starting with the head of
|
||||
the revision history, until the limit of the revision history is equal to
|
||||
the StatefulSet's `.Spec.RevisionHistoryLimit`.
|
||||
1. As a StatefulSet's `.Spec.RevisionHistoryLimit` is always at least two, and
|
||||
as the PodTemplates corresponding to `.Status.TemplateRevision`
|
||||
or `.Status.TargetTemplateRevision` are always the most recent PodTemplates
|
||||
as the PodTemplates corresponding to `.Status.TemplateGeneration`
|
||||
or `.Status.TargetTemplateGeneration` are always the most recent PodTemplates
|
||||
in the revision history, the StatefulSet controller will not delete any
|
||||
`PodTemplates` that represent the current or target revisions.
|
||||
|
||||
|
|
@ -346,21 +348,21 @@ The StatefulSet controller will create PodTemplates upon mutation of the
|
|||
`.Spec.Template` of a StatefulSet.
|
||||
|
||||
1. When the StafefulSet controller observes a mutation to a StatefulSet's
|
||||
`.Spec.Template` it will compare the `.Spec.TemplateRevision` to the
|
||||
`.Status.TargetTemplateRevision`.
|
||||
1. If the `.Spec.TemplateRevision` is equivalent to the
|
||||
`.Status.TargetTemplateRevision`, no update has occurred. Note that, in the
|
||||
`.Spec.Template` it will compare the `.Spec.TemplateGeneration` to the
|
||||
`.Status.TargetTemplateGeneration`.
|
||||
1. If the `.Spec.TemplateGeneration` is equivalent to the
|
||||
`.Status.TargetTemplateGeneration`, no update has occurred. Note that, in the
|
||||
event that both are nil, they are considered to be equivalent, and we expect
|
||||
this to occur after an initial upgrade to a version of Kubernetes that supports
|
||||
StatefulSet update form one that does not.
|
||||
1. If the `.Status.TemplateRevision` field is nil, and the
|
||||
`.Spec.TemplateRevision` is not nil, then the StatefulSet has no revision
|
||||
1. If the `.Status.TemplateGeneration` field is nil, and the
|
||||
`.Spec.TemplateGeneration` is not nil, then the StatefulSet has no revision
|
||||
history. To initialize its revision history, the StatefulSet controller will
|
||||
set both `.Status.TemplateRevision` and `.Status.TargetTemplateRevision`
|
||||
to `.Spec.TemplateRevision` and
|
||||
set both `.Status.TemplateGeneration` and `.Status.TargetTemplateGeneration`
|
||||
to `.Spec.TemplateGeneration` and
|
||||
[create a new PodTemplate](#podtemplate-creation).
|
||||
1. If the `.Status.TemplateRevision` is not nil, and if the
|
||||
`.Spec.TemplateRevision` is not equal to the `.Status.TargetTemplateRevision`,
|
||||
1. If the `.Status.TemplateGeneration` is not nil, and if the
|
||||
`.Spec.TemplateGeneration` is not equal to the `.Status.TargetTemplateGeneration`,
|
||||
the StatefulSet controller will do the following.
|
||||
1. The controller will
|
||||
[reconstruct the revision history](#history-reconsturction) of the
|
||||
|
|
@ -382,49 +384,49 @@ Pod. These criteria allow the controller to continue to make progress toward
|
|||
its target state, while respecting its guarantees and allowing for rolling
|
||||
updates back and forward.
|
||||
|
||||
1. If the StatefulSet's `.Spec.TemplateRevision` is nil, then the cluster
|
||||
1. If the StatefulSet's `.Spec.TemplateGeneration` is nil, then the cluster
|
||||
has been upgraded from a version that does not support StatefulSet update to
|
||||
a version that does.
|
||||
1. In this case the `.Spec.Template` is the current revision,
|
||||
and no Pods in the StatefulSet should be labeled with a
|
||||
`StatefulSetPodTemplateRevision` label.
|
||||
`StatefulSetPodTemplateGeneration` label.
|
||||
1. The StatefulSet will initialize its revision history on the first
|
||||
update to its `.Spec.Template`.
|
||||
1. If the StatefulSet's `.Spec.TemplateRevision` is equal to its
|
||||
`.Status.TemplateRevision`, then there is no update in progress and all
|
||||
1. If the StatefulSet's `.Spec.TemplateGeneration` is equal to its
|
||||
`.Status.TemplateGeneration`, then there is no update in progress and all
|
||||
Pods will be created from the PodTemplate matching this revision.
|
||||
1. If the Pod's ordinal is in the sequence `[0,.Status.CurrentReplicas)`,
|
||||
then it was previously created from the PodTemplate matching the
|
||||
StatefulSet's `.Status.TemplateRevision`, and it will be recreated
|
||||
StatefulSet's `.Status.TemplateGeneration`, and it will be recreated
|
||||
from this PodTemplate.
|
||||
1. If the Pod's ordinal is in the sequence
|
||||
`[.Spec.Replicas-.Status.UpdatedReplicas,.Spec.Replicas)`, then it was
|
||||
previously created from the PodTemplate matching the StatefulSet's,
|
||||
`.Status.TargetTemplateRevision`, and it will be recreated from this
|
||||
`.Status.TargetTemplateGeneration`, and it will be recreated from this
|
||||
PodTemplate.
|
||||
1. If the ordinal does not meet either of the prior two conditions, and
|
||||
if ordinal is in the sequence `[0, .Spec.RevisionPartition)`, it will be created
|
||||
if ordinal is in the sequence `[0, .Spec.GenerationPartition)`, it will be created
|
||||
from the PodTemplate matching the StatefulSet's
|
||||
`.Status.TemplateRevision`.
|
||||
`.Status.TemplateGeneration`.
|
||||
1. Otherwise, the Pod is created from the PodTemplate matching the
|
||||
StatefulSet's `.Status.TargetTemplateRevision`.
|
||||
StatefulSet's `.Status.TargetTemplateGeneration`.
|
||||
|
||||
### Update Completion
|
||||
A StatefulSet update is complete when the following conditions are met.
|
||||
|
||||
1. All Pods with ordinals in the sequence `[0,.Spec.Replicas)` have a Status of
|
||||
Running and a Ready Condition.
|
||||
1. The StatefulSet's `.Spec.RevisionPartition` is equal to `0`.
|
||||
1. The StatefulSet's `.Spec.GenerationPartition` is equal to `0`.
|
||||
1. All Pods in the StatefulSet are labeled with a
|
||||
`StatefulSetTemplateRevisionLabel` equal to the StatefulSet's
|
||||
`.Status.TargetTemplateRevision` (This implies they have been created from
|
||||
`StatefulSetTemplateGenerationLabel` equal to the StatefulSet's
|
||||
`.Status.TargetTemplateGeneration` (This implies they have been created from
|
||||
the PodTemplate at that revision).
|
||||
|
||||
When a StatefulSet update is complete, the controller will signal completion by
|
||||
doing the following.
|
||||
|
||||
1. The controller will set the StatefulSet's `.Status.TemplateRevision` to its
|
||||
`.Status.TargetTemplateRevision`.
|
||||
1. The controller will set the StatefulSet's `.Status.TemplateGeneration` to its
|
||||
`.Status.TargetTemplateGeneration`.
|
||||
1. The controller will set the StatefulSet's `Status.CurrentReplicas` to its
|
||||
`Status.UpdatedReplicas`.
|
||||
1. The controller will set the StatefulSet's `Status.UpdatedReplicas` to 0.
|
||||
|
|
@ -449,8 +451,8 @@ the `.Generation` of the StatefulSet object that was observed.
|
|||
created Pods.
|
||||
1. The controller will set the `.Status.ReadyReplicas` to the current number of
|
||||
Pods that have a Status of Running and a ReadyCondition.
|
||||
1. The controller will set the `.Status.TemplateRevision` and
|
||||
`.Status.TargetTemplateRevision`
|
||||
1. The controller will set the `.Status.TemplateGeneration` and
|
||||
`.Status.TargetTemplateGeneration`
|
||||
in accordance with [maintaining its revision history](#history-maintenance)
|
||||
and the status of any [complete updates](#update-completion).
|
||||
1. The controller will set the `.Status.CurrentReplicas` to the number of
|
||||
|
|
@ -464,7 +466,7 @@ communicate it to observers.
|
|||
|
||||
## API Server
|
||||
The API Server will perform validation for StatefulSet updates and ensure that
|
||||
a StatefulSet's `.Spec.TemplateRevision` is a generator for a strictly
|
||||
a StatefulSet's `.Spec.TemplateGeneration` is a generator for a strictly
|
||||
monotonically increasing sequence.
|
||||
|
||||
### StatefulSet Validation
|
||||
|
|
@ -473,13 +475,13 @@ fields of the StatefulSet object other than `.Spec.Replicas` and
|
|||
`.Spec.Template.Containers`. This design imposes the following, additional
|
||||
constraints.
|
||||
|
||||
1. The `.Spec.RevisionHistoryDepty` must be greater than or equal to `2`.
|
||||
1. The `.Spec.RevisionHistoryLimit` must be greater than or equal to `2`.
|
||||
1. The `.Spec.PositionOrdinal` must be in the sequence `[0,.Spec.Replicas)`.
|
||||
|
||||
### TemplateRevision Maintenance
|
||||
### TemplateGeneration Maintenance
|
||||
It will be the responsibility of the API Server to enforce that updates to
|
||||
StatefulSet's `.Spec.Template` atomically increment the
|
||||
`.Spec.TemplateRevision` counter. There is no need for the value to be
|
||||
`.Spec.TemplateGeneration` counter. There is no need for the value to be
|
||||
strictly sequential, but it must be strictly, monotonically increasing.
|
||||
As validation will not allow mutation to any field other than the
|
||||
`.Spec.Template.Containers` field, the API Server need not track all fields of
|
||||
|
|
@ -599,7 +601,7 @@ kubectl apply -f web.yaml
|
|||
### Canaries
|
||||
Users can create a canary using `kubectl apply`. The only difference between a
|
||||
[rolling update](#rolling-out-an-update) and a canary is that the
|
||||
`.Spec.RevisionPartition` is set to `.Spec.Replicas - 1`.
|
||||
`.Spec.GenerationPartition` is set to `.Spec.Replicas - 1`.
|
||||
|
||||
```yaml
|
||||
apiVersion: apps/v1beta1
|
||||
|
|
@ -623,7 +625,7 @@ spec:
|
|||
volumeMounts:
|
||||
- name: www
|
||||
mountPath: /usr/share/nginx/html
|
||||
revisionPartition: 2
|
||||
generationParition: 2
|
||||
volumeClaimTemplates:
|
||||
- metadata:
|
||||
name: www
|
||||
|
|
@ -661,7 +663,7 @@ spec:
|
|||
volumeMounts:
|
||||
- name: www
|
||||
mountPath: /usr/share/nginx/html
|
||||
partitionOrdinal: 3
|
||||
generationParition: 3
|
||||
volumeClaimTemplates:
|
||||
- metadata:
|
||||
name: www
|
||||
|
|
@ -676,7 +678,7 @@ spec:
|
|||
|
||||
### Staged Roll Outs
|
||||
Users can create a canary using `kubectl apply`. The only difference between a
|
||||
[canary](#canaries) and a staged roll out is that the `.Spec.RevisionPartition`
|
||||
[canary](#canaries) and a staged roll out is that the `.Spec.GenerationPartition`
|
||||
is set to value less than `.Spec.Replicas - 1`.
|
||||
|
||||
```yaml
|
||||
|
|
@ -701,7 +703,7 @@ spec:
|
|||
volumeMounts:
|
||||
- name: www
|
||||
mountPath: /usr/share/nginx/html
|
||||
revisionParition: 2
|
||||
generationParition: 2
|
||||
volumeClaimTemplates:
|
||||
- metadata:
|
||||
name: www
|
||||
|
|
@ -718,7 +720,7 @@ Staged roll outs can be used to roll out a configuration, image, or resource
|
|||
update to some portion of the fleet maintained by the StatefulSet prior to
|
||||
updating the entire fleet. It is useful to support linear, geometric, and
|
||||
exponential roll out of an update. Users can modify the
|
||||
`.Spec.RevisionPartition` to allow the roll out to progress.
|
||||
`.Spec.GenerationPartition` to allow the roll out to progress.
|
||||
|
||||
```yaml
|
||||
apiVersion: apps/v1beta1
|
||||
|
|
@ -742,7 +744,7 @@ spec:
|
|||
volumeMounts:
|
||||
- name: www
|
||||
mountPath: /usr/share/nginx/html
|
||||
revisionPartition: 1
|
||||
generationParition: 1
|
||||
volumeClaimTemplates:
|
||||
- metadata:
|
||||
name: www
|
||||
|
|
@ -771,8 +773,8 @@ Rolling back is usually the safest, and often the fastest, strategy to mitigate
|
|||
deployment failure, but rolling forward is sometimes the only practical solution
|
||||
for stateful applications (e.g. A users has a minor configuration error but has
|
||||
already modified the storage format for the application). Users can use
|
||||
sequential `kubectl apply`'s to update the `.Status.TargetRevision` of a
|
||||
StatefulSet. This will respect the `.Spec.RevisionPartition` with respect to the
|
||||
sequential `kubectl apply`'s to update the `.Status.TargetGeneration` of a
|
||||
StatefulSet. This will respect the `.Spec.GenerationPartition` with respect to the
|
||||
target state, and it therefor interacts well with canaries and staged roll outs.
|
||||
Note that, while users can update the target template revision, they can not
|
||||
update the current template revision. The only way to advance the current
|
||||
|
|
@ -829,7 +831,7 @@ would for these events for StatefulSet update.
|
|||
While this proposal does not address
|
||||
[VolumeTemplateSpec updates](https://github.com/kubernetes/kubernetes/issues/41015),
|
||||
this would be a valuable feature for production users of storage systems that use
|
||||
intermittent compaction as a form of garbage collection. Application that use
|
||||
intermittent compaction as a form of garbage collection. Applications that use
|
||||
log structured merge trees with size tiered compaction (e.g Cassandra) or append
|
||||
only B(+/*) Trees (e.g Couchbase) can temporarily double their storage usage when
|
||||
compacting their on disk storage. If there is insufficient space for compaction
|
||||
|
|
|
|||
Loading…
Reference in New Issue