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Fixes typo in guarantees 

Removes deprecation from comment wrt PetSets
Creates separate section in concepts/index.md for Controllers
Fixes grammer "an integer"
Removes claim about persistent storage being auto-deleted
Clarifies stability
Adds call out tick around attributes
This commit is contained in:
Kenneth Owens 2016-11-18 15:35:14 -08:00
parent 7aa8c5d2e6
commit 094a51fc2e
2 changed files with 11 additions and 8 deletions
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17
docs/concepts/controllers/statefulsets.md
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@ -10,13 +10,13 @@ assignees:
--- ---
{% capture overview %} {% capture overview %}
**Stateful Sets are a beta feature in 1.5. This feature replaces the deprecated **Stateful Sets are a beta feature in 1.5. This feature replaces the
Pet Sets feature from 1.4. Users of Pet Sets are referred to the 1.5 Pet Sets feature from 1.4. Users of Pet Sets are referred to the 1.5
[Upgrade Guide](/docs/tasks/stateful-set/upgrade-from-petsets-to-stateful-sets/) [Upgrade Guide](/docs/tasks/stateful-set/upgrade-from-petsets-to-stateful-sets/)
for further information on how to upgrade existing Pet Sets to Stateful Sets.** for further information on how to upgrade existing Pet Sets to Stateful Sets.**
A Stateful Set is a Controller that ensures that provides a unique identity to A Stateful Set is a Controlle provides a unique identity to its Pods, and it provides
its Pods, and provides garuantees about the ordering of deployment and scaling. guarantees about the ordering of deployment and scaling.
{% endcapture %} {% endcapture %}
{% capture body %} {% capture body %}
@ -30,6 +30,7 @@ following.
* Ordered, graceful deployment and scaling. * Ordered, graceful deployment and scaling.
* Ordered, graceful deletion and termination. * Ordered, graceful deletion and termination.
In the above, by stable, we mean persistent across Pod (re) schedulings.
As it is generally easier to manage, if an application doesn't require any of As it is generally easier to manage, if an application doesn't require any of
the above guarantees, and if it is feasible to do so, it should be deployed as the above guarantees, and if it is feasible to do so, it should be deployed as
a set of stateless replicas. a set of stateless replicas.
@ -38,7 +39,7 @@ a set of stateless replicas.
* Stateful Set is a beta resource, not available in any Kubernetes release prior to 1.5. * Stateful Set is a beta resource, not available in any Kubernetes release prior to 1.5.
* As with all alpha/beta resources, it can be disabled through the `--runtime-config` option passed to the apiserver. * As with all alpha/beta resources, it can be disabled through the `--runtime-config` option passed to the apiserver.
* The storage for a given Pod must either be provisioned by a [Persistent Volume Provisioner](http://releases.k8s.io/{{page.githubbranch}}/examples/experimental/persistent-volume-provisioning/README.md) based on the requested `storage class`, or pre-provisioned by an admin. * The storage for a given Pod must either be provisioned by a [Persistent Volume Provisioner](http://releases.k8s.io/{{page.githubbranch}}/examples/experimental/persistent-volume-provisioning/README.md) based on the requested `storage class`, or pre-provisioned by an admin.
* Deleting and/or scaling a Stateful Set down will *not* delete the volumes associated with the Stateful Set. This is done to ensure safety first, your data is more valuable than an auto purge of all related Stateful Set resources. **Deleting the Persistent Volume Claims will result in a deletion of the associated volumes**. * Deleting and/or scaling a Stateful Set down will *not* delete the volumes associated with the Stateful Set. This is done to ensure safety first, your data is more valuable than an auto purge of all related Stateful Set resources.
* Stateful Sets currently require a [Headless Service](/docs/user-guide/services/#headless-services) to be responsible for the network identity of the Pods. The user is responsible for this Service. * Stateful Sets currently require a [Headless Service](/docs/user-guide/services/#headless-services) to be responsible for the network identity of the Pods. The user is responsible for this Service.
* Updating an existing Stateful Set is currently a manual process, meaning you either need to deploy a new Stateful Set with the new image version, or orphan Pods one by one, update their image, and join them back to the cluster. * Updating an existing Stateful Set is currently a manual process, meaning you either need to deploy a new Stateful Set with the new image version, or orphan Pods one by one, update their image, and join them back to the cluster.
@ -108,9 +109,9 @@ regardless of which node it's (re) scheduled on.
__Ordinal Index__ __Ordinal Index__
For a Stateful Set with N replicas, each Pod in the Stateful Set will be For a Stateful Set with N replicas, each Pod in the Stateful Set will be
assigned a integer ordinal, in the range [0,N), that is unique over the Set. assigned an integer ordinal, in the range [0,N), that is unique over the Set.
__Stable Network Id__ __Stable Network ID__
The hostname of a Pod in a Stateful Set is derived from the name of the The hostname of a Pod in a Stateful Set is derived from the name of the
Stateful Set and the ordinal of the Pod. The pattern for the constructed hostname Stateful Set and the ordinal of the Pod. The pattern for the constructed hostname
@ -141,9 +142,9 @@ __Stable Storage__
[Persistent Volumes](/docs/user-guide/volumes/), one for each Volume Claim Template, [Persistent Volumes](/docs/user-guide/volumes/), one for each Volume Claim Template,
are created based on the `volumeClaimTemplates` field of the Stateful Set. In the are created based on the `volumeClaimTemplates` field of the Stateful Set. In the
example above, each Pod will receive a single persistent volume with a storage example above, each Pod will receive a single persistent volume with a storage
class of anything and 1 Gib of provisioned storage. When a Pod is (re) scheduled onto class of `anything` and 1 Gib of provisioned storage. When a Pod is (re) scheduled onto
a node, its `volumeMounts` mount the Persistent Volumes associated with its a node, its `volumeMounts` mount the Persistent Volumes associated with its
Persistent Volume Claims. That is, the Note that, the Persistent Volumes associated with the Persistent Volume Claims. Note that, the Persistent Volumes associated with the
Pods' Persistent Volume Claims are not deleted when the Pods, or Stateful Set are deleted. Pods' Persistent Volume Claims are not deleted when the Pods, or Stateful Set are deleted.
This must be done manually. This must be done manually.

2
docs/concepts/index.md
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@ -7,6 +7,8 @@ The Concepts section of the Kubernetes documentation is a work in progress.
* [Annotations](/docs/concepts/object-metadata/annotations/) * [Annotations](/docs/concepts/object-metadata/annotations/)
#### Controllers
* [Stateful Sets](/docs/concepts/controllers/statefulsets/) * [Stateful Sets](/docs/concepts/controllers/statefulsets/)