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Merge pull request #155 from janetkuo/update-deployment-user-guide

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Update deployment user guide
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johndmulhausen
2016-03-16 17:34:44 -07:00
parent 85b579dd27 0e30139550
commit 3da0f7cc74
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docs/user-guide/deployments.md
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@@ -7,9 +7,9 @@
## What is a _Deployment_? ## What is a _Deployment_?
A _Deployment_ provides declarative updates for Pods and ReplicaSets. A _Deployment_ provides declarative updates for Pods and ReplicaSets.
Users describe the desired state in a Deployment object, and the deployment You only need to describe the desired state in a Deployment object, and the deployment
controller changes the actual state to the desired state at a controlled rate. controller will change the actual state to the desired state at a controlled rate for you.
Users can define Deployments to create new resources, or replace existing ones You can define Deployments to create new resources, or replace existing ones
by new ones. by new ones.
A typical use case is: A typical use case is:
@@ -181,12 +181,12 @@ template does not match `.spec.template` are scaled down.
Eventually, the new replica set will be scaled to `.spec.replicas` and all old replica sets will Eventually, the new replica set will be scaled to `.spec.replicas` and all old replica sets will
be scaled to 0. be scaled to 0.
If the user updates a Deployment while an existing deployment is in progress, If you update a Deployment while an existing deployment is in progress,
the Deployment will create a new replica set as per the update and start scaling that up, and the Deployment will create a new replica set as per the update and start scaling that up, and
will roll the replica set that it was scaling up previously -- it will add it to its list of old replica sets and will will roll the replica set that it was scaling up previously -- it will add it to its list of old replica sets and will
start scaling it down. start scaling it down.
For example, suppose the user creates a Deployment to create 5 replicas of `nginx:1.7.9`, For example, suppose you create a Deployment to create 5 replicas of `nginx:1.7.9`,
but then updates the Deployment to create 5 replicas of `nginx:1.9.1`, when only 3 but then updates the Deployment to create 5 replicas of `nginx:1.9.1`, when only 3
replicas of `nginx:1.7.9` had been created. In that case, Deployment will immediately start replicas of `nginx:1.7.9` had been created. In that case, Deployment will immediately start
killing the 3 `nginx:1.7.9` pods that it had created, and will start creating killing the 3 `nginx:1.7.9` pods that it had created, and will start creating
@@ -195,7 +195,7 @@ before changing course.
## Rolling Back a Deployment ## Rolling Back a Deployment
Sometimes we may want to rollback a Deployment; for example, when the previous Deployment is crash looping. Sometimes we may want to rollback a Deployment; for example, when the Deployment is not stable, such as crash looping.
Suppose that we made a typo while updating the Deployment, by putting the image name as `nginx:1.91` instead of `nginx:1.9.1`: Suppose that we made a typo while updating the Deployment, by putting the image name as `nginx:1.91` instead of `nginx:1.9.1`:
@@ -214,7 +214,7 @@ nginx-deployment-2035384211 0 0 36s
nginx-deployment-3066724191 2 2 6s nginx-deployment-3066724191 2 2 6s
``` ```
Looking at the pods created, you will see that the 2 pods created by new replica set are crash looping. Looking at the pods created, you will see that the 2 pods created by new replica set are stuck in an image pull loop.
```console ```console
$ kubectl get pods $ kubectl get pods
@@ -415,7 +415,7 @@ All existing pods are killed before new ones are created when
The Deployment updates pods in a [rolling update](/docs/user-guide/update-demo/) fashion The Deployment updates pods in a [rolling update](/docs/user-guide/update-demo/) fashion
when `.spec.strategy.type==RollingUpdate`. when `.spec.strategy.type==RollingUpdate`.
Users can specify `maxUnavailable` and `maxSurge` to control You can specify `maxUnavailable` and `maxSurge` to control
the rolling update process. the rolling update process.
##### Max Unavailable ##### Max Unavailable