whentimeslows/website
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

address enisoc comments

Browse Source
This commit is contained in:
Kenneth Owens
2016-11-29 11:33:21 -08:00
parent eead3799b9
commit 5e15fc667f
2 changed files with 75 additions and 74 deletions
Download Patch File Download Diff File Expand all files Collapse all files
_data/tutorials.yml
+1 -1
View File
@@ -51,7 +51,7 @@ toc:
path: /docs/tutorials/stateless-application/expose-external-ip-address-service/ path: /docs/tutorials/stateless-application/expose-external-ip-address-service/
- title: Exposing an External IP Address to Access an Application in a Cluster - title: Exposing an External IP Address to Access an Application in a Cluster
path: /docs/tutorials/stateless-application/expose-external-ip-address/ path: /docs/tutorials/stateless-application/expose-external-ip-address/
title: Stateful Applications - title: Stateful Applications
section: section:
- title: StatefulSet Basics - title: StatefulSet Basics
path: /docs/tutorials/stateful-application/basic-stateful-set/ path: /docs/tutorials/stateful-application/basic-stateful-set/
docs/tutorials/stateful-application/basic-stateful-set.md
+74 -73
View File
@@ -11,7 +11,7 @@ assignees:
{% capture overview %} {% capture overview %}
This tutorial provides an introduction to the This tutorial provides an introduction to the
[StatefulSet](/docs/concepts/controllers/statefulsets.md) concept. It [StatefulSet](/docs/concepts/controllers/statefulsets/) concept. It
demonstrates how to create, delete, scale, and update the container image of a demonstrates how to create, delete, scale, and update the container image of a
StatefulSet. StatefulSet.
{% endcapture %} {% endcapture %}
@@ -25,11 +25,11 @@ following Kubernetes concepts.
* [Headless Services](/docs/user-guide/services/#headless-services) * [Headless Services](/docs/user-guide/services/#headless-services)
* [PersistentVolumes](/docs/user-guide/volumes/) * [PersistentVolumes](/docs/user-guide/volumes/)
* [PersistentVolume Provisioning](http://releases.k8s.io/{{page.githubbranch}}/examples/experimental/persistent-volume-provisioning/) * [PersistentVolume Provisioning](http://releases.k8s.io/{{page.githubbranch}}/examples/experimental/persistent-volume-provisioning/)
* [StatefulSets](/docs/concepts/controllers/statefulsets.md) * [StatefulSets](/docs/concepts/controllers/statefulsets/)
* [kubeclt CLI](/docs/user-guide/kubectl) * [kubectl CLI](/docs/user-guide/kubectl)
This tutorial assumes that your cluster is configured to dynamically provision This tutorial assumes that your cluster is configured to dynamically provision
and PersistentVolumes. If your cluster is not configured to do so, you PersistentVolumes. If your cluster is not configured to do so, you
will have to manually provision five 1 GiB volumes prior to starting this will have to manually provision five 1 GiB volumes prior to starting this
tutorial. tutorial.
{% endcapture %} {% endcapture %}
@@ -39,8 +39,7 @@ StatefulSets are intended to be used with stateful applications and distributed
systems. However, the administration of stateful applications and systems. However, the administration of stateful applications and
distributed systems on Kubernetes is a broad, complex topic. In order to distributed systems on Kubernetes is a broad, complex topic. In order to
demonstrate the basic features of a StatefulSet, and to not conflate the former demonstrate the basic features of a StatefulSet, and to not conflate the former
topic with the latter, a simple web application will be used as a running topic with the latter, you will deploy a simple web application using StatefulSets.
example throughout this tutorial.
After this tutorial, you will be familiar with the following. After this tutorial, you will be familiar with the following.
@@ -56,40 +55,42 @@ After this tutorial, you will be familiar with the following.
Begin by creating a StatefulSet using the example below. It is similar to the Begin by creating a StatefulSet using the example below. It is similar to the
example presented in the example presented in the
[StatefulSets](/docs/concepts/controllers/statefulsets.md) concept. It creates [StatefulSets](/docs/concepts/controllers/statefulsets/) concept. It creates
a [Headless Service](/docs/user-guide/services/#headless-services), `nginx`, to a [Headless Service](/docs/user-guide/services/#headless-services), `nginx`, to
control the domain of the StatefulSet, `web`. control the domain of the StatefulSet, `web`.
{% include code.html language="yaml" file="web.yaml" ghlink="/docs/tutorials/stateful-application/web.yaml" %} {% include code.html language="yaml" file="web.yaml" ghlink="/docs/tutorials/stateful-application/web.yaml" %}
Download the example above, and save it to a file named `web.yaml`
You will need to use two terminal windows. In the first terminal, use You will need to use two terminal windows. In the first terminal, use
[`kubectl get`](/docs/user-guide/kubectl/kubectl_get/) to watch the creation [`kubectl get`](/docs/user-guide/kubectl/kubectl_get/) to watch the creation
of the StatefulSet's Pods. of the StatefulSet's Pods.
```shell ```shell
$ kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
``` ```
In the second terminal, use In the second terminal, use
[`kubeclt create`](/docs/user-guide/kubectl/kubectl_create/) to create the [`kubectl create`](/docs/user-guide/kubectl/kubectl_create/) to create the
Headless Service and StatefulSet defined in `web.yaml`. Headless Service and StatefulSet defined in `web.yaml`.
```shell ```shell
$ kubectl create -f web.yml kubectl create -f web.yml
service "nginx" created service "nginx" created
statefulset "web" created statefulset "web" created
``` ```
The command above creates two Pods, each running a The command above creates two Pods, each running an
[NGINX](https://www.nginx.com) webserver. Get the `nginx` Service and the [NGINX](https://www.nginx.com) webserver. Get the `nginx` Service and the
`web` StatefulSet to verify that they were created successfully. `web` StatefulSet to verify that they were created successfully.
```shell ```shell
$ kubectl get service nginx kubectl get service nginx
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
nginx None <none> 80/TCP 12s nginx None <none> 80/TCP 12s
$ kubectl get statefulset web kubectl get statefulset web
NAME DESIRED CURRENT AGE NAME DESIRED CURRENT AGE
web 2 1 20s web 2 1 20s
``` ```
@@ -102,7 +103,7 @@ created sequentially, in order from {0..N-1}. Examine the output of the
look like the example below. look like the example below.
```shell ```shell
$ kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
web-0 0/1 Pending 0 0s web-0 0/1 Pending 0 0s
@@ -126,18 +127,18 @@ launching `web-1`. In fact, `web-1` is not launched until `web-0` is
Get the StatefulSet's Pods. Get the StatefulSet's Pods.
```shell ```shell
$ kubectl get pods -l app=nginx kubectl get pods -l app=nginx
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
web-0 1/1 Running 0 1m web-0 1/1 Running 0 1m
web-1 1/1 Running 0 1m web-1 1/1 Running 0 1m
``` ```
As mentioned in the [StatefulSets](/docs/concepts/controllers/statefulsets.md) As mentioned in the [StatefulSets](/docs/concepts/controllers/statefulsets/)
concept, the Pods in a StatefulSet have a sticky, unique identity. This identity concept, the Pods in a StatefulSet have a sticky, unique identity. This identity
is based on a unique ordinal index that is assigned to each Pod by the Stateful is based on a unique ordinal index that is assigned to each Pod by the Stateful
Set controller. The Pods names take the form Set controller. The Pods' names take the form
`$(statefulset name)-$(ordinal index)`. Since the `web` StatefulSet has two `<statefulset name>-<ordinal index>`. Since the `web` StatefulSet has two
replicas, it creates two Pods, `web-0` and `web-1`. replicas, it creates two Pods, `web-0` and `web-1`.
#### Stable Network Identity #### Stable Network Identity
@@ -146,7 +147,7 @@ Each Pod has a stable hostname based on its ordinal index. Use
`hostname` command in each Pod. `hostname` command in each Pod.
```shell ```shell
$ for i in 0 1; do kubectl exec web-$i -- sh -c 'hostname'; done for i in 0 1; do kubectl exec web-$i -- sh -c 'hostname'; done
web-0 web-0
web-1 web-1
``` ```
@@ -157,15 +158,15 @@ Using `nslookup` on the Pods' hostnames, you can examine their in-cluster DNS
addresses. addresses.
```shell ```shell
$ kubectl run -i --tty --image busybox dns-test --restart=Never /bin/sh kubectl run -i --tty --image busybox dns-test --restart=Never --rm /bin/sh
$ nslookup web-0.nginx nslookup web-0.nginx
Server: 10.0.0.10 Server: 10.0.0.10
Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local
Name: web-0.nginx Name: web-0.nginx
Address 1: 10.244.1.6 Address 1: 10.244.1.6
$ nslookup web-1.nginx nslookup web-1.nginx
Server: 10.0.0.10 Server: 10.0.0.10
Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local
@@ -180,22 +181,23 @@ contain the Pods' IP addresses.
In one terminal, watch the StatefulSet's Pods. In one terminal, watch the StatefulSet's Pods.
```shell ```shell
$ kubectl get pod -w -l app=nginx kubectl get pod -w -l app=nginx
``` ```
In a second terminal, use In a second terminal, use
[`kubectl delete`](/docs/user-guide/kubectl/kubectl_delete/) to delete all [`kubectl delete`](/docs/user-guide/kubectl/kubectl_delete/) to delete all
the Pods in the StatefulSet. the Pods in the StatefulSet.
```shell ```shell
$ kubectl delete pod -l app=nginx kubectl delete pod -l app=nginx
pod "web-0" deleted pod "web-0" deleted
pod "web-1" deleted pod "web-1" deleted
``` ```
Wait for both Pods to transition to Running and Ready. Wait for the StatefulSet to restart them, and for both Pods to transition to
Running and Ready.
```shell ```shell
$ kubectl get pod -w -l app=nginx kubectl get pod -w -l app=nginx
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
web-0 0/1 ContainerCreating 0 0s web-0 0/1 ContainerCreating 0 0s
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
@@ -210,19 +212,19 @@ Use `kubectl exec` and `kubectl run` to view the Pods hostnames and in-cluster
DNS entries. DNS entries.
```shell ```shell
$ for i in 0 1; do kubectl exec web-$i -- sh -c 'hostname'; done for i in 0 1; do kubectl exec web-$i -- sh -c 'hostname'; done
web-0 web-0
web-1 web-1
$ kubectl run -i --tty --image busybox dns-test --restart=Never /bin/sh kubectl run -i --tty --image busybox dns-test --restart=Never --rm /bin/sh
$ nslookup web-0.nginx nslookup web-0.nginx
Server: 10.0.0.10 Server: 10.0.0.10
Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local
Name: web-0.nginx Name: web-0.nginx
Address 1: 10.244.1.7 Address 1: 10.244.1.7
$ nslookup web-1.nginx nslookup web-1.nginx
Server: 10.0.0.10 Server: 10.0.0.10
Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local
@@ -252,17 +254,17 @@ StatefulSet (e.g `web-0.nginx.default.svc.cluster.local`,
Get the PersistentVolumeClaims for `web-0` and `web-1`. Get the PersistentVolumeClaims for `web-0` and `web-1`.
```shell ```shell
$ kubectl get pvc -l app=nginx kubectl get pvc -l app=nginx
NAME STATUS VOLUME CAPACITY ACCESSMODES AGE NAME STATUS VOLUME CAPACITY ACCESSMODES AGE
www-web-0 Bound pvc-15c268c7-b507-11e6-932f-42010a800002 1Gi RWO 48s www-web-0 Bound pvc-15c268c7-b507-11e6-932f-42010a800002 1Gi RWO 48s
www-web-1 Bound pvc-15c79307-b507-11e6-932f-42010a800002 1Gi RWO 48s www-web-1 Bound pvc-15c79307-b507-11e6-932f-42010a800002 1Gi RWO 48s
``` ```
The StatefulSet controller created two PersistentVolumeClaims that are The StatefulSet controller created two PersistentVolumeClaims that are
bound to two [PersistentVolume](/docs/user-guide/volumes/). As the cluster used bound to two [PersistentVolumes](/docs/user-guide/volumes/). As the cluster used
in this tutorial is configured to dynamically provision PersistentVolumes, the in this tutorial is configured to dynamically provision PersistentVolumes, the
PersistentVolumes were created and bound automatically. PersistentVolumes were created and bound automatically.
The containers NGINX webservers, by default, will serve an index file at The NGINX webservers, by default, will serve an index file at
`/usr/share/nginx/html/index.html`. The `volumeMounts` field in the `/usr/share/nginx/html/index.html`. The `volumeMounts` field in the
StatefulSets `spec` ensures that the `/usr/share/nginx/html` directory is StatefulSets `spec` ensures that the `/usr/share/nginx/html` directory is
backed by a PersistentVolume. backed by a PersistentVolume.
@@ -271,9 +273,9 @@ Write the Pods' hostnames to their `index.html` files and verify that the NGINX
webservers serve the hostnames. webservers serve the hostnames.
```shell ```shell
$ for i in 0 1; do kubectl exec web-$i -- sh -c 'echo $(hostname) > /usr/share/nginx/html/index.html'; done for i in 0 1; do kubectl exec web-$i -- sh -c 'echo $(hostname) > /usr/share/nginx/html/index.html'; done
$ for i in 0 1; do kubectl exec -it web-$i -- curl localhost; done for i in 0 1; do kubectl exec -it web-$i -- curl localhost; done
web-0 web-0
web-1 web-1
``` ```
@@ -287,7 +289,7 @@ kubectl get pod -w -l app=nginx
In a second terminal, delete all of the StatefulSet's Pods. In a second terminal, delete all of the StatefulSet's Pods.
```shell ```shell
$ kubectl delete pod -l app=nginx kubectl delete pod -l app=nginx
pod "web-0" deleted pod "web-0" deleted
pod "web-1" deleted pod "web-1" deleted
``` ```
@@ -295,7 +297,7 @@ Examine the output of the `kubectl get` command in the first terminal, and wait
for all of the Pods to transition to Running and Ready. for all of the Pods to transition to Running and Ready.
```shell ```shell
$ kubectl get pod -w -l app=nginx kubectl get pod -w -l app=nginx
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
web-0 0/1 ContainerCreating 0 0s web-0 0/1 ContainerCreating 0 0s
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
@@ -306,10 +308,10 @@ web-1 0/1 ContainerCreating 0 0s
web-1 1/1 Running 0 34s web-1 1/1 Running 0 34s
``` ```
Verify the web servers continue to server their hostnames. Verify the web servers continue to serve their hostnames.
``` ```
$ for i in 0 1; do kubectl exec -it web-$i -- curl localhost; done for i in 0 1; do kubectl exec -it web-$i -- curl localhost; done
web-0 web-0
web-1 web-1
``` ```
@@ -322,7 +324,7 @@ appropriate mount points.
### Scaling a StatefulSet ### Scaling a StatefulSet
When we refer to scaling a StatefulSet, we mean increasing or decreasing the When we refer to scaling a StatefulSet, we mean increasing or decreasing the
number of replicas in the StatefulSet. This is accomplished by by updating number of replicas in the StatefulSet. This is accomplished by updating
the `replicas` field. You can use either the `replicas` field. You can use either
[`kubectl scale`](/docs/user-guide/kubectl/kubectl_scale/) or [`kubectl scale`](/docs/user-guide/kubectl/kubectl_scale/) or
[`kubectl patch`](/docs/user-guide/kubectl/kubectl_patch/) to scale a Stateful [`kubectl patch`](/docs/user-guide/kubectl/kubectl_patch/) to scale a Stateful
@@ -333,14 +335,14 @@ Set.
In one terminal window, watch the Pods in the StatefulSet. In one terminal window, watch the Pods in the StatefulSet.
```shell ```shell
$ kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
``` ```
In another terminal window, use `kubectl scale` to scale the number of replicas In another terminal window, use `kubectl scale` to scale the number of replicas
to 5. to 5.
```shell ```shell
$ kubectl scale statefulset web --replicas=5 kubectl scale statefulset web --replicas=5
statefulset "web" scaled statefulset "web" scaled
``` ```
@@ -348,7 +350,7 @@ Examine the output of the `kubectl get` command in the first terminal, and wait
for the three additional Pods to transition to Running and Ready. for the three additional Pods to transition to Running and Ready.
```shell ```shell
$kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
web-0 1/1 Running 0 2h web-0 1/1 Running 0 2h
web-1 1/1 Running 0 2h web-1 1/1 Running 0 2h
@@ -378,21 +380,21 @@ subsequent Pod.
In one terminal, watch the StatefulSet's Pods. In one terminal, watch the StatefulSet's Pods.
```shell ```shell
$ kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
``` ```
In another terminal, use `kubectl patch` to scale the StatefulSet back down to In another terminal, use `kubectl patch` to scale the StatefulSet back down to
3 replicas. 3 replicas.
```shell ```shell
$ kubectl patch statefulset web -p '{"spec":{"replicas":3}}' kubectl patch statefulset web -p '{"spec":{"replicas":3}}'
"web" patched "web" patched
``` ```
Wait for `web-4` and `web-3` to transition to Terminating. Wait for `web-4` and `web-3` to transition to Terminating.
``` ```
$ kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
web-0 1/1 Running 0 3h web-0 1/1 Running 0 3h
web-1 1/1 Running 0 3h web-1 1/1 Running 0 3h
@@ -410,14 +412,13 @@ web-3 1/1 Terminating 0 42s
#### Ordered Pod Termination #### Ordered Pod Termination
The controller deleted one Pod at a time, with respect to its ordinal index, The controller deleted one Pod at a time, with respect to its ordinal index,
in reverse order, and it waited for each to be completely shutdown in reverse order, and it waited for each to be completely shutdown before
(past its [terminationGracePeriodSeconds](/docs/user-guide/pods/index#termination-of-pods)) deleting the next.
before deleting the next.
Get the StatefulSets PersistentVolumeClaims. Get the StatefulSet's PersistentVolumeClaims.
```shell ```shell
$ kubectl get pvc -l app=nginx kubectl get pvc -l app=nginx
NAME STATUS VOLUME CAPACITY ACCESSMODES AGE NAME STATUS VOLUME CAPACITY ACCESSMODES AGE
www-web-0 Bound pvc-15c268c7-b507-11e6-932f-42010a800002 1Gi RWO 13h www-web-0 Bound pvc-15c268c7-b507-11e6-932f-42010a800002 1Gi RWO 13h
www-web-1 Bound pvc-15c79307-b507-11e6-932f-42010a800002 1Gi RWO 13h www-web-1 Bound pvc-15c79307-b507-11e6-932f-42010a800002 1Gi RWO 13h
@@ -444,14 +445,14 @@ each Pod with the new image.
Patch the container image for the `web` StatefulSet. Patch the container image for the `web` StatefulSet.
```shell ```shell
$ kubectl patch statefulset web --type='json' -p='[{"op": "replace", "path": "/spec/template/spec/containers/0/image", "value":"gcr.io/google_containers/nginx-slim:0.7"}]' kubectl patch statefulset web --type='json' -p='[{"op": "replace", "path": "/spec/template/spec/containers/0/image", "value":"gcr.io/google_containers/nginx-slim:0.7"}]'
"web" patched "web" patched
``` ```
Delete the `web-0` Pod. Delete the `web-0` Pod.
```shell ```shell
$ kubectl delete pod web-0 kubectl delete pod web-0
pod "web-0" deleted pod "web-0" deleted
``` ```
@@ -474,7 +475,7 @@ web-0 1/1 Running 0 3s
Get the Pods to view their container images. Get the Pods to view their container images.
```shell{% raw %} ```shell{% raw %}
$ for p in 0 1 2; do kubectl get po web-$p --template '{{range $i, $c := .spec.containers}}{{$c.image}}{{end}}'; echo; done for p in 0 1 2; do kubectl get po web-$p --template '{{range $i, $c := .spec.containers}}{{$c.image}}{{end}}'; echo; done
gcr.io/google_containers/nginx-slim:0.7 gcr.io/google_containers/nginx-slim:0.7
gcr.io/google_containers/nginx-slim:0.8 gcr.io/google_containers/nginx-slim:0.8
gcr.io/google_containers/nginx-slim:0.8 gcr.io/google_containers/nginx-slim:0.8
@@ -484,7 +485,7 @@ gcr.io/google_containers/nginx-slim:0.8
Pods. Pods.
```shell ```shell
$ kubectl delete pod web-1 web-2 kubectl delete pod web-1 web-2
pod "web-1" deleted pod "web-1" deleted
pod "web-2" deleted pod "web-2" deleted
``` ```
@@ -492,7 +493,7 @@ pod "web-2" deleted
Watch the Pods, and wait for all of them to transition to Running and Ready. Watch the Pods, and wait for all of them to transition to Running and Ready.
``` ```
$ kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
web-0 1/1 Running 0 8m web-0 1/1 Running 0 8m
web-1 1/1 Running 0 4h web-1 1/1 Running 0 4h
@@ -515,7 +516,7 @@ web-2 1/1 Running 0 36s
Get the Pods to view their container images. Get the Pods to view their container images.
```shell{% raw %} ```shell{% raw %}
$ for p in 0 1 2; do kubectl get po web-$p --template '{{range $i, $c := .spec.containers}}{{$c.image}}{{end}}'; echo; done for p in 0 1 2; do kubectl get po web-$p --template '{{range $i, $c := .spec.containers}}{{$c.image}}{{end}}'; echo; done
gcr.io/google_containers/nginx-slim:0.7 gcr.io/google_containers/nginx-slim:0.7
gcr.io/google_containers/nginx-slim:0.7 gcr.io/google_containers/nginx-slim:0.7
gcr.io/google_containers/nginx-slim:0.7 gcr.io/google_containers/nginx-slim:0.7
@@ -535,7 +536,7 @@ deleted.
In one terminal window, watch the Pods in the StatefulSet. In one terminal window, watch the Pods in the StatefulSet.
``` ```
$ kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
``` ```
Use [`kubectl delete`](/docs/user-guide/kubectl/kubectl_delete/) to delete the Use [`kubectl delete`](/docs/user-guide/kubectl/kubectl_delete/) to delete the
@@ -544,14 +545,14 @@ command. This parameter tells Kubernetes to only delete the StatefulSet, and to
not delete any of its Pods. not delete any of its Pods.
```shell ```shell
$ kubectl delete statefulset web --cascade=false kubectl delete statefulset web --cascade=false
statefulset "web" deleted statefulset "web" deleted
``` ```
Get the Pods to examine their status. Get the Pods to examine their status.
```shell ```shell
$ kubectl get pods -l app=nginx kubectl get pods -l app=nginx
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
web-0 1/1 Running 0 6m web-0 1/1 Running 0 6m
web-1 1/1 Running 0 7m web-1 1/1 Running 0 7m
@@ -562,14 +563,14 @@ Even though `web` has been deleted, all of the Pods are still Running and Ready.
Delete `web-0`. Delete `web-0`.
```shell ```shell
$ kubectl delete pod web-0 kubectl delete pod web-0
pod "web-0" deleted pod "web-0" deleted
``` ```
Get the StatefulSet's Pods. Get the StatefulSet's Pods.
```shell ```shell
$ kubectl get pods -l app=nginx kubectl get pods -l app=nginx
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
web-1 1/1 Running 0 10m web-1 1/1 Running 0 10m
web-2 1/1 Running 0 7m web-2 1/1 Running 0 7m
@@ -580,7 +581,7 @@ As the `web` StatefulSet has been deleted, `web-0` has not been relaunched.
In one terminal, watch the StatefulSet's Pods. In one terminal, watch the StatefulSet's Pods.
``` ```
$ kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
``` ```
In a second terminal, recreate the StatefulSet. Note that, unless In a second terminal, recreate the StatefulSet. Note that, unless
@@ -625,7 +626,7 @@ Let's take another look at the contents of the `index.html` file served by the
Pods' webservers. Pods' webservers.
```shell ```shell
$ for i in 0 1; do kubectl exec -it web-$i -- curl localhost; done for i in 0 1; do kubectl exec -it web-$i -- curl localhost; done
web-0 web-0
web-1 web-1
``` ```
@@ -641,21 +642,21 @@ PersistentVolume was remounted.
In one terminal window, watch the Pods in the StatefulSet. In one terminal window, watch the Pods in the StatefulSet.
```shell ```shell
$ kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
``` ```
In another terminal, delete the StatefulSet again. This time, omit the In another terminal, delete the StatefulSet again. This time, omit the
`--cascade=false` parameter. `--cascade=false` parameter.
```shell ```shell
$ kubectl delete statefulset web kubectl delete statefulset web
statefulset "web" deleted statefulset "web" deleted
``` ```
Examine the output of the `kubectl get` command running in the first terminal, Examine the output of the `kubectl get` command running in the first terminal,
and wait for all of the Pods to transition to Terminating. and wait for all of the Pods to transition to Terminating.
```shell ```shell
$ kubectl get pods -w -l app=nginx kubectl get pods -w -l app=nginx
NAME READY STATUS RESTARTS AGE NAME READY STATUS RESTARTS AGE
web-0 1/1 Running 0 11m web-0 1/1 Running 0 11m
web-1 1/1 Running 0 27m web-1 1/1 Running 0 27m
@@ -673,7 +674,7 @@ web-1 0/1 Terminating 0 29m
As we saw in the [Scaling Down](#ordered-pod-termination) section, the Pods As we saw in the [Scaling Down](#ordered-pod-termination) section, the Pods
are terminated one at a time, with respect to the reverse order of their ordinal are terminated one at a time, with respect to the reverse order of their ordinal
indices, and, before terminating a Pod, the StatefulSet controller waits for indices. Before terminating a Pod, the StatefulSet controller waits for
the Pod's successor to be completely terminated. the Pod's successor to be completely terminated.
Note that, while a cascading delete will delete the StatefulSet and its Pods, Note that, while a cascading delete will delete the StatefulSet and its Pods,
@@ -681,7 +682,7 @@ it will not delete the Headless Service associated with the StatefulSet. You
must delete the `nginx` Service manually. must delete the `nginx` Service manually.
```shell ```shell
$ kubectl delete service nginx kubectl delete service nginx
service "nginx" deleted service "nginx" deleted
``` ```
@@ -694,10 +695,10 @@ statefulset "web" created
``` ```
When all of the StatefulSet's Pods transition to Running and Ready, retrieve When all of the StatefulSet's Pods transition to Running and Ready, retrieve
thecontents of their `index.html` files. the contents of their `index.html` files.
```shell ```shell
$ for i in 0 1; do kubectl exec -it web-$i -- curl localhost; done for i in 0 1; do kubectl exec -it web-$i -- curl localhost; done
web-0 web-0
web-1 web-1
``` ```
@@ -709,10 +710,10 @@ Pods are recreated with their PersistentVolumes mounted, and `web-0` and
Finally delete the `web` StatefulSet and the `nginx` service. Finally delete the `web` StatefulSet and the `nginx` service.
```shell ```shell
$ kubectl delete service nginx kubectl delete service nginx
service "nginx" deleted service "nginx" deleted
$ kubectl delete statefulset web kubectl delete statefulset web
statefulset "web" deleted statefulset "web" deleted
``` ```