ceph-csi/vendor/k8s.io/client-go/examples/create-update-delete-deployment/README.md

94 lines
3.0 KiB
Markdown
Raw Normal View History

2018-12-19 14:29:25 +00:00
# Create, Update & Delete Deployment
This example program demonstrates the fundamental operations for managing on
[Deployment][1] resources, such as `Create`, `List`, `Update` and `Delete`.
You can adopt the source code from this example to write programs that manage
other types of resources through the Kubernetes API.
## Running this example
Make sure you have a Kubernetes cluster and `kubectl` is configured:
kubectl get nodes
Compile this example on your workstation:
```
cd create-update-delete-deployment
go build -o ./app
```
Now, run this application on your workstation with your local kubeconfig file:
```
./app
# or specify a kubeconfig file with flag
./app -kubeconfig=$HOME/.kube/config
```
Running this command will execute the following operations on your cluster:
1. **Create Deployment:** This will create a 2 replica Deployment. Verify with
`kubectl get pods`.
2. **Update Deployment:** This will update the Deployment resource created in
previous step by setting the replica count to 1 and changing the container
image to `nginx:1.13`. You are encouraged to inspect the retry loop that
handles conflicts. Verify the new replica count and container image with
`kubectl describe deployment demo`.
3. **Rollback Deployment:** This will rollback the Deployment to the last
revision. In this case, it's the revision that was created in Step 1.
Use `kubectl describe` to verify the container image is now `nginx:1.12`.
Also note that the Deployment's replica count is still 1; this is because a
Deployment revision is created if and only if the Deployment's pod template
(`.spec.template`) is changed.
4. **List Deployments:** This will retrieve Deployments in the `default`
namespace and print their names and replica counts.
5. **Delete Deployment:** This will delete the Deployment object and its
dependent ReplicaSet resource. Verify with `kubectl get deployments`.
Each step is separated by an interactive prompt. You must hit the
<kbd>Return</kbd> key to proceed to the next step. You can use these prompts as
a break to take time to run `kubectl` and inspect the result of the operations
2018-12-19 14:29:25 +00:00
executed.
You should see an output like the following:
```
Creating deployment...
Created deployment "demo-deployment".
-> Press Return key to continue.
Updating deployment...
Updated deployment...
-> Press Return key to continue.
Rolling back deployment...
Rolled back deployment...
-> Press Return key to continue.
Listing deployments in namespace "default":
* demo-deployment (1 replicas)
-> Press Return key to continue.
Deleting deployment...
Deleted deployment.
```
## Cleanup
Successfully running this program will clean the created artifacts. If you
terminate the program without completing, you can clean up the created
deployment with:
kubectl delete deploy demo-deployment
## Troubleshooting
If you are getting the following error, make sure Kubernetes version of your
cluster is v1.6 or above in `kubectl version`:
panic: the server could not find the requested resource
[1]: https://kubernetes.io/docs/user-guide/deployments/