mirror of
https://github.com/kubernetes/client-go.git
synced 2025-11-12 13:10:33 +00:00
ddf6c35ca5
This updates the create-update-delete-deployment example with the following: Make use of client-go retry util in Update() steps instead of simple for loops. Using RetryOnConflict is generally better practice as it won't become stuck in a retry loop and uses exponential backoff to prevent exhausting the apiserver. Instead of changing annotations to demonstrate Updates/Rollbacks, change the container image as it is less confusing for readers and a better real-world example. Improve comments and README to reflect above changes. Signed-off-by: John Kelly <jekohk@gmail.com> Kubernetes-commit: 94f5bcf6f77d5b35074dfab47b5de37096d8ee00
94 lines
3.1 KiB
Markdown
94 lines
3.1 KiB
Markdown
# 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 proceeed 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
|
|
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/
|