Question: I need to restart the Elasticsearch node after installing the injest-attachment plugin on Kubernetes Engine on Google Cloud Platform. I have deployed Elasticsearch on a pod. What is the best way to restart the Elasticsearch nodes?

Answer: 
If Elasticsearch is running directly on the VM:

```
systemctl restart elasticsearch

```

If Elasticsearch is running as a container on docker:

```
docker restart <container-id>

```

If Elasticsearch is running as a Kubernetes pod (deployed through a Kubernetes manifest):

* update the image tag in the manifest if needed, and do `kubectl apply`
* Or use `kubectl replace` or `kubectl edit` commands

On Kubernetes, ideally, you should use the declarative way of updating the manifests and then do a `kubectl apply -f`
I ran into the same problem when installing the ltr plugin on a Minikube deployment of Elasticsearch.

Following the instructions of using initContainer to install the plugin [1] did not work since I could not figure out how to restart Elasticsearch after plugin installation since I was not able to get root access to the elasticsearch pod.

However, following the instructions on how to build a custom image containig the plugin [2] did solve my problem since in that way the plugin is installed before elasticsearch is started.

[1] <https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-bundles-plugins.html>

[2] <https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-custom-images.html>