Installing Image Puller on OpenShift by using the CLI

You can install the Kubernetes Image Puller on OpenShift by using OpenShift oc management tool.

Prerequisites

An active oc session with administrative permissions to the OpenShift cluster. See Getting started with the OpenShift CLI.

Procedure

Gather a list of relevant container images to pull by navigating to the links:
- https://<che_fqdn>/plugin-registry/v3/external_images.txt
- https://<che_fqdn>/devfile-registry/devfiles/external_images.txt
Define the memory requests and limits parameters to ensure pulled containers and the platform have enough memory to run.

When defining the minimal value for CACHING_MEMORY_REQUEST or CACHING_MEMORY_LIMIT, consider the necessary amount of memory required to run each of the container images to pull.

When defining the maximal value for CACHING_MEMORY_REQUEST or CACHING_MEMORY_LIMIT, consider the total memory allocated to the DaemonSet Pods in the cluster:
```
(memory limit) * (number of images) * (number of nodes in the cluster)
```
Pulling 5 images on 20 nodes, with a container memory limit of 20Mi requires 2000Mi of memory.

Clone the Image Puller repository and get in the directory containing the OpenShift templates:

$ git clone https://github.com/che-incubator/kubernetes-image-puller
$ cd kubernetes-image-puller/deploy/openshift

Configure the app.yaml, configmap.yaml and serviceaccount.yaml OpenShift templates using following parameters:

Table 1. Image Puller OpenShift templates parameters in `app.yaml`
Value	Usage	Default
`DEPLOYMENT_NAME`	The value of `DEPLOYMENT_NAME` in the ConfigMap	`kubernetes-image-puller`
`IMAGE`	Image used for the `kubernetes-image-puller` deployment	`quay.io/eclipse/kubernetes-image-puller`
`IMAGE_TAG`	The image tag to pull	`latest`
`SERVICEACCOUNT_NAME`	The name of the ServiceAccount created and used by the deployment	`kubernetes-image-puller`

Table 2. Image Puller OpenShift templates parameters in `configmap.yaml`
Value	Usage	Default
`CACHING_CPU_LIMIT`	The value of `CACHING_CPU_LIMIT` in the ConfigMap	`.2`
`CACHING_CPU_REQUEST`	The value of `CACHING_CPU_REQUEST` in the ConfigMap	`.05`
`CACHING_INTERVAL_HOURS`	The value of `CACHING_INTERVAL_HOURS` in the ConfigMap	`"1"`
`CACHING_MEMORY_LIMIT`	The value of `CACHING_MEMORY_LIMIT` in the ConfigMap	`"20Mi"`
`CACHING_MEMORY_REQUEST`	The value of `CACHING_MEMORY_REQUEST` in the ConfigMap	`"10Mi"`
`DAEMONSET_NAME`	The value of `DAEMONSET_NAME` in the ConfigMap	`kubernetes-image-puller`
`DEPLOYMENT_NAME`	The value of `DEPLOYMENT_NAME` in the ConfigMap	`kubernetes-image-puller`
`IMAGES`	The value of `IMAGES` in the ConfigMap	`{}`
`NAMESPACE`	The value of `NAMESPACE` in the ConfigMap	`k8s-image-puller`
`NODE_SELECTOR`	The value of `NODE_SELECTOR` in the ConfigMap	`"{}"`

Table 3. Image Puller OpenShift templates parameters in `serviceaccount.yaml`
Value	Usage	Default
`SERVICEACCOUNT_NAME`	The name of the ServiceAccount created and used by the deployment	`kubernetes-image-puller`

Create an OpenShift project to host the Image Puller:
```
$ oc new-project <k8s-image-puller>
```

Process and apply the templates to install the puller:

$ oc process -f serviceaccount.yaml | oc apply -f -
$ oc process -f configmap.yaml | oc apply -f -
$ oc process -f app.yaml | oc apply -f -

Verification steps

Verify the existence of a <kubernetes-image-puller> deployment and a <kubernetes-image-puller> DaemonSet. The DaemonSet needs to have a Pod for each node in the cluster:
```
$ oc get deployment,daemonset,pod --namespace <k8s-image-puller>
```

Verify the values of the <kubernetes-image-puller> ConfigMap.

$ oc get configmap <kubernetes-image-puller> --output yaml