You can install the OpenShift sandboxed containers Operator using either the web console or OpenShift CLI (oc). Before installing the OpenShift sandboxed containers Operator, you must prepare your OpenShift Container Platform cluster.
Before you install OpenShift sandboxed containers, ensure that your OpenShift Container Platform cluster meets the following requirements:
Your cluster must be installed on bare-metal infrastructure, on premise with Red Hat Enterprise Linux CoreOS (RHCOS) workers.
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OpenShift sandboxed containers lets users run workloads on their OpenShift Container Platform clusters inside a sandboxed runtime (Kata). Each pod is represented by a virtual machine (VM). Each VM runs in a QEMU process and hosts a kata-agent process that acts as a supervisor for managing container workloads, and the processes running in those containers. Two additional processes add more overhead:
containerd-shim-kata-v2 is used to communicate with the pod.
virtiofsd handles host file system access on behalf of the guest.
Each VM is configured with a default amount of memory. Additional memory is hot-plugged into the VM for containers that explicitly request memory.
A container running without a memory resource consumes free memory until the total memory used by the VM reaches the default allocation. The guest and its I/O buffers also consume memory.
If a container is given a specific amount of memory, then that memory is hot-plugged into the VM before the container starts.
When a memory limit is specified, the workload is terminated if it consumes more memory than the limit. If no memory limit is specified, the kernel running on the VM might run out of memory. If the kernel runs out of memory, it might terminate other processes on the VM.
The following table lists some the default values for resource allocation.
| Resource | Value |
|---|---|
Memory allocated by default to a virtual machine |
2Gi |
Guest Linux kernel memory usage at boot |
~110Mi |
Memory used by the QEMU process (excluding VM memory) |
~30Mi |
Memory used by the |
~10Mi |
Memory used by the |
~20Mi |
File buffer cache data after running |
~300Mi* [1] |
File buffers appear and are accounted for in multiple locations:
In the guest where it appears as file buffer cache.
In the virtiofsd daemon that maps allowed user-space file I/O operations.
In the QEMU process as guest memory.
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Total memory usage is properly accounted for by the memory utilization metrics, which only count that memory once. |
Pod overhead describes the amount of system resources that a pod on a node uses. You can get the current pod overhead for the Kata runtime by using oc describe runtimeclass kata as shown below.
$ oc describe runtimeclass katakind: RuntimeClass
apiVersion: node.k8s.io/v1
metadata:
name: kata
overhead:
podFixed:
memory: "500Mi"
cpu: "500m"You can change the pod overhead by changing the spec.overhead field for a RuntimeClass. For example, if the configuration that you run for your containers consumes more than 350Mi of memory for the QEMU process and guest kernel data, you can alter the RuntimeClass overhead to suit your needs.
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The specified default overhead values are supported by Red Hat. Changing default overhead values is not supported and can result in technical issues. |
When performing any kind of file system I/O in the guest, file buffers are allocated in the guest kernel. The file buffers are also mapped in the QEMU process on the host, as well as in the virtiofsd process.
For example, if you use 300Mi of file buffer cache in the guest, both QEMU and virtiofsd appear to use 300Mi additional memory. However, the same memory is being used in all three cases. In other words, the total memory usage is only 300Mi, mapped in three different places. This is correctly accounted for when reporting the memory utilization metrics.
You can deploy OpenShift sandboxed containers workloads from the web console. First, you must install the OpenShift sandboxed containers Operator, then create the KataConfig custom resource (CR). Once you are ready to deploy a workload in a sandboxed container, you must manually add kata as the runtimeClassName to the workload YAML file.
You can install the OpenShift sandboxed containers Operator from the OpenShift Container Platform web console.
You have OpenShift Container Platform 4.9 installed.
You have access to the cluster as a user with the cluster-admin role.
From the Administrator perspective in the web console, navigate to Operators → OperatorHub.
In the Filter by keyword field, type OpenShift sandboxed containers.
Select the OpenShift sandboxed containers tile.
Read the information about the Operator and click Install.
On the Install Operator page:
Select preview-1.1 from the list of available Update Channel options.
Verify that Operator recommended Namespace is selected for Installed Namespace. This installs the Operator in the mandatory openshift-sandboxed-containers-operator namespace. If this namespace does not yet exist, it is automatically created.
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Attempting to install the OpenShift sandboxed containers Operator in a namespace other than |
Verify that Automatic is selected for Approval Strategy. Automatic is the default value, and enables automatic updates to OpenShift sandboxed containers when a new z-stream release is available.
Click Install.
The OpenShift sandboxed containers Operator is now installed on your cluster.
From the Administrator perspective in the web console, navigate to Operators → Installed Operators.
Verify that the OpenShift sandboxed containers Operator is listed in the in operators list.
You must create one KataConfig custom resource (CR) to enable installing kata as a RuntimeClass on your cluster nodes.
You have installed OpenShift Container Platform 4.9 on your cluster.
You have access to the cluster as a user with the cluster-admin role.
You have installed the OpenShift sandboxed containers Operator.
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Kata is installed on all worker nodes by default. If you want to install |
From the Administrator perspective in the web console, navigate to Operators → Installed Operators.
Select the OpenShift sandboxed containers Operator from the list of operators.
In the KataConfig tab, click Create KataConfig.
In the Create KataConfig page, select to configure the KataConfig CR via YAML view.
Copy and paste the following manifest into the YAML view:
apiVersion: kataconfiguration.openshift.io/v1
kind: KataConfig
metadata:
name: cluster-kataconfigIf you want to install kata as a RuntimeClass only on selected nodes, include the label in the manifest:
apiVersion: kataconfiguration.openshift.io/v1
kind: KataConfig
metadata:
name: cluster-kataconfig
spec:
kataConfigPoolSelector:
matchLabels:
<label_key>: '<label_value>' (1)| 1 | Labels in kataConfigPoolSelector only support single values; nodeSelector syntax is not supported. |
Click Create.
The new KataConfig CR is created and begins to install kata as a RuntimeClass on the worker nodes.
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OpenShift sandboxed containers installs Kata only as a secondary, optional runtime on the cluster and not as the primary runtime. |
In the KataConfig tab, select the new KataConfig CR.
In the KataConfig page, select the YAML tab.
Monitor the installationStatus field in the status.
A message appears each time there is an update. Click Reload to view the updated KataConfig CR.
Once the value of Completed nodes equals the number of worker or labeled nodes, the installation is complete. The status also contains a list of nodes where the installation is completed.
OpenShift sandboxed containers installs Kata as a secondary, optional runtime on your cluster, and not as the primary runtime.
To deploy a pod-templated workload in a sandboxed container, you must manually add kata as the runtimeClassName to the workload YAML file.
You have installed OpenShift Container Platform 4.9 on your cluster.
You have access to the cluster as a user with the cluster-admin role.
You have installed the OpenShift sandboxed containers Operator.
You have created a KataConfig custom resource (CR).
From the Administrator perspective in the web console, expand Workloads and select the type of workload you want to create.
In the workload page, click to create the workload.
In the YAML file for the workload, in the spec field where the container is listed, add runtimeClassName: kata.
apiVersion: v1
kind: Pod
metadata:
name: example
labels:
app: httpd
namespace: openshift-sandboxed-containers-operator
spec:
runtimeClassName: kata
containers:
- name: httpd
image: 'image-registry.openshift-image-registry.svc:5000/openshift/httpd:latest'
ports:
- containerPort: 8080 apiVersion: apps/v1
kind: Deployment
metadata:
name: example
namespace: openshift-sandboxed-containers-operator
spec:
selector:
matchLabels:
app: httpd
replicas: 3
template:
metadata:
labels:
app: httpd
spec:
runtimeClassName: kata
containers:
- name: httpd
image: >-
image-registry.openshift-image-registry.svc:5000/openshift/httpd:latest
ports:
- containerPort: 8080Click Save.
OpenShift Container Platform creates the workload and begins scheduling it.
You can deploy OpenShift sandboxed containers workloads using the CLI. First, you must install the OpenShift sandboxed containers Operator, then create the KataConfig custom resource. Once you are ready to deploy a workload in a sandboxed container, you must add kata as the runtimeClassName to the workload YAML file.
You can install the OpenShift sandboxed containers Operator using the OpenShift Container Platform CLI.
You have OpenShift Container Platform 4.9 installed on your cluster.
You have installed the OpenShift CLI (oc).
You have access to the cluster as a user with the cluster-admin role.
You have subscribed to the OpenShift sandboxed containers catalog.
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Subscribing to the OpenShift sandboxed containers catalog provides |
Create the Namespace object for the OpenShift sandboxed containers Operator.
Create a Namespace object YAML file that contains the following manifest:
apiVersion: v1
kind: Namespace
metadata:
name: openshift-sandboxed-containers-operatorCreate the Namespace object:
$ oc create -f Namespace.yamlCreate the OperatorGroup object for the OpenShift sandboxed containers Operator.
Create an OperatorGroup object YAML file that contains the following manifest:
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
name: openshift-sandboxed-containers-operator
namespace: openshift-sandboxed-containers-operator
spec:
targetNamespaces:
- openshift-sandboxed-containers-operatorCreate the OperatorGroup object:
$ oc create -f OperatorGroup.yamlCreate the Subscription object to subscribe the Namespace to the OpenShift sandboxed containers Operator.
Create a Subscription object YAML file that contains the following manifest:
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
name: openshift-sandboxed-containers-operator
namespace: openshift-sandboxed-containers-operator
spec:
channel: "preview-1.1"
installPlanApproval: Automatic
name: sandboxed-containers-operator
source: redhat-operators
sourceNamespace: openshift-marketplace
startingCSV: sandboxed-containers-operator.v1.1.0Create the Subscription object:
$ oc create -f Subscription.yamlThe OpenShift sandboxed containers Operator is now installed on your cluster.
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All the object file names listed above are suggestions. You can create the object YAML files using other names. |
Ensure that the Operator is correctly installed:
$ oc get csv -n openshift-sandboxed-containers-operatorNAME DISPLAY VERSION REPLACES PHASE
openshift-sandboxed-containers openshift-sandboxed-containers-operator 1.1.0 1.0.2 SucceededYou must create one KataConfig custom resource (CR) to install kata as a RuntimeClass on your nodes. Creating the KataConfig CR triggers the OpenShift sandboxed containers Operator to do the following:
Install the needed RHCOS extensions, such as QEMU and kata-containers, on your RHCOS node.
Ensure that the CRI-O runtime is configured with the correct kata runtime handlers.
Create a RuntimeClass CR named kata with a default configuration. This enables users to configure workloads to use kata as the runtime by referencing the CR in the RuntimeClassName field. This CR also specifies the resource overhead for the runtime.
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Kata is installed on all worker nodes by default. If you want to install |
You have installed OpenShift Container Platform 4.9 on your cluster.
You have installed the OpenShift CLI (oc).
You have access to the cluster as a user with the cluster-admin role.
You have installed the OpenShift sandboxed containers Operator.
Create a YAML file with the following manifest:
apiVersion: kataconfiguration.openshift.io/v1
kind: KataConfig
metadata:
name: cluster-kataconfig(Optional) If you want to install kata as a RuntimeClass only on selected nodes, create a YAML file that includes the label in the manifest:
apiVersion: kataconfiguration.openshift.io/v1
kind: KataConfig
metadata:
name: cluster-kataconfig
spec:
kataConfigPoolSelector:
matchLabels:
<label_key>: '<label_value>' (1)| 1 | Labels in kataConfigPoolSelector only support single values; nodeSelector syntax is not supported. |
Create the KataConfig resource:
$ oc create -f <file name>.yamlThe new KataConfig CR is created and begins to install kata as a RuntimeClass on the worker nodes.
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OpenShift sandboxed containers installs Kata only as a secondary, optional runtime on the cluster and not as the primary runtime. |
Monitor the installation progress:
$ watch "oc describe kataconfig | sed -n /^Status:/,/^Events/p"Once the value of Is In Progress appears as false, the installation is complete.
OpenShift sandboxed containers installs Kata as a secondary, optional runtime on your cluster, and not as the primary runtime.
To deploy a pod-templated workload in a sandboxed container, you must add kata as the runtimeClassName to the workload YAML file.
You have installed OpenShift Container Platform 4.9 on your cluster.
You have installed the OpenShift CLI (oc).
You have access to the cluster as a user with the cluster-admin role.
You have installed the OpenShift sandboxed containers Operator.
You have created a KataConfig custom resource (CR).
Add runtimeClassName: kata to any pod-templated object:
Pod objects
ReplicaSet objects
ReplicationController objects
StatefulSet objects
Deployment objects
DeploymentConfig objects
apiVersion: v1
kind: Pod
metadata:
name: mypod
spec:
runtimeClassName: kata apiVersion: apps/v1
kind: Deployment
metadata:
name: mypod
labels:
app: mypod
spec:
replicas: 3
selector:
matchLabels:
app: mypod
template:
metadata:
labels:
app: mypod
spec:
runtimeClassName: kata
containers:
- name: mypod
image: myImageOpenShift Container Platform creates the workload and begins scheduling it.
Inspect the runtimeClassName field on a pod-templated object. If the runtimeClassName is kata, then the workload is running on a OpenShift sandboxed containers.
The OpenShift sandboxed containers Operator is supported in a restricted network environment. For more information, Using Operator Lifecycle Manager on restricted networks.
When using a disconnected cluster on a restricted network, you must configure proxy support in Operator Lifecycle Manager to access the OperatorHub. Using a proxy allows the cluster to fetch the OpenShift sandboxed containers Operator.