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Merge pull request #86750 from xenolinux/diff-ocp-hcp
OSDOCS#10488: Differences between OCP and HCP
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‎hosted_control_planes/index.adoc

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toc::[]
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include::modules/hosted-control-planes-overview.adoc[leveloffset=+1]
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include::modules/hcp-ocp-differences.adoc[leveloffset=+1]
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[role="_additional-resources"]
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.Additional resources
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* xref:../security/encrypting-etcd.adoc#encrypting-etcd[Enabling etcd encryption]
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include::modules/hcp-mce-acm-relationship-intro.adoc[leveloffset=+1]
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include::modules/hcp-acm-discover.adoc[leveloffset=+2]
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‎modules/hcp-ocp-differences.adoc

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// Module included in the following assemblies:
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//
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// * hosted_control_planes/index.adoc
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:_mod-docs-content-type: REFERENCE
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[id="hcp-ocp-differences_{context}"]
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= Differences between {hcp} and {product-title}
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{hcp-capital} is a form factor of {product-title}. Hosted clusters and the stand-alone {product-title} clusters are configured and managed differently. See the following tables to understand the differences between {product-title} and {hcp}:
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[id="cluster-creation_{context}"]
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== Cluster creation and lifecycle
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[cols="2a,2a",options="header"]
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|===
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|{product-title} |{hcp-capital}
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|You install a standalone {product-title} cluster by using the `openshift-install` binary or the Assisted Installer.
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|You install a hosted cluster by using the `hypershift.openshift.io` API resources such as `HostedCluster` and `NodePool`, on an existing {product-title} cluster.
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|===
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[id="cluster-configuration_{context}"]
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== Cluster configuration
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[cols="2a,2a",options="header"]
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|===
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|{product-title} |{hcp-capital}
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|You configure cluster-scoped resources such as authentication, API server, and proxy by using the `config.openshift.io` API group.
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|You configure resources that impact the control plane in the `HostedCluster` resource.
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|===
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[id="etcd-encryption_{context}"]
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== etcd encryption
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[cols="2a,2a",options="header"]
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|===
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|{product-title} |{hcp-capital}
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|You configure etcd encryption by using the `APIServer` resource with AES-GCM or AES-CBC. For more information, see "Enabling etcd encryption".
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|You configure etcd encryption by using the `HostedCluster` resource in the `SecretEncryption` field with AES-CBC or KMS for {aws-full}.
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|===
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[id="operators-and-control-plane_{context}"]
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== Operators and control plane
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[cols="2a,4a",options="header"]
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|===
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|{product-title} |{hcp-capital}
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|A standalone {product-title} cluster contains separate Operators for each control plane component.
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|A hosted cluster contains a single Operator named Control Plane Operator that runs in the hosted control plane namespace on the management cluster.
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|etcd uses storage that is mounted on the control plane nodes. The etcd cluster Operator manages etcd.
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|etcd uses a persistent volume claim for storage and is managed by the Control Plane Operator.
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|The Ingress Operator, network related Operators, and {olm-first} run on the cluster.
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|The Ingress Operator, network related Operators, and {olm-first} run in the hosted control plane namespace on the management cluster.
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|The OAuth server runs inside the cluster and is exposed through a route in the cluster.
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|The OAuth server runs inside the control plane and is exposed through a route, node port, or load balancer on the management cluster.
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|===
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[id="upgrades_{context}"]
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== Updates
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[cols="2a,2a",options="header"]
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|===
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|{product-title} |{hcp-capital}
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|The Cluster Version Operator (CVO) orchestrates the update process and monitors the `ClusterVersion` resource. Administrators and OpenShift components can interact with the CVO through the `ClusterVersion` resource. The `oc adm upgrade` command results in a change to the `ClusterVersion.Spec.DesiredUpdate` field in the `ClusterVersion` resource.
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|The {hcp} update results in a change to the `.spec.release.image` field in the `HostedCluster` and `NodePools` resources. Any changes to the `ClusterVersion` resource are ignored.
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|After you update an {product-title} cluster, both the control plane and compute machines are updated.
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|After you update the hosted cluster, only the control plane is updated. You perform node pool updates separately.
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|===
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[id="machine-config-manage_{context}"]
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== Machine configuration and management
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[cols="2a,2a",options="header"]
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|===
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|{product-title} |{hcp-capital}
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|The `MachineSets` resource manages machines in the `openshift-machine-api` namespace.
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|The `NodePool` resource manages machines on the management cluster.
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|A set of control plane machines are available.
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|A set of control plane machines do not exist.
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|You enable a machine health check by using the `MachineHealthCheck` resource.
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|You enable a machine health check through the `.spec.management.autoRepair` field in the `NodePool` resource.
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|You enable autoscaling by using the `ClusterAutoscaler` and `MachineAutoscaler` resources.
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|You enable autoscaling through the `spec.autoScaling` field in the `NodePool` resource.
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|Machines and machine sets are exposed in the cluster.
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|Machines, machine sets, and machine deployments from upstream {cluster-capi-operator} are used to manage machines but are not exposed to the user.
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|All machine sets are upgraded automatically when you update the cluster.
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|You update your node pools independently from the hosted cluster updates.
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|Only an in-place upgrade is supported in the cluster.
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|Both replace and in-place upgrades are supported in the hosted cluster.
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|The Machine Config Operator manages configurations for machines.
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|The Machine Config Operator does not exist in {hcp}.
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|You configure machine Ignition by using the `MachineConfig`, `KubeletConfig`, and `ContainerRuntimeConfig` resources that are selected from a `MachineConfigPool` selector.
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|You configure the `MachineConfig`, `KubeletConfig`, and `ContainerRuntimeConfig` resources through the config map referenced in the `spec.config` field of the `NodePool` resource.
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|The Machine Config Daemon (MCD) manages configuration changes and updates on each of the nodes.
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|For an in-place upgrade, the node pool controller creates a run-once pod that updates a machine based on your configuration.
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|You can modify the machine configuration resources such as the SR-IOV Operator.
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|You cannot modify the machine configuration resources.
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|===
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[id="netowrking_{context}"]
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== Networking
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[cols="2a,2a",options="header"]
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|===
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|{product-title} |{hcp-capital}
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|The Kube API server communicates with nodes directly, because the Kube API server and nodes exist in the same Virtual Private Cloud (VPC).
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|The Kube API server communicates with nodes through Konnectivity. The Kube API server and nodes exist in a different Virtual Private Cloud (VPC).
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|Nodes communicate with the Kube API server through the internal load balancer.
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|Nodes communicate with the Kube API server through an external load balancer or a node port.
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|===
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[id="web-console_{context}"]
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== Web console
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[cols="2a,2a",options="header"]
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|===
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|{product-title} |{hcp-capital}
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|The web console shows the status of a control plane.
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|The web console does not show the status of a control plane.
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|You can update your cluster by using the web console.
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|You cannot update the hosted cluster by using the web console.
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|The web console displays the infrastructure resources such as machines.
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|The web console does not display the infrastructure resources.
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|You can configure machines through the `MachineConfig` resource by using the web console.
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|You cannot configure machines by using the web console.
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|===

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