Update EC Architecture Diagram to include Operator #3077
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| The following diagram shows the architecture of an HA multi-node Embedded Cluster installation: | ||
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| [View a larger version of this image](/images/embedded-architecture-multi-node-ha.png) | ||
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| As shown in the diagram above, in HA installations with Embedded Cluster: | ||
| * A single replica of the Embedded Cluster Operator is deployed and runs on a controller node. | ||
| * A single replica of the KOTS Admin Console is deployed and runs on a controller node. | ||
| * Three replicas of rqlite are deployed in the kotsadm namespace. Rqlite is used by KOTS to store information such as support bundles, version history, application metadata, and other small amounts of data needed to manage the application. | ||
| * For installations that include disaster recovery, the Velero pod is deployed on one node. The Velero Node Agent runs on each node in the cluster. The Node Agent is a Kubernetes DaemonSet that performs backup and restore tasks such as creating snapshots and transferring data during restores. | ||
| * For air gap installations, two replicas of the air gap image registry are deployed. | ||
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There was a problem hiding this comment. ^ air gap registry deployed as 2 replicas |
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| Any Helm [`extensions`](/reference/embedded-config#extensions) that you include in the Embedded Cluster Config are installed in the cluster depending on the given chart and whether or not it is configured to be deployed with high availability. | ||
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There was a problem hiding this comment.
Updated this to remove the implication that this is something that can be configured in Embedded Cluster |
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| import EmbeddedCluster from "../partials/embedded-cluster/_definition.mdx" | ||
| import Requirements from "../partials/embedded-cluster/_requirements.mdx" | ||
| import EmbeddedClusterPortRequirements from "../partials/embedded-cluster/_port-reqs.mdx" | ||
| import HaArchitecture from "../partials/embedded-cluster/_multi-node-ha-arch.mdx" | ||
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| # Embedded Cluster Overview | ||
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@@ -14,7 +15,7 @@ If you are instead looking for information about creating Kubernetes Installers | |
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| <EmbeddedCluster/> | ||
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| ## Architecture | ||
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| This section describes the Embedded Cluster architecture, including the built-in extensions deployed by Embedded Cluster. | ||
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@@ -28,41 +29,51 @@ The following diagram shows the architecture of a single-node Embedded Cluster i | |
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| As shown in the diagram above, the user downloads the Embedded Cluster installation assets as a `.tgz` in their installation environment. These installation assets include the Embedded Cluster binary, the user's license file, and (for air gap installations) an air gap bundle containing the images needed to install and run the release in an environment with limited or no outbound internet access. | ||
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| When the user runs the Embedded Cluster install command, the Embedded Cluster binary first installs the k0s cluster as a systemd service. | ||
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| After all the Kubernetes components for the cluster are available, the Embedded Cluster binary then installs the Embedded Cluster built-in extensions. For more information about these extensions, see [Built-In Extensions](#built-in-extensions) below. | ||
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| Any Helm extensions that were included in the [`extensions`](/reference/embedded-config#extensions) field of the Embedded Cluster Config are also installed. The namespace or namespaces where Helm extensions are installed is defined by the vendor in the Embedded Cluster Config. | ||
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| Finally, Embedded Cluster also installs Local Artifact Mirror (LAM). In air gap installations, LAM is used to store and update images. | ||
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| ### Multi-Node Architecture | ||
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| The following diagram shows the architecture of a multi-node Embedded Cluster installation: | ||
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| [View a larger version of this image](/images/embedded-architecture-multi-node.png) | ||
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| As shown in the diagram above, in multi-node installations, the Embedded Cluster Operator, KOTS, and the image registry for air gap installations are all installed on one controller node. | ||
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| For installations that include disaster recovery with Velero, the Velero Node Agent runs on each node in the cluster. The Node Agent is a Kubernetes DaemonSet that performs backup and restore tasks such as creating snapshots and transferring data during restores. | ||
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Member
There was a problem hiding this comment. any reason this isn't mentioned in the single-node stuff too?
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There was a problem hiding this comment. I think it was because I wrote this with the purpose of explaining how the node agent is the component that runs on all the nodes in multi-node installs (versus single node installs where that's not relevant). The basic info about the Velero extension though (ie, agnostic of install type) is over in the Built-In Extensions section: https://deploy-preview-3077--replicated-docs-upgrade.netlify.app/vendor/embedded-overview#built-in-extensions I could update that section with this velero pod v agent info
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There was a problem hiding this comment. i'm not particular about it. i assumed it was describing all that's in the diagram, but that's fine if not.
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There was a problem hiding this comment. yeah the single node section used to list out all the extensions in the diagram, but I replaced that with "After all the Kubernetes components for the cluster are available, the Embedded Cluster binary then installs the Embedded Cluster built-in extensions. For more information about these extensions, see Built-In Extensions below." since these descriptions of the extensions were not really specific to single-node |
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| Additionally, any Helm [`extensions`](/reference/embedded-config#extensions) that you include in the Embedded Cluster Config are installed in the cluster depending on the given chart and how it is configured to be deployed. | ||
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| ### Multi-Node Architecture with High Availability | ||
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| :::note | ||
| High availability (HA) for multi-node installations with Embedded Cluster is Alpha and is not enabled by default. For more informaiton about enabling HA, see [Enable High Availability for Multi-Node Clusters (Alpha)](/enterprise/embedded-manage-nodes#ha). | ||
| ::: | ||
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| <HaArchitecture/> | ||
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| ## Built-In Extensions {#built-in-extensions} | ||
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| Embedded Cluster includes several built-in extensions. The built-in extensions provide capabilities such as application management and storage. Each built-in extension is installed in its own namespace. | ||
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| The built-in extensions installed by Embedded Cluster include: | ||
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| * **Embedded Cluster Operator**: The Operator is used for reporting purposes as well as some clean up operations. | ||
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There was a problem hiding this comment. ^ would the Operator be considered an extension? Seemed like it since it's installed alongside the others but wasn't sure |
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| * **KOTS:** Embedded Cluster installs the KOTS Admin Console in the kotsadm namespace. End customers use the Admin Console to configure and install the application. Rqlite is also installed in the kotsadm namespace alongside KOTS. Rqlite is a distributed relational database that uses SQLite as its storage engine. KOTS uses rqlite to store information such as support bundles, version history, application metadata, and other small amounts of data needed to manage the application. For more information about rqlite, see the [rqlite](https://rqlite.io/) website. | ||
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| * **OpenEBS:** Embedded Cluster uses OpenEBS to provide local PersistentVolume (PV) storage, including the PV storage for rqlite used by KOTS. For more information, see the [OpenEBS](https://openebs.io/docs/) documentation. | ||
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| * **(Disaster Recovery Only) Velero:** If the installation uses the Embedded Cluster disaster recovery feature, Embedded Cluster installs Velero, which is an open-source tool that provides backup and restore functionality. For more information about Velero, see the [Velero](https://velero.io/docs/latest/) documentation. For more information about the disaster recovery feature, see [Disaster Recovery for Embedded Cluster (Alpha)](/vendor/embedded-disaster-recovery). | ||
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| * **(Air Gap Only) Image registry:** For air gap installations in environments with limited or no outbound internet access, Embedded Cluster installs an image registry where the images required to install and run the application are pushed. For more information about installing in air-gapped environments, see [Air Gap Installation with Embedded Cluster](/enterprise/installing-embedded-air-gap). | ||
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| ## Comparison to kURL | ||
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^ update the clarify that kots and the operator are both deployed as single replicas and run on "a controller node" (instead of saying "the primary node")