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88 lines
3.8 KiB
Plaintext
88 lines
3.8 KiB
Plaintext
// Module included in the following assemblies:
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//
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// * installing/installing_aws/installing-aws-user-infra.adoc [Eventually]
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// * installing/installing_azure/installing-azure-user-infra.adoc [Eventually]
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// * installing/installing_gcp/installing-gcp-user-infra.adoc [Eventually]
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// * installing/installing_gcp/installing-restricted-networks-gcp.adoc [Eventually]
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// * installing/installing_bare_metal/installing-bare-metal.adoc
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// * installing/installing_aws/installing-restricted-networks-aws.adoc [Eventually]
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// * installing/installing_bare_metal/installing-restricted-networks-bare-metal.adoc
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// * installing/installing_platform_agnostic/installing-platform-agnostic.adoc
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// * installing/installing_vsphere/installing-restricted-networks-vsphere.adoc [Eventually]
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// * installing/installing_vsphere/installing-vsphere.adoc [Eventually]
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// * installing/installing_ibm_z/installing-ibm-z.adoc [Eventually]
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ifeval::["{context}" == "installing-ibm-z"]
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:ibm-z:
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endif::[]
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ifeval::["{context}" == "installing-ibm-z-kvm"]
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:ibm-z-kvm:
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endif::[]
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ifeval::["{context}" == "installing-restricted-networks-ibm-z"]
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:ibm-z:
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:restricted:
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endif::[]
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ifeval::["{context}" == "installing-restricted-networks-ibm-z-kvm"]
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:ibm-z-kvm:
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:restricted:
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endif::[]
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[id="installation-three-node-cluster_{context}"]
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= Configuring a three-node cluster
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You can optionally deploy zero compute machines in a bare metal cluster that consists of three control plane machines only. This provides smaller, more resource efficient clusters for cluster administrators and developers to use for testing, development, and production.
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In three-node {product-title} environments, the three control plane machines are schedulable, which means that your application workloads are scheduled to run on them.
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.Prerequisites
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* You have an existing `install-config.yaml` file.
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.Procedure
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* Ensure that the number of compute replicas is set to `0` in your `install-config.yaml` file, as shown in the following `compute` stanza:
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+
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[source,yaml]
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----
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compute:
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- name: worker
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platform: {}
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replicas: 0
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----
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+
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[NOTE]
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====
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You must set the value of the `replicas` parameter for the compute machines to `0` when you install {product-title} on user-provisioned infrastructure, regardless of the number of compute machines you are deploying. In installer-provisioned installations, the parameter controls the number of compute machines that the cluster creates and manages for you. This does not apply to user-provisioned installations, where the compute machines are deployed manually.
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====
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ifdef::ibm-z,ibm-z-kvm[]
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+
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[NOTE]
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====
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The minimum for control plane nodes is 21 GB. For three control plane nodes this is the memory equivalent of a minimum five node cluster.
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====
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endif::ibm-z,ibm-z-kvm[]
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.Next steps
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For three-node cluster installations, follow these next steps:
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* If you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes. See the _Load balancing requirements for user-provisioned infrastructure_ section for more information.
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* When you create the Kubernetes manifest files in the following procedure, ensure that the `mastersSchedulable` parameter in the `<installation_directory>/manifests/cluster-scheduler-02-config.yml` file is set to `true`. This enables your application workloads to run on the control plane nodes.
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* Do not deploy any compute nodes when you create the {op-system-first} machines.
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ifeval::["{context}" == "installing-ibm-z"]
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:!ibm-z:
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endif::[]
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ifeval::["{context}" == "installing-ibm-z-kvm"]
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:!ibm-z-kvm:
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endif::[]
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ifeval::["{context}" == "installing-restricted-networks-ibm-z"]
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:!ibm-z:
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:!restricted:
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endif::[]
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ifeval::["{context}" == "installing-restricted-networks-ibm-z-kvm"]
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:!ibm-z-kvm:
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:!restricted:
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endif::[]
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