Chapter 7. Creating infrastructure machine sets

Procedure

1. Create a new YAML file that contains the machine set custom resource (CR) sample and is named <file_name>.yaml.

   Ensure that you set the <clusterID> and <role> parameter values.

   1. If you are not sure which value to set for a specific field, you can check an existing machine set from your cluster:

      $ oc get machinesets -n openshift-machine-api

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      Example output

      NAME                                DESIRED   CURRENT   READY   AVAILABLE   AGE
      agl030519-vplxk-worker-us-east-1a   1         1         1       1           55m
      agl030519-vplxk-worker-us-east-1b   1         1         1       1           55m
      agl030519-vplxk-worker-us-east-1c   1         1         1       1           55m
      agl030519-vplxk-worker-us-east-1d   0         0                             55m
      agl030519-vplxk-worker-us-east-1e   0         0                             55m
      agl030519-vplxk-worker-us-east-1f   0         0                             55m

      Copy to Clipboard Toggle word wrap

   2. Check values of a specific machine set:

      $ oc get machineset <machineset_name> -n \
           openshift-machine-api -o yaml

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      Example output

      ...
      template:
          metadata:
            labels:
              machine.openshift.io/cluster-api-cluster: agl030519-vplxk 

      1

      
              machine.openshift.io/cluster-api-machine-role: worker 

      2

      
              machine.openshift.io/cluster-api-machine-type: worker
              machine.openshift.io/cluster-api-machineset: agl030519-vplxk-worker-us-east-1a

      Copy to Clipboard Toggle word wrap

      1

      The cluster ID.

      2

      A default node label.

2. Create the new MachineSet CR:

   $ oc create -f <file_name>.yaml

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3. View the list of machine sets:

   $ oc get machineset -n openshift-machine-api

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   Example output

   NAME                                DESIRED   CURRENT   READY   AVAILABLE   AGE
   agl030519-vplxk-infra-us-east-1a    1         1         1       1           11m
   agl030519-vplxk-worker-us-east-1a   1         1         1       1           55m
   agl030519-vplxk-worker-us-east-1b   1         1         1       1           55m
   agl030519-vplxk-worker-us-east-1c   1         1         1       1           55m
   agl030519-vplxk-worker-us-east-1d   0         0                             55m
   agl030519-vplxk-worker-us-east-1e   0         0                             55m
   agl030519-vplxk-worker-us-east-1f   0         0                             55m

   Copy to Clipboard Toggle word wrap

   When the new machine set is available, the DESIRED and CURRENT values match. If the machine set is not available, wait a few minutes and run the command again.

Procedure

1. Add a label to the worker node that you want to act as application node:

   $ oc label node <node-name> node-role.kubernetes.io/app=""

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2. Add a label to the worker nodes that you want to act as infrastructure nodes:

   $ oc label node <node-name> node-role.kubernetes.io/infra=""

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3. Check to see if applicable nodes now have the infra role and app roles:

   $ oc get nodes

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4. Create a default cluster-wide node selector. The default node selector is applied to pods created in all namespaces. This creates an intersection with any existing node selectors on a pod, which additionally constrains the pod’s selector.

   Important

   If the default node selector key conflicts with the key of a pod’s label, then the default node selector is not applied.

   However, do not set a default node selector that might cause a pod to become unschedulable. For example, setting the default node selector to a specific node role, such as node-role.kubernetes.io/infra="", when a pod’s label is set to a different node role, such as node-role.kubernetes.io/master="", can cause the pod to become unschedulable. For this reason, use caution when setting the default node selector to specific node roles.

   You can alternatively use a project node selector to avoid cluster-wide node selector key conflicts.

   1. Edit the Scheduler object:

      $ oc edit scheduler cluster

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   2. Add the defaultNodeSelector field with the appropriate node selector:

      apiVersion: config.openshift.io/v1
      kind: Scheduler
      metadata:
        name: cluster
      ...
      spec:
        defaultNodeSelector: topology.kubernetes.io/region=us-east-1 

      1

      
      ...

      Copy to Clipboard Toggle word wrap

      1

      This example node selector deploys pods on nodes in the us-east-1 region by default.

   3. Save the file to apply the changes.

Procedure

1. Add a label to the node you want to assign as the infra node with a specific label:

   $ oc label node <node_name> <label>

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   $ oc label node ci-ln-n8mqwr2-f76d1-xscn2-worker-c-6fmtx node-role.kubernetes.io/infra=

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2. Create a machine config pool that contains both the worker role and your custom role as machine config selector:

   $ cat infra.mcp.yaml

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   Example output

   apiVersion: machineconfiguration.openshift.io/v1
   kind: MachineConfigPool
   metadata:
     name: infra
   spec:
     machineConfigSelector:
       matchExpressions:
         - {key: machineconfiguration.openshift.io/role, operator: In, values: [worker,infra]} 

   1

   
     nodeSelector:
       matchLabels:
         node-role.kubernetes.io/infra: "" 

   2

   Copy to Clipboard Toggle word wrap

   1

   Add the worker role and your custom role.

   2

   Add the label you added to the node as a nodeSelector.

   Note

   Custom machine config pools inherit machine configs from the worker pool. Custom pools use any machine config targeted for the worker pool, but add the ability to also deploy changes that are targeted at only the custom pool. Because a custom pool inherits resources from the worker pool, any change to the worker pool also affects the custom pool.

3. After you have the YAML file, you can create the machine config pool:

   $ oc create -f infra.mcp.yaml

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4. Check the machine configs to ensure that the infrastructure configuration rendered successfully:

   $ oc get machineconfig

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   Example output

   NAME                                                        GENERATEDBYCONTROLLER                      IGNITIONVERSION   CREATED
   00-master                                                   365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             31d
   00-worker                                                   365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             31d
   01-master-container-runtime                                 365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             31d
   01-master-kubelet                                           365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             31d
   01-worker-container-runtime                                 365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             31d
   01-worker-kubelet                                           365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             31d
   99-master-1ae2a1e0-a115-11e9-8f14-005056899d54-registries   365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             31d
   99-master-ssh                                                                                          2.2.0             31d
   99-worker-1ae64748-a115-11e9-8f14-005056899d54-registries   365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             31d
   99-worker-ssh                                                                                          2.2.0             31d
   rendered-infra-4e48906dca84ee702959c71a53ee80e7             365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             19s
   rendered-master-072d4b2da7f88162636902b074e9e28e            5b6fb8349a29735e48446d435962dec4547d3090   2.2.0             31d
   rendered-master-3e88ec72aed3886dec061df60d16d1af            02c07496ba0417b3e12b78fb32baf6293d314f79   2.2.0             31d
   rendered-master-419bee7de96134963a15fdf9dd473b25            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             17d
   rendered-master-53f5c91c7661708adce18739cc0f40fb            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             13d
   rendered-master-a6a357ec18e5bce7f5ac426fc7c5ffcd            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             7d3h
   rendered-master-dc7f874ec77fc4b969674204332da037            5b6fb8349a29735e48446d435962dec4547d3090   2.2.0             31d
   rendered-worker-1a75960c52ad18ff5dfa6674eb7e533d            5b6fb8349a29735e48446d435962dec4547d3090   2.2.0             31d
   rendered-worker-2640531be11ba43c61d72e82dc634ce6            5b6fb8349a29735e48446d435962dec4547d3090   2.2.0             31d
   rendered-worker-4e48906dca84ee702959c71a53ee80e7            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             7d3h
   rendered-worker-4f110718fe88e5f349987854a1147755            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             17d
   rendered-worker-afc758e194d6188677eb837842d3b379            02c07496ba0417b3e12b78fb32baf6293d314f79   2.2.0             31d
   rendered-worker-daa08cc1e8f5fcdeba24de60cd955cc3            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   2.2.0             13d

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   You should see a new machine config, with the rendered-infra-* prefix.

5. Optional: To deploy changes to a custom pool, create a machine config that uses the custom pool name as the label, such as infra. Note that this is not required and only shown for instructional purposes. In this manner, you can apply any custom configurations specific to only your infra nodes.

   Note

   After you create the new machine config pool, the MCO generates a new rendered config for that pool, and associated nodes of that pool reboot to apply the new configuration.

   1. Create a machine config:

      $ cat infra.mc.yaml

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      Example output

      apiVersion: machineconfiguration.openshift.io/v1
      kind: MachineConfig
      metadata:
        name: 51-infra
        labels:
          machineconfiguration.openshift.io/role: infra 

      1

      
      spec:
        config:
          ignition:
            version: 3.1.0
          storage:
            files:
            - path: /etc/infratest
              mode: 0644
              contents:
                source: data:,infra

      Copy to Clipboard Toggle word wrap

      1

      Add the label you added to the node as a nodeSelector.

   2. Apply the machine config to the infra-labeled nodes:

      $ oc create -f infra.mc.yaml

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6. Confirm that your new machine config pool is available:

   $ oc get mcp

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   Example output

   NAME     CONFIG                                             UPDATED   UPDATING   DEGRADED   MACHINECOUNT   READYMACHINECOUNT   UPDATEDMACHINECOUNT   DEGRADEDMACHINECOUNT   AGE
   infra    rendered-infra-60e35c2e99f42d976e084fa94da4d0fc    True      False      False      1              1                   1                     0                      4m20s
   master   rendered-master-9360fdb895d4c131c7c4bebbae099c90   True      False      False      3              3                   3                     0                      91m
   worker   rendered-worker-60e35c2e99f42d976e084fa94da4d0fc   True      False      False      2              2                   2                     0                      91m

   Copy to Clipboard Toggle word wrap

   In this example, a worker node was changed to an infra node.

Procedure

1. Add a taint to the infra node to prevent scheduling user workloads on it:

   1. Determine if the node has the taint:

      $ oc describe nodes <node_name>

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      Sample output

      oc describe node ci-ln-iyhx092-f76d1-nvdfm-worker-b-wln2l
      Name:               ci-ln-iyhx092-f76d1-nvdfm-worker-b-wln2l
      Roles:              worker
       ...
      Taints:             node-role.kubernetes.io/infra:NoSchedule
       ...

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      This example shows that the node has a taint. You can proceed with adding a toleration to your pod in the next step.

   2. If you have not configured a taint to prevent scheduling user workloads on it:

      $ oc adm taint nodes <node_name> <key>:<effect>

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      For example:

      $ oc adm taint nodes node1 node-role.kubernetes.io/infra:NoSchedule

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      This example places a taint on node1 that has key node-role.kubernetes.io/infra and taint effect NoSchedule. Nodes with the NoSchedule effect schedule only pods that tolerate the taint, but allow existing pods to remain scheduled on the node.

      Note

      If a descheduler is used, pods violating node taints could be evicted from the cluster.

2. Add tolerations for the pod configurations you want to schedule on the infra node, like router, registry, and monitoring workloads. Add the following code to the Pod object specification:

   tolerations:
     - effect: NoSchedule 

   1

   
       key: node-role.kubernetes.io/infra 

   2

   
       operator: Exists 

   3

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   1

   Specify the effect that you added to the node.

   2

   Specify the key that you added to the node.

   3

   Specify the Exists Operator to require a taint with the key node-role.kubernetes.io/infra to be present on the node.

   This toleration matches the taint created by the oc adm taint command. A pod with this toleration can be scheduled onto the infra node.

   Note

   Moving pods for an Operator installed via OLM to an infra node is not always possible. The capability to move Operator pods depends on the configuration of each Operator.

3. Schedule the pod to the infra node using a scheduler. See the documentation for Controlling pod placement onto nodes for details.

Procedure

1. View the IngressController custom resource for the router Operator:

   $ oc get ingresscontroller default -n openshift-ingress-operator -o yaml

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   The command output resembles the following text:

   apiVersion: operator.openshift.io/v1
   kind: IngressController
   metadata:
     creationTimestamp: 2019-04-18T12:35:39Z
     finalizers:
     - ingresscontroller.operator.openshift.io/finalizer-ingresscontroller
     generation: 1
     name: default
     namespace: openshift-ingress-operator
     resourceVersion: "11341"
     selfLink: /apis/operator.openshift.io/v1/namespaces/openshift-ingress-operator/ingresscontrollers/default
     uid: 79509e05-61d6-11e9-bc55-02ce4781844a
   spec: {}
   status:
     availableReplicas: 2
     conditions:
     - lastTransitionTime: 2019-04-18T12:36:15Z
       status: "True"
       type: Available
     domain: apps.<cluster>.example.com
     endpointPublishingStrategy:
       type: LoadBalancerService
     selector: ingresscontroller.operator.openshift.io/deployment-ingresscontroller=default

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2. Edit the ingresscontroller resource and change the nodeSelector to use the infra label:

   $ oc edit ingresscontroller default -n openshift-ingress-operator

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   Add the nodeSelector stanza that references the infra label to the spec section, as shown:

     spec:
       nodePlacement:
         nodeSelector:
           matchLabels:
             node-role.kubernetes.io/infra: ""

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3. Confirm that the router pod is running on the infra node.

   1. View the list of router pods and note the node name of the running pod:

      $ oc get pod -n openshift-ingress -o wide

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      Example output

      NAME                              READY     STATUS        RESTARTS   AGE       IP           NODE                           NOMINATED NODE   READINESS GATES
      router-default-86798b4b5d-bdlvd   1/1      Running       0          28s       10.130.2.4   ip-10-0-217-226.ec2.internal   <none>           <none>
      router-default-955d875f4-255g8    0/1      Terminating   0          19h       10.129.2.4   ip-10-0-148-172.ec2.internal   <none>           <none>

      Copy to Clipboard Toggle word wrap

      In this example, the running pod is on the ip-10-0-217-226.ec2.internal node.

   2. View the node status of the running pod:

      $ oc get node <node_name> 

      1

      Copy to Clipboard Toggle word wrap

      1

      Specify the <node_name> that you obtained from the pod list.

      Example output

      NAME                          STATUS  ROLES         AGE   VERSION
      ip-10-0-217-226.ec2.internal  Ready   infra,worker  17h   v1.19.0

      Copy to Clipboard Toggle word wrap

      Because the role list includes infra, the pod is running on the correct node.

Procedure

1. View the config/instance object:

   $ oc get configs.imageregistry.operator.openshift.io/cluster -o yaml

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   Example output

   apiVersion: imageregistry.operator.openshift.io/v1
   kind: Config
   metadata:
     creationTimestamp: 2019-02-05T13:52:05Z
     finalizers:
     - imageregistry.operator.openshift.io/finalizer
     generation: 1
     name: cluster
     resourceVersion: "56174"
     selfLink: /apis/imageregistry.operator.openshift.io/v1/configs/cluster
     uid: 36fd3724-294d-11e9-a524-12ffeee2931b
   spec:
     httpSecret: d9a012ccd117b1e6616ceccb2c3bb66a5fed1b5e481623
     logging: 2
     managementState: Managed
     proxy: {}
     replicas: 1
     requests:
       read: {}
       write: {}
     storage:
       s3:
         bucket: image-registry-us-east-1-c92e88cad85b48ec8b312344dff03c82-392c
         region: us-east-1
   status:
   ...

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2. Edit the config/instance object:

   $ oc edit configs.imageregistry.operator.openshift.io/cluster

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3. Modify the spec section of the object to resemble the following YAML:

   spec:
     affinity:
       podAntiAffinity:
         preferredDuringSchedulingIgnoredDuringExecution:
         - podAffinityTerm:
             namespaces:
             - openshift-image-registry
             topologyKey: kubernetes.io/hostname
           weight: 100
     logLevel: Normal
     managementState: Managed
     nodeSelector:
       node-role.kubernetes.io/infra: ""

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4. Verify the registry pod has been moved to the infrastructure node.

   1. Run the following command to identify the node where the registry pod is located:

      $ oc get pods -o wide -n openshift-image-registry

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   2. Confirm the node has the label you specified:

      $ oc describe node <node_name>

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      Review the command output and confirm that node-role.kubernetes.io/infra is in the LABELS list.

Procedure

1. Save the following ConfigMap definition as the cluster-monitoring-configmap.yaml file:

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: cluster-monitoring-config
     namespace: openshift-monitoring
   data:
     config.yaml: |+
       alertmanagerMain:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
       prometheusK8s:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
       prometheusOperator:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
       grafana:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
       k8sPrometheusAdapter:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
       kubeStateMetrics:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
       telemeterClient:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
       openshiftStateMetrics:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
       thanosQuerier:
         nodeSelector:
           node-role.kubernetes.io/infra: ""

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   Running this config map forces the components of the monitoring stack to redeploy to infrastructure nodes.

2. Apply the new config map:

   $ oc create -f cluster-monitoring-configmap.yaml

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3. Watch the monitoring pods move to the new machines:

   $ watch 'oc get pod -n openshift-monitoring -o wide'

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4. If a component has not moved to the infra node, delete the pod with this component:

   $ oc delete pod -n openshift-monitoring <pod>

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   The component from the deleted pod is re-created on the infra node.

Procedure

1. Edit the ClusterLogging custom resource (CR) in the openshift-logging project:

   $ oc edit ClusterLogging instance

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   apiVersion: logging.openshift.io/v1
   kind: ClusterLogging
   
   ...
   
   spec:
     collection:
       logs:
         fluentd:
           resources: null
         type: fluentd
     curation:
       curator:
         nodeSelector: 

   1

   
           node-role.kubernetes.io/infra: ''
         resources: null
         schedule: 30 3 * * *
       type: curator
     logStore:
       elasticsearch:
         nodeCount: 3
         nodeSelector: 

   2

   
           node-role.kubernetes.io/infra: ''
         redundancyPolicy: SingleRedundancy
         resources:
           limits:
             cpu: 500m
             memory: 16Gi
           requests:
             cpu: 500m
             memory: 16Gi
         storage: {}
       type: elasticsearch
     managementState: Managed
     visualization:
       kibana:
         nodeSelector: 

   3

   
           node-role.kubernetes.io/infra: ''
         proxy:
           resources: null
         replicas: 1
         resources: null
       type: kibana
   
   ...

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