container.training/slides/exercises/tf-nodepools-details.md

Exercise — Terraform Node Pools

• Write a Terraform configuration to deploy a cluster

• The cluster should have two node pools with autoscaling

• Deploy two apps, each using exclusively one node pool

• Bonus: deploy an app balanced across both node pools

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Cluster deployment

• Write a Terraform configuration to deploy a cluster

• We want to have two node pools with autoscaling

• Example for sizing:

  • 4 GB / 1 CPU per node

  • pools of 1 to 4 nodes

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Cluster autoscaling

• Deploy an app on the cluster

  (you can use nginx, jpetazzo/color...)

• Set a resource request (e.g. 1 GB RAM)

• Scale up and verify that the autoscaler kicks in

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Pool isolation

• We want to deploy two apps

• The first app should be deployed exclusively on the first pool

• The second app should be deployed exclusively on the second pool

• Check the next slide for hints!

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Hints

• One solution involves adding a nodeSelector to the pod templates

• Another solution involves adding:

  • taints to the node pools

  • matching tolerations to the pod templates

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Balancing

• Step 1: make sure that the pools are not balanced

• Step 2: deploy a new app, check that it goes to the emptiest pool

• Step 3: update the app so that it balances (as much as possible) between pools