container.training/slides/exercises/helm-generic-chart-details.md

Exercise - Helm Charts

• We want to deploy dockercoins with a Helm chart

• We want to have a "generic chart" and instantiate it 5 times

  (once for each service)

• We will pass values to the chart to customize it for each component

  (to indicate which image to use, which ports to expose, etc.)

• We'll use helm create as a starting point for our generic chart

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Goal

• Have a directory with the generic chart

  (e.g. generic-chart)

• Have 5 value files

  (e.g. hasher.yml, redis.yml, rng.yml, webui.yml, worker.yml)

• Be able to install dockercoins by running 5 times:

  helm install X ./generic-chart --values=X.yml

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Hints

• There are many little things to tweak in the generic chart

  (service names, port numbers, healthchecks...)

• Check the training slides if you need a refresher!

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Bonus 1

• Minimize the amount of values that have to be set

• Option 1: no values at all for rng and hasher

  (default values assume HTTP service listening on port 80)

• Option 2: no values at all for worker

  (default values assume worker container with no service)

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Bonus 2

• Handle healthchecks

• Make sure that healthchecks are enabled in HTTP services

• ...But not in Redis or in the worker

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Bonus 3

• Make it easy to change image versions

• E.g. change v0.1 to v0.2 by changing only one thing in one place

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Bonus 4

• Make it easy to use images on a different registry

• We can assume that the images will always have the same names

  (hasher, rng, webui, worker)

• And the same tag

  (v0.1)