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container.training/slides/k8s/create-chart.md
2019-06-01 20:02:53 -05:00

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## Creating a chart
- We are going to show a way to create a *very simplified* chart
- In a real chart, *lots of things* would be templatized
(Resource names, service types, number of replicas...)
.exercise[
- Create a sample chart:
```bash
helm create dockercoins
```
- Move away the sample templates and create an empty template directory:
```bash
mv dockercoins/templates dockercoins/default-templates
mkdir dockercoins/templates
```
]
---
## Exporting the YAML for our application
- The following section assumes that DockerCoins is currently running
.exercise[
- Create one YAML file for each resource that we need:
.small[
```bash
while read kind name; do
kubectl get -o yaml $kind $name > dockercoins/templates/$name-$kind.yaml
done <<EOF
deployment worker
deployment hasher
daemonset rng
deployment webui
deployment redis
service hasher
service rng
service webui
service redis
EOF
```
]
]
---
## Testing our helm chart
.exercise[
- Let's install our helm chart! (`dockercoins` is the path to the chart)
```
helm install dockercoins
```
]
--
- Since the application is already deployed, this will fail:<br>
`Error: release loitering-otter failed: services "hasher" already exists`
- To avoid naming conflicts, we will deploy the application in another *namespace*
---
## Switching to another namespace
- We can create a new namespace and switch to it
(Helm will automatically use the namespace specified in our context)
- We can also tell Helm which namespace to use
.exercise[
- Tell Helm to use a specific namespace:
```bash
helm install dockercoins --namespace=magenta
```
]
---
## Checking our new copy of DockerCoins
- We can check the worker logs, or the web UI
.exercise[
- Retrieve the NodePort number of the web UI:
```bash
kubectl get service webui --namespace=magenta
```
- Open it in a web browser
- Look at the worker logs:
```bash
kubectl logs deploy/worker --tail=10 --follow --namespace=magenta
```
]
Note: it might take a minute or two for the worker to start.