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Show quick demo of Kustomize

Browse Source 
Use Replicated Ship to generate the base and overlays
from the kubercoins GitHub repo.

The namespaces chapter has been slightly tweaked so
that we can use it for either Helm or Kustomize demo.
This commit is contained in:
Jerome Petazzoni
2019-04-22 05:18:45 -05:00
parent 06aba6737a
commit c367ad1156
8 changed files with 259 additions and 76 deletions
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71
slides/k8s/create-chart.md Normal file
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@@ -0,0 +1,71 @@
## 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 --export $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*

74
slides/k8s/helm.md
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@@ -176,77 +176,3 @@ The chart's metadata includes an URL to the project's home page.
```
]
---
## 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 --export $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*

148
slides/k8s/kustomize.md Normal file
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@@ -0,0 +1,148 @@
# Kustomize
- Kustomize lets us transform YAML files representing Kubernetes resources
- The original YAML files are valid resource files
(e.g. they can be loaded with `kubectl apply -f`)
- They are left untouched by Kustomize
- Kustomize lets us define *overlays* that extend or change the resource files
---
## Differences with Helm
- Helm Charts use placeholders `{{ like.this }}`
- Kustomize "bases" are standard Kubernetes YAML
- It is possible to use an existing set of YAML as a Kustomize base
- As a result, writing a Helm Chart is more work ...
- ... But Helm Charts are also more powerful; e.g. they can:
- use flags to conditionally include resources or blocks
- check if a given Kubernetes API group is supported
- [and much more](https://helm.sh/docs/chart_template_guide/)
---
## Kustomize concepts
- Kustomize needs a `kustomization.yaml` file
- That file can be a *base* or a *variant*
- If it's a *base*:
- it lists YAML resource files to use
- If it's a *variant* (or *overlay*):
- it refers to (at least) one *base*
- and some *patches*
---
## An easy way to get started with Kustomize
- We are going to use [Replicated Ship](https://www.replicated.com/ship/) to experiment with Kustomize
- The [Replicated Ship CLI](https://github.com/replicatedhq/ship/releases) has been installed on our clusters
- Replicated Ship has multiple workflows; here is what we will do:
- initialize a Kustomize overlay from a remote GitHub repository
- customize some values using the web UI provided by Ship
- look at the resulting files and apply them to the cluster
---
## Getting started with Ship
- We need to run `ship init` in a new directory
- `ship init` requires an URL to a remote repository containing Kubernetes YAML
- It will clone that repository and start a web UI
- Later, it can watch that repository and/or update from it
- We will use the [jpetazzo/kubercoins](https://github.com/jpetazzo/kubeercoins) repository
(it contains all the DockerCoins resources as YAML files)
---
## `ship init`
.exercise[
- Change to a new directory:
```bash
mkdir ~/kubercoins
cd ~/kubercoins
```
- Run `ship init` with the kubercoins repository:
```bash
ship init https://github.com/jpetazzo/kubercoins
```
]
---
## Access the web UI
- `ship init` tells us to connect on `localhost:8800`
- We need to replace `localhost` with the address of our node
(since we run on a remote machine)
- Follow the steps in the web UI, and change one parameter
(e.g. set the number of replicas in the worker Deployment)
- Complete the web workflow, and go back to the CLI
---
## Inspect the results
- Look at the content of our directory
- `base` contains the kubercoins repository + a `kustomization.yaml` file
- `overlays/ship` contains the Kustomize overlay referencing the base + our patch(es)
- `rendered.yaml` is a YAML bundle containing the patched application
- `.ship` contains a state file used by Ship
---
## Using the results
- We can `kubectl apply -f rendered.yaml`
(on any version of Kubernetes)
- Starting with Kubernetes 1.14, we can apply the overlay directly with:
```bash
kubectl apply -k overlays/ship
```
- But let's not do that for now!
- We will create a new copy of DockerCoins in another namespace

34
slides/k8s/namespaces.md
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@@ -155,7 +155,7 @@
## Using our new namespace
- Let's check that we are in our new namespace, then deploy the DockerCoins chart
- Let's check that we are in our new namespace, then deploy a new copy of Dockercoins
.exercise[
@@ -164,6 +164,16 @@
kubectl get all
```
]
---
## Deploy DockerCoins with Helm
*Follow these instructions if you previously created a Helm Chart.*
.exercise[
- Deploy DockerCoins:
```bash
helm install dockercoins
@@ -176,9 +186,29 @@ we created our Helm chart before.
---
## Deploy DockerCoins with Kustomize
*Follow these instructions if you previously created a Kustomize overlay.*
.exercise[
- Deploy DockerCoins:
```bash
kubectl apply -f rendered.yaml
```
- Or, with Kubernetes 1.14, you can also do this:
```bash
kubectl apply -k overlays/ship
```
]
---
## Viewing the deployed app
- Let's see if our Helm chart worked correctly!
- Let's see if this worked correctly!
.exercise[

2
slides/kube-fullday.yml
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@@ -50,6 +50,8 @@ chapters:
- k8s/logs-cli.md
- k8s/logs-centralized.md
#- - k8s/helm.md
# - k8s/create-chart.md
# - k8s/kustomize.md
# - k8s/namespaces.md
# - k8s/netpol.md
# - k8s/authn-authz.md

2
slides/kube-halfday.yml
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@@ -53,6 +53,8 @@ chapters:
# Bridget hasn't added EFK yet
#- k8s/logs-centralized.md
- k8s/helm.md
- k8s/create-chart.md
#- k8s/kustomize.md
- k8s/namespaces.md
#- k8s/netpol.md
- k8s/whatsnext.md

2
slides/kube-selfpaced.yml
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@@ -50,6 +50,8 @@ chapters:
- k8s/logs-cli.md
- k8s/logs-centralized.md
- - k8s/helm.md
#- k8s/create-chart.md
- k8s/kustomize.md
- k8s/namespaces.md
- k8s/netpol.md
- k8s/authn-authz.md

2
slides/kube-twodays.yml
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@@ -50,6 +50,8 @@ chapters:
- k8s/logs-cli.md
- k8s/logs-centralized.md
- - k8s/helm.md
#- k8s/create-chart.md
- k8s/kustomize.md
- k8s/namespaces.md
- k8s/netpol.md
- k8s/authn-authz.md