From 795a97466527a5f02e79e47b7fb316c78ffde667 Mon Sep 17 00:00:00 2001 From: Vincent Ambo Date: Fri, 20 Dec 2019 22:13:07 +0000 Subject: chore(kontemplate): Prepare kontemplate for depot-merge This merge will not yet include moving over to buildGo.nix, as support for testing and such is not present in that library yet. --- ops/kontemplate/docs/resource-sets.md | 170 ++++++++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) create mode 100644 ops/kontemplate/docs/resource-sets.md (limited to 'ops/kontemplate/docs/resource-sets.md') diff --git a/ops/kontemplate/docs/resource-sets.md b/ops/kontemplate/docs/resource-sets.md new file mode 100644 index 000000000000..1444dd491249 --- /dev/null +++ b/ops/kontemplate/docs/resource-sets.md @@ -0,0 +1,170 @@ +Resource Sets +================ + +Resource sets are collections of Kubernetes resources that should be passed to `kubectl` together. + +Technically a resource set is simply a folder with a few YAML and/or JSON templates in it. + + +**Table of Contents** + +- [Resource Sets](#resource-sets) +- [Creating resource sets](#creating-resource-sets) + - [Default variables](#default-variables) +- [Including resource sets](#including-resource-sets) + - [Fields](#fields) + - [`name`](#name) + - [`path`](#path) + - [`values`](#values) + - [`args`](#args) + - [`include`](#include) + - [Multiple includes](#multiple-includes) + - [Nesting resource sets](#nesting-resource-sets) + - [Caveats](#caveats) + + + +# Creating resource sets + +Simply create a folder in your Kontemplate repository and place a YAML or JSON file in it. These +files get interpreted as [templates][] during Kontemplate runs and variables (as well as template +logic or functions) will be interpolated. + +Refer to the template documentation for information on how to write templates. + +## Default variables + +Sometimes it is useful to specify default values for variables that should be interpolated during +a run if the [cluster configuration][] does not specify a variable explicitly. + +This can be done simply by placing a `default.yaml` or `default.json` file in the resource set +folder and filling it with key/value pairs of the intended default variables. + +Kontemplate will error during interpolation if any variables are left unspecified. + +# Including resource sets + +Under the cluster configuration `include` key resource sets are included and required variables +are specified. For example: + +```yaml +include: + - name: some-api + values: + version: 1.2-SNAPSHOT +``` + +This will include a resource set from a folder called `some-api` and set the specified `version` variable. + +## Fields + +The available fields when including a resource set are these: + +### `name` + +The `name` field contains the name of the resource set. This name can be used to refer to the resource set +when specifying explicit includes or excludes during a run. + +By default it is assumed that the `name` is the path to the resource set folder, but this can be overridden. + +This field is **required**. + +### `path` + +The `path` field specifies an explicit path to a resource set folder in the case that it should differ from +the resource set's `name`. + +This field is **optional**. + +### `values` + +The `values` field specifies key/values pairs of variables that should be available during templating. + +This field is **optional**. + +### `args` + +The `args` field specifies a list of arguments that should be passed to `kubectl`. + +This field is **optional**. + +### `include` + +The `include` field specifies additional resource sets that should be included and that should inherit the +variables of this resource set. + +The fully qualified names of "nested" resource sets are set to `${PARENT_NAME}/${CHILD_NAME}` and paths are +merged in the same way. + +This makes it easy to organise different resource sets as "groups" to include / exclude them collectively +during runs. + +This field is **optional**. + +## Multiple includes + +Resource sets can be included multiple times with different configurations. In this case it is recommended +to set the `path` and `name` fields explicitly. For example: + +```yaml +include: + - name: forwarder-europe + path: tools/forwarder + values: + source: europe + - name: forwarder-asia + path: tools/forwarder + values: + source: asia +``` + +The two different configurations can be referred to by their set names, but will use the same resource +templates with different configurations. + +## Nesting resource sets + +As mentioned above for the `include` field, resource sets can be nested. This lets users group resource +sets in logical ways using simple folder structures. + +Assuming a folder structure like: + +``` +├── backend +│   ├── auth-api +│   ├── message-api +│   └── order-api +└── frontend + ├── app-page + └── login-page +``` + +With each of these folders being a resource set, they could be included in a cluster configuration like so: + +```yaml +include: + - name: backend + include: + - name: auth-api + - name: message-api + - name: order-api + - name: frontend: + include: + - name: app-page + - name: login-page +``` + +Kontemplate could then be run with, for example, `--include backend` to only include the resource sets nested +in the backend group. Specific resource sets can also be targeted, for example as `--include backend/order-api`. + +Variables specified in the parent resource set are inherited by the children. + +### Caveats + +Two caveats apply that users should be aware of: + +1. The parent resource set can not contain any resource templates itself. + +2. Only one level of nesting is supported. Specifying `include` again on a nested resource set will be ignored. + +[templates]: templates.md +[cluster configuration]: cluster-config.md -- cgit 1.4.1