Merge pull request #2132 from pwittrock/kustomize

SIG CLI KEP for Kustomize subproject

4 files changed, 230 insertions, 1 deletions

diff --git a/keps/NEXT_KEP_NUMBER b/keps/NEXT_KEP_NUMBER
index 45a4fb75..ec635144 100644
--- a/keps/NEXT_KEP_NUMBER
+++ b/keps/NEXT_KEP_NUMBER
@@ -1 +1 @@
-8
+9
diff --git a/keps/sig-cli/0008-kustomize.md b/keps/sig-cli/0008-kustomize.md
new file mode 100644
index 00000000..4a300314
--- /dev/null
+++ b/keps/sig-cli/0008-kustomize.md
@@ -0,0 +1,222 @@
+---
+kep-number: 8
+title: Kustomize
+authors:
+  - "@pwittrock"
+  - "@monopole"
+owning-sig: sig-cli
+participating-sigs:
+  - sig-cli
+reviewers:
+  - "@droot"
+approvers:
+  - "@maciej"
+editor: "@droot"
+creation-date: 2018-05-5
+last-updated: 2018-05-5
+status: implemented
+see-also:
+  - n/a
+replaces:
+  - kinflate # Old name for kustomize
+superseded-by:
+  - n/a
+---
+
+# Kustomize
+
+## Table of Contents
+
+- [Kustomize](#kustomize)
+   - [Table of Contents](#table-of-contents)
+   - [Summary](#summary)
+   - [Motivation](#motivation)
+      - [Goals](#goals)
+      - [Non-Goals](#non-goals)
+   - [Proposal](#proposal)
+      - [Implementation Details/Notes/Constraints [optional]](#implementation-detailsnotesconstraints-optional)
+      - [Risks and Mitigations](#risks-and-mitigations)
+      - [Risks of Not Having a Solution](#risks-of-not-having-a-solution)
+   - [Graduation Criteria](#graduation-criteria)
+   - [Implementation History](#implementation-history)
+   - [Drawbacks](#drawbacks)
+   - [Alternatives](#alternatives)
+   - [FAQ](#faq)
+
+## Summary
+
+Declarative specification of Kubernetes objects is the recommended way to manage Kubernetes
+production workloads, however gaps in the kubectl tooling force users to write their own scripting and
+tooling to augment the declarative tools with preprocessing transformations.
+While most of theser transformations already exist as imperative kubectl commands, they are not natively accessible
+from a declarative workflow.
+ 
+This KEP describes how `kustomize` addresses this problem by providing a declarative format for users to access
+the imperative kubectl commands they are already familiar natively from declarative workflows.
+
+## Motivation
+
+The kubectl command provides a cli for:
+
+- accessing the Kubernetes apis through json or yaml configuration
+- porcelain commands for generating and transforming configuration off of commandline flags.
+
+Examples:
+
+- Generate a configmap or secret from a text or binary file
+  - `kubectl create configmap`, `kubectl create secret`
+  - Users can manage their configmaps and secrets text and binary files
+
+- Create or update fields that cut across other fields and objects
+  - `kubectl label`, `kubectl annotate`
+  - Users can add and update labels for all objects composing an application
+  
+- Transform an existing declarative configuration without forking it
+  - `kubectl patch`
+  - Users may generate multiple variations of the same workload
+
+- Transform live resources arbitrarily without auditing
+  - `kubectl edit`
+
+To create a Secret from a binary file, users must first base64 encode the binary file and then create a Secret yaml
+config from the resulting data.  Because the source of truth is actually the binary file, not the config,
+users must write scripting and tooling to keep the 2 sources consistent.
+
+Instead, users should be able to access the simple, but necessary, functionality available in the imperative
+kubectl commands from their declarative workflow.
+
+#### Long standing issues
+
+Kustomize addresses a number of long standing issues in kubectl.
+
+- Declarative enumeration of multiple files [kubernetes/kubernetes#24649]
+- Declarative configmap and secret creation: [kubernetes/kubernetes#24744], [kubernetes/kubernetes#30337]
+- Configmap rollouts: [kubernetes/kubernetes#22368]
+  - [Example in kustomize](https://github.com/kubernetes/kubectl/blob/master/cmd/kustomize/demos/helloWorld.md#how-this-works-with-kustomize)
+- Name/label scoping and safer pruning: [kubernetes/kubernetes#1698]
+  - [Example in kustomize](https://github.com/kubernetes/kubectl/blob/master/cmd/kustomize/demos/breakfast.md#demo-configure-breakfast)
+- Template-free add-on customization: [kubernetes/kubernetes#23233]
+  - [Example in kustomize](https://github.com/kubernetes/kubectl/blob/master/cmd/kustomize/demos/helloWorld.md#staging-kustomization)
+
+### Goals
+
+- Declarative support for defining ConfigMaps and Secrets generated from binary and text files
+- Declarative support for adding or updating cross-cutting fields
+  - labels & selectors
+  - annotations
+  - names (as transformation of the original name)
+- Declarative support for applying patches to transform arbitrary fields
+  - use strategic-merge-patch format
+- Ease of integration with CICD systems that maintain configuration in a version control repository
+  as a single source of truth, and take action (build, test, deploy, etc.) when that truth changes (gitops).
+
+### Non-Goals
+
+#### Exposing every imperative kubectl command in a declarative fashion
+
+The scope of kustomize is limited only to functionality gaps that would otherwise prevent users from
+defining their workloads in a purely declarative manner (e.g. without writing scripts to perform pre-processing
+or linting).  Commands such as `kubectl run`, `kubectl create deployment` and `kubectl edit` are unnecessary
+in a declarative workflow because a Deployment can easily be managed as declarative config.
+
+#### Providing a simpler facade on top of the Kubernetes APIs
+
+The community has developed a number of facades in front of the Kubernetes APIs using
+templates or DSLs.  Attempting to provide an alternative interface to the Kubernetes API is
+a non-goal.  Instead the focus is on:
+
+- Facilitating simple cross-cutting transformations on the raw config that would otherwise require other tooling such
+  as *sed*
+- Generating configuration when the source of truth resides elsewhere
+- Patching existing configuration with transformations
+
+## Proposal
+
+### Capabilities
+
+**Note:** This proposal has already been implemented in `github.com/kubernetes/kubectl`.
+
+Define a new meta config format called *kustomization.yaml*.
+
+#### *kustomization.yaml* will allow users to reference config files
+
+- Path to config yaml file (similar to `kubectl apply -f <file>`)
+- Urls to config yaml file (similar to `kubectl apply -f <url>`)
+- Path to *kustomization.yaml* file (takes the output of running kustomize)
+
+#### *kustomization.yaml* will allow users to generate configs from files
+
+- ConfigMap (`kubectl create configmap`)
+- Secret (`kubectl create secret`)
+
+#### *kustomization.yaml* will allow users to apply transformations to configs
+
+- Label (`kubectl label`)
+- Annotate (`kubectl annotate`)
+- Strategic-Merge-Patch (`kubectl patch`)
+- Name-Prefix
+
+### UX
+
+Kustomize will also contain subcommands to facilitate authoring *kustomization.yaml*.
+
+#### Edit
+
+The edit subcommands will allow users to modify the *kustomization.yaml* through cli commands containing
+helpful messaging and documentation.
+
+- Add ConfigMap - like `kubectl create configmap` but declarative in *kustomization.yaml*
+- Add Secret - like `kubectl create secret` but declarative in *kustomization.yaml*
+- Add Resource - adds a file reference to *kustomization.yaml*
+- Set NamePrefix - adds NamePrefix declaration to *kustomization.yaml*
+
+#### Diff
+
+The diff subcommand will allow users to see a diff of the original and transformed configuration files
+
+- Generated config (configmap) will show the files as created
+- Transformations (name prefix) will show the files as modified
+
+### Implementation Details/Notes/Constraints [optional]
+
+Kustomize has already been implemented in the `github.com/kubernetes/kubectl` repo, and should be moved to a
+separate repo for the subproject.
+
+Kustomize was initially developed as its own cli, however once it has matured, it should be published
+as a subcommand of kubectl or as a statically linked plugin.  It should also be more tightly integrated with apply.
+
+- Create the *kustomize* sig-cli subproject and update sigs.yaml
+- Move the existing kustomize code from `github.com/kubernetes/kubectl` to `github.com/kubernetes-sigs/kustomize`
+
+### Risks and Mitigations
+
+
+### Risks of Not Having a Solution
+
+By not providing a viable option for working directly with Kubernetes APIs as json or
+yaml config, we risk the ecosystem becoming fragmented with various bespoke API facades.
+By ensuring the raw Kubernetes API json or yaml is a usable approach for declaratively
+managing applications, even tools that do not use the Kubernetes API as their native format can
+better work with one another through transformation to a common format.
+
+## Graduation Criteria
+
+- Dogfood kustomize by either:
+  - moving one or more of our own (OSS Kubernetes) services to it.
+  - getting user feedback from one or more mid or large application deployments using kustomize.
+- Publish kustomize as a subcommand of kubectl.
+
+## Implementation History
+
+kustomize was implemented in the kubectl repo before subprojects became a first class thing in Kubernetes.
+The code has been fully implemented, but it must be moved to a proper location.
+
+## Drawbacks
+
+
+## Alternatives
+
+1. Users write their own bespoke scripts to generate and transform the config before it is applied.
+2. Users don't work with the API directly, and use or develop DSLs for interacting with Kubernetes.
+
+## FAQs
diff --git a/sig-cli/README.md b/sig-cli/README.md
index 6c3a1892..f44c4e86 100644
--- a/sig-cli/README.md
+++ b/sig-cli/README.md
@@ -40,6 +40,9 @@ The following subprojects are owned by sig-cli:
   - Owners:
     - https://raw.githubusercontent.com/kubernetes/kubectl/master/OWNERS
     - https://raw.githubusercontent.com/kubernetes/kubernetes/master/pkg/kubectl/OWNERS
+- **kustomize**
+  - Owners:
+    - https://raw.githubusercontent.com/kubernetes-sigs/kustomize/master/OWNERS
 
 ## GitHub Teams
 
diff --git a/sigs.yaml b/sigs.yaml
index cab103d9..615656d3 100644
--- a/sigs.yaml
+++ b/sigs.yaml
@@ -557,6 +557,10 @@ sigs:
       owners:
       - https://raw.githubusercontent.com/kubernetes/kubectl/master/OWNERS
       - https://raw.githubusercontent.com/kubernetes/kubernetes/master/pkg/kubectl/OWNERS
+    - name: kustomize
+      owners:
+      # "owners" entry
+      - https://raw.githubusercontent.com/kubernetes-sigs/kustomize/master/OWNERS
   - name: Cluster Lifecycle
     dir: sig-cluster-lifecycle
     mission_statement: >