Commit bdfedafd authored by Dave Cunningham's avatar Dave Cunningham

Major rework of chart_format.md

parent 39897eaf
This diff is collapsed.
_Note: When a chart file is deployed, a [provenance file](#the-provenance-file) is generated for the chart. That file is not stored inside of the chart, but is considered part of the chart’s packaged format._
Testing and provenancing attach badges to the Chart that attest to its quality and provenance.
### The Provenance File
The provenance file contains a chart’s YAML file plus several pieces of verification information. Provenance files are designed to be automatically generated.
The following pieces of provenance data are added:
* The chart file (Chart.yaml) is included to give both humans and tools an easy view into the contents of the chart.
* Every image file that the project references is checksummed (SHA-256?), and the sum included here. If two versions of the same image are used by the template, both checksums are included.
* The signature (SHA-256) of the chart package (the .tgz file) is included, and may be used to verify the integrity of the chart package.
* The entire body is signed using PGP (see [http://keybase.io] for an emerging way of making crypto signing and verification easy).
The combination of this gives users the following assurances:
* The images this chart references at build time are still the same exact version when installed (checksum images).
* This is distinct from asserting that the image Kubernetes is running is exactly the same version that a chart references. Kubernetes does not currently give us a way of verifying this.
* The package itself has not been tampered with (checksum package tgz).
* The entity who released this package is known (via the GPG/PGP signature).
The format of the file is as follows:
```
-----BEGIN PGP SIGNED MESSAGE-----
name: nginx
description: The nginx web server as a replication controller and service pair.
version: 0.5.1
keywords:
- https
- http
- web server
- proxy
source: https://github.com/foo/bar
home: http://nginx.com
depends:
kubernetes:
version: >= 1.0.0
---
files:
nginx-0.5.1.tgz: “sha256:9f5270f50fc842cfcb717f817e95178f”
images:
“hub.docker.com/_/nginx:5.6.0”: “sha256:f732c04f585170ed3bc99”
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)
iEYEARECAAYFAkjilUEACgQkB01zfu119ZnHuQCdGCcg2YxF3XFscJLS4lzHlvte
WkQAmQGHuuoLEJuKhRNo+Wy7mhE7u1YG
=eifq
-----END PGP SIGNATURE-----
```
Note that the YAML section contains two documents (separated by ---\n). The first is the Chart.yaml. The second is the checksums, defined as follows.
* Files: A map of filenames to SHA-256 checksums (value shown is fake/truncated)
* Images: A map of image URLs to checksums (value shown is fake/truncated)
The signature block is a standard PGP signature, which provides [tamper resistance](http://www.rossde.com/PGP/pgp_signatures.html).
## Appendix A: User Stories for Charts
Personas:
- Operator: Responsible for running an application in production.
- Chart Dev: Responsible for developing new charts
- App Dev: Developer who creates applications that make use of existing charts, but does not create charts.
Stories:
- As an operator, I want a deployment that is 100% reproducible (exact versions)
- As an app dev, I want to be able to search for charts using keys defined in the [chart file](#the-chart-file)...
* by keyword, where one app may have multiple keywords (e.g. Redis has storage, message queue)
* by name (meaning name of the chart), where name may be "fuzzy".
* by author
* by last updated date
- As a chart dev, I want a well-defined set of practices to follow
- As a chart dev, I want to be able to work with a team on the same chart
- As a chart dev, I want to be able to indicate when a particular chart is stable, and how stable it is
- As a chart dev, I want to indicate the role I played in building a chart
- As a chart dev, I want to be able to use all of the low-level Kubernetes kinds
- As an operator, I want to be able to determine how stable a package is
- As an operator, I want to be able to determine what version of Kubernetes I need to run a chart
- As an operator, I want to determine whether a chart requires extension kinds (e.g. DaemonSet or something custom), and determine this _before_ I try to install
- As a chart dev, I want to be able to express that my chart depends on others, even to the extent that I specify the version or version range of the other chart upon which I depend
- As a chart dev, I do not want to install additional tooling to write, test, or locally run a chart (this relates to the file format in that the format should not require additional tooling)
- As a chart dev, I want to be able to store auxiliary files of arbitrary type inside of a chart (e.g. a PDF with documentation)
- As a chart dev, I want to be able to store my chart in one repository, but reference a chart in another repository
- As a chart dev, I want to embed my template inside of the code that it references. For example, I want to have the code to build a docker image and the chart to all live in the same source code repository.
...@@ -16,7 +16,7 @@ against other workflows. ...@@ -16,7 +16,7 @@ against other workflows.
### Helm Official ### Helm Official
The _Helm Official_ project focuses on maintaining a repository of high-quality production-ready charts. Charts may be contributed by anyone in the broad community, and they are vetted and maintained by the Helm Official core contributors. The _Helm Official_ project focuses on maintaining a repository of high-quality production-ready charts. Charts may be contributed by anyone in the broad community, and they are vetted and maintained by the charts-maintainers team in the Github Kubernetes organization.
Stage | Devel | Review | Release | Store | Use Stage | Devel | Review | Release | Store | Use
------|-------|--------|---------|-------|----- ------|-------|--------|---------|-------|-----
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment