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saasherder

There are many services in OpenShift.io SaaS. To track what is deployed in production and to be able redeploy the very same versions of all components quickly, we created this SaaS Herder tool. It helps helps to track all the OpenShift templates in various repositories and to process them for deployment.

Services and their deployment templates are tracked in other repositories. OpenShift.io and associated services are currently tracked in these repositories:

The Process

Repositories above not only contain references to all OpenShift templates for OpenShift.io, but also serve to enforce promote-to-prod process for our services. Whole process is as follows:

  1. Code is checked in project git repository (e.g. new commit abcd1234)
  2. CI build is kicked off (e.g. for the commit abcd1234)
  3. If the build is successful, image tagged with commit hash is pushed to repository (e.g. core:abcd12)
  4. New image is deployed to staging cluster (e.g. oc process -f openshift/template.yaml IMAGE_TAG=abcd12 | oc apply -f -)
  5. A developer verifies new deployment in staging cluster and creates a PR, which changes commit hash for the given service, for a tracking repository (e.g. hash: is updated in https://github.com/openshiftio/saas-openshiftio/blob/master/dsaas-services/core.yaml)
  6. PR to change the commit hash is merged in the tracking repository (i.e. this is the promote-to-prod manual step)
  7. Once the PR merged into the tracking repository, CI job is kicked off, which deploys new version to production (e.g. checkouts a template from git repo for a given commit hash, processes it with $IMAGE_TAG and performs oc apply)

Tracking repositories

Service YAML

services:
- hash: aab9fc5fa5c24360079998f2209b2b55c3af29ae
  hash_length: 7
  name: some-name
  path: /openshift/template.yaml
  url: https://github.com/org/repo/
  skip: True
  parameters:
    SOME_PARAM: some_value
  environments:
  - name: production
    parameters:
      SOME_PARAM: prod_value
    skip: True
  • hash: Commit hash (SHA1) or special value which is used for downloading the OpenShift template and to generate image tag for template processing. Possible values are:
    • <commit_sha1> (40 chars): Download OpenShift templates from that commit, and use the first hash_length chars of the sha1 tag for IMAGE_TAG.
    • master: Downloads OpenShift templates from the last commit of the master branch, and will use IMAGE_TAG=latest.
    • ignore: Downloads OpenShift templates from the last commit of the master branch, and will not generate IMAGE_TAG.
  • hash_length: Number of characters to be used from hash as an image tag
  • name: Name of the service
  • path: Path to the template in the repo
  • url: URL of the repository which contains the template
  • skip: False by default, if True, the service will be skipped from processing (i.e. template will not be processed and output file for service will not be produced)
  • parameters: An object where key is the parameter name and value is the parameter value. These parameters will be added to oc process when processing the template
  • environments: A list where you can specify multiple environments which can be selected by passing an argument --environment. Values in a given environment will override values in the top level section. Anything can be overridden but name, url and hash.

Note: If parameters contains IMAGE_TAG it will override any dynamically generated value by the hash parameter. This can be used to deploy a new version of the manifest while using a previously built image.

Config YAML

Config file should be located in the root of the repository (to be automatically picked up by the tool). It helps SaaS Herder to find tracked services and provides default locations for download and processing of the files.

It can contain multiple contexts, which can point to multiple service folders. We use this to map service yaml files to projects in OpenShift - i.e. context dsaas will map to project dsaas-production.

current: dsaas
contexts:
- name: dsaas
  data:
    output_dir: dsaas-processed
    services_dir: dsaas-services
    templates_dir: dsaas-templates

Basic Usage

Install

python setup.py install

Run

All of the following command assume being run in the tracking repository clone (e.g. https://github.com/openshiftio/saas-openshiftio)

saasherder -h

You can pull all the templates by running the following

saasherder --context dsaas pull

You'll find the downloaded templates in dsaas-templates/ dir (as defined in config.yaml in the tracking repository - https://github.com/openshiftio/saas-openshiftio/blob/master/config.yaml).

You can update commit hash in the $service.yaml file by running

saasherder --context dsaas update -o foo.yaml hash core b52c33c8f6c40a5dca70c8b3c25387b01881bf2d

This will create file foo.yaml which will be a copy of file dsaas-services/core.yaml with updated commit hash for core service.

You can also process downloaded templates to use commit hash as an image tag.

saasherder  --context dsaas template --output-dir test tag

This will take templates in dsaas-templates/ and commit hashes in dsaas-services/*.yaml and produce processed template to test/ directory. It requires oc binary to be present on path and logged into some OpenShift instance (it actually calls oc process to leverage existing tooling). If you don't want to, or cannot login to OpenShift instance for processing, you can use --local option

saasherder  --context dsaas template --output-dir test --local tag

Environments

If you deploy to multiple environments (like we do, e.g. production, staging, etc.) you might need to slightly adjust how your service is deployed. There is a structure environments for it (see above for explanation). Let's assume you are now deploying to production. As you can change path in service yaml file for environments (to ensure upgrade path without breaking other environments), first pull templates with environment specified

saasherder --context dsaas --environment production pull

Next step is to process templates - and again, we need to specify the environment to make sure right values (e.g. parameters) are used

saasherder --context dsaas --environment production template tag

To give you real world example - we have services which set replicas through parameters to make it easy to scale in a predictable way. In production environment, we'll want to scale to 100 pods. But in staging environment we will be fine with 10. To do this is as simple as adding

environments:
- name: production
  parameters:
    REPLICAS: 100
- name: staging
  parameters:
    REPLICAS: 10

Assuming you have parameter REPLICAS in your OpenShift template.

Another example might be when adding new service. You want to deploy to staging, catch all bugs and then deploy to production. You can do it simply by adding

environments:
- name: production
  skip: True

This snippet will ensure your new service will skip deployment to production, but will still deploy for other environments and also if there is no environment given to CLI.

Test

SaaS Herder tests are run in an isolated container, but talks to the host docker daemon to talk to the oc cluster.

NOTE: You might have to additionally enable Insecure Registries on your host machine. You can do this with a single command on Fedora and CentOS.

sed -i.bckp '/OPTIONS=.*/c\OPTIONS="--selinux-enabled --insecure-registry 172.30.0.0/16"' /etc/sysconfig/docker

To run tests, simply run

make test

If you make changes to code or tests, you can check them in the container without rebuild

make local-test

dsaas-tracking-services

these are tracking services that we are not deploying via saas, but come via another pipeline we still need to track where to get the content, and the ver deployed