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Package Development💣

Package is the term we use for an application that has been prepared to be deployed with the Big Bang helm chart. Big Bang Packages are wrappers around Helm charts. All the pertinent information should be included in the chart/values.yaml for configuration of the Package. These values are then available to be overridden in the Big Bang chart/values.yaml file. The goal of these Packages is to take something that might be very complex and simplify it for consumers of Big Bang. Rational and safe defaults should be used where possible while also allowing for overriding values when fine-grained control is needed. As much as possible test after each step so that the errors don’t pile up, “code a little, test a little”. Here are the steps:

  1. Create a repository under the appropriate group ( example: Security Tools, Developer Tools, Collaboration Tools) in Repo1.

  2. Create a “main” branch that will serve as the master branch.

  3. There are two ways to start a new Package.
    A. If there is no upstream helm chart we create a helm chart from scratch. Create a directory called “chart” in your repo, change to the chart directory, and scaffold a new chart in the chart directory

# Scaffold new helm chart
mkdir chart
cd chart
helm create name-of-your-application

Tip

If there is an existing upstream chart we will use it and modify it. Essentially we create a “fork” of the upstream code. Use kpt to import the helm chart code into your repository.

Note

Note that kpt is not used to keep the Package code in sync with the upstream chart. It is a one time pull just to document where the upstream chart code came from. Kpt will generate a Kptfile that has the details. Do not manually create the “chart” directory. The kpt command will create it. Here is an example from when Gitlab Package was created. It is a good idea to push a commit “initial upstream chart with no changes” so you can refer back to the original code while you are developing.

kpt pkg get https://gitlab.com/gitlab-org/charts/gitlab.git@v4.8.0 chart
  1. Run a helm dependency update that will download any external sub-chart dependencies. Commit any *.tgz files that are downloaded into the “charts” directory. The reason for doing this is that Big Bang Packages must be able to be installed in an air-gap without any internet connectivity.
helm dependency update
  1. Edit the Chart.yaml and set the chart version: number to be compliant with the charter versioning which is {UpstreamChartVersion}-bb.{BigBangVersion}.

Note

Note that the chart version is not the same thing as the application version. If this is a patch to an existing Package chart then increment the {BigBangVersion}. Here is an example from Gitlab Runner.

apiVersion: v1
name: gitlab-runner
version: 0.19.2-bb.3
appVersion: 13.2.2
description: GitLab Runner
  1. In the values.yaml replace public upstream images with IronBank hardened images. The image version should be compatible with the chart version. Here is a command to identify the images that need to be changed.
# list images
helm template <releasename> ./chart -n <namespace> -f chart/values.yaml | grep image:

Add the “imagePullSecrets” tag if not already there. You can still test without the private-registry secret existing if your k8s cluster is configured with the pull credentials. Here is an example from Gitlab Package.

registry:
  enabled: true
  host: "registry.bigbang.dev"
  image:
    repository: registry1.dso.mil/ironbank/gitlab/gitlab/gitlab-container-registry
    tag: 13.7.2
    pullSecrets:
    - name: private-registry

  1. Add a VirtualService if your application has a back-end API or a front-end GUI. Create the VirtualService in the sub-directory “chart/templates/bigbang/VirtualService.yaml”. You will need to manually create the “bigbang” directory. It is convenient to copy VirtualService code from one of the other Packages and then modify it. You should be able to load the application in your browser if all the configuration is correct.

  2. Add NetworkPolices templates in the sub-directory “chart/templates/bigbang/networkpolicies/*.yaml”. The intent is to lock down all ingress and egress traffic except for what is required for the application to function properly. Start with a deny-all policy and then add additional policies to open traffic as needed. Refer to the other Packages code for examples. The Gitlab package is a good/complete example.

  3. Add a continuous integration (CI) pipeline to the Package. A Package should be able to be deployed by itself, independently from the Big Bang chart. The Package pipeline takes advantage of this to run a Package pipeline test. The package testing is done with a helm test library. Reference the pipeline documentation for how to create a pipeline and also detailed instructions in the gluon library. Instructions are not repeated here.

  4. Documentation for the Package should be included. A “docs” directory would include all detailed documentation. Reference other that Packages for examples.

  5. Add the following markdown files to complete the Package. Reference other that Packages for examples of how to create them.

CHANGELOG.md      <  standard history of changes made  
CODEOWNERS        <  list of the code maintainers. Minimum of two people from separate organizations  
CONTRIBUTING.md   <  instructions for how to contribute to the project  
README.md         <  introduction and high level information
  1. Create a top-level tests directory and inside put a test-values.yaml file that includes any special values overrides that are needed for CI pipeline testing. Refer to other packages for examples. But this is specific to what is needed for your package.
mkdir tests
touch test-values.yaml
  1. At a high level, a Package structure should look like this when you are finished 
├── chart/
   └── templates/
      └── bigbang/
         ├── networkpolicies/
            ├── egress-*.yaml
            └── ingress-*.yaml
         └── virtualservice.yaml
   ├── tests/
      ├── cypress/
      └── scripts/
├── docs/
   ├── documentation-file-1.md
   └── documentation-file-2.md
├── tests/
   └── test-values.yaml
├── CHANGELOG.md
├── CODEOWNERS
├── CONTRIBUTING.md
└── README.md
  1. Merging code should require approval from a minimum of 2 codeowners. To setup merge requests to work properly with CODEOWNERS approval change these settings in your project:

Under Settings → General → Merge Request Approvals, change “Any eligible user” “Approvals required” to ensure that “Require new approvals when new commits are added to an MR” is checked.

Under Settings → Repository → Protected Branches, add the main branch with “Developers + Maintainers” allowed to merge, “No one” allowed to push, and “Codeowner approval required” turned on.

Under Settings → Repository → Default Branch, ensure that main is selected.

  1. Development Testing Cycle: Test your Package chart by deploying with helm. Test frequently so you don’t pile up multiple layers of errors. The goal is for Packages to be deployable independently of the bigbang chart. Most upstream helm charts come with internal services like a database that can be toggled on or off. If available use them for testing and CI pipelines. In some cases this is not an option. You can manually deploy required in-cluster services in order to complete your development testing.
    Here is an example of an in-cluster postgres database
helm repo add bitnami https://charts.bitnami.com/bitnami
helm install postgres bitnami/postgresql -n postgres --create-namespace --set postgresqlPostgresPassword=postgres --set postgresqlPassword=postgres
# test it
kubectl run postgresql-postgresql-client --rm --tty -i --restart='Never' --namespace default --image bitnami/postgresql --env="PGPASSWORD=postgres" --command -- psql --host postgres-postgresql-headless.postgres.svc.cluster.local -U postgres -d postgres -p 5432
# Postgres commands
 \l             < list tables
 \du            < list users
 \q             < quit

Here is an example of an in-cluster object storage service using MinIO (api compatible with AWS S3 storage)

helm repo add minio https://helm.min.io/
helm install minio minio/minio --set accessKey=myaccesskey --set secretKey=mysecretkey -n minio --create-namespace
# test and configure it
kubectl run minio-mc-client --rm --tty -i --restart='Never' --namespace default --image minio/mc --command -- bash
# MinIo commands
mc alias set minio http://minio.minio.svc.cluster.local:9000 myaccesskey mysecretkey      < set a connection alias
mc mb minio/myBucket          < make a bucket
mc ls minio                   < list the buckets

Create a local directory on your workstation where you store your helm values override files. Don’t make test changes in the Package values.yaml because they could accidentally be committed. The most convenient location is in a sibling directory next to the Package repo. Here is an example directory structure:

├── PackageRepo/
└── overrides/
      └── override-values.yaml

Here are the dev test steps you can iterate:

# Test that the helm chart templates successfully and examine the output to insure expected results
helm template <releasename> ./chart -n <namespace> -f ../overrides/override-values.yaml
# Deploy with helm
helm upgrade -i <releasename> ./chart -n <namespace> --create-namespace -f ../overrides/override-values.yaml
# Conduct testing
# Tear down
helm delete <releasename> -n <namespace>
# Manually delete the namespace to insure that everything is gone
kubectl delete ns <namespace>
  1. Wait to create a git tag release until integration testing with Big Bang chart is completed. You will very likely discover more Package changes that are needed during Big Bang integration. When you are confident that the Package code is complete, squash commits and rebase your development branch with the “main” branch.
git rebase origin/main
git reset $(git merge-base origin/main $(git rev-parse --abbrev-ref HEAD))
git add -A
git commit -m "feat: example conventional commit"
git push --force

  1. Then, create a merge request to branch “main”

  2. After the merge create a git tag following the charter convention of {UpstreamChartVersion}-bb.{BigBangVersion}. The tag should exactly match the chart version in the Chart.yaml. example: 1.2.3-bb.0

Private registry secret creation💣

In some instances you may wish to manually create a private-registry secret in the namespace or during a helm deployment. There are a couple of ways to do this:

  1. The first way is to add the secret manually using kubectl. This method is useful for standalone package testing/development.
kubectl create secret docker-registry private-registry --docker-server="https://registry1.dso.mil" --docker-username='Username' --docker-password="CLI secret" --docker-email=<your-email> --namespace=<package-namespace>
  1. The second is to create a yaml file containing the secret and apply it during a helm install. This method is applicable when installing your new package as part of the Big Bang chart. In this example the file name is registry-values.yaml:

Create the file with the secret contents:

registryCredentials:
  registry: registry1.dso.mil
  username: ""
  password: ""
  email: ""

Then include a reference to your file during your helm install command by adding the below -f to your Big Bang install command, where registry-values.yaml is located in an overrides directory outside of Big Bang:

-f ../overrides/registry-values.yaml

Quiz Questions💣

What does “package” mean in Big Bang?

“Package” is the term we use for an application that has been prepared to be deployed with the Big Bang helm chart. Big Bang packages are wrappers around Helm charts. All the pertinent information should be included in the chart/values.yaml for configuration of the package.

What command would you use to download any external sub-chart dependencies?

helm dependency update

In Big Bang, what images should you use to replace public upstream images?

IronBank hardened images

What is the minimum number of CODEOWNERS required for approval on a merge request?

Merging code should require approval from a minimum of 2 codeowners

For detailed information on how to fully integrate a new package into Big Bang, please see Big Bang Docs Package Integration.💣