applyconfig

ApplyConfig

ApplyConfig is the GitOps tool used by Test Platform team to validate the kubernetes/OpenShift resource manifests stored in openshift/release repository and maintain their presence in all clusters in the OpenShift CI system.

What it does

ApplyConfig is basically an oc apply -f <file> wrapper, behaving similarly to the oc apply -f directory/ --recursive command (it recursively traverses the given directory and calls oc apply -f on every file it finds). In addition to that, it adds several lightweight features required by Test Platform team, its workflows and conventions:

1. Allows non-resource YAML files to be present in the traversed directory
2. Ignores JSON files
3. Ignores directories and files that are marked by a convention, or ones that are explicitly exempted by a parameter
4. Processes and applies OpenShift templates and substitutes values read from environment variables as template parameters
5. Censors values read form environment variables in its output
6. While running in server-side dry mode, it handles the situation when both a namespace manifest and a manifest of a resource that would be placed in that namespace are not yet present in the cluster (in a normal dry run, applying the resource to a namespace that does not exist in the cluster would fail). It does so by bookkeeping which namespaces would be applied if not in dry run, and creating them temporarily if they do not exist.
7. Add --server-side to the apply command if a filename starts with SS_

Why it exists

ApplyConfig is a simple GitOps tool that unifies the procedure to:

1. Validate the manifests in PRs to openshift/release before they are merged
2. Commit the manifests to the cluster after they are merged

How it works

applyconfig --config-dir DIRECTORY searches for all resource config files under DIRECTORY and applies it. Subdirectories are searched recursively and directories with names starting with _ are skipped. Files and directories are searched and applied in lexicographical order. All YAML files are considered to bXLe a config to apply, except those with filenames starting with _.

By default, applyconfig only runs in dry-mode, validating that eventual full run would be successful. To issue a full run that actually commits the config to the cluster, add a --confirm=true option.

The --context=<context_name> and --kubeconfig=<kubeconfig_file> options can be used to specify <context_name> and <kubeconfig_file> respectively when executing oc-apply commands.

How is it deployed

• The pull-ci-openshift-release-master-$CLUSTER-dry presubmits execute on openshift/release PRs and validate changes to the manifests in the repository.
• The branch-ci-openshift-release-master-$CLUSTER-apply postsubmits execute after merges to openshift/release and commits the manifests to the clusters
• The periodic-openshift-release-master-$CLUSTER-apply periodics regularly re-commit the manifests to the form present in the repository, reverting manual changes even when there are no changes to the openshift/release repository

Additionally, the tool is exposed in the Makefile targets in the openshift/release repository for manual usage. This manual usage is likely obsolete and discouraged.