apourchet / kubemgr

kubemgr

A simple tool to templatize and organize kubernetes deployments. Essentially just a thin wrapper around kubectl with some templatizing syntactic sugar, and resource-dependency management.

Installation

go install github.com/apourchet/kubemgr

Example usage

In this example, we want do deploy an app that depends on a DB deployment as well as a syslog service. This means that we want both of those kubernetes resources available before we create the app deployment. The syslog service has its own kubemgr configuration file and might depend on some other k8s resources, so we need to import it in our kubeconfig.json:

"imports": [
    {
        "path": "example_import/kubeconfig.json"
    }
],

For resources, we will have the following:

"resources": {
    "db-svc": {
        "path": "k8s/db-svc.json"
    },
    "db-dp": {
        "path": "k8s/db-dp.json",
        "deps": ["db-svc"]
    },
    "app-svc": {
        "path": "k8s/app-svc.json"
    },
    "app-dp": {
        "path": "k8s/app-dp.json",
        "deps": ["app-svc", "db-dp", "kubemgr_subtest.syslog-svc"]
    }
}

Now if we want to apply our app deployment "app-dp", kubemgr will automatically check that db-dp has finished deploying, and that app-svc and syslog-svc are both also present. Thus we can safely apply "app-dp" without worrying about the current state of our cluster.

kubemgr apply app-dp

Similarly we could also apply all of the resources in our kubeconfig.json file using regular expressions:

kubemgr apply "*"

It is also possible to describe dependencies using regexp:

"app-dp": {
    "path": "k8s/app-dp.json",
    "deps": ["*-svc", "db-dp"]
}

The two actions other than "apply" that are currently supported are "check" and "delete", which both behave exactly like what you would imagine.

Injects

Injects are the way you can templatize your k8s files in a more granular way. They contain key-value bindings that you can use in your k8s resources. However you also have the benefit namespacing that you didn't have before. For instance the syslog-svc NAMESPACE field is able to get overridden by the toplevel injects.json. You also have the ability to specify multiple injects with colliding key names that you can then differentiate using that namespacing.

The injected variable's name will have the format: <packagename>_<injectname>.<varname>. For instance, this inject:

"package": "kubemgr_test",
"injects": [
    {
        "name": "mine",
        "path": "injects.json"
    }
]

will allow resources to use {{$.kubemgr_test_mine.NAMESPACE}}.

Planned improvements

Pull resources from the Web
Check dependency cycles