[znapzend] Add documentation

charts/znapzend/README.md

@@ -1,3 +1,62 @@
-## Znapzend
+# Znapzend Chart
 
-Some docs to follow soon.
+[Znapzend](https://github.com/oetiker/znapzend) - zfs backup with remote capabilities and mbuffer integration. http://www.znapzend.org
+
+[Znapzend Exporter](https://github.com/ccremer/znapzend-exporter) - a Znapzend exporter for Prometheus
+
+## TL;DR;
+
+```console
+helm install ccremer/znapzend
+```
+
+> **Important**: By default, znapzend runs as a privileged container in order to access ZFS.
+
+## Configuration
+
+The following table lists the configurable chart specific parameters. For default values consult `values.yaml`.
+
+| Parameter                          | Description |
+| ---                                | --- |
+| `host.zfsDevice`                   | Path of the ZFS device on the host (bind-mounted to container) |
+| `ssh.path`                         | Path where the SSH files are being mounted |
+| `ssh.config`                       | Specify the contents of the `ssh_config(5)` config file |
+| `ssh.identities`                   | List all private keys to access remote SSH server for znapzend targets |
+| `ssh.knownHosts`                   | List of known_hosts entries |
+| `ssh.knownHosts[].host`            | Hostname of the known Host |
+| `ssh.knownHosts[].pubKey`          | Public Key of the known Host (e.g. `ssh-rsa AA...`) |
+| `ssh.externalSecretName`           | Specify the name of the existing secret with the private keys, makes `ssh.knownHosts`, `ssh.config` and `ssh.identities` ineffective |
+| `metrics.enabled`                  | If the znapzend-exporter should be enabled |
+| `metrics.jobs.register[]`          | List of ZFS datasets that are expected in the metrics |
+| `metrics.env`                      | Additional environment Variables for znapzend-exporter |
+| `metrics.service.enabled`          | Whether the metrics service is enabled for Prometheus scrapes |
+
+There are far more parameters, including common ones (`image.tag`, etc.)
+
+Specify each parameter using the `--set key=value[,key=value]` argument to `helm install`.
+
+Alternatively, a YAML file that specifies the values for the parameters can be provided while installing the chart. For example,
+
+```console
+helm install --name my-release -f values.yaml ccremer/znapzend
+```
+
+> **Tip**: You can use the default [values.yaml](values.yaml)
+
+## Testing
+
+### Template testing
+
+This chart uses some Go code to test the generated templates against the
+Kubernetes client API. With this we are more flexible than `helm lint`, as
+linting would not catch errors such as: "If we are in clustered mode, we expect
+an init container, otherwise not". The test code would also catch typos in a
+limited manner (e.g. if `initContainer` is spelled `initcontainer`, it will
+generate an error).
+
+```console
+cd znapzend
+helm dep build
+cd test
+go test ./...
+```